COST C16Improving the Quality of Existing Urban Building Envelopes STATE OF THE ART Research in Architectural Engineering Series Volume 2 ISSN 1873-6033 Previously published in this series: Volume 1. M. Crisinel, M. Eekhout, M. Haldimann and R. Visser (Eds.) EU COST C13 Glass and Interactive Building Envelopes – Final Report COST C16 Improving the Quality of Existing Urban Building Envelopes STATE OF THE ART edited by: Marie Therèse Andeweg Silvia Brunoro Leo G.W. Verhoef IOS Press © 2007 IOS Press and the Authors. All rights reserved ISBN 978-1-58603-734-5 Published by IOS Press under the imprint Delft University Press Publisher IOS Press BV Nieuwe Hemweg 6b 1013 BG Amsterdam The Netherlands tel: +31-20-688 3355 fax: +31-20-687 0019 e-mail:
[email protected] www.iospress.nl www.dupress.nl LEGAL NOTICE The publisher is not responsible for the use which might be made of the following information PRINTED IN THE NETHERLANDS v Table of Contents Preface vii L.G.W. Verhoef Introduction 1 M.T. Andeweg, S. Brunoro A Change of Heart 7 J. Allan Developing the Existing 23 A. Gooijer, G.J. te Velde Northern and Eastern Europe Countries State of the Art: Sweden 31 S. Schulz, B. JO Johansson, S, Vidén State of the Art: Denmark 45 J. Engelmark, T. Dahl, E. Melgaard State of the Art: Germany 57 Y. Frech, F.G. Hofmann, F.U. Vogdt, C. Wetzel State of the Art: Poland 71 Z. Plewako, A. Kozowski, A. Rybka Northern and Central Europe Countries State of the Start: Hungary 85 Á. Novák State of the Art: The Netherlands 95 M.T. Andeweg, F.W.A. Koopman State of the Art: Belgium 111 A. De Naeyer State of the Art: France 125 D. Groleau, M. Chazelas, F. Allard, G. Guarracino Mediterranean Countries State of the Art: Portugal 137 L. Bragança, M. Guedes de Almeida, R. Mateus State of the Art: Italy 155 R. Di Giulio, S. Brunoro, E. Arbizzani State of the Art: Greece 169 L. Baniotopoulos, D. Bikas, T. Stathopoulos, K. Tsikaloudaki, K. Chatzinikos State of the Art: Cyprus 183 P. Lapithis, Ch. Efstathiades, G. Hadjimichael Outsiders Countries State of the Art: F.Y.R. of Macedonia 195 T. Stojkov State of the Art: Malta 211 V.M. Buhgiar State of the Art: Slovenia 225 M. Šijanec Zavrl, R.. Žarni, J. Šelih vi Conclusions 241 S. Brunoro, M.T. Andeweg Annex COST C16 Management Committee 257 COST C16 Working Group Members 261 vii In front of you lies one of the four books produced within the scope of Action C16 “Improving the quality of existing urban building envelopes” which started as a COST UCE programme. The acronym ‘COST’ stands for European COoperation in the field of Scientific and Technical research, and falls under the Urban Civil Engineering Technical Committee (UCE). The main characteristic of COST is a ‘bottom-up approach’. The idea and subject of a COST Action comes from the European scientists themselves. Participation is open to all COST countries but only those countries that wish to participate in an Action do so. As a precursor to advanced mul- tidisciplinary research, COST has a very important role in building the European Research area (ERA), anticipating and complementing the activities of the Framework Programmes, acting as a bridge between the scientific communities of emerging countries, increasing the mobility of researchers across Europe and fostering the establishment of large Framework Programme pro- jects in many key scientific domains. It covers both basic and applied or technological research and also addresses issues of a pre-normative nature or of societal importance. The organisation of COST reflects its inter-governmental nature. Key decisions are taken at Ministerial confer- ences and also delegated to the Committee of Senior Officials (CSO), which is charged with the oversight and strategic development of COST. The COST Action C16 “Improving the quality of existing urban building envelopes” is directed to multi-storey residential blocks from the period after World War II, especially those built dur- ing the period when the need for housing in Europe was at its greatest. That is why the COST Action C16 focussed on the period 1950 to 1980. We found it necessary to propose this Action after the completion of Action C5 “Urban heritage/building maintenance”. According to studies carried out by Action COST C-5, the estimated value of the European Ur- ban Heritage amounts to about 40 trillion Euro (1998 prices) for the housing stock alone. The same research indicated the differences between the countries of the EU as well as what they have in common. The age profile of the building stock of a country like the Netherlands differs from that of the UK. Of interest too, are the costs of maintenance, renovation and refurbishment of the building stock. For the EU as a whole, this amount is about 1 trillion Euros per year (1998 prices). At the same time the three ‘Building Decay Surveys’ issued by the Federal Government of Germany that were based on systematic, scientific building research projects, indicated that 80% of all building decay is found in urban building envelopes (roof, walls, foundation). There are elements in the building stock that are common to the countries in Europe. These in- clude: Most of the buildings were completed after 1950. For a country like the Netherlands this means 75% of the existing buildings. The maintenance costs are mainly incurred in urban building envelopes, The renovation of buildings and reconstruction to provide an improved or different range of use will influence the building envelope, The quality of the building envelope very often fails to meet current demands and will cer- tainly not meet future demands. Preface viii An important conclusion deriving from the points mentioned above is that however important maintenance may be, it does not lead to the desired improvement in the quality of urban build- ing envelopes. Improvement of the quality of urban building envelopes must be the real task. Such improvement requires the development of new and suitable strategies for local authorities, housing corporations and owners and also architects and civil engineers. Until now integrated engineering aspects have been disregarded in this process. In many Euro- pean countries new technologies have been developed, but these have either not yet been trans- lated into practice, or have been only locally used to achieve a higher quality in urban buildings. This results in a limited impact on urban environments. Therefore it is essential to bring all kinds of local solutions together, to learn from these and to find a more general approach that can be used for building systems. Often problems and their solutions are approached in isola- tion. The wish to improve the quality of an individual building envelope usually leads to a local, project-based solution. Solving the specific problems of this renovation-project becomes the sole target. To reach maximum value for money, it is essential to integrate all the factors influ- encing urban building envelopes and look at them in a broader scope. As a result of changes in the composition of the population, society continuously changes with respect to various factors including age-structure, family composition and the availability of en- ergy. Changes lead to situations that are reflected in the commissioning of buildings, which is gradually shifting from new construction to the reuse and renovation of existing buildings that often requires the modification of their facades. Even when buildings may still be functionally satisfactory, there may be external factors, such as the dullness of the image that they summon up or their poor technical quality, that require that attention should be paid to the shell of the building. There are many reasons why buildings may no longer be adequate. Failure to satisfy current demands may be expressed in lack of oc- cupancy and further deterioration of the neighbourhood. This establishes a vicious circle, which can and must be broken. All too quickly discussions turn to demolition and new development, without prior investigation of the reasons for the situation. From an economic point of view, renovation and the reuse of buildings, which takes into consideration the technical and spatial functions and also the urban and architectural aspects, often appears to provide a better solution. The aim of the COST Action C16 is to improve techniques and methods used to adapt the enve- lopes of buildings constructed during the second half of the 20th century in the COST countries. These ‘non-traditional buildings' were constructed from in situ poured concrete systems, large scale prefabricated systems and/or small concrete/mixed elements although in some countries brick or stone was still used. The demand for housing in the post-war period necessitated the rapid production of large numbers of dwellings. Qualitative aspects were less important. Fur- thermore dwellings of the types constructed at that time no longer fulfil contemporary or antici- pated future demands for housing, with the possible exception only of those built during the last 5 years. At this stage, it must be noted that two other ongoing Actions in the field of Urban Civil Engi- neering, also address issues related to buildings: COST Action C12 on “Improving buildings’ structural quality by new technologies”; and COST Action C13 on “Glass and interactive build- ing envelopes”. The Technical Committee on Urban Civil Engineering considers that in addition to the tasks di- rectly connected to the main objective of their Action, participants in the COST Action on “Im- proving the quality of existing urban building envelopes” should establish and maintain close contacts with the two above mentioned Actions. This will foster co-operation with these Actions and avoid potential overlaps. About one year after the start of COST Action C16, it was put on a hold for more than 8 months, to permit the ‘renaissance’ of the COST programmes, while in the meantime COST C12 had almost ended and it was considered that the C13 Action had only a slight connection ix with the targets of COST C16. The CSO therefore agreed with the request of the Management Committee that the end of this Action should also be postponed by 8 months so that it would still last for the planned duration of four years. SCIENTIFIC PROGRAMME To date problems relating “Urban Building Envelopes” and their solutions are approached in isolation. The original design planners, architects and engineers work together to realise a build- ing according the current state of knowledge, but this co-operation longer exists during the life- cycle of the building. For far too long prolongation of the occupation by the use of maintenance was sole aim. If im- provement did become an option only a few aspects were considered. At present the current state of knowledge is usually local, being concentrated in some of the housing co-operations, ar- chitectural and engineering companies. However much has been done to spread this information in order to initiate discussion about when and how existing buildings with their envelopes can be improved to fit them for the future. The COST mechanism will foster international concentration on the integrated problems related to non-traditional dwellings. It will create a direction for improvement of urban building enve- lopes and also illustrate the state of the art in the various countries concerned.. What has already been learned in one country can now easily be shared or can be translated to fit the needs of other countries. His will make the implementation of new practices much easier. The World Wide Web will be used to bring all the information on the major non-traditional housing systems in Europe together as well as the various techniques for the improvement of urban building envelopes. We are happy to announce that for the first time since the establish- ment COST, it has become possible not only to publish books but to place the information on the World Wide Web. See www.costc16.org. High schools and universities interested in the subject of the renovation of existing buildings can now have east access to this knowledge. This study was based on the following scientific programme: Description and analysis of the types of system related to the factors influencing urban build- ing envelopes; Analysis and comparison of the legislation and technical regulations relating to renovation in European countries; Analysis of how urban building envelopes have been changed to date in relation to relevant factors; A survey of existing engineering techniques that can be used, modified or developed to reach this goal; A synthesis of possible global approaches leading to guidelines on how to reach maximum value for money in relation to the desired quality and working conditions in the urban envi- ronment and also how this approach can be reached for other types of buildings. THE SCHEME OF THE APPROACH OF ACTION C16 The original idea given in the technical annex of the Action was to start with a preliminary ap- proach lasting six months. After that, three working groups would be set up on the themes of: the current envelopes, the needs and the techniques. A period of three years was allocated for this. The last six months of this period would have been used to integrate the result of the work- ing groups and to prepare the final international symposium. As stated above, one year after the start of the Action C16, together with other Actions, was placed on hold, because of the reorganisation of the COST organisation to create an umbrella organisation. At the beginning of 2004, on the basis of the contract between the European Sci- ence Foundation and the European Commission for the Support of COST, this reorganisation started with the establishment of the fully operative COST office in Brussels. x This delay caused to loss of some momentum. A second problem that had to be solved was that the members of C16 came from a variety disciplines and included structural engineers, archi- tects and physicians. Although an interdisciplinary approach is one of the targets of a COST Ac- tion, this did give rise to problems in the working group on techniques. For example bearing structures demand a different specialisation from that required for secondary elements, such as facades and roofs. The management committee was wise in its decision to split the Techniques Working Group into a working group on structures and a working group on facades and roofs. THE METHODOLOGY The methodology used for the work of the four working groups of the Action C16 “Improving the quality of existing urban building envelopes” differs. The first book entitled ‘The state of the art’ is divided into two parts. The first part comprises a survey on the housing stock for each country. It contains data related to the building period, main typology and technologies. In the second part the topics covered describe the quality of the housing stock. The ‘state of the art’ depends on the time at which a survey takes place. That is why we consider it an advantage to also publish the two keynote lectures in this first book. These describe approaches to the modification of the multi storey family stock that is currently under investigation. In the second book, ‘The needs’, the method used to obtain precise information was to develop a table that includes the needs, solutions and priorities for each country. It is evident that these needs and priorities will differ greatly from country to country, as illustrated for example by comparing Sweden to Malta. To determine these aspects, criteria such as land use, architectural aspects and building physics are used, as well as aspects relating to finance and management. In the third book, ‘Structures’, a framework for possible solutions has been set up. It contains 20 case studies in which changes in bearing structures to fit for future purposes was the goal. Ex- amples include descriptions of how to build extra floors onto existing buildings for both finan- cial reasons and also to make the installation of elevators more profitable.. Another example il- lustrates the need for greater flexibility, and shows how a part of the bearing structure can be changed to provide this. In the fourth book, ‘Facades and roofs’, which is based on the results of the working groups’ The state of the art’ and ‘Needs’, two documents have been developed, ‘Technical Improvement of housing Envelopes’ and ‘Country Criteria in the form of a matrix’. Relations between the most frequently used refurbishing solutions and their impact on sustainability have been worked out in depth. Sustainability is described in a set of performances such as, technical, economic, functional/social and environmental. Case studies illustrate these theories. Together these books provide much information and can help countries and people to learn from each other. It is my wish that that you will all profit from their content. Leo G.W. Verhoef (Chairman COST Action C16) April 2007 As a result of ongoing changes in the composition of the population, housing stocks need to be continuously adapted to keep pace with the current demand. In the last few decades we have seen considerable changes in the population all over Europe, like a significant reduction in the number of persons per household, and in the next few decades changes in the age-profile of the European population will be a big issue. The necessity to reduce our energy consumption requires also wide-scaled adaptations to the existing European housing stock. The first few decades after WW II, most European countries experienced a large housing shortage caused by the devastations of the war, economic migration, and a rapid increase of the population. These shortages were tackled with a high level of building activities, the emphasis being on quantity at the expense of qualitative aspects. As a result, the European housing stock originating from that period lacks both technical and functional performance. Due to the necessity to produce large numbers of houses in a short period of time, many countries have started experimenting shortly after WW II with new building methods, the focus being on laboursaving and the use of alternative, non-traditional building materials. To make the most of the available means, large parts of the housing stock were realized as multifamily housing blocks, consisting of small apartments being supplied only with basic equipment. Over time the technical quality of some of these new building systems has proven to be questionable, and sixty years later the standard for what can be considered as functional adequate housing facilities has changed significantly. Therefore, both the technical and the functional quality of the European post-war multifamily housing stock needs to be adapted to nowadays standards. On an urban scale, there appears to be a lot of similarity in the way these new neighbourhoods were developed. The CIAM ideas of constructing free standing, well oriented building blocks that allowed air, light and sunshine into every apartment seemed to be the leading principles for the urban planning, and wide-scaled areas have been developed accordingly, all over Europe. In virtually every European country governments have taken an interest in the renewal of their post-war housing stock. In the last decade of the past century we have seen research programs put into action all over Europe. These programs are aimed twofold: first of all, to draw up an inventory of its technical and functional quality in order to establish the shortcomings of this part of the housing stock, and secondly to examine the options to improve its quality. On an urban scale, social problems like vandalism and high crime rates, caused by the anonymity that results from the size of the areas, are considered to be major issues. Of course the quality of the housing stock as well as the ideas of what can be considered to be the nowadays standard of housing varies from country to country. Differences of opinion in this matter are caused by differences in climate, prosperity, culture, and societal conditions. Nevertheless, there are significant similarities in the problems most European countries are coping with, like the necessity for a large reduction of the energy consumption and the need to improve the accessibility of their housing stock in view of the increasing numbers of senior citizens. Introduction M.T. Andeweg Delft, University of technology, Department of Real Estate and Housing S. Brunoro University of Ferrara, Department of architecture Introduction 2 Although most countries planned large housing production schemes directly after the war, it took several decades before the peak in the housing production was reached. Most countries see a continuous increase in the completion until the early seventies. If we express the annual housing production of each country as a percentage of the total volume of their housing stock, we notice that by the early seventies this percentage has risen to approximately 2%. In 1972, the joint production of the former German Democratic Republic and the federal Republic of Germany added up to a total of approximately 860.000 dwellings. This number equals 2.5 % of their total housing stock at that time. From the mid-seventies onward, the general tendency in Europe seems to be a sharp decrease in the annual housing production. For the first time since the WW II, in a number of European countries like Sweden and the Netherlands large numbers of less attractive dwellings in less popular neighbourhoods were standing void. Europe-wide the housing shortage seems to have been finally resolved and building activity shifts from new completions to the maintenance, refurbishment and renovation of the existing housing stock. Europe–wide, building standards are evaluated and reset on a higher technical and functional level. Over the last decade, housing production in Europe has slowed down further to an annual production of less than 1% of the existing stock. Exceptions to this tendency are Portugal, where building activity has been unceasingly high ever since, resulting in a percentage of 20% of the Portuguese housing stock dating from the nineties, and Slovenia where the annual housing production remained continuously high until the independence in 1991. After that date we see a sharp decrease in the Slovenian housing production until it reached it lowest point in 1998 with an annual production of only 0.1% of the existing stock. If we look at the age-profiles of the housing stocks of the participating countries, the European housing stock appears to be fairly new. Over 2/3 of the total stock has been built after WW II, therefore the majority of the European dwellings is less than 60 years old. In urban areas this percentage is often higher. In rural areas were the housing stock mainly consists of farmhouses, the average age of dwellings can be considerably older. The percentage of the housing stock that has been built after WW II varies of course from country tot country. From all participating countries Portugal and Slovenia have the youngest housing stock with just over 80 % of the dwellings been built after WW II. This book is the first of a series of four books, and it contains contributions from 15 European countries, representing a total of 315.5 million inhabitants. The total number of dwellings in these 15 countries amounts to almost 130 million as can be established in table 1. Therefore, it can safely be assumed that this volume gives a Europe-wide inventory of the qualities and the shortcomings of the post-war apartment stock. Even though the majority of the European housing stock is fairly new, significant improvements are necessary in order to keep up with the ongoing changes in demand. For instance, shortly after WW II the average number of persons per dwelling amounted to an average of five or six. From table 1 can be derived that the occupation rate has decreased to an average of 2.43 persons per dwelling in 2002. The lowest occupation rate is to be found in Denmark where the average number of persons per household has fallen to just beyond two. The highest occupation rate can be found in Poland where the average number of persons per household is just over three. Over the same period of time, the space consumption per person has more than doubled to an average of 40 m2 per person, and standards for sanitary equipment and heating facilities are also substantially higher compared to the early post-war period. The highest increase in space consumption is to be found in Denmark and the Netherlands where the average available space is now over 50 m2 per person. In former communist countries the increase in space consumption seems to have been much lower. In Poland for instance, up till 1987 the obligatory dwelling standard for a family of five was set on a maximum area of 75- 85 m2, which comes Introduction 3 down to 15–17 m2 per person, while in 1947 a maximum of 11 m2 per person was indicated. In Slovenia, the guideline for social housing was set on a floor area of 68 m2 for a family of four in 1957, and in 1983 the guideline for social housing in Ljubljana was set on 68-78 m2 for a three bedroom apartment, also serving a family of four. If we look at the balance between single- and multifamily dwellings, there are geographic differences noticeable as well as a shift in time. The highest share of apartments is to be found in Slovenia, where 63% of the total housing stock has been realized as apartments. Germany is in second place with 55%, followed by Sweden with 53%. With only 20% of the housing stock being apartments, Belgium and Portugal have proportionally very few apartments. On Malta, until recently, hardly any apartment stock had been erected, and on Cyprus, apartment stock dating from before 1980 is scarce. In Germany, the share of multifamily housing expressed as a percentage of the total annual housing production has grown steadily since WW II, until it peaked in 1993 with a percentage of 57%. The last decade this percentage has sharply decreased till 31% in 2002. From these data can be deducted that the majority of the German apartment stock is fairly young. In the first two decades after the war, all over Europe apartment stock has been largely realized as three to five storey high building blocks without elevator-access. The apartments dating from this period are compared to nowadays standards poorly equipped, and originally built with an average functional area of 11-20 m2 per person. Building blocks dating from this period of time have been erected parallel or perpendicular in wide-scaled newly developed areas, laid out according to the CIAM-principles. On an urban scale this lay-out results in large, monotonous, purely residential areas with little differentiation in dwelling size or type, and little or no identity added to the individual apartment blocks. The size of these neighbourhoods varies. In the Netherlands the average size was aimed to house 5000 people. In Poland neighbourhoods for up to 80.000 people were built, creating large desolate areas. Table 1: Participating countries, number of inhabitants and number of dwellings, data from 2002. Country Inhabitants x 1000 Dwellings x 1000 Belgium 10 200 4 000 Cyprus 800 300 Denmark 5 300 2 600 France 60 400 29 500 FYR of Macedonia 2 000 700 Germany 82 000 29 700 Greece 10 500 4 700 Hungary 10 200 4 087 Italy 57 600 25 100 Malta 400 155 The Netherlands 15 800 6 800 Poland 38 600 12 000 Portugal 10 400 5 046 Slovenia 2 000 780 Sweden 8 900 4 300 Total 315 500 129 768 Introduction 4 Starting from the late fifties, high-rise building blocks with elevator-access become more current. Depending on the country, the height of these apartment blocks varies from 8 to 18 storeys. Ten years later, all over Europe high-rise building blocks with elevator-access are the prevailing type of apartment blocks. In most countries the lift-shafts are situated inside the building blocks and elevators have to be shared by only a few apartments per floor. In the Netherlands, as a rule, these high-rise building blocks have externally situated elevators with a gallery-access, resulting in large numbers of apartments sharing the same elevator per floor. Although this concept economizes on the number of elevators, it has severe disadvantages, since the long galleries cause a lack of privacy and a feeling of anonymity among the tenants. In France, we find some experimental building blocks dating from this period, with a corridor- access and with revolutionary floor plans like the ‘Cité Radieuse’ of Le Corbusier. The technology used for non-traditional building seems to be geographically defined. In the eastern part of Europe, as well as in Sweden and in Denmark large panel building is the prevailing building technique. The large storey-high slabs of prefabricated concrete were joined and fixed together with in situ concrete. In Germany welded steel plates were used for the fixation. Since these steel plates are relatively easy to dislodge, this type of assembling facilitates the reuse of the single panels. The prefabricated load bearing walls can be with or without reinforcement, depending on the system. Light weight prefabricated concrete slabs are used for façades and partition walls. The matching floor systems make either use of prefabricated concrete slabs, or consist of pre-strengthened beams with filling blocks, similar to the ones used with the skeleton structures of beams and pillars. Due to the standardisation of the prefabricated concrete elements, the floor plans of apartments constructed in these building systems turn out to be very uniform and difficult to adapt. Since there are limits to the weight, there are also limits to the dimensions of the prefabricated elements. Therefore, in general, the use of large panel building techniques results in building structures with narrow spans. Germany forms a remarkable exception to this rule with large panel systems that allow spans of up to six metres. In the Mediterranean countries the main technology has been to build with a bearing structure of steel reinforced concrete beams and pillars of in situ concrete. To this skeleton, façades and partition walls are added, using hollow brick blocks. The floor systems vary. Reinforced concrete slab floors as well as floors constructed with pre-strengthened beams with filling blocks are both commonly used. Building blocks with a structure of bearing façades and a spine wall are to be found in Denmark and France. This building technique was mainly used in the sixties and seventies. Building blocks constructed with spine-walls are fairly versatile, since alterations to the floor plans are only limited by the dimensions between the spine wall and the façades. In France and in the Netherlands there are also examples to be found of experimental building systems that made use of stacked prefabricated hollow concrete blocks. The cavities in the blocks were placed on top of each other and afterwards filled with in situ concrete to form solid load bearing walls. In building blocks erected with this technique the structure is generally not steel reinforced. Since this building principle is only suitable for low-rise building blocks of up to five floors, these systems were only in use during the first few decades after the war. In both countries, from the mid-sixties onwards the prevailing building technique for high rise building blocks has been to use in situ concrete in combination with tunnel moulds. Although less frequently, this technique has also been used in Italy. There are large similarities noticeable between the participating countries concerning their housing policy during the first few decades after WW II. Most countries created legislative frameworks to facilitate and encourage a wide-scaled production of social housing. For several Introduction 5 decades, all over Europe consecutive programs aim for increasing numbers of dwellings to be completed. The first oil crisis in the early seventies, results in a widely spread government interference in order to stimulate energy savings. Europe-wide, requirements concerning thermal insulation values are either set on higher levels or added to building codes for the first time and subventions come into force in order to stimulate home-owners to take energy saving measures. Legislation issued by governments has greatly influenced the present technical state of their housing stocks. The present situation regarding the upkeep of the housing stock in Portugal and on the Maltese Islands for instance needs mentioning. Due to government interference, for several decades the rental proceeds in these two countries have not been sufficient to cover the cost of adequate maintenance. In Portugal this has led to a strong reduction of the rental market and to a significant decay of large portions of the Portuguese housing stock. It has been estimated that 33 % of the Portuguese housing stock dating from the post-war period is in need of some kind of reparation. Another example is to be found in Germany. Before the Reunification, for several decades the policy in East Germany has been to demolish and rebuild instead of maintaining the existing housing stock. The quality of these newly completed dwellings however was inferior. As a result, although only 20% of the present German housing stock is located in former East Germany, the refurbishment cost for this part of the stock adds up to 70% of the estimated cost for the refurbishment of the total German housing stock. From the above numbers can be derived that the amount of money that has to be spent per dwelling on refurbishment is in former East Germany almost ten times higher than in the western part of Germany. The last few decades, with the focus shifting from quantity to quality and from new completions to the maintenance and improvement of the existing stock, the ratio between rental and privately owned housing stock has become an important factor for governments in order to outline their policy. On average, about 60% of the European housing stock is owner-occupied, although the ratio between rental and privately owned property varies strongly from country to country. As a rule, single-family dwellings are more often owner-occupied than apartment stock. With 87% Slovenia has the highest rate of privately-owned housing stock. With percentages between 70% and 80% Portugal, Greece, and Cyprus have proportionally also large quantities of owner- occupied housing stock. Maintenance of privately owned apartment stock is hampered by the shared possession of the building block, which means the owners have to reach agreement on the investments spent on maintenance. For the last decade, the priority in the intervention programs has been on solving social problems. On a lower scale, the main issues have been a further reduction of the energy spill, and the need to obtain better accessibility with respect to changes in the age-profile of the European population. Noticeable improvements have already been achieved on the first topic. Nevertheless, since the demands on energy saving are continuously being reset on ever higher levels, ongoing efforts are required in this respect. Although the necessity to improve the accessibility of the early post-war multifamily housing stock seems to be widely acknowledged, so far, the achievements in this respect have been limited. These poor results can largely be attributed to the architectural features of the early post-war apartment blocks. Considering the numerous intervention programs that have been put into action, large efforts have already been made in order to assure that the quality of the European post-war multifamily housing stock keeps pace with the present and future changes in demand. However, post-war apartment blocks form proportionally a large part of the total European housing stock, and there are still large discrepancies noticeable between the present demands and the original technical and functional quality of these building blocks. Therefore, further substantial efforts are required in order to assure adequate improvements to nowadays standards. Introduction 6 Originally the COST C16-action was focussed on the improvement of the building envelopes, in order to tackle physical problems like dampness and energy spill and at the repair of structural damage to foundations. However, soon the awareness arose among the participants, that these improvements could not been seen separately from the necessary overall renovation of these parts of the European housing stock. Renovating façades often coincides with changes in the architectural appearance of a building block, and large investments to improve the quality of the building envelope are only justified if the building block as a whole can meet future requirements. The focus was therefore widened to comprise functional and architectural aspects as well, in order to be able to give a full scope of the shortcomings of the European post-war multifamily housing stock as experienced in the participating countries. With the decrease of annual productions, new completions become proportionally less important. This emphasizes the question: what is the state of the existing housing stock? The purpose of this volume is to compare the different contributions from all participating countries in order to be able to give an overall survey of the technical and functional quality of the European post-war multifamily housing stock and the problems that have to be dealt with in this respect. Similarities and differences between the various countries become clear and the extent of the common shortcomings can be established. In each contribution the State of the Art of the present housing stock of that particular country is recorded. In order to facilitate a comparison between all participating countries, a format was created to function as a lead for all authors. The format consists of two parts. Each contribution starts with a survey on the housing stock that has been built in that particular country since WW II. This survey includes data related to different building periods, followed by a description of the main typologies of the various apartment blocks and a description of the technologies that were used for the completion of these parts of the housing stock. This first part is concluded with relevant information on housing policy in order to sketch the legislative framework that was valid during the production and maintenance of these parts of the housing stock. In the second part the focus is on topics concerning the (lack of) quality of the post-war multifamily housing stock. The topics are divided in physical, structural, functional, and architectural aspects. Physical aspects are subdivided into thermal insulation, protection against moisture, and noise insulation. Functional aspects are subdivided into safety and accessibility. Not all aspects will apply to every country and some aspects will be interpreted differently. The topic ‘structural aspects’ for instance includes earthquake resistance. This is an issue however, that is mainly relevant in countries in the south-eastern part of Europe. Thermal insulation on the other hand, will be of greater importance in countries with a cold climate like Sweden, than in Mediterranean countries. In each contribution therefore, only the aspects that apply to the housing stock of that specific country will be addressed. Nevertheless, the format used in this volume guaranties easy access to all information, as provided by its authors with the intention to make a contribution to improving the quality of the post-war European apartment stock. Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. INTRODUCTION In this paper I should like to examine how recent changes in the perception and value of mod- ernism’s social housing legacy have brought about a significant revaluation of elements of its remaining stock. This process involves both cultural and practical issues and these in turn im- pact on the manner of its conservation and improvement. I will illustrate the inquiry with two projects carried out by my practice Avanti Architects in London in which the circumstances of each case have produced different types of response. Yet both have been directed towards the considerate preservation and qualitative improvement of previously problematic urban housing stock and could be seen to demonstrate a significant change of heart. My message – which I be- lieve these examples illustrate – is to call attention to the enormous potential that is available in the residue of modern social housing that still characterises many of our inner cities. FROM LAUNCH TO LEGACY The story of progressive social housing in Britain could be traced back deep into the 19th cen- tury and the various commercial and philanthropic initiatives that emerged in response to the depredations of the Industrial Revolution. But to take it up only from a modernist perspective it is a narrative of how small scale experimental work launched by pioneering architects and committed private or voluntary clients in the 1930s developed into a post-war hegemony in which modern architects were recruited by national and municipal authorities in the delivery of increasingly large public sector projects in every city in the land. What started as a research adventure into new, more appropriate, forms of urban living became a national reconstruction programme adopted by governments of all political colours as a cen- tral, albeit increasingly controversial, policy of the British welfare state. Driven partly by the urgent need to address the housing deficit resulting from war damage, partly by the longer standing need for slum clearance and replacement of inadequate Victorian housing stock, and partly by demographic pressures to accommodate greater numbers of new households, the post- A Change of Heart John Allan Director of Avanti Architects, London, United Kingdom ABSTRACT: This paper reflects on the experience of working with large modern housing pro- jects from a practitioner’s viewpoint, and explores both the technical and cultural issues in- volved. A review of two case studies reveals the ways in which problems of performance and pressures for change can be addressed through design intervention and systems of governance. The paper concludes with an appeal to revalue the legacy of modern housing and identify the potential for creative conservation in the widest sense that this legacy offers. A Change of Heart 8 war housing drive together with comprehensive educational reform and the development of the National Health Service represent the three key projects of social betterment in contemporary Britain. In the field of housing despite the huge variation in circumstance, output and quality over the period in question – say 1945 to 1980 – results of major significance were achieved in almost all the typologies that were explored. Isokon Apartments, 1934 Highpoint Apartments, 1935-38 But this original and massive project of social and capital investment has now also created its own mixed and problematic legacy that is demanding new initiatives in terms of technical and cultural revaluation. Much of the stock has been poorly managed and maintained, as well as suf- fering from the broader effects of economic and social disadvantage in the communities in- volved. These problems in addition to a number of high profile failures resulted in a stigma be- coming attached to the whole project of public sector housing such that it is now as much to do with the changing of hearts and minds as with the technical issues involved that the retrieval of this legacy must be concerned. Thus whilst sometimes involving conservationists on account of the selective listing of a few celebrated examples, the challenges go well beyond a narrow defi- nition of conservation, to touch on major issues of national economic policy and urban regen- eration. I will therefore try to indicate both the larger social dimension of the issues as well as the specific architectural implications. Although my references are to the UK scene I feel sure that there will be similarities in many other European countries, and indeed beyond, as a result of shared history and experience, so I hope my examples will have a wider than merely local application. My case studies will con- sider two housing projects in central London – Priory Green, a large early post-war estate and The Barbican, a major urban reconstruction project on a vast scale. In the first case our response took the form of direct intervention in the building fabric, not so much a ‘change of heart’ as an actual heart transplant; in the second it indeed involved changing attitudes in the sense of culti- vating a consensus for new systems of management. Yet together the examples serve to indicate the range of transformation entailed in making modern housing of the mid-20th century fit for a 21st century future. A Change of Heart 9 CASE STUDY 1 – PRIORY GREEN My first example really covers two projects though they are both part of the same estate. Priory Green was the largest of three housing developments designed by the architect Berthold Lubet- kin and his firm Tecton for the Metropolitan Borough of Finsbury after the war. These projects were among the most ambitious and architecturally sophisticated of any in the country at that time, not only incorporating many of the new technical advances of the early post-war period but also attempting new values and vocabulary in terms of urban planning and architectural composition. Priory Green 1943-57, Model Priory Green – Phase 1 completed, 1952 In this connection I was interested to note in the C16 website the statement ‘the demand for housing in the post-war period necessitated the rapid production of large numbers of dwellings. Qualitative aspects were less important’. If Lubetkin’s contribution may be distinguished from that of many of his contemporaries by a single factor it is his rejection of this assumption that the demand for quantity in post-war re- construction justified a lack of quality. His work and polemic consistently registered a concern to go beyond the functional solution of specific housing briefs and demonstrate the potential quality of urban living that was achievable through good modern design. It is for this reason that two of these three projects have been listed as buildings of special architectural significance and the third is now designated as a Conservation Area. My case study example, Priory Green, although originally popular with its tenants, later de- clined and deteriorated over years of mismanagement and inadequate maintenance, such that in 1996 its owners Islington Council offered the by then derelict northern section known as Wyn- ford House to the open market to take it off their hands and even demolish the buildings and re- develop the site, which would have been quite feasible as they were not protected by listing. My practice, Avanti Architects working with Community Housing Association, however, won the bid with a scheme for complete regeneration, whereby the buildings would be repaired, re- engineered and reoccupied under a mixed tenure programme which combined social rental for council tenants with private leaseholds in a cross-subsidy arrangement that eliminated any de- pendency on grant aid. In technical terms the challenge was to re-engineer and re-present the es- tate in a way that would make it attractive and relevant to a new audience. Our additional self- imposed objective was to achieve this not by disguising, but rather by re-presenting its original character. A Change of Heart 10 Wynford House completed, 1957 Wynford House derelict, 1996 Wynford House, now re-named Priory Heights, forms the northern part of the Priory Green Es- tate and comprises three blocks of 4, 5 and 8 stories respectively, arranged in a U plan to create a large north facing courtyard. The 8 storey block forms the closure to the principal south-facing open space of the estate as a whole. The original accommodation consisted of flats of various sizes served by access galleries, staircases and lifts. The building structure consists of in-situ re- inforced concrete cross wall, the facades being infilled and clad with pre-cast exposed aggregate concrete panels, cavity brickwork and glazed tiles. Priory Heights new plan The scale of the rescue exercise really took the project well beyond conservation in any conven- tional sense to become one of major regeneration. As far as the building envelope was con- cerned there were all the issues of roof, concrete and brick repair, retiling, thermal upgrade and complete replacement of windows and building services. I will summarise these works briefly in turn. A Change of Heart 11 The roofs of buildings in distress are always a first priority, and in this instance all three blocks were completely re-covered using tapered foamglass insulation and high-performance mineral felt with new aluminium flashings and improved drainage falls. The wall areas of cavity brick- work were cleaned and repointed, with the insertion of additional remedial brick ties for en- hanced stabilisation and then injected with cavity insulation. All the tiled areas were renewed with matching fully vitrified tiles on the original grid layout, but with state of the art adhesives on a new render bed and enhanced provision for thermal movement. The external dwelling walls along the galleries were replaced in their entirety – this being structurally feasible by vir- tue of the crosswall structure which meant that none of these walls had a load-bearing function. This not only facilitated the redesign of kitchens, bathrooms and their associated services along the interior side of this wall, but also enabled the new walling itself to be specified in turbo- blockwork to provide substantial thermal improvement. The windows were also all replaced us- ing new double glazed argon filled units in either steel frames (on the external building facades) or aluminium (along the more sheltered gallery walls.) The combined effect of all these inter- ventions, together with internal dry-lining and additional insulation at potential cold bridge posi- tions to eliminate thermal shock, was to substantially raise the thermal performance and air tightness of the building envelope to comply with current standards. Priory Heights repaired concrete, brick and tiling, with new windows The extensive concrete remedial work presented a specific challenge. The architectural treat- ment of the façade design was especially characteristic of Lubetkin’s work in all his post-war housing, and Priory Green was particularly ingenious in its organisation of the elements of the building envelope into an overall composition. Here the combination of exposed aggregate pan- els, contrasting brickwork, white pre-cast planters and alternating fenestration produced a dy- namic rhythmic pattern which had been eroded by years of weathering. The conventional reme- A Change of Heart 12 dial approach would have been to overclad the buildings which would have resulted in a bland uniformity of expression, but we wanted to recapture the original vigour and contrasts of the elevation and re-present this as an intrinsic aspect of the buildings’ original identity. Every panel of the defective concrete was individually surveyed and repaired, using a range of tech- niques including mortar replacement, injected corrosion inhibitors and clear anti-carbonation coatings. But specifically they were treated to match the exposed aggregate surface and colour characteristics of the original panels – this blending process occupying a team of 24 unem- ployed local artists for a whole year. At the same time the brickwork and planters were also treated with mineral coatings in black and white respectively to restore the original contrasts. The façade is now not only re-secured in terms of its material integrity, it also once again pre- sents the distinctive dynamic character of Lubetkin’s original design. There were also significant strategic interventions in the original design. The bridge links be- tween the three blocks were removed, and the ‘missing’ staircase half-flights introduced in order to make each block free standing. This not only reduced the number of dwellings served from a single core, but also enabled more southern light to penetrate the main landscaped courtyard through the new gaps. Then the ground and first floor flats were conjoined and reconfigured as maisonette units for larger families and the whole ground plane being re-landscaped to allow all the lowest level units to be released from gallery access and gain their own front doors at ground level. Priory Heights with new staircases Priory Heights re-landscaped In the main block the roof was seen as a major opportunity for adding value. First it had to be cleared of service housings. The original lifts were replaced with new sidewinder installations incorporating the lift motors within the shafts which eliminated the need for rooftop plantrooms. Then the introduction of a new pumped water supply from basement level storage tanks enabled the original tanks on the roof to be removed as well. In effect we created a new floor for devel- opment, on which we then planned two penthouses which added value to the estate as a whole. A Change of Heart 13 Priory Heights with restored façade and new penthouses Meanwhile a disused tenants’ meeting room at lower ground level was redesigned as a chil- dren’s nursery facility for the whole estate with new internal and external activity areas. Finally, the new management regime enabled a concierge point to be provided in a new entrance porch formed from the original stair hall thus providing a permanent security presence on the estate. This was integrated with the landscape and public realm works, derived from Lubetkin’s origi- nal but unexecuted design, upgrading the estate environment and enabling the whole ensemble to be re-presented as a new residential neighbourhood. Such was the success of this project that Islington Council, realising now that the estate was ca- pable of being revived, designated the whole of Priory Green a Conservation Area. This had the effect of making it eligible for Heritage Lottery Grant Aid, such that when the new social land- lords of the southern part of estate, Peabody Housing Trust, embarked on a major regeneration of their section we were able to secure a grant of £2m (the largest such grant ever awarded) to supplement the main budget in order to carry out the works to a conservation standard. This second phase of the project, carried out with tenants in occupation, also included re- roofing, concrete repair and tile replacement, new windows, new services and re-coating in original colours, as well as complete re-landscaping of the estate grounds with a scheme based on Lubetkin’s original design, which had been lost. A Change of Heart 14 Priory Green, regeneration completed 2004 There are now some 360 homes at Priory Green that are equipped to current standards, popular with their occupants, have a secure future and are more authentic in terms of their architectural character than at any time since their original completion in the mid 1950s. In short, Priory Green has been saved by being changed, but changed in a way that gives the estate back its au- thenticity. The lesson for conservationists is surely that it is necessary in projects of this type and scale to recognise that larger considerations of economics, social policy and urban logistics must drive the agenda, but that to acknowledge this is not to concede that conservation values can play no part at all. In other words, the project demonstrated that modern building envelopes are capable of transformation not only in relation to operational and technical performance but also in terms of enhanced architectural authenticity. CASE STUDY 2 – THE BARBICAN My second case study, The Barbican, differs from this not only in scale but also in terms of type of response. Whereas Priory Green entailed direct intervention and technical re-engineering the Barbican involved the development of new management guidelines and the cultivation of a con- sensus to adopt them. The Barbican was planned and built by the Corporation of London in a massive project of post-war reconstruction and in a policy of great enlightenment deliberately aimed at re-populating the centre of the bomb-damaged city on an extensive site that could well have been exploited for more valuable office development. It contains over 2000 dwelling units, housing over 4000 people, as well as comprising two schools, a youth hostel, library, cinema, theatre, art gallery, concert hall, conservatory, restaurants, pubs and shops. It was designed by the architectural firm Chamberlin, Powell and Bon, built over nearly quarter of a century (1959 – 82), and now stands as one of the largest and most ambitious central urban redevelopment schemes in post-war Europe. A Change of Heart 15 Barbican Estate, aerial view Not surprisingly for such a massive and uncompromisingly modern project, it has, for most of its existence, been controversial both in public and professional circles. In his popular and widely distributed visual survey ‘Above London’, first published in 1980, the Anglophile American commentator Alistair Cooke felt able to write that ‘Nobody, except some of the peo- ple who live there, has a good word to say for The Barbican…It has been variously described as a cross between a medieval fortress and the worst of Le Corbusier’. Yet twenty one years later in 2001 it was judged to be of such significance in Britain’s post-war architectural achievements that the whole estate was listed Grade II and the landscaping specifically designated Grade II*. Indeed at the very time of writing this paper the Barbican Centre, with its theatre, concert hall, library and related cultural facilities is celebrating its 25th anniversary to universal acclaim. The estate as a whole is believed to be the largest object ever listed – but this raises some sig- nificant questions and problems. How is it possible to apply the procedures and protocols of list- ing to several acres of London accommodating over 4000 people, the majority of whom are now leaseholders and owners of their apartments, not rental tenants. How could it be policed ? List- ing as a method of statutory protection was aimed at single buildings in single ownership, not whole tracts of city. The issues presented by this case study therefore consist not so much of technical upgrade (though this is constantly a pressure for change) as matters of cultural posi- tioning and voluntary governance. A Change of Heart 16 Barbican Estate, General plan In 2003 my practice Avanti Architects was commissioned by the Corporation of London and English Heritage to draw up Management Guidelines to provide guidance and clarity for all stakeholders. The specific objectives of the project were defined as follows. To enhance listing as a mode of active conservation To provide clarity for stakeholders To promote stakeholder consensus To provide a framework for good stewardship and managing change To increase understanding of the asset To serve as model for other projects The criterion specified in the 1990 Planning Act which regulates listed buildings, and by which listed building consent is triggered is that of ‘special interest’ and the requirement that ‘any work that would affect the character of a building listed on account of its special interest’ should be subject to a formal application to the local authority for consent. Our objective was to find a way of balancing the constraints of listing with the pressures for change, or to try to distinguish between interventions that would not affect the ‘special interest’ of the buildings (and therefore should avoid the formal consent procedures) from those that would. The first task was thus to seek to define, locate and prioritize ‘special interest’. This of course applied at many levels - from the facades of the towers, through the silhouettes of the roof, to the design of the windows down to the details of the kitchen sink or the door ironmon- gery. A Change of Heart 17 Barbican – Facades Barbican – Typical Kitchen A work syllabus was undertaken involving both historical and archival research into the origins and design evolution of the estate and also a comprehensive site survey of the buildings them- selves, including visits to each of the numerous apartment types used across the estate. We then came up with what we called the ‘traffic light system’, whereby examples are given of all types of works which could be envisaged, ranging from the exteriors of the buildings through the common parts to the individual apartments, which were then categorised according to their potential impact on the special interest of the design. Thus those interventions that would not af- fect special interest and could therefore be undertaken without triggering consent procedures were classified Green; works the implications of which were uncertain, and which would re- quire further enquiry were given status Amber; works that would clearly affect special interest and would certainly require application for consent were classed Red, though this would not necessarily mean that consent would not be given; and finally works that were most unlikely to get consent because of their obviously detrimental impact were categorised Black. Barbican – The Traffic Light System A Change of Heart 18 The appeal of this system was its simplicity - the concept of special interest is related to the is- sue of consent procedure at a glance. Anyone contemplating changing anything – whether it is the Corporation itself undertaking works in their capacity as landlord, or an individual resident looking to alter their own apartment - can establish immediately what obligations they may in- cur. The guidelines also proposed a series of Conservation Strategies including the designation of a small number of representative Heritage Flats, which could be preserved in all details to serve as a permanent record of the original design; the establishment of a Salvage Store where residents could find replacement items or fittings that were lost; a section on Best Practice for the routine maintenance of the estate by the Corporation’s own management team, and proposals for a sys- tem of periodic reviews in order to ‘future proof’ of the document, ensure it was operating as in- tended and make any necessary adjustments. Just as important as the research and evaluation work – if not more so – was the process of cul- tivating a consensus within the stakeholder group to support the project. It was clear from the outset that it would be vital to secure a sufficient measure of agreement to sustain the operation of the guidelines in order that their application could largely be through voluntary observance rather than dependent on official enforcement – a task which would be both unfeasible in terms of resources and also defeat the whole objective. The vehicle by which this consensus was cul- tivated was a Working Party, chaired by a City Alderman and representing all key stakeholders including a number of estate residents, officers from the Corporation and English Heritage and a representative from the Twentieth Century Society - - the statutory consultee on listed 20th cen- tury buildings. There were two rounds of public consultation when first and second drafts of the document were circulated for comment and feedback, and also two public meetings were held with formal presentations, questions and discussion. The whole project extended over 93 weeks in all, but the effect was to enable all interested parties to feel that they had been listened to, al- lowed to contribute and thus share in the ‘ownership’ of the eventual document. Specifically, the medium of reaching consensus through consultation and the assimilation of feedback en- abled closure of the project to be achieved collectively through the Working Party representa- tion rather than through attempting to secure individual agreement of every resident or house- holder, which would have been quite impracticable. Following the second round of consultation, the consequential revisions and final editing the Management Guidelines were formally adopted by the Corporation with the status of SPG (Supplementary Planning Guidance) as part of its planning policy in May 2005. This means that they function as ‘a material consideration’ in the determination of any relevant planning propos- als or listed building application. They are now operating in the management of the estate, with the system of periodic reviews in place, the salvage store up and running, the heritage flats con- cept approved in principle and work in progress on the establishment of a permanent exhibition or building record. They are the first example of such a conservation technique at such a scale in the UK. What were the key issues ? At the heart of the whole process was the building of trust. Trust be- tween the residents and their landlord (The Corporation), trust between the residents and other stakeholders - English Heritage, the 20th Century Society; trust between residents outside the Working Party (which was necessarily restricted in numbers) and those representing them within it, and trust between all parties and ourselves as independent consultants. When we ar- rived on the scene it was clear that there was still a residue of resentment and distrust of English Heritage by a section of the residents for whom the original listing in 2001 was seen as an un- wanted constraint on their freedom of action and indeed a factor that could limit the market value of their property. (This despite consistent evidence from commercial surveys and local es- tate agents that properties in their original state held their value and attracted at least as much purchaser interest as those that have been altered.) Meanwhile some residents had apparently been led to believe that listing restrictions only applied to the building exteriors and not the in- side of their own apartments. (In fact listing covers everything that exists at the moment of list- ing – whether or not it is even original.) A Change of Heart 19 Barbican – The Management Guidelines Document Some elements of the guidelines were particularly controversial in the first round of consulta- tion – for example whether the replacement of kitchen and bathroom fittings should trigger the formal consent process, - ie. be placed in the green or the red category. In the end it was ac- cepted that changes of fittings and cabinetry only should not require consent, whereas changes to kitchens or bathrooms that involved altering the actual apartment plan would do so. Such was their preoccupation with the potential constraints of listing on their individual free- dom that residents generally seemed slow to appreciate that the guidelines were not necessarily simply a mechanism for the authorities to control them, but were equally a means through which they could exercise a controlling and monitoring function on the authorities and specifically their landlord. Indeed the most conspicuous (and occasionally controversial) changes on the es- tate over its lifetime have been those carried out by the Corporation itself, and the guidelines now provide explicit criteria for the acceptability or otherwise of such interventions whether they consist of major projects or just incremental small alterations – the cumulative result of which could still have significant impact on the overall character of the estate. In fact the whole basis of the project is one of reciprocity – the implied compact that each party should be able to expect the other to observe its obligations if they observed theirs. More generally the project as a whole has served as a consciousness-raising process and it seems fair to say that there is now a greater awareness both within the resident community and within the various departments of Corporation itself of the unique history and significance of the Barbican estate. This can surely only favour the cultivation of a virtuous cycle of improve- ment. Indeed the success of this project has led directly to an equivalent exercise in relation to its immediate neighbour, the Golden Lane Estate designed slightly earlier by the same architects Chamberlin, Powell & Bon. The management guidelines for this estate, also prepared by Avanti Architects, have recently been completed and are due to be formally adopted in Spring 2007. Taken together we believe these projects may serve as a model for other large listed housing schemes and urban complexes both in the UK and indeed beyond. A Change of Heart 20 The Golden Lane Estate CONCLUSIONS How does all this relate to the theme of this conference ? Well, it seems to me that there is con- siderable resonance in the title - ‘Improving the quality of existing urban building envelopes’. The two words that stand out are surely ‘improving’ and ‘existing’. If we were all only 50 years older such a title would be inconceivable. It would all be focussed on the replacement, not the improvement, and on the new not the existing. But if we have learnt anything from that extraor- dinary phase of building in the second half of the 20th century it is surely that despite the mas- sive commitment of energy and capital there is no technological short-cut to the creation of communities. Culture means exactly what it says – something that is grown. Indeed, the Medie- val Latin root reminds us that the word itself is derived from the Latin cultus or colere – to till, or toil over. And ‘toiling’ takes time. In both the projects I have illustrated the ‘change of heart’ referred to in my title has occurred first gradually - inasmuch as an extended period necessarily elapsed before the buildings were either considered worthy of regeneration, in the case of Priory Green, or listing in the case of the Barbican - and then momentously in the commitment of the resources needed to consolidate that change through the projects described. The projects themselves whether constructional or managerial proceeded to convert that incremental change in attitudes into a step change in terms A Change of Heart 21 of a specific and hopefully sustainable outcome. It is thus doubtful that either of these exercises could have occurred much earlier. Neither the participants nor the audience would have been ready. But as well as being the inheritors of the first wave of modern rebuilding after World War II, and becoming aware of its continuing potential for improvement our generation has also begun to understand it has some new responsibilities of its own. For over virtually the same period as it has taken these buildings to be reassessed we have come to appreciate that the earth’s re- sources are finite, that the planet’s bank account is slipping into overdraft and that we must learn how to rebuild the world with things that exist already. Thus the Green Agenda and sus- tainability issues are suggesting larger arguments for thinking carefully about the embodied en- ergy (and value) of previous investment before scrapping it in favour of re-development. It is clear that one aspect of the task in making mid-20th century buildings fit for an extended future is essentially technical, and involves increasingly complex issues of building physics and operational performance. But it would be an oversimplification to assume that this was the only – or perhaps even the main – challenge. Just as important is surely the change of heart entailed in looking again at some of these buildings and estates and beginning to consider them as assets rather than liabilities. It takes time to appreciate what the still fairly recent past achieved. All the buildings within the timeframe I have been considering were built in my own lifetime – and I am ‘only’ 61. Not all housing estates – even the problematic and unpopular ones - are the same. Certainly this is not to deny that in many cases redevelopment has got to be the only response. Alongside the sort of work I have illustrated my practice is currently involved in the complete re-building of some 1000 houses in Yorkshire which are barely 40 years old, for the unarguable reason that the cost of upgrading these dwellings to comply with the Government’s mandatory Decent Homes standard is greater than that of re-building them. But every building venture has its own story and it takes a more discriminating mindset than we are sometimes ready to offer to analyse the difference between an unredeemable failure that could never be saved and an under- performing success that has just been the victim of bad stewardship. The fact that Britain is regarded as an enlightened ‘first world’ nation does not necessarily mean that it has consistently enlightened attitudes to its own past – especially its modern past. Cer- tainly we can summon the technical resources available to transform the tired buildings of yes- terday into the valued real estate of tomorrow. But before we can undertake this vital task we have to change our hearts in order to cultivate the desire to do so. A Change of Heart 22 PROJECT REFERENCES Priory Green Architects’ Journal, 9th October 1952, pp.433-42 Architectural Review 1952, Vol. 112, pp.241-53 Building, 5th December 1997 The Architects’ Journal, 3rd September 1998 p.32 Concrete, October 2000 pp.64 -65 Highbury & Islington Express, 26th May 2000, p.11 Building Design, 17th November 2000 pp. 16 - 19 The Barbican Barbican Redevelopment 1959, Report to the Court of Common Council of the Corporation of London by Chamberlin, Powell & Bon, April 1959 Barbican Redevelopment 1959, The Builder, 29th May 1959, p.949 Heathcote, D. Barbican: Penthouse over the City, Wiley-Academy 2004 Barbican Listed Building Management Guidelines, Corporation of London & English Heritage, May 2005 Daly B., March D. & Mascall R., ‘Management guidelines for the Barbican’, Context 91, September 2005 JOHN ALLAN - GENERAL REFERENCES Modern Theory of Repair, The Architects’ Journal Renovation Supplement, 22nd March 1989 pp. 18 – 21 Instruments or Icons?, Architectural Review, November 1990, pp.5 – 9 Conservation of the Works of Lubetkin & Tecton, Docomomo 1st Conference Proceedings, 1991 pp. 180 – 186 Berthold Lubetkin - Architecture and the tradition of progress, RIBA Publications 1992 The Conservation of Modern Buildings, in Building Maintenance & Preservation, 2nd Edition, Butter- worth-Heinemann 1994, pp. 140 - 180 Conservation of Modern Buildings in England, Icomos, Germany 1996 Conservation of Modern Buildings Modern Matters, English Heritage 1996 pp. 123 - 138 Momo’s Second Chance, Modern Movement Heritage Spon 1998, pp. 18 – 28 Preserving Heritage or Revaluing Resources? Preserving Post-War Heritage, English Heritage 2001 pp. 201 - 208 Berthold Lubetkin, Merrell Publishers 20 A Challenge of Values, in Back From Utopia, Docomomo 010 Publishers, Rotterdam 2002 Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. The work-field of Van Schagen architekten is the existing city. Huge parts of the dutch cities are built after the second world war. During the city-renewal of the ‘70 and ’80, the districts from the 19 th century were renewed. Nowadays we face the renewal of the post-war (modernistic) neighbourhoods. These disctricts have deteriorated within the last 20 years due to the urban re- newal of the inner cities and the development of large suburban areas. The image of the postwar districts is a bad one: too much of the same small dwellings; a con- centration of social housing; too many foreigners; bad quality of public space; unclear bounda- ries between public and private; too much collective space turned into no-mans-land; a functio- nalist architecture not very popular: dull blocks in a dull environment. Complex 50 in Amsterdam-Osdorp: former apartments have been transformed into a building with a new big gate, with new access galleries in stead of staircases above the gate, with maisonnettes on the ground floor and new apartments on the roof Developing the Existing Arjan Gooijer, Gert Jan te Velde Van Schagen architekten, Rotterdam, The Netherlands Developing the Existing 24 RENEWAL STRATEGIES Housing associations own almost all the housing estate in this areas. Logically they play an im- portant role in the renewal. This role is not yet defined. In former days these associations were public institutions. Since 1995 they are privatized and often more market-orientated. They are often looking for short term profits; forgetting their role as provider of good social housing. Almost all space around the housing-blocks is owned and maintained by the local government. An expensive job they would like to reduce. In the renewal of the post-war city three different strategies are possible: 1. building maintenance: This strategy focuses on maintaining the present situation and is not future-focused. Just maintaining the existing housing estates is not enough. The dwellings stay too small and in a too poor condition. 2. adapting: This strategy focuses on consolidation of the market-position of the district. The misfits between housing-estate and targeted-groups are ‘repaired’. Renovation is used as a means to create affordable housing for target-groups. This is financially almost impossible in the case of restructuring and building anew. The existing housing supply is transformed for existing (or new) groups of inhabitants: large low-income families (often foreign); elderly people; startergroups with small budgets. The goals of the project are continuity, step-by-step renewal, balance between old and new, between low- and average income. This strategy of consolidation is often not strong enough. When other parts of the city are restructured, tenants will move to the consolidated neigborhood because of the affordable housing. The careful, step-by-step renewal will easily be frustrated. 3. restructuring: This strategy focuses on improving the market-position of the area. The ac- cent is on renewal by demolition. Demolish completely and built anew; a new urban de- sign, different functions, different types of dwelling, different architecture. Only in this way it seems possible to create a completely new district with a new position on the housing- market. Not only the housing-stock (types and households) is changed, also the urban layout. On the long term, building maintenance or adapting won’t be enough. Restructuring seems to be an easy ánd possible solution. The housing associations own the complete housing supply and can decide what to maintain, and what to demolish. But time seems to change. Nowadays it is quite hard to sell large quantities of new and rather expensive apartments. Housing corporations are downsizing their targets and cancelling projects. Moreover, cities need the supply of affordable housing for economic reasons. They need to attract young working class (hand- and headworkers), students, the creative class. Above this, inhabitants of the demolished buildings do have to live somewhere. The affordable postwar housing supply is too important to destroy completely. TRANSFORMATION: AN ALTERNATIVE STRATEGY But the method of tabula rasa is not renewal. It is just starting over again. The method ignores the history of the city and inhabitants. It ignores qualities and possibilities. Restructuring means wiping out existing human urban patterns and social structure. It implies demolition of every- thing: quality and beauty together with problems and ugliness. Last but not least it is very re- source intensive and not environmentally friendly. In our way of working, demolition is a mean, not a goal or a solution. The existing city should not be destroyed by new buildings. They should support the ever changing city. We try to design projects to make the city adapt. We design plans to transform the existing as a step to a new and richer setting, fitting the new urban life and needs. Developing the Existing 25 The designer should not just design new buildings, he has to play a different role. He should look for hidden qualities in the existing city, take them up and make them flourish. To find these qualities and chances we work in a way that is open for all kinds of information and communication. We use open design strategies; we interact with the people living in the dis- trict; we search for the meaning of the original plans. We are looking for the keys to transform the district, without destroying qualities and ignoring history. My opinion is that post-war neighbourhoods do have enough qualities and chances to make a second life possible. The key qualities are: the favourable position in the growing urban net- work; the spacious lay-out and mature greenery; and the modest and careful architecture. Florijn in Amsterdam-Bijlmer: in order to preserve the existing good-quality apartments the image of the building has been improved and the connection between the builing and the environment has been ameliorated by new construcions on the head of the building, by transformation the ground en first lev- el into atelier houses and by improving the entrances. Developing the Existing 26 OUR TOPICS OF TRANSFORMATION In all our research and plans we often face the same items for transformation 1 . We often focus on: 1. housing supply: can we re-use the existing dwellings (the casco) by reorganizing the floor- plan or putting dwellings together? Is it possible to realize new, extra dwellings? For example: - Complex 50 and Enschedelaan: mixture of re-using the existing appartments and making maisonnettes. In Complex 50 new, extra dwellings on the roof - Florijn: renewing the context, maintaining the existing dwellings and – partly – selling them. There is a difference between the housing-stock of the ‘50/’60 and the more industialized large scale houding blocks of the ‘60/’70. The early post-war housing estate (often porti- coes) contains small dwellings (40-70 m2), with very small kitchens and bathrooms. The appartments of the seventies (Florijn) are of a better quality (larger 75-100 m2, good kitchens and bathrooms, often an elevator). Here we face the malfunctioning collective parts around the block: dead facades on the ground floor (storage), badly designed public space (parking, garbagecollection), and bad connection to urban routes. 2. organisation of the block: combination of different types of households in one block: large families, elderly people and small starting households. We try to reorganize a block in a way that these groups don’t give hindrance to one another: entrances on the street for the large families, all elderly connected to an elevator, and all starters on porticos. By doing this, we transform the mass-housing-block into a collective building for living and working. 3. public space: redefining public/collective space around the block, making possible social control and a better use. For example: in Complex 50 the green space is re-defined as col- lective gardens. These playing grounds are directly connected with the gardens of the family houses, and accessible via the stairwells. In the project Enschedelaan we defined the space between the blocks as collective playing ground – a huge quality compared to newly built suburban disctricts. In the project Florijn the surroudings are completely transformed: streets instead of badly controled green. Still the original spacious layout gives quality: existing trees, green parks, compound, water. 4. the role of the inhabitants: taking both inhabitants and our role as an architect seriously. In- habitants are a necessary source of information. Often they return to the project after reno- vation. The designer has to take them seriously, but also stay focused on the whole of the project; the goals of the renewal and the crucial problems. The architect has to take care of the whole of the project on the short and long term. Often the collective parts of the project are more important than the dwellings as such. Complex 50: open spacious porticoes instead of balconies. Florijn: huge part of the budget went to the probelmatic parts of the complex: elevator hall, facades, floor 1+2 and the end parts of the complex. Difficult for the inhabitants of the existing flats. 1 Three projects as an example: 1. Den Haag Zuidwest – Enschedelaan. 2. Amsterdam Osdorp – Complex 50 & 117. 3.Amsterdam Zuid-Oost – Florijn. For more information see also www.vanschagenarchitekten.com Developing the Existing 27 5. sustainability: looking for tehnical, sustainable improvement – taking it to the same level as new buildings: insulation of existing facades (Enschedelaan), or completely new facades (Complex 50); use of low-temperature central heating (Florijn); using solar-energy (projects: Huize Patrimonium, Die delfgaauwse weye). 6. architecture: looking for an architecture that fits the goals of the renewal and fits in a logi- cal way in the ever changing city. As a result every project has its own architectural lan- guage, so we don not have a standard office-style: - Complex 50: a completely renewed facades, referring to the former look of repetition and industrialization. Referring to that, the façade gives no expression to the new contents of family houses, appartments. - Enchedelaan: maintaining the original brick-look, combined with a layer of new balconies and galleries. - Florijn: complete new, changed look by using glass railings, and by splitting up the long slab in different parts (compartiments). At the same time the old honey-comb structure is still to be recognized. The old inner street – the most hated part of the old stucture – is still there, transformed into the livings of the ateliers. Architecture in this case can use three concepts: - conversion: changing the old, bad image into something completely new and modern (Flo- rijn) - rehabilitation: bringing life into the old, worn-out image (Complex 50) - restoration: In some we have to deal with ‘monuments’ of the fifties. In that case we look for a way to restore the building in its architecture (project: Vissekommen). PRIVATE AND PUBLIC VALUES In the case of Enschedelaan, Florijn and Complex 50 is chosen for transformation instead of re- structuring. This is due to the market-view of the clients, and to the design-proces. In this ‘open- plan-proces’ more aspects than only market-value play a role. Public aspects – quality of sur- roundings, position of inhabitants, importance of affordable housing, re-use instead of demoli- tion – are as important as the private interest of the client. In restructuring, these public aspects are often not taken into account. The process is domi- nated by the market. It reflects the changed position of the housing association and local gov- ernment. The housing association is privatized; the local government is looking to diminish pub- lic task. In the renewal of the postwar city there is a lack of balance between public and private inter- est. Good, sustainable city-forms were often a result of strong ideas on public and private. For example: the italian cities of the renaissance, the amsterdam canals of the ‘Golden age’ or the american cities of the 19 th century (grids and parks). There were also strong ideas about the public during the post-war period. Although the ideas were too optimistic (about collectivism), and too static (about life-styles), the result were new, unique urban compositions. The specific qualities and aspect broadened the repertoire of types of city-layout in Europe and are still meaningful. Every era has made its own contributions to this repertoire. The qualities are recognized later on – and often too late. 2 Due to the lack of balance between public and private, these unique urban compositions are under threat. The dominance of market-thinking is reflecting this disbalance. The value of the existing blocks depends only on the value of the location. The lower the value of the blocks re- lated to the value of the location, the bigger the chance of restructuring. 2 Van Pendrecht tot Ommoord,geschiedenis en toekomst van de naoorloges wijken in Rotterdam, p. 19, essay Han Meyer. Toth, Bussum 2005 Developing the Existing 28 The designer should show the client the complete value of the post-war areas, in all aspects and scales. He should be trained to see the hidden treasures of the living city, and deal with them. Renewal of the city needs the designer in a different role. He should be an engineer to know the technical possibilities of existing structures. He should be a communicator to make use of in- formation of tenants and inhabitants. He should be visionary to visualize the possible future. Together with this, he should be able to discuss his plans with different groups: housing associa- tion, inhabitants, city-government, etc. THE NEW ROLE OF THE DESIGNER 1. design as search for qualities, problems and possibilities on different scales Research on the possibilities of existing structures: the dwellings (casco), the block and sur- roundings and the position of the neigborhood in the city. What kinds of dwelling-types can be realized, and how difficult (or easy) is that? On what scale are the possibilities of transformation located? The research is looking for the possibilities, the extra value. What to change and what to embrace? 2. a new way of analyzing the city We lack a language to discuss the specific qualities of the post-war city. To prevent the demolo- tion of inner cities, different ways of analyzing were developed during the ’80. The drawings show the complexity and richness of this tradional city. Doing this, they offer a language to dis- cuss them. Because of the complete different setup it is impossible to analyzing the postwar city in the same way. Talking about streets and blocks is not fruitful. Using the ‘glasses’ of the traditiona- listic city, we only see floating housingblocks in indifferent surroundings. But the composition of the districts is about balance between open space and masses, between public and private domain. Often there is a very subtle composition of dwelling types, types of public space, green-design and sort of trees. We have to develop a method of analysis in which this richness is made public. Enschedelaan in Den Haag Zuid-West: former small apartments have been transformed into larger apartments by making two new ones out of three existing dwellings horizontally, or by making one maisonette out of two vertically; an elevator has been added to improve the accessibility for the elderly Developing the Existing 29 3. making plans open to discussion: feeding the process Apart from the technical building-plans the designer should be able to make another kind of plan: a vision which shows the possible future of a district. The quality and value of new dwel- lings or new district everyone can easily imagine: new is always better. But what will be the ef- fect of transformation? In the drawing of such a visionary plan, the designer is forced to deal with the whole com- plexity of city renewal. Everyting comes together: the different scales, groups (owners, tenants, government) and interests. The plan, in this way, is also a vehicle for the process: people discuss not only the plan itself, but also their own interests, position, future. Different aspects and initia- tives can get there place. For the client, this open-plan process means complexity and taking a risk. City renewal is of- ten focused on avoiding risks and reducing complexity. Difficult processes are cut into small pieces. Different functions (shops, dwellings, offices) are positioned in different buildings. The project-boundaries are as narrow as possible. Due to that, there is no room for transformation, discussion or change. 4. ability to speak different architectural languages Instead of using an own office-style, the architect has to develop a modest architectural lan- guage. The architecture has to fit on the goals of the projects and to fit into the surroundings. The green environment is as important as the architecture of the buildings. An egoist architec- ture will not fit in. The newly built (or renovated complexes) should fit into the existing and new neigbourhoods. No contrast or unique piece, but careful architecture; in which the ‘rules’ of surrounding architecture are respected and renewed. In this way old, forbidden, dull architecture (ready to erase) is changed into an object that still reflects a certain – and in its way unique – pe- riod of our cities. CONCLUDING Our projects show transformation as an alternative approach to renew the postwar city. The districts develop, adapt and change while existing qualities and values are preserved. It is possi- ble to reposition a district by transformation, without restructure it completely. Research, analysis and an open plan process is necessary to know where the key to transfor- mation can be found. What aspects have to be changed, what points are strong enough to main- tain and what parts are important to embrace. In this process, there is an important role for the architect; as visonary, researcher and engi- neer. He is able to show the existing strengths and possiblities. He can develop a language to discuss the future of the postwar city. He is offering the material to make the redevelopment of these districts suitable for a public discussion, instead of a narrow housing-market topic. In this way, the city physically and socially can develop, adapt, change, grow. In short enrich instead of starting all over again every 30 years. This page intentionally left blank Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. State of the Art: Sweden Solveig Schulz, Bengt JO Johansson Department of Architecture, Chalmers University of Technology, Gothenburg Sonja Vidén Department of Architecture, Royal Institute of Technology, Stockholm ABSTRACT: The article deals with the background and situation for Swedish residential areas constructed during the “record years”, i.e. 1961-1975, when more than 900.000 flats in multi- family-houses were built. The flats had generally good standards and space and also well studied and functioning plans, but some of the areas were criticized because of poor out-door environments, as well as monotonous and large scale buildings. Through the years investments have been made, both on national and local levels, for upgrading the environments but also to some extent for rebuilding and renovating the buildings. 1 OVERVIEW OF THE HOUSING STOCK 1.1 Data related to building periods Today Sweden has 9 million inhabitants and about 4.3 million dwellings, out of which 2.3 million in multi-family houses. The population has increased from about 6 ½ million around the year 1950. During the same period Sweden changed from being a largely agrarian country, to a country where 84% live in population centres with more than 200 people, and 55% in urban areas with more than 10.000 inhabitants. As a consequence of the growing population, a better family economy and an accelerating migration to urban areas the housing shortage grew larger in Sweden during the 1950s and 60s. It became one of the hottest political issues during the time. Sweden had a very low housing standard, with many families living in just one room and a kitchen, many without modern facilities. The post-war housing 1946-75 can be divided in two main typologies: the first one with houses erected 1946-60 in more traditional style and technology; the second with houses erected 1961-75 in more industrialized construction. In this paper we are discussing the latter period, which has been named the “record years”. Figuur 1: Number of completed dwellings according to type of building 1960-2002 (Source Statistics Sweden 2004) State of the Art: Sweden 32 The government made great efforts to raise the amount and the size of flats and the standards of equipment. During the 1950s state initiatives were taken for a more industrialized way of construction to reach the goals, but the housing shortage in the urban areas remained severe in the early 1960s. In 1965 the government started the so-called Million program; the intention was to build one million new dwellings in ten years. Constructors were encouraged to build rationally and in large entities. Housing construction became very efficient: prefabrication of facade and room units was developed, as well as the technology for handling the material on the building site with rail-mounted cranes. Although the degree of rationalisation was high, only 1/5 of the dwellings were built in pre-cast concrete houses during the period 1961-75. Although slab blocks and towers of eight storeys were frequently built, still 60% of the dwellings were built in three-storey slab houses or lower (Vidén 1999). Nearly 55% of the flats in multi-family houses were built by municipal housing companies, about 25% by housing cooperatives and about 20% by private housing companies and owners. The municipal housing companies had been established since the 1930s and 40s with support from the government as a means of improving the housing situation. Along with the rational construction principles they were tools for eliminating the housing shortage. Figuur 2: Number of completed dwellings in flat blocks according to type of owner (Source Statistics Sweden 2004) Standards of space were raised – 1960 over 40 % of the dwellers lived in overcrowded homes, 15 years later the figure was about 10 %. Also the standards of equipment were raised, with modern kitchens and bathrooms in all new flats. Figuur 3: Overcrowding in percentage of the dwellers according to standard 2 (= more than 2 persons per room, not counting kitchen and living room) 1960-1990 (Source Statistics Sweden 2004) housing co-operatives private owners government or municipalities State of the Art: Sweden 33 The goal of building a million dwellings was reached and the new flats were of good standards and functions. About 1/3 were one-family homes. But there were also problems, which started to show up at the end of the programme. Many of the new areas were seen as too large scaled and too monotonous; in particular the out-door environment was criticized. Suddenly the shortage turned out to be a surplus – in the mid 70s about 30.000 flats were empty in the country, most of them in the new suburbs. In addition management of older existing residential buildings was poor and plans for many of the oldest areas were that they should be demolished as soon as the housing shortage was combated. That was what happened in many towns and cities starting in the 60s. Media and the public opinion turned against both the newly erected suburbs and the demolition of older areas. The surplus of flats lasted more or less until the beginning of the 90s when immigration grew. This led to a diminishing surplus of flats, but also to a substantial ethnic segregation. 1.2 Description of main typologies The architecture – including the townscape and the design of the buildings – has been pointed out as a cause of the problems. A strongly generalized image of the architecture has been spread and established by media, an image of dull, indifferently designed grey concrete buildings in hard and inhuman environments. It seems difficult to replace this image with a more balanced one. Nevertheless, many skilful architects were engaged to design the new suburbs and their different housing areas. The fact is that, in spite of certain common characteristics, the architecture of the “record years” shows broad variation in scale, building types, form, materials, and architectural values. Most of the residential areas from this period were built in the periphery of towns and cities, very often like islands in the landscape. Car and bus traffic was led around the area with connecting parking, so that pedestrians could walk safely. Public transportation, if rail bound, was usually planned centrally in the neighbourhoods. The buildings were surrounding a local centre with shops for convenience goods, a school and day care centre, and maybe a library. Figuur 4: Residential area in Gothenburg with multi-family houses of different types, constructed in situ and with brick façades, completed in 1965. At the far left houses with precast concrete facade panels. Most multi-family houses were slab blocks in three, sometimes four storeys. They were usually relatively cheap in building because of the lift regulations. Lifts were not required in houses where the top floor was no higher than 9 meters above the ground, a prerequisite fulfilled by most four-storey houses with the bottom floor just above the ground level. Other dominant types are slab blocks or tower blocks in six to eight storeys, or more. State of the Art: Sweden 34 The slab blocks can be short or long, attached to each other in different ways, curved, and even twining like snakes over the land. The tower blocks can be compact or more slender, square or star-shaped. Most dwellings were very well planned and equipped, with qualities still appreciated by many residents and flat-hunters. Functional design, space and sunlight in the flats as well as in the yards/playgrounds – were important factors in the planning processes. 1.3 Description of main technologies Since the 1930s and 1940s reinforced concrete structures were used in most multi-family houses, in slabs supported by walls of masonry or in entire structures. All houses were built in situ. In the 1950s the industrialization of construction started in Sweden in an effort of large- scale production and minimizing of building costs, started by political resolutions and investments and by the big constructors. Its utmost result became pre-cast construction. At the same time traditional housing construction went on for some years. Concrete became predominant structural material. In the beginning of the 1960s almost all multi-family houses were still built in situ, but in the same decade pre-cast construction became more common. However, pre-cast construction, so strongly associated with the period 1960 to 1975, makes only about 20% of the total building construction of that time. Houses built in Situ Multi-family houses built in situ were two to three to four-storey houses, and multi-storey houses and tower blocks of six to eight storeys. Often the houses had no basement storey. Instead laundry, storages etc. were housed in the ground floor. Figuur 5: Typical plan of dwellings in an in situ constructed three-storey house from early 1960s (Bygg, volume V, 1962) The structures were built with bearing transverse internal walls, gable walls and floors of reinforced concrete. Both the exterior and the interior were traditionally shaped. The façades were often in brick. The roofs were either gable-formed and built up in wood covered with roofing felt, asbestos cement tiles, brick tiles or other materials, or they were flat covered with roofing felt. The plans of the common slab blocks followed traditions from post-war housing with two or three dwellings around each staircase. Most dwellings had two or three rooms, a well-equipped kitchen, a bathroom, sometimes a separate toilet, and a quite big balcony. One early result of industrialization was that pre-cast flight of steps was used in nearly all houses. As time went on industrialisation affected all construction. Leaving formworks built up for every casting for prefabricated formworks of sheets of plywood or steel for re-use forced building structures and details of building structures to be repeated. State of the Art: Sweden 35 Houses with pre-cast structure Pre-cast concrete units were initiated about 1950 as part of the industrialization process and effectiveness of construction. Prefabrication technique was then rapidly developed during the 1950s and 1960s, and used for both pre-cast structures and pre-cast external wall panels. They were used together or combined with in situ constructions. The assembly technique imprinted all pre-cast buildings: the exterior with the concrete wall panels; the interior with dimensions, details, room shapes, and plans formed after pre-cast slab and wall units with sizes adapted to the modular grids of 3 M (30 centimetres). The structural systems were erected on in situ constructed basement storeys or, mostly, on non-basement- storey foundations. These latter foundations were designed as in situ ground slabs or in situ foundation columns with pre-cast foundation beams. In the late 1960s there were about ten larger unit constructors to support the floor structures in Sweden. A majority of them used structural internal transverse walls and structural gable walls. Just some of them used all external walls to support the slabs. Structural systems The structural systems can be divided into the following main technologies, depending of the size of the pre-cast slab units: - Room-sized slab units The units were solid, non-tensioned reinforced slabs and room-sized or smaller, spanning over one room. They demanded structural room-dividing walls. The structural principles were developed for family housing and originated from traditional dwelling plans. System Skarne 66 (Ohlsson & Skarne) differed from other systems in this group by structural external walls and internal columns instead of structural room-dividing walls. To this group also belonged System Skånska Cementgjuteriet with right-angled units with slab and wall panel cast in one piece. - Slab units, more than room-size The units were pre-stressed slabs with a hollow section or a TT-section. The slabs spanned more than one room, from one dwelling-dividing wall to the other. The structural principles originated from industrial and office buildings. - External wall panels The external wall elements were almost always room-sized sandwich units (covering one spacing of the facade). They were made with an internal self-supporting wall panel, an external facade panel, also making the surface of the facade, and between them thermal insulation. Figuur 6: A right-angled unit of System Skånska Cementgjuteriet. Figuur 7: External wall unit of System Bygg- Tema. State of the Art: Sweden 36 About 15% of the facade surfaces were made by concrete, often with exposed aggregates or some decorative texture. Other common surface materials were brick, plaster or metal sheets. Thermal insulation and tight joints between facade units played important roles in the external walls. There should be no thermal bridges, which also affected mounting of balconies to walls and floor slabs. Room-sized slab units This technology can be subdivided into three categories depending on different structural principles: structural systems with internal columns, structural systems with two-dimensional units, and structural systems with three-dimensional units (volume units). Each category will be illustrated by one example. System Skarne 66 (Ohlsson & Skarne) belongs to the first category – structural systems with internal columns. The most well known buildings built in this way were erected in Västra Orminge – a large housing area in Nacka, a city next to Stockholm – in 1966-71. In this system bearing walls are surrounding each dwelling. Floor structures are supported by the walls and the internal columns. Installations are assembled to one of the walls, and large free areas were created where rooms could be arranged in different ways. The town plan was formed with two- storey buildings grouped around small yards and with free standing three-five storey blocks. The structural system made it possible to form buildings adapted to the different levels of the ground. The facade panels have “raked”, rough concrete surfaces. Vegetation and life of the surroundings were important complements to the anonymous façades. Using internal columns was rather unusual. Instead, it was structural systems with two-dimensional units that became the common system in family housing. Figuur 8: System Skarne 66, Västra Orminge, Nacka, (Arkitektur 1971/12) Figuur 9: System Skarne 66. Västra Orminge, plan (Byggforskningen 42 1967) State of the Art: Sweden 37 System Bygg-Tema (AB Göteborgsbostäder) belongs to the second category – structural systems with two-dimensional slab and wall units. These systems were dominant. System Bygg- Tema was used for example in Backa Röd, Gothenburg, erected in 1969-71. The frame structure consists of slabs and wall panels, usually less than room-size. The slabs were supported by structural room-dividing walls. The external walls were non-structural. The structural system gave certain possibilities to adapt buildings to different ground conditions and form squares and places. Buildings with right angles were created by putting straight-shaped buildings together. The system could be used in both high and low, in both thin and thick, and in tower buildings. The external walls consisted of sandwich units with surfaces of exposed aggregates. This type of surface became one of the most common of concrete façades of the time. By varying the gavel material referring to colours and sizes colour and general impression of the surface could be varied. Also different kinds of adornment were used, such as low recesses in the surface. Surfaces with exposed aggregates can very closely be experienced diversified, but at some distance almost monotonous. The use of exposed aggregates was therefore very criticized. Figuur 10: System Bygg-Tema. Backa Röd, Gothenburg (Elementbyggda flerfamiljshus, 1969) System Bygg-Tema.Backa Röd, Gothenburg Figuur 11: Plan. Principle of unit assembly. (Elementbyggda flerfamiljshus, 1969 State of the Art: Sweden 38 System Göteborgs Bostads AB belongs to the third category – systems with three-dimensional units (volume units). Originally System Göteborgs Bostads AB was a further developed Danish structural system. For example it was used in Östra Gårdsten, Gothenburg, erected in 1969-70. The structural frame consists of volume units combined with two dimensional room-sized slabs and wall panels. Volume units were delivered completely furnished and enclosed kitchens, bathrooms, washrooms, and installation shafts. They also hold all fittings and cupboards to be placed in the dwelling. The very heavy units were assembled by enormously big mobile cranes demanding totally even, long and straight built-up roads. The ground was reshaped because of the construction method by blasting rocks and filling up hollows with stones, all to one level. The buildings have large depths and the dwellings have deep, narrow rooms and recessed balconies. The volume units contributed to the depths. The structural system is very static and possibilities to make changes are very small. The façades have just a few types of wall panels, all with exposed aggregates. In Östra Gårdsten blocks are characterised by long multi-storey buildings with monotonous façades, in two parallel rows along a one kilometer long and narrow yard. This is architecture expressing repetition and the process of the construction technology – very consciously designed. Figuur 12: System Göteborgs Bostads AB. Östra Gårdsten. Photo and plan. (Elementbyggda flerfamiljshus, 1969) Slab units, more than room-size System S (AB Strängbetong) belonged to these structural systems. It had pre-stressed slabs with a TT-section and was usually supported by transverse dwelling-dividing walls. The system was limited to long building volumes. In the interior there were changing possibilities within the dwellings, which had no structural room-dividing walls. The installations were concentrated to certain walls. Figuur 13: System S. Elevation and Plan. (Elementbyggda flerfamiljshus, 1969) State of the Art: Sweden 39 The stability of these pre-fabricated structural systems was executed by the joints of the units and by the slabs and wall panels themselves. Therefore there is very little possibility to make bigger changes, such as making larger holes in the wall panels or other changes of the plans affecting the structure. 1.4 Housing policy Swedish post-war housing policy was aimed at getting away from the housing shortage and to give all people healthy and convenient dwellings with enough space, at reasonable costs. State subsidies were paid, both on an individual and a general level, much improved since the start in the 1930s. The loans for housing construction were particularly favourable for municipal housing companies, but also for cooperatives. Building codes and regulations gave the frames for technical solutions. Changes in the building laws and codes gave special frames for the period discussed here, 1961-1975. New ways of construction were introduced, with new materials and technology. Many of these changes were gradual, but still some features are very characteristic of different age groups. Concerning housing special national guidelines were edited with some years of interval during the post war period - God bostad (Good Housing). It was needed to follow the guidelines for getting favourable state loans. It did not regulate the technical standards, but the standards of size, space and equipment in the flats and areas. What was new in the 1964 edition was that these factors were still more emphasized than earlier, as well as the design of out-door environments and structure plans. But there were also some new more technical sections about acoustic insulation and climatic and electric installations. In 1975-86 a state subsidy for environmental improvements lead to about half of the residential areas from the period 1961-75 being upgraded. The energy crisis involved new subsidies for thermal insulation in the 70s and 80s, which to a certain extent lead to façades, or just the gables, being insulated, and even more the roofs. For rebuilding it was possible to get state subsidised loans until the beginning of the 90s, when state loans were replaced by other more limited subsidies. In recent years big state investments have been directed to specific issues in housing rehabilitation. In the end of 1990s the Swedish government initiated a Metropolitan project, especially devoted to the most disadvantaged areas from the 60s and 70s in the three biggest cities, Stockholm, Gothenburg and Malmö (Local Development Agreements 1997-). The project aimed at breaking the ethnic and social segregation by raising job opportunities, language skills and democratic participating. The last goal could also include work with the environment. The three municipalities had to co-finance the state subsidies, and in some few cases it was done through modernization and rebuilding of the concerned residential areas (i.e. in Gothenburg), which were raised from a low level of maintenance to be much more attractive. Another extensive state investment in recent years has been directed towards ecological and sustainable improvements (Local Investment Programmes 1998-2003). Municipalities and local actors could apply for financial support for energy efficiency, thrifty water use, recycling of household and building waste or choice of healthy and renewable materials, but also social and educational actions. The projects carried through show a great variety from changing technical systems to rebuilding whole areas. State of the Art: Sweden 40 2 TOPICS: QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK The technical standards of the buildings and the plans and outfits in the flats were generally good. Housing research in Sweden had been going on since the twenties and could now give knowledge for designing well functioning dwellings. Building codes, guidelines and favourable state loans were regulating the design and standards. Flats got good and practical plans and convenient and hygienic facilities. Even today most of them are seen as modern, and the critique that the areas met when they were new did not deal with the dwellings. The problems which early appeared had to do with the out-door environments, and about half of the dwellings have later got upgraded yards and neighbourhoods with state subsidies. Other problems in some areas were, as mentioned, connected with the large scale and monotony in design and function. The fast erection involved that many areas did not get enough social and commercial service. And the untested new methods of industrialization gave sometimes little care to details, joints and processing of materials. Through the years many measures have been taken to upgrade or renovate the buildings and areas. Most common measures beside improvement of the out-door environment has been exchange of water and waste pipes, ventilation, electricity, kitchen interiors and upgrading of façades. Exteriors might also have been changed without being registered in the national modernization statistics. Today, 2006, about 20% of the multifamily housing stock built 1961- 75 have been rebuilt or modernized. 2.1 Physical aspects The thermal insulation was relatively good to start with, but does not full-fill standards today. From 1960 till the end of the 1970s the standards and regulations of thermal transmittance was raised, particular after the energy crisis in the mid 70s. In 1960 the standards of the U-value for walls was set to 0,40 – 1,10, depending on where in Sweden the building was situated (Sweden has about 2000 kilometres from south to north). The U-values for roofs were 0,35-0,50 and for floors 0,35-0,70. In 1977 the U-values were lowered for walls to 0,25 – 0,60, for roofs to 0,17 – 0,60 and for floors to 0,17 – 0,40. The demand for windows in 1960 was that they should have two glass panes, but no U-value was regulated. In 1977 the U-value for windows was set to 2,00-3,00. The windows had originally mostly two glass panes, more seldom three, but many had bad wood quality and were soon exchanged, by then to three panes. In 1980 15-20% of the buildings from the period 1960-1975 were able to get state grants for insulation, and many of these were upgraded. 2.2 Structural aspects Different types of constructions and envelopes have been described under headline 1.3 Description of main technologies. The strength of the building structure is mostly adequate and does not cause problems. A possible weakness in some cases is a sparse dimension, making it hard to rebuild with new openings in walls and floors. More problems might appear when it comes to parts or details of buildings, like façades, balconies or roofs. The bearing parts of the façades are made of wood, concrete or brick. The surface is made of brick, plaster or wood and, particularly in higher houses, of different types of sheets, including sandwich panels. Most flats in multi family houses have a balcony or out door space. The floors in the balconies are made of reinforced concrete; the fronts might be of concrete, metal sheets or wood. The concrete parts might have damages; - if the reinforcement is too close to the surface it rusts and expands the concrete. State of the Art: Sweden 41 Roofs were often flat and built up as wooden structures on the top slab covered with roofing- felt. Many of these have the drainpipes inside the façades, which often have caused damages in the construction. 2.3 Functional aspects As mentioned the standards and functions of the flats built during the “record years” were high. All flats got a bathroom. In four-room and larger flats an additional, separate lavatory was demanded. Even many smaller flats were given this standard. The kitchen got stoves and refrigerators and later also freezers; many were combined with a small laundry. In almost ¾ of the buildings mechanical fans were installed. Lifts were installed when five storeys or higher. Today when the buildings are 30-45 years old much maintenance is needed in the near future. 2.4 Architectural aspects Generally, the architecture can be characterized as “Late Modernism”, reflecting ideals of the Early Modern movement, like rationality, plain forms and lack of decorations, but more heavy and compact than the generally light and elegant early modernism. Even “brutal” features are apparent in some buildings. Many Swedish planners and architects were inspired by internationally famous architectural works and by study tours to Denmark, Germany, England and the US. Some apparent similarities can be pointed out between internationally well-known buildings and Swedish “ordinary housing”. The idea of “the infinite perspective” of Early Modernism can be traced in many multi-family areas, but there is great variation of block forms and patterns. Figuur 14: Residential area in Tranås, clearly influenced by Early Modernism. Some of the common architectural characteristics are: emphasized vertical and horizontal elements such as balconies or continuous rows of big unbarred window, slightly sloping or flat roofs which can barely be seen from the ground, thus giving the buildings a box-like form, lack of decorations, fastidious details, “hard” and machine-made materials like glass, hard-baked brick, concrete, and very plain and slightly glittering plaster. The natural colours of the materials were displayed, if possible. Red or yellow machine-made brick, off-white, greyish or brownish plaster or grey concrete – which, in fact, sometimes was decorated by the casting methods or by exposed aggregates of various colours and textures – were the predominant façade materials. Around 1970 and onwards, strong and bright shades of green, orange, brown, red and blue were used in quite a few areas. Even coloured concrete panels were produced for special projects. State of the Art: Sweden 42 Figuur 15: Many yards were poor to start with. Köping, Nygård (left) Later improvements have been done, e.g. to individualize entrances. Alingsås, Östlyckan (right) The outdoor environment was often poorly treated. In many cases ambitious landscape planning was not fulfilled, due to limited resources, in other cases the industrial building methods destroyed the conditions for a nice environment. The large scale and monotonous design of many new housing areas, without any softening effect of established vegetation and – last but not least – neglected or unfinished common facilities and spaces, led as mentioned to intense criticism shortly after completion. The townscape and the architecture of the buildings reflected ideals such as rationality, plain, rectangular forms, and lack of decorations. The architectural qualities vary widely; there are many areas and blocks worth careful preservation as well as areas calling for visual and social improvements, as well as technical renovation. Rebuilding in accordance with architectural trends The ageing Late Modern housing of Sweden, built in the “record years” of the 1960s and early 1970s, is much discussed these days. Renovation is necessary almost everywhere due to the physical ageing of buildings and areas. In addition, more radical renewal is necessary in several problematic areas all over the country. In Sweden, according to the Planning and Building Law, every building renovation should be carried through with care for existing qualities and with respect to the character of the building. In several areas, vacant dwellings and other problems have led to more or less radical rebuilding efforts ever since the mid-eighties. In “turn-around” projects, as well as in more limited actions, new architectural features have been introduced, often inspired by current architectural trends. Even in the majority of housing areas without special problems, where just ordinary maintenance has been needed, the influence of new fashions is visible in many renovation measures. In the 1980s and the early 1990s “Post-Modernism” was the architectural style in fashion, leaving its mark on many new buildings and housing areas. Symmetry and a play with stylistic features borrowed from classic architecture are characteristics of this period. This had an influence on single buildings as well as area plans, and led to a totally different way of planning compared to the “record years”. Instead of starting “from inside” – the flats and the standards for practical dwelling functions – the new buildings and areas were planned “from outside in”. The varying townscape created by the volumes of the buildings provided the framework for the design of flats and other dwelling facilities. The visual and spatial experience of buildings and areas was given a more dominant role in the design process. These ideas exerted a great influence on rebuilding, too, especially since many of the multi-family areas and blocks were criticized for being too plain, grey and monotonous. The buildings were given new forms with new, conspicuous span or hip roofs, similar to those built in the 1920s, bay windows, and bigger, glazed-in balconies. Architectural motifs such as pediments and different façades on the ground floor, often inspired by old Italian Gothic façades, were added to many slab blocks. State of the Art: Sweden 43 Many of the previously next to invisible entrances, often characterized as “holes in the walls”, were redesigned to be more inviting and high-class. Many variations of free standing porches, temple gables etc. were added to the buildings. A variety of pastel colours were used for façades and balcony fronts. New circular or semicircular windows with false glazing bars were added, and several details just meant as decorations. In the 1990s a “New Modernism” trend started to replace Post-Modernism, and has dominated for some years now. In new construction the volumes of the single buildings are subdivided to make them look more light and elegant. Also, in more and more reconstruction projects the heavy and sometimes “brutal” building volumes of the Late Modernism of the 1960s, and the too plain façades of repetitive blocks, have been given architectural features more like the light and elegant Modernism of the 1930s. Visually light roof and balcony structures are frequently used. The original roofs, not visible from the ground, may be replaced with new ones with conspicuous eaves, as thin as possible. Old dense balcony rails, like ageing concrete or industrially painted aluminium panels, may be replaced by transparent materials like glass, wire netting, and other rails that are light in all respects. Even when balconies are enlarged, designs and colours are chosen to make them look more slender. The rectangular forms may be replaced or modified by softly rounded corners. Off-white or bright, often yellowish colours are used for plaster and other façade materials, window frames etc, but also more saturated yellowish or reddish earth colours like the ones used in the 1920s and 1950s are used. Ornamental details and artistic adornment are added especially to entrances and other spaces where many people pass. Materials which were frequently used in the 1950 – and in the early 1960s – such as mosaic wall and pillar facings or linings, glassed entrance doors with frames of solid oak, and marble or clinker slab floors in common spaces, are frequently used to help to revalue shabby buildings and housing areas. Both the type and the level of rebuilding have shown a great variation in different projects. To summarize the following methods have been used: - Out-door environmental improvements supported by special state subsidies 1976-86 - Maintenance and daily care - the most common way of support - Maintenance with ambitions to change the aesthetics - Improvement and renovation according to residents´ decisions - Turn-around without demolition (when exteriors are changed) - Large-scale turn-around (when building volumes are changed) - Demolition to reduce the number of dwellings and/or change the type of building - Environmental-friendly actions, concerning the buildings as well as the areas - Restoration – a new way to take care of the buildings as part of the cultural heritage Figuur 16: Hjällbo in Gothenburg is today proposed to be listed as an historic area, part of the cultural heritage (Photos: L. Särnbratt) State of the Art: Sweden 44 New townscape ideals Today, when problematic housing areas of the “record years” are discussed, the townscape ideals that characterize the majority of them are often questioned. The intimate small town or the densely populated grid town – far from the modernistic ideas about “houses in a park” – are new ideals. Streets lined with trees, fences and varied façades, where pedestrian and vehicle traffic share the space and create a vivid street scene, are suggested as a model for redesigning housing areas criticized for their desolation, monotony and lack of “human scale”. In practice, significant improvements may be produced in many housing areas by additional buildings, fences, and vegetation. However, a thorough redesign in accordance with the new ideals is inconsistent with fundamental ideas and qualities of the areas, such as spacious and sun-lit yards and surroundings, traffic separation and safety, and carefully planned pedestrian systems connecting the blocks of flats with schools, local centres and other local facilities. REFERENCES Andersson, Göran (1967) “Elementbyggda flerfamiljshus”, Arkitektur 1967/6. Bostads- och byggnadsstatistisk årsbok (2004) Statistiska centralbyrån (Statistics Sweden 2004) Botta, Marina, (2005) Towards sustainable renovation. Three renovation projects. Diss Royal Institute of Technology, School of Architecture Boverket (2003) Bättre koll på underhåll Boverket (2003) Flerbostadshusens förnyelse – behov och förutsättningar 2002/03 Boverket (2005) Förnyelse för hållbar utveckling i olika boendemiljöer Curman, Jöran (1966) “Orminge i Boo kommun, Stor-Stockholm”, Arkitektur 1966/8 Elementbyggda flerfamiljshus (1969) Chalmers tekniska högskola. Göteborg Gillberg, Ulf (1971) “Planeringen – så gick det till”, Arkitektur 1971/12 God Bostad idag och i morgon (1964) Kungliga Bostadsstyrelsen Hall, Thomas & Vidén, Sonja (2005) ”The Million Homes Programme: a review of the great Swedish planning project”. In Planning Perspectives 20 (July 2005) pp301-328 Handboken Bygg, volume V (1962) Hjertén, Inge (1969) Elementa. Göteborgsbostäders skriftserie nr 12. ”Inventering av stomsystem för elementbyggda flerfamiljshus” Byggforskningen, nr 42, 1967. Schulz, S. & Jivén, G. & Malmqvist, I. & Stenberg, J. & Särnbratt L. 2004. Arkitektur betyder (Architecture matters). City of Gothenburg. Stenberg, Jenny & Liane Thuvander (2005) Att länka miljöeffekter och sociala effekter: Utvärdering av LIP-finansierade bostadsförnyelseprojekt (Linking Environmental and Social Effects: Evaluation of Housing Regeneration Projects) Stockholm, Naturvårdsverket Särnbratt, Lotta (2006) Perspektiv på miljonprogrammet. Arkitektur, kulturhistoria och miljöanpassning som delar av hållbar utveckling (Perspectives on Million Homes Programme. Aspects of architectural, cultural and environmental values). Lic. Chalmers University of Technology, School of Architecture Turkington, R. & van Kempen, R & Wassenberg (eds) (2004) High-rise housing in Europe Vi bygger i Göteborg (1968) En berättelse om Göteborgs Stads Bostads AB. Göteborg. Vidén, Sonja (1999) ”Rekordårens bostadsbyggande” & ”Vård och förändring av hus och utemiljöer” in Rekordåren, en epok i svenskt bostadsbyggande Boverket Vidén, Sonja (2004) ”Architectural Ideals in Rebuilding and Rehabilitation of Modern Housing”. Paper for the DOCOMOMO Conference in New York, USA, October 2004 Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW OF THE HOUSING STOCK Status January 2000: The land area was 43.000 km 2 , of which roughly 65% was used for agri- culture and around 15% for towns and infrastructures, the rest was “nature”. Population was 5.300.000. Employees in the building sector were 120.000, of which 30% in new building, 40% in maintenance/renovation and the rest in construction works. The total floor (gross-) area of the building stock was 655 km 2 , of which 350 km 2 was housing and the rest - 305 km 2 – non-housing (factories, offices, schools, institutions etc.). The average floor space in dwellings pr. person was thus around 65 m 2 . Of the housing stock was 95 km 2 in multi storey apartment buildings – the rest being all other buildings for living: one-family houses, terrace houses, summer houses (fit for living all year) etc. The total number of dwellings/apartments was 2.500.000, of which more than 90% was furnished with toilet, bath and central heating. Less than 10% was lacking one or more of these facilities. The average size of a dwellings/apartment was 140 m 2 , and the average number of persons pr. Dwelling/household was just beyond 2. The number of apartments in multi-storey buildings was 975.000, of which close to 90% were furnished with toilet, bath and central heating – so a little more than 10% are lacking one or more of these facilities. The average size of apartments in multi-storey buildings was up around 95 m 2 , and the average number of persons pr. apartment/household was less than but close to 2. 1.2 Data related to building periods During World War 2 the annual output of newly built dwellings was in average up around 15.000. Compared to the situation in the period before the war, it was around 5.000 less, and as Denmark was not directly involved in combat actions during the war, practically none of the ex- isting dwellings were harmed. Therefore, the post war situation in Denmark was far from as grave as in the majority of European countries. But the growing welfare, starting slowly already in the second part of the 1930’s and just delayed because of the war and the first years after, called for more and bigger dwellings/apartments. State of the Art: Denmark Jesper Engelmark BYG.DTU, Dept. of Civil Engineering, DTU, Technical University of Denmark Torben Dahl & Ebbe Melgaard The Royal Danish Academy of Fine Arts, School of Architecture ABSTRACT: The part of the Danish housing stock built after World War 2 being apartments in multi-storey buildings accounts for around 20% of the total stock of dwellings. In general this part of the building stock is of a reasonable standard of to day both functional and technical, as major renovation and repair have been executed over the last decades. Future problems are therefore of a nature described as projecting (heavy) trends of to day: a much wider demand for apartments being very different by size, by lay out and by possibility for individual equipment – of cause in respect of a future with over all demands to sustainability and also a quite different composition of the labour market. State of the Art: Denmark 46 So, in the end of the 1940’s, during the 1950’s and the first half of the 1960’s the annual output of newly built dwellings was in average up around 25.000 and increasing during the period ending up with an output of 30.000 units a year in the mid –60’s. In these 20 years there was also a change in the composition of the housing stock. The one-family house began to be reasonable in price for a steady growing part of the population, and in the mid –60’s the majority of the new build dwellings were one-family houses. This situation is still the same. The decade 1965-75 gave the biggest rise in new build dwellings ever seen in Denmark. The annual output was in average 45.000 newly built dwellings with a peak production of 55.000 (1973) and the lowest 40.000 (1966). This was a result partly of the growth in material welfare and partly because the war situation gave a significant rise in population, which at this time had the resulting effect in needs of dwellings. From 1975 to 1990 the annual production was in average up around 30.000 units, but with bigger alternations ranging from a peak production of 40.000 (1976) to 20.000 (1982). The last 10 years of the century the production of newly built dwellings has been just about 15.000 units in average a year – nearly the same number as under the war, but now with a popu- lation being 1.500.000 bigger. Figure 1 (left). Typical façade and lay-out of apartments in buildings with transverse load bearing walls, as they were built from the start of the 1960’s and to present days (ref. Bertelsen, 1997). Figure 2 (right). Façade and lay-out of apartment in buildings with load bearing façades and spine wall, as a minor part of the building stock from the 1970’s and on were built (ref. KBI, 1973). The total number of dwellings built from 1940 to present days is just about 1.600.000, and of these are 550.000 apartments in multi-storey buildings. Almost all of these dwellings were originally equipped with toilet, bath and central heating – just a small percentage of them missing bath and only in the part built before 1950. The majority of the apartments in multi- storey buildings – around 85% - are rented, the rest is owned individually by the tenants. The State of the Art: Denmark 47 rented part is predominantly social/corporate housing and a minor part owned by private companies and by public ones – communes or the state. The 550.000 apartments in multi storey buildings focused on are roughly subdivided by their time of erection: 1940-49: 80.000, 1950- 59: 100.000, 1960-69: 140.000, 1970-79: 120.000, 1980-89: 55.000 and 1990-99: 55.000. 1.2 Description of main typologies The typical lay out of apartment blocks in Danish multi-storey buildings has not changed radically over the last hundred years: The basic unit being preferably 2 apartments pr. storey – till the 1930’s served by 2 staircases made of wood, and after by only one made of concrete. The smallest of the apartments being just a kitchen and 2 rooms. Additions of more rooms to this core gave the bigger ones. The number of storeys was up to 6, but in general 5. The appearance of toilet and bath in the apartments in the beginning of the 20 th century did not affect this lay out in any significant way. (Fig-1-2) From this basic lay out the blocks were composed in size according to the client and the actual building site. After the breakthrough of functionalism in the 1930’s the blocks were preferably arranged parallel in the direction north-south and with equal distance in between to give not only all apartments the same amount of sunlight and fresh air, but also the rooms with same functions these same features. The introduction of lifts in multi-storey housing was until the 1950’s reserved for a limited part built to satisfy tenants being able to pay for this extra. But with the upcoming of buildings with more storeys and/or more apartments pr. storey served by a lift, the installation of lifts became economically possible for a broader part of tenants. So new lay outs of apartments/blocks came up in the 1950’s and on: a core or access balcony giving access to more than 2 apartment’s pr. storey was introduced. Still the standard did not normally include lift unless a building had at least 6 storeys and 3 apartment’s pr. storey. Now a days the building code demand access by lift if a building is higher than 2 storeys, and without regard to the number of apartments. Balconies in Danish housing were not introduced more generally until the 1930’s. This was caused partly as a result of the upcoming functionalism and partly as a precondition for substituting the two staircases of wood with only one of concrete – and in that case the demand was related to rescue in case of fire (even though the staircase should be made of concrete). To sum up: The lay out of apartments in Danish multi storey housing – generally speaking – has not changed radically over the period focused on. But there has been a general tendency to wards bigger and better equipped units – better in the meaning of standard and quantity of installations and floor area. The major changes are to be found in the location, the composition and the design of the housing estates. 1.3 Description of main technologies Building in Denmark in the case of housing, is in general described as being “traditional” up to the middle of the 20 th century, and hereby meaning: the predominant use of the two structural elements/materials: wood- and brickwork, and also including that the majority of the work was concentrated to the actual building site. In Fact, just the fabrication of bricks, the rough shaping of structural wood, the finer shaping of additional wooden parts like flooring and some additional work-shop jobs as the production of windows, doors etc. were not related to the building site (Fig. 3). Even if there were attempts in the 1920’s and –30’s to use new or different ways in building, the situation did not really change until the 1950’s. The part of the housing built in the 1950’s and not being “traditional” built, is characterized by numerous experiments using new techniques and materials different from the former. This “untraditional” build part of the housing stock could be described as “semi-industrialized” – State of the Art: Denmark 48 meaning in general a mixture of the older techniques with some kind of labour-saving elements. The big change came in the 1960’s. Almost all multi storey buildings were then made from concrete, factory made load bearing and bracing elements, vertical as well as horizontal, just assembled by crane at the site and usually on foundations/basement cast in situ (Fig.5). Figure 3. The traditional floor construction (left) having wooden beams spanning from facade to facade, supported on the spine wall, was later partly supplemented with iron beams (centre) for the reason of im- plementation of balconies and waterproof bathroom floors. As an example of one of the many new floor constructions coming up in the pre- and post war period, is shown a so called “hulstens dæk” (right) con- sisting of minor hollow elements made of tile or concrete, reinforced and topped with concrete (ref. Kjærgaard, 1948). Figure 4 (left). The almost overall used building system: “The Jespersen System” with load bearing trans- verse walls. The standardization of joints (Fig. 6-9) and modular based sizes of components (Fig. 10 –11) was accepted as the base common used in lay-out, planning and fabrication of apartment buildings from the 1960’s and on – only leaving a smaller part of the final design to the individual projects. The system as shown is with a light weight wooden facade construction, but the facade might as well be concrete sandwich elements (ref. Munch-Petersen, 1982). Figure 5 (right). The erection of one of the first big housing estates (Ballerup planen), where the com- pleted “Jespersen System” was used for the first time. The elements are all of a very limited size com- pared to the situation later on (ref. Nissen, 1973). Two ways of construction were dominant. One was a system with load bearing transverse walls and non-bearing (preferably) light weight façade elements (Fig. 1, 4 and 6-9). The other was a system with load-bearing facades of sandwich type and spine wall (Fig. 4). The first system is State of the Art: Denmark 49 far the most common. Other systems based on the use of columns, beams, frames etc. are very seldom. Whatever load-bearing system is used in these buildings, the top floor is always like the rest: concrete slabs. On top of this the roof is established, either as flat or hipped, but in general as a wooden construction. In the first case covered with asphalt felt on boards, and in the second covered with panes of tiles or cement. Figure 6 (left). Vertical section: joint of transverse bearing wall and slab. Figure 7 (right). Horizontal section: joint of transverse bearing wall and light weight facade element. (Figures ref. Nissen, 1972). Internal walls are in general made from light weight concrete elements having room height, and a size not bigger than to allow later furnishing with a minimum of manpower. All other finishing elements were prefabricated as much as possible and to the extent, where only fitting at the site is necessary. Figure 8 (left). Vertical section: joint of bearing (gable) sandwich element and slab. Figure 9 (right). Ver- tical section: joint of light weight facade element and slab. In the 1960’s double glass in windows were still obtained by single panes in coupled frames, as shown. And the demands to heat insulation in opaque parts of facades were much less than to days, accordingly the facade element is shown only with 70 mm of mineral wool – to day it would have been at least 200 mm. (figures ref. Nissen, 1972). State of the Art: Denmark 50 In general the buildings from the decades after just followed the standard set out in the 1960’s. But now – as a reaction to the results of the former and trying not to look “prefabricated” – of- ten half-bricked facades were chosen as the finishing layer instead of concrete or cement based siding. Also some of the internal works returned to partly be done at site for the same reason. Figure 10 (left). Since the start of the 1960’s government supported housing should be designed accord- ing to a modular grid of 3M (300 mm) horizontal and 2M (200 mm) vertical, to enable the upcoming of an industry of building elements independent of the single project. Figure 11 (right). Almost all components in the industrialized housing in Denmark build since the 1960’s are modular standardized (Both figures ref. Nissen, 1972). 1.3 Housing policy Despite Denmark’s special situation in World War 2, there was a shortage of dwellings in the post war period. This was partly due to the war situation with less civil building activity, and partly due to the start of growth in welfare that had characterized the late 1930’s, now giving the reason for peoples wish for better future accommodation. This situation did not improve in the first years after the war, and in the 1950’s it was realized that the big number of new-born from the wartime would show up with an additional bigger claim for dwellings. It was rather soon realized that the present way of building would not be able to produce the foreseeable claim for dwellings: the number of skilled workers would quite simple be too small to do the job. So the 1950’s were the decade of testing different ways to overcome this situation. The part of buildings from this period not being “traditional” built are characterized by numerous experiments using new techniques and materials different from earlier, and all having as a goal to reduce skilled workers participation as well as reducing the manpower at site to a minimum, as described ahead. At the end of the 1950’s the scene was set for the radical change in building. It consisted of 3 major parts. First of all: a uniform building code for the country as a whole and with demands related to properties of constructions and not – as it was earlier – related to fixed examples. Second: as a precondition for subsidy given by the state, housing should be designed according to principles of modularity in building production and reduction of skilled workers participation – both as means to enable the shift to industrialization. And third: the state offered a first guarantee of financing 6.000 apartments to secure the trades interest in the project. State of the Art: Denmark 51 The result was as asked for. The shift was done over night - so to speak – in the early 1960’s. And the way of building in Denmark has not changed in any significant way since then. Over the years the Danish State has been more or less involved in subsidizing the building trade and especially the housing sector. Two major interventions are noticeable: The improving of en- ergy efficiency in the build environment caused by the “oil crisis” starting in the early 1970’s and rapidly accelerating in the years after, and the renovation/modernization of the older part of the housing stock. The last started in the late 1950’s as pure “slum clearance”, but have over the years turned into a very high degree of preservation combined with upgrading of not only the buildings, but also the estates. Finally it should be noticed that the building sector as almost only national orientated always has been used as a regulator of the national economy. This has often been critiqued from the sector it self, but with no effect – of cause. 2 TOPICS: QUALITY OF THE POST-WAR MULTI-FAMILY HOUSING STOCK The post-war buildings have over the years been maintained, renovated and updated in different ways according to age, technical performance, ownership etc. The following will therefore be descriptions of the original standard, followed up by the present, if significant changes have oc- curred. As earlier mentioned building in Denmark was from the very start of the 1960’s regulated by a common building code. This code was different from the former ones - being as many as the number of communes – by expressing demands in terms of performance of building parts and materials in stead of descriptions of fixed constructions/materials. Anyhow the new demands were based on the minimum performances of the earlier prescribed, so to a start the new building code did not give reasons to a complete delete of the traditional way of building, but made it easier to introduce new materials, constructions and methods. This first code from 1961 was revised in 1966, 1972, 1977, 1982 and 1995. The latest revision is foreseen to be in force late in 2006. Over the years the demands have all been sharpened – and especially the oil crisis as well as the growing awareness of the limited energy recourses have set their marks, not only when the code was revised as a whole, but also as running revisions. In the following only main aspects of the different topics will be mentioned. 2.1 Physical aspects Thermal insulation: As late as 1 st of April 2006 the chapter in the code of 1995 on thermal insulation was renamed “energy consumption”, and by this a new attitude was fulfilled. Hereafter the demands are based only on a calculation on the total energy use for heating, cooling, ventilation and hot domestic water in a building and based on the supply for this from none renewal resources; but taking in account alternative supply of energy e.g. from the sun directly. As an alternative to the traditional way of handling thermal insulation, this had all ready been introduced as a possibility in the code of 1995 as originally issued. This so-called energy-frame for domestic buildings is in the revised chapter in the 1995 code defined as: (70 + 2.200/A) kWh per m2 a year, where A is the heated area of the building. Accompanying this overall demand the dimensioning transmission loss for buildings must not exceed 6 W respectively 8 W per m2 of the envelope exclusive windows and doors for buildings up to 3 storeys high respectively higher. Also demands to a minimum U-value of the different State of the Art: Denmark 52 building parts are still in force, as described below. But as the overall demands are supposed to effectively reduce energy consumption in buildings, the demands to the single building part is rather relaxed compared to the earlier. According to the building code of 1961 external walls should satisfy U-values ranging from a minimum of 0,6 to 1.3 W/m2C determined by the choice of construction. The lowest value be- ing the demand to a light-weight construction (defined as types with a weight less than 100 kg/m 2 ). The highest value was the demand to a heavy one (e.g. a massive brick-built wall with a thickness of 48 cm). Other values in between these were fixed to likewise heavy constructions of different materials/thickness. According to the building code of 1995, as it was issued originally, the same demands were 0,2 respectively 0,3 W/m 2 C, the lowest value as defined above and the highest to walls with a weight of 100 kg/m 2 or more. The latest revision describes a minimum U-value of 0,4 W/m 2 C. Windows and glazed walls should according to the code of 1961 be “2 panes of glass with a minimum distance of 12 mm” – equivalent to a U-value of 2,9 W/m 2 C. The original issued code of 1995 prescribed 1,8 W/m 2 C. The latest revision describes 2,3 W/m 2 C, which after 1 st of Janu- ary 2008 should be 2,0 W/m 2 C. The building code of 1961 demanded a minimum U-value of 0.5 W/m 2 C for floors over base- ments, solid ground floors and roofs. The same demands in the code of 1995, as it was issued originally, were 0,2 W/m 2 C. The latest revision describes 0,3 W/m 2 C for floors over basements and solid ground floors, and for roofs 0,25 W/m 2 C. The housing stock built before the appearance of the common code of 1961 has originally less U-values than stated here. Far the majority of the buildings were build with massive facades of brickwork or alike heavy materials. Windows were at the most of the type with 2 panes in coupled frames, but often just single paned. Floors and roofs were merely insulated at all. All of these buildings have undergone some kind of updating in thermal insulation over the years, partly in combination with (regular) maintenance and/or partly as a result of the oil crisis. This is also in general the situation for the oldest part of the buildings being build according to the code of 1961. Moisture: With a climate like the Danish and with a temperature in winter popping up and down around zero degree, the construction of envelopes has always had to be in accordance with this situa- tion. So problems with moisture mostly occur as a result of either bad work in the actual case or by using new and not yet proved constructions – of cause also the combination of the two. An example of this was a wide spread use of flat roofs in the 1960’s and –70’s; now a days in general solved by replacing the old with new ones. The buildings from the period where brick-built external walls were used, have not offered bigger problems than known for centuries and coped with accordingly. The 1950’s with all the experiments in alternative constructions and methods of building gave lessons in how to cope with other kinds of envelopes, but no definite solutions. From the 1960’s and forwards there has been a focus on the construction of envelopes securing that internal produced moisture should not give reasons for accumulation in the construction, and that external water was appropriate rejected. State of the Art: Denmark 53 Sound insulation: According to the building code of 1961 horizontal airborne-sound insulation in between apartments should be at least 50 dB and vertical at least 52 dB, also including impact-sound insulation. These values would be obtained with e.g. a massive brick-build wall with a thickness of 23 cm – a normal thickness of a wall also fulfilling demands to fire safety. Respectively a floor construction of concrete with a mass of 2400 kg/m3 – either as 12 cm massive concrete cast in situ or as 18 cm of hollow prefabricated concrete slabs, in both cases topped with a raised wooden floor on battens supported on soft material. The building code of 1977 sharpened the demands to 52 dB horizontal and 53 dB vertical. In this code the demands to impact-sound insulation were redefined as demands to the impact- sound level in the apartments. The demand was set as a maximum of 63 dB – in practice to be obtained with the same kind of constructions as the ones giving an airborne-sound insulation vertical of the required 53 dB. Nowadays the demands to airborne-sound insulation are still the same, but the demand to impact-sound level insulation is a maximum of 58 dB. Demands to sound insulation of doors to the apartments from the staircase was in the building code of 1961 30 dB, in the code of 1982 sharpened to 32 dB, and this is still the valid value. In the building code of 1966 demands were introduced to the reverberation time in staircases and shared passages to be of a maximum of 1.5 respectively 1.0 seconds. These demands were sharpened to 1,3 seconds; respectively 0,9 – and these demands are still in force. Of a special interest in connection with the envelope are the demands from the 1982 code and later. It was here stated that, “Buildings adjacent to roads and railways with a traffic intensity causing a noise level in excess of 55 dB near the individual building, airborne-sound insulation shall be provided against outdoor noise in order that the indoor noise level does not exceed 30 dB in habitable rooms”. Buildings from before 1961 do in general not live up to the demands in the code from this year. The partition walls between apartments and the wooden floor constructions widely used in the traditional build part of the housing stock have less capacity in airborne-sound insulation as well as in impact-sound insulation. Only demands to reverberation time will as a rule were fulfilled, when stairs are of wooden construction. The experimental part of the building stock from the 1950’s does in general suffer likewise. 2.2 Structural aspects There have not been serious problems registered in the structural part (the load bearing and bracing system) of the actual building stock as a whole. The very few accidents of collapse have all been class with bad work either in execution or in the design process. A special problem is cantilevered balconies in the older part, as they often show needs of repair, but in general just because of a limited and not recognized service life for this kind of constructions. Problems are in general related to the building stock from the 1960’s and –70’s and concentrated to the durability of the finishing parts like light weight facade elements, the exterior layer of heavy bearing as well as non-bearing concrete facades and flat roofs. Reasons for this are as a rule related to the introduction of new materials and techniques, which were taken in widespread use without being adequately tested, and also as a result of an State of the Art: Denmark 54 accelerated tempo in the building process in these years. And in the end the large-scale production of cause multiplied the number of faults. Intensive maintenance work were required far sooner than anticipated, but then often combined with upgrading of the thermal insulation, and therefore these buildings are to a big number living up to present days technical standard. In the older part the wish for a better standard of thermal insulation is obtained first of all by replacing windows and by the application of inside extra insulation in order to avoid changing the exterior appearance of the buildings. Secondly by glazing balconies and in this case often in combination with major repair. 2.3 Functional aspects Comparing a contemporary apartment with one being built half a century earlier will always come out in the favor of the newer – at least in terms of number and standard of installations. The lay out, the number and size of rooms in a given apartment is of cause very dependant on the person(s) living there. Of cause one can point out such things as absence of lift or balconies as functional lacks in a building, but often really of minor influence, as long as the choice of apartment is free. Also the surroundings play a major role in people’s acceptance or not of a given apartment. It is an ever on going experience that the existing parts of towns original being developed and inhabited by a certain category of society change over the years – mostly by being “upgraded” by new inhabitants and often even if a period with the opposite situation has taken place. Prob- lems related to these issues will be discussed below. 2.4 Architectural aspects It is well known that a building dating from the parents generation very often is not aesthetically acceptable to people, but it is as soon as it dates back to the generation before. The same can be experienced in our choice of nearly all the goods we surround us with. Apparently there is some kind of security in aesthetics connected to the past. The housing stock from the period just after the war has just begun to be if not desired, then acceptable. The pre-war housing has been for some time, and the even older part has been a primary choice (when refurbished) in the last decades. It is different with the buildings from the 1960’s and –70’s. They are not popular. The exterior appearance of the buildings is as a rule of a very limited variation in form as well as in color. The “prefabrication-look” does not appeal to people in general. The predominant lay out of the estates underlines this, as they reflect all too often the tracks of the cranes lining up the blocks in the building process. The part of the housing stock build in the decades after tried to avoid this image, by breaking up the fixed uniform rhythm, by in-situ bricked facades or just by using paint in a many-colored way. But behind the surface of the facades the buildings are not just alike, but also like the former ones. The lay out of the estates does not show any significant change from the earlier, but because the size of them in general are much smaller, they do not offer the same endless look. CONCLUSIONS Problems with the post-war housing stock could be described as technical and as social, as todays and as tomorrows – and as the combination of these. Today’s problems will more or less State of the Art: Denmark 55 be the ones, which are recognized as problems and taken care of – or last least measures taken to handle them. Most of these problems are of a technical nature. Tomorrows problems should be seen as possible ones if society is still moving along the path laid out decades ago. There have not yet been serious problems with the services: water, heating and electrical installations are still rather new. Although problems by age can be expected to turn up in the near future for the older part, there is no prospect at present that the appearance of requirements of this sort will be additional driving force to the coming refurbishment. The same goes for the lay out of the apartments Types and sizes of apartments – especially in the part build after 1960 – have not been questioned since they were build. Apparently there has been overall satisfaction with their size, their design and level of equipment – at least by the present tenants. This has probably been strong supported by a belief that these buildings are fixed in their original form once and for ever, determined by their bearing structure and also their access conditions. Almost from the very start in the 1960’s the new estates were nick-named concrete slums, but without any true explanation to why. Anyhow, there are several reasons for this negative image. One was their location: “outside town”, “on bare soil” etc. Another was their size: often as big as a traditional borough with around 8.000 inhabitants. A third reason was the absence of everything except for a shopping center and then dwellings all of about same standard and size. And on top of these: the all too often uniform composition of tenants socially and economically and – in the last decades – also by nativity. Finally there was (is) a sheer monotony of the buildings. May be this is not directly a social problem, but it is supporting the total. The social problems have only been taken serious in the last decades. Even if handling problems of this kind with still growing efforts and with a great variety of initiatives, there have not been very many attempts to seriously incorporating a “rebuilding” of the buildings and the estates as factors that might be of importance. Future social problems in these estates could be avoided by a much more varied composition of their population, what concerns e.g. age, education, family conditions, economical ability and nativity. A restructuring of these estates incorporating other functions than just “living” and a much more varied supply of apartments as regards size, lay out and standard in general will incorporate not just new building, but also rebuilding of the existing buildings. In doing so the existing ones should be looked upon as being “3-dimensional building sites”, and limitations in their use as such should only be of a structural nature. This means that all kinds of interior rebuilding as well as exterior extensions could be of interest in this process and regardless of present day’s concept of architecture. In this connection it is necessary to realize and accept that the building sector of to morrow will be quite different from to day. If the change of society will continue as it has done in the former century, (almost) all kinds of production will be industrialized. Also new building as well as maintenance and modernization of buildings will of cause have to follow up. Methods of yesterday including a major contribution of skilled workers will be history and reserved only for memorials. And as the future quite simple calls for a sustainable way of living, it is of cause a must that not only the coming new buildings, but also the existing being rebuild, should be of a construction in accordance to a “0-ressource-use” design. In this aspect there are good reasons for preparing alternatives to our fixed ways of judging aesthetics – our attitude towards architecture. The coming generations have to accept, that building and the concept of architecture as known, from now will never be as it used to be. State of the Art: Denmark 56 REFERENCES Bertelsen, S. 1997. Bellahøj, Ballerup, Brøndby Strand – 25 år der industrialiserede byggeriet. Hørsholm Statens Byggeforskningsinstitut (SBI). Danmarks Statistik 2001. Statistisk Årbog 2001. København. Danmarks Statistik. Engelmark, J. 1983. Københavnsk Etaboligbyggeri 1850-1900. Hørsholm. Statens Byggeforskningsinstitut (SBI). Engelmark, J. 2003. The Existing Buildings in the Future. Bruxelles. Proceedings of the International Seminar, Lisbon 19 and 20 April 2002: Improvement of Buildings Structural Quality by new Techniques, COST Action C-12. Pp. 195-205. KBI, 1973. Typeetagehuse. København. (Company brochure). Koch, S. 1981. IFH-rapport 150: Arkitektens rolle i byggeteknologiens udvikling efter den anden Verdenskrig. Lyngby. Instituttet for Husbygning (IFH), Danmarks Tekniske Universitet (DTU). Kjærgaard, P. (ed.) 1948. Byggebogen. København. Arnold Busck Forlag. Langberg, H & Langkilde, H.E. 1942. Dansk byggesæt omkring 1792 og 1942. København. Arnold Busck Forlag. Munch-Petersen, J.F. 1982. Dæk- og vægelementer (lecture notes). Lyngby. Danmarks Tekniske Universitet (DTU). Nissen, H. 1972. Industrialized Building and Modular Design. London. Cement and Concrete Association. Rasmussen, Aa.D. & Vedel Petersen, F. 1956. Nyere etageboligplaner. København. Statens Byggeforskningsinstitut (SBI). Skaarup & Jespersen. 1987. Ældre etage-ejendomme. København. Boligstyrelsen. Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. INTRODUCTION The data described below is an aggregation of statistical data from the German federal office for Statistics and from other public authorities in Germany. 1 OVERVIEW OF THE HOUSING STOCK 1.1 Data related to building periods Figure 1: Licensed and completed buildings in West Germany from 1960 to 2002 The number of licensed and completed buildings, as shown in the figure above for the western states of Germany remained quite constant after the Second World War until around 1965 with the completion of around 500.000 to 600.000 residential units per year. Until 1972 an increasing number of residential units were completed with 769.000 residential units in 1972. After that building-boom the need for new residential units was satisfied, so the total amount of licensed and completed buildings was decreasing steadily down to 208.600 residential units in State of the Art: Germany Yosrea Frech Calcon Holding GmbH, Munich, Franz.G. Hofmann retired from the German Ministry for transport, housing and town planning Frank U. Vogdt Institut für Erhaltung und Modernisiering Von Bauwerken (IEMB), Berlin Christian Wetzel Calcon Deutchland AG, Munich State of the Art: Germany 58 1988. After 1988 a new increase of the licensed a completed buildings came until 1994 with 400.400 residential units. Since that time fewer and fewer buildings were completed, with the result, that in 2002 only 240.600 buildings were completed. Table 1: Completed dwellings and social housing In the former German Democratic Republic fewer residential units have been built compared to the Federal Republic of Germany. In the early 50'ies only 30.000 residential units have been completed annually rising to 92.000 residential units in 1961. During the 1960ies the building activity decreased down to 70.000 residential units. It was in 1974 when for the first time in Eastern Germany more than 100.000 residential units have been completed. This amount was held for many forthcoming years. When the building activity of prefabricated concrete slab buildings decreased in the late 80'ies the amount of completed buildings decreased to 62.500 residential units in 1990. After the re-unification of Germany the building activity increased again. 1994 67.700 residential units, 1995 104.200 residential units, 1996 143.400 residential units were completed and 1997 with 177.800 residential units the production peak was reached. Already in 1998 this value decreased down to 128.400. In 2000 only 86.300 residential units, 2001 58.300 and in 2002 only 49.000 homes were completed. The number of completed build- ings depended on several influencing factors. First of all the demand for new residential units depended on the need for living space after World War II. On the one hand many residential units especially in the western part and in the major cities were destroyed through heavy bomb- ing, on the other hand refugees from the eastern parts of Germany, now Poland, Czech Republic and Russia were in need for homes. In the forthcoming years after the basic need for homes was satisfied, the development depended on other influencing factors like financial support from the state, interest rates and economical prosperity of the regions and the overall prosperity of the State of the Art: Germany 59 state. While heavy industry dominated the first years after World War II especially in the Ruhr area, later service based industries in other parts of Germany became the main employers for the people with according need for residential units. Besides some rural areas were loosing inhabi- tants due to fluctuation to other more prosperous parts of the country. In consequence the high- est vacancy rates today are observed in parts of the country with former heavy industry and where only little service industry exists. E.g. vacancy rates in the heavy industry region in East- ern Germany (Leipzig / Bitterfeld / Halle) are in most cases over 10 %. Even worse is the situa- tion in the North-Eastern State of Germany (Mecklenburg-Vorpommern) neighbouring Poland and the Baltic Sea. There it is planned to demolish in the next years 30.000 apartments to over- come the problem of deserted living quarters. Evolution of the building cost In 1960 the average cost for erecting 1 m² of residential unit was 197 €. 1970 it cost 355 €, while in 2000 it was 1.254 € as shown in the table below: Table 2: costs of new residential buildings in € Age of the housing stock in Germany 27.9% of the residential units in Germany date before 1948, 61% have been built between 1949 and 1990. In Eastern Germany the percentage of buildings erected before 1948 is at 42,6%. The reason why the amount of old residential units in Eastern Germany is higher can also be ex- plained by the political system, where free entrepreneurship was suppressed and the total dam- age due to bombing in World War II was also lower. As described in the chapter above, after the reunification in 1989 the construction activity raised over 200%. State of the Art: Germany 60 Table 3: Dwellings in residential buildings 2002 according to year of construction Ownership The ownership status of German housing units is structured as follows: 20 Million of the 35,1 Million housing units are used by tenants, 15 Million are used by the owners themselves. The number of own used housing units is increasing. Evaluations performed within the European project INVESTIMMO showed a dependency of maintenance cycles depending on the owner- ship structure of the building. Multi-family buildings with a high percentage of owners that use the apartment on their own show longer refurbishment cycles for the staircase and other com- mon areas, as these areas are better maintained by the owners. On the other hand in some cases also longer refurbishment cycles of the exterior parts of the building were found, meaning that the owners accept a higher degradation state before investing into a refurbishment action. Gen- erally there are completely different actions and refurbishment cycles for single and multi- family buildings. 1.2 Description of main typologies 54.4% of the residential units in Germany can be found in multi-family-buildings whereas 45.6% residential units are based in single-family and two-family-houses. If we distinct between Western and Eastern Germany, we can see, that in the West the ratio between multi-family and single-family/two-family-houses is nearly equal (13.8 million dwellings in multi-family- buildings to 13.2 million dwellings in single-family/two-family-buildings). In Eastern Germany the ratio is different: More than 2/3 of all dwellings are situated in multi-family buildings (most of them in prefabricated concrete slab buildings). Taking a look at the age-structure of the build- ing stock in Germany the following statistical data have been found: around 20% of the residen- tial units date from 1918 or earlier, 13% were built between the World Wars, almost 40% were built between 1948-1970, while 30% date between 1971 and 1990. Looking at the building pro- duction in the years after 1990 the following data was found: While 1993 the major effort was the erection of multi-family-houses (57%) and only 29% single-family-houses and 14% two- family-houses were built, this ratio changed over the following years with an increasing number of single-family-houses (54%) a steady number of two-family-houses and a decreasing number of multi-family-houses (31%). Table 4: completed buildings in Germany (residential building) in % State of the Art: Germany 61 1.3 Description of main technologies Apart from a regionally varying share of timber-frame construction in the housing stock con- structed until 1918, multi-family housing construction was dominated by brickwork construc- tions, especially in the western federal states. In the course of reconstruction after World War II, industrial housing construction was introduced especially in the former GDR and increasingly replaced conventional construction methods. The stock of industrially constructed residential buildings in the old and the new federal states differs pronouncedly. While merely 3.3% of the residential units were built with prefabricated construction units in the old federal states in 1995 (e.g. large slab construction), this share amounted to 31% of the residential units in the new fed- eral states. The following chapters show the main housing systems in West Germany and in East Germany including information about the total living area of this type and the average heating-energy demand. State of the Art: Germany 62 1.3.1 West Germany SMALL MULTI-FAMILY HOUSES Year of construction: 1958-1968 Living area: 170 Mio. m² Heating energy demand: 173 kWh/(m²a) Year of construction: 1969-1978 Living area: 127 Mio. m² Heating energy demand: 127 kWh/(m²a) Year of construction: 1979-1983 Living area: 54 Mio. m² Heating energy demand: 98 kWh/(m²a) Year of construction: 1984-1990 Living area: 49 Mio. m² Heating energy demand: 76 kWh/(m²a) BIG MULTI-FAMILY HOUSES Year of construction: 1919-1948 Living area: 12 Mio. m² Heating energy demand: 164 kWh/(m²a) Year of construction: 1949-1957 Living area: 16 Mio. m² Heating energy demand: 151 kWh/(m²a) Year of construction: 1958-1968 Living area: 43 Mio. m² Heating energy demand: 153 kWh/(m²a) HIGH-RISE BUILDINGS Year of construction: 1958-1968 Living area: 14 Mio. m² Heating energy demand: 105 kWh/(m²a) Year of construction: 1969-1978 Living area: 16 Mio. m² Heating energy demand: 120 kWh/(m²a) Figure 2: examples for buildings in West Germany State of the Art: Germany 63 1.3.2 East Germany SMALL MULTI-FAMILY HOUSES Year of construction: 1919-1945 Living area: 41 Mio. m² Heating energy de- mand: 161 kWh/(m²a) Year of construction: 1946-1965 Living area: 15 Mio. m² Heating energy de- mand: 175 kWh/(m²a) Year of construction: 1961-1985 Living area: 40 Mio. m² Heating energy de- mand: 174 kWh/(m²a) BIG MULTI-FAMILY HOUSES Year of construction: 1965-1980 Living area: 32 Mio. m² Heating energy de- mand: 109 kWh/(m²a) Year of construction: 1981-1985 Living area: 21 Mio. m² Heating energy de- mand: 106 kWh/(m²a) Year of construction: 1986-1990 Living area: 19 Mio. m² Heating energy de- mand: 87 kWh/(m²a) HIGH-RISE BUILDINGS Year of construction: 1965-1980 Living area: 18 Mio. m² Heating energy de- mand: 111 kWh/(m²a) Year of construction: 1971-1985 Living area: 4 Mio. m² Heating energy de- mand: 159 kWh/(m²a) Figure 3: examples for buildings in East Germany State of the Art: Germany 64 The following groups of load bearing structure can be identified in Germany: Masonry with wooden flooring, masonry with hollow block flooring (waffle beam flooring), reinforced con- crete, concrete columns with masonry and concrete floors, timber constructions and natural stone with wooden flooring. Façade The covering of the façade can be put into the following classes: Cladding, brick or natural stone, concrete elements, light weight boards (sometimes with asbestos), wood and metal cover- ings. Of course mixtures of the coverings below can be found. Especially the natural stone fa- çade in the ground floor and cladding in the upper floors is a very common way of façade cov- ering in Germany. The brick façade are common in northern Germany, while the cladding is found in the southern parts of the country. The wooden façade coverings are mainly common in Bavaria. Metal façade coverings and concrete elements are usually only found at large multi- family buildings. The façade also is in most cases fitted with balconies. In Germany we can distinct between four main types: Balconies/loggias massive floor and massive parapet, balconies/loggias massive floor and light/metal parapet, balconies/loggias metal floor and light/metal parapet, balco- nies/loggias wooden floor and wooden parapet. Furthermore the façade especially from build- ings older than 1948 show different kinds of decorations that can vary between simple decora- tions around windows up to intensive decorations of the whole façade. In alpine parts of Germany also paintings on the cladding can be found. The following groups of entrance doors can be found in Germany. All groups can be found with or without fixed glazing elements: wooden entrance door, metal entrance door and plastic En- trance door. The windows have wooden, plastic or metal frames. Especially big housing corporations tend to get rid of their wooden frames because of the higher maintenance cost. The glazing varies from single glazing (in very old houses and in unheated stairwells), double-glazed with/without gas filling and with/without coating and finally triple glazing in modern or newly refurbished houses. The following additional weather and solar protection is common in Germany: Shutters, roller shutters (plastic or wooden) and exterior roller blinds. Roofs Generally we can distinct between flat and sloped roofs. As well as for Façade for new and the refurbishment of existing buildings in Germany regulations exist, that force the owner to take energy saving measures into account. For sloped roofs we can differ between mansard roofs and sloped roofs. In some houses the attic is heated in others the attic is only used for storage. In these cases the upper ceiling has to be insulated. The following structures can be found in Ger- many: Sloped roofs are either insulated above, beneath or under the spars. The roof tiles are made of brick, concrete or bituminous material. Seldom sloped roofs are covered with steel or copper. The drain pipes are in most cases set on the exterior side of the building. The flat roof design with an inward slope and according interior drain pipe system as well as an exterior drain pipe system can be found. The upper layer of the flat roofs can be ventilated underneath or not. The thermal insulation is installed on the topmost story ceiling. The exterior layer is in most cases bituminous material or plastic foils. Some flat roofs also have a steel or copper exterior layer. To avoid excessive vegetation sometimes stone are put over the exterior layer. Few roofs are using vegetation as an additional insulating and protecting layer above the exterior plastic foil. Other roofs are used as terraces for the inhabitants. State of the Art: Germany 65 1.4 Housing policy In 1948 little resources were available. Politics in Western Germany tried to support the devel- opment of the building sector by regulations for the construction, standardisation and by dem- onstration projects, where new technologies and methodologies were demonstrated to the practi- tioners, architects, engineers, craftsmen, owners and tenants. Especially these demonstration projects led to an increasing knowledge of the involved stakeholders in the construction sector, with the result that the quality of the buildings was increasing rapidly. The first focus was set on erecting as many new apartments as possible. Later on politics supported besides the European wide tendency in creating suburbs also the revitalisation of inner city centres. Another special case for West Germany is the impact of the federal system, where each state had its own regulations. It was until 1962 where for the first time a common regulation about planning, town-planning and building requirement was commonly accepted for all West Ger- many. Nevertheless each state of Germany still has its own regulations in the building sector. e.g. fire protection regulations or the regulations what minimum thickness for spars had to be fulfilled. In 1971 a new law for town-planning and support for building construction passed the parliament. Besides general regulations the law regulated financial benefits for building houses. The law explains the high increase of the completed living units in the following years. In 1978 the program was changed, as on the one hand enough living space for the people was created and on the other hand more emphasis should be put on existing buildings and town structures. Another political influence in the building sector was the support for social housing, where the owners enjoyed benefits, if they keep the rent at a small level for a certain period. The rent level in Germany is regulated in every municipality for living units. A landlord may not exceed the upper level (except, if he can proof, that an energy saving measure reduces the cost for heating of the tenant simultaneously). In East Germany the development was completely different due to the political system. The inhabitants of East Germany were 16 Mio people in 1948 and they were 16 Mio people in 1989, meaning that there was no need to build additional living units for an increasing population. The buildings also were not so much influenced by bombing com- pared to the western part of Germany. Therefore the building activity was not so much caused by the need to provide living space but more to maintain the living space. The policy tried to demonstrate political power, when they decided not to maintain, but to build new living units for the people and to demolish the existing structures. This strategy was found in all East Euro- pean countries. After the reunification the legal and political system of West Germany was adapted with according emphasis on preservation of existing buildings, especially the ones be- fore WWII. 2 TOPICS, QUALITY OF THE MULTI FAMILY HOUSING STOCK The predicted total refurbishment cost for the German housing stock is estimated at 83,7 Bil- lion €. For East Germany covering only 20% of the total housing stock 70% of this amount are calculated. Looking at urgent refurbishment actions it is estimated, that 20,3 Billion € are neces- sary. The evaluation of the refurbishment need, ordered by the ministry of Building and Trans- port also regarded avoidable damages and according refurbishment actions for new buildings. Dew to planning and building errors the following table lists the predicted amount of "avoid- able" refurbishment cost (See also the currently ongoing European Project "PePBu - Performance based Building" that deals with this topic): State of the Art: Germany 66 Table 5: Total cost for new and existing buildings, estimated cost of avoidable damage for new buildings. Looking at the time scale of the damages, 80% of all damaged occurred in the first 5 years after completion of the building with 2/3 in the first two years. Furthermore it became clear, that dif- ferent components of the building show different times when the damage occurs. Flat roofs show avoidable construction damages even 8-12 years after the completion, while for sloped roofs more than 90% of the avoidable construction damages become obvious in the first two years after completion of the building. 2.1 Physical aspects The German climatic boundary conditions do not vary a lot. Regarding heat degree days (based on 12°C) the values vary between 4623 [Kd] in Hof in the Eastern Bavarian hillside region close to the Czech border and Freiburg in the upper Rhine-valley with 3178 [Kd]. The solar rad- iation varies from 53 [kWh/m²] (December value for Harzgerode in northern Germany to 608 [kWh/m²] (July value for Garmisch in southern Bavaria). According to these climatic boundary conditions heating and warm water production are contribution to the energy consumption of the building stock. Cooling energy is only necessary in modern office buildings with large win- dow areas. The heating period in Germany usually starts October 1 st and ends April 30. In 1985 the first regulation for energy saving in construction passed the German parliament. From that time on every new building had to fulfill certain heat insulation requirements. This means for buildings younger than 1985, that acceptable heat insulation is already existing. Nev- ertheless these buildings contain only around 12,5% of the whole dwellings in Germany, mean- ing that around 87,5% of the German building stock were built without legal obstruction to ful- fill a certain heating energy demand. The energy directives issued since 1985 also contain requirements for existing buildings, e.g. for Façade: if more than 25% of the existing cladding of one side of the building façade have to be removed caused by a refurbishment action, the whole side of the façade had to reach an U-value lower than 0,4 [W(/m²K]. In most cases this reduced U-value only can be reached by implementing an additional insulation layer on the façade. But, as the energy directive for existing buildings was not coupled with a fine or penalty most building owners in Germany did not obey to the directive. Beside the legal obligation the development of new building materials as well as the custom- ers/users requirements for proper indoor environment quality with according reduced "cold" radiation from inside of exterior walls caused also in the years before 1985 improvements of the thermal insulation of the building envelopes. More information about physical aspects in Ger- many can be found in the book “Façade and Roofs” that is issued simultaneously with this book. State of the Art: Germany 67 2.2 Structural aspects 2.2.1 Safety There is no general legislation concerning fire protection, the regulations are based on the indi- vidual states of Germany. The fire protection specifications must be fulfilled all times during repair and maintenance work. The regulations valid at the time of the building construction can be used as basis here. With modernization, it needs to be checked whether this is more than an insignificant change the construction, e.g. in case additional thermal insulation is installed on the exterior wall of a high-rise building. Then the currently valid fire protection regulations come into effect. It is advisable to review the fire protection aspects in individual cases in case of constructional changes. 2.2.2 Earthquake /mining / underground traffic The load bearing structure of buildings is affected by earthquake, mining and underground traf- fic. Tensions in the load bearing structure of course affect the envelope of the building with cracks on the façade and even influence of the stability of the whole building. Germany is not lying in a region with high earth-activity. Little influence is recorded by earthquakes in the Rhine valley and the influence from the Italian shell (earthquake in the Italian province of Friuli caused damages in Bavaria). Heavier influence on the load bearing structure in Germany is caused by men and not by nature itself. Especially in regions with underground and over-ground mining the ground water level is increased or reduced significantly. In some regions in Germany the ground water level was changed more than 200 meters with according changes in the struc- ture of the ground and according structural problems of the building stock in the neighbouring areas. Especially in the Ruhr- and Saarregion with intensive coal mining the problem still is tremendous. Although the mining activities are mainly stopped since years, still the mining cor- porations are forced to pump water mixed with concrete into the mining pits in order to avoid collapses of large inhabited areas. Another problem is found through the building of under- ground traffic lines in the cities. First the problems occurred during the building phase with the lowering of the ground water level and then the vibrations of the passing trains cause problems for the load bearing structure. 2.3 Functional aspects Referring to the topic of the COST Action C16 "Improving the quality of existing urban build- ing envelopes", it is not relevant to debate whether it is necessary to enlarge the size of residen- tial units to improve the well-being of each resident or not, as in most cases this measure does not influence the façade. Functional aspects of the building envelope are e.g. balconies, the per- centage of glass in the façade and improvements of the access situation. Measures to increase these topics are: to modernise apartments without balconies by installing balconies in front of the façade, the retrofit of the attic by changing from a storage floor to living units with accord- ing changes in the façade and especially in the roof (new dormers and roof windows), to cover up balconies with glass to enlarge their possibilities of use, to increase the percentage of glass in the façade, to glaze stairwells with galleries. Accessibility Barrier-free living is one of the big topics referring to the structural retrofit of apartments and whole buildings. The age structure of Germany shows a tendency of increasing demand for housing units for elderly people. The housing industry reacts on this trend by installing elevators either in the stairwell or, if not possible, at the exterior side of the building. This measure is taken into account for buildings with more than 4 floors. As the ground floor of some buildings in many cases is leading by some steps to the street, ramparts for older people and handicapped people are installed. State of the Art: Germany 68 Aspects of the surrounding area The following measures are common in order to improve the surroundings of the building: In- creasing the green surfaces, by demolishing hard surfaces, Planting bushes and trees, planting vegetation on Façade, building children's playgrounds in unused areas, improvement of artificial lighting especially of the access area, construction of garbage collection facilities for the whole building. Living conditions Even 15 years after the German reunification the living conditions are still differing between East and West. The table below shows the different average living area per housing unit and per person. The data include also single and two-family houses with larger areas per housing unit. Table 6: Average living area per housing unit and per person in West and East Germany (basis 2002) Improving the Residential Value Portfolio-Management regards the following topics as most important for improving the resi- dential value of the building: Bathrooms should have a window, if not change the layout of the apartment in order to provide bathrooms with window; Apartments should have a balcony, if not available but possible, install balconies at the outside of the façade; Improve sound insula- tion to prevent residents from noise from outside and from neighbours; Furthermore the follow- ing aspects are regarded as important: Number of parking possibilities (garages or on the street); Building is regarded as monument with according restrictions for refurbishment actions; Num- ber of floors; Number of apartments; Number of stairwells; Fluctuation rate; Number of tenants, where the rent is paid (partially) by the state; Number of foreign tenants; Number of unpaid rents; Vacancy; Age structure / age mix of the tenants; Special shops in the building that influ- ence the tenants (noise/odour/opening hours); Rent compared to rent level; Energy consump- tion; Cost for garbage, cleaning, maintenance; Housekeeper existing, if yes situated in- side/outside the building; Security (video/speaker controlled access); Green surfaces and gardens (individual use / common use); Electrical / Media supply in the building; Contamination of the building and the ground; Distance to public transport; Distance to railway station; Dis- tance to airport; Distance to motorway; Distance to post office; Distance to shopping facility – food; Distance to shopping facility -clothing and other goods; Distance to city centre; Emissions from outside (factories etc.); Image of the quarter. Social structure of neighbourhood and building The European project INVESTIMMO also regarded the influence of the tenant structure on the degradation of building elements. Results were: Children and animals in the buildings increase the maintenance frequency of the common spaces and the surrounding. There was no direct connection found to the degradation of the façade (Graffiti from youngsters and salt exposition State of the Art: Germany 69 from urinating dogs). The social structure of the inhabitants and the surrounding living quarter influences the degradation of the whole building. On the one hand in poor quarters low rents are expected and therefore cheaper materials have been used for the construction with according faster degradation of the building. On the other hand also for buildings that have been con- structed with components of average and even high quality the degradation frequency is shorter the lower the income of the tenants and the higher the social problems of the quarter are. 2.4 Architectural aspects The value of a building depends a lot on the aesthetic aspects like the façade or their surround- ings. With some easy measures like a new paint or a new entrance area, one can grade up not only the coating, but also the estimation of the building and their dwellings themselves. Especially the aesthetic aspects of prefabricated concrete slab buildings in East Germany are be- ing improved by such measures. The attractiveness of these industrial housing constructions is enhanced by paintings and there are also cases in which they put sloped roofs on top of the buildings to make them look like a common multi-family house. This page intentionally left blank Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW OF BUILDING STOCK As in many other countries in Europe, in Poland the end of WWII was the starting point of a new era, both in building policy and in techniques used. For Poland, it can be observed that the background to post-war housing construction was formed by the following: 1. Extensive destruction of infrastructure, including the destruction of ca 50% of dwellings, especially in towns. 2. Migration of people after the signing of the Yalta Pact, which resulted in the repatriation of people from the eastern parts of former Poland that were ceded to the Soviet Union. 3. Industrialisation of the Polish economy, which resulted in the migration of about 30% of the population of rural areas to towns (Fig. 1). 4. Significant population growth, which in the period 1945 – 1988 reached almost 14 million (an increase amounting to 58% of the 1945 population – Figure 1). 0 5 10 15 20 25 30 35 40 1946 1950 1960 1970 1978 1988 1995 2001 P o p u l a t i o n o f P o l a n d , m l n . Rural areas Urban areas 1 1,05 1,1 1,15 1,2 1,25 1960 1970 1980 1990 2000 F A M I L I E S P E R D W E L L I N G 0,7 0,9 1,1 1,3 1,5 1,7 P E R S O N P E R R O O M Figure 1. Population in Poland Figure 2. “Dwelling demand” in Poland State of the Art: Poland Z. Plewako, A. Kozlowski & A. Rybka Rzeszów University Of Technology, Poland ABSTRACT: This paper presents the main typologies of the multi-story residential building stock in the post WWII period and problems arising from the poor quality of the housing policy, the architectural and structural principles, and the construction work, as well as over 50 years of inappropriate exploitation. The physical, structural, urban and social aspects are considered State of the Art: Poland 72 For these reasons a great demand for dwellings arose (Fig. 2) in urban areas, especially in in- dustrial centres located in biggest cities or in cities that had became industrial or administrative centres. Other factors influencing this demand were: 5. The national urban planning and housing policy, which led to total standardization of per- ceived needs and the technical provisions in dwelling houses. 6. Almost entirely social housing construction, controlled by the communistic party system for dwelling production, financing and distribution. The above-mentioned factors resulted in the acceptance of buildings that were of very low architectural quality. This was attributable to the demand for rapid, low-cost construction and to the poor quality of the workmanship, construction methods, equipment and materials (e.g. win- dow frames, doors, piping, wiring). This is the main reason for our interest in Improving the quality of existing urban building envelopes. The need for new dwellings has not yet been satisfied (Fig. 2). Increases in the diversity and total number of dwellings have not kept pace with population growth, so there is still a shortage of dwellings. However this situation will probably change in the future. Figure 3. Age structure of housing stock in Poland (Data (%) related to building age (post war period) With regard to the age of buildings, over quarter of the housing stock was built before 1945 (Fig. 3). Most of the population live in dwellings built after WWII, including about 30% in dwellings erected before 1970, while almost 20% live in dwellings built in the seventies and eighties. Newer dwellings amount to only just over 20%. 70% of the present total housing stock, the greater part of which is multi-dwelling buildings, and is owned by co-operatives, munici- palities, companies and condominiums. State of the Art: Poland 73 Figure 4. Increases in the dwelling stock in Poland From the mid-sixties onwards the construction of non-traditional dwelling housing, started to develop rapidly with the general application of the national building policy and was based on the use of large-panel technology. In years 1967-1988 every year ca 200 000 dwellings were built, the number even rising to 300 000 in 1978. By the end of the seventies 2.04 million large- panel dwellings had been completed. According to the most recently accessible data, in 1995 the total number of dwellings reached 11.5 million, including 30% of buildings constructed by using large-panel technology (Fig. 4). In May 1995 the total area of flats reached about 700 million m 2 , including 430 million m 2 constructed by using large-slab technology and about 270 million m 2 m by using other meth- ods. 1.1 Description of main typologies 1.1.1 Dwelling standardisation The need for new dwellings to replace war losses as well as population increase and migration in the centrally controlled socialist economy soon (1947) resulted in the formulation of an obligatory dwelling standard with 11m 2 of usable floor space per inhabitant (equipped with bath-room, lavatory and kitchen). In following years this standard was revised, even defining particular parts of the dwelling so strictly that it was possible to design only limited variants of dwelling systems. It was stated that every room should be assigned to provide sleeping accom- modation for 1 or 2 residents, so the personal and communal spaces within the dwelling were not separated. Table 1 Obligatory dwelling standard: 1947 – 1987 (Konieczny, 2003 Number of inhabitants Category of dwelling Maximum usable floor space of dwelling according to com- pulsory national standard, m 2 1947 1959 1972 1974 1 M-1 11 m 2 / 1 Resident. 20 23.5 2528 2 M-2 30 33.5 3035+1* 3 M-3 38 45.5 4448+4* 4 M-4 48 54.0 5661+2* 5 M-5 57 59.5 6570+3* 6 M-6 65 65.5 7585 7 M-7 71 74.5 * - additional area owing technological requirements of large-panel building Table 2 Obligatory room standard: 1974 (Konieczny, 2003) Category of compartment Minimum area m 2 Allowable reduction, to m 2 Minimum breadth M Maximum length m Living room 18 - - 6.00 2-bed room 11 10 2.50 2.50x2 1-bed room 8 7 2.20 2.20x2 Kitchen 6 5 1.70 - Bathroom *) - 1.40 - Lavatory *) - 0.80x1.10 - Balcony (log- gia) not included - 0.90 - Anteroom Resulting - - - *) – Due to Technical Specification requirements From 1959, the compulsory standard prescribed rigorous limits for usable floor space within the dwelling and for its components, but these requirements did not fit the modular system nec- State of the Art: Poland 74 essary for the use of industrialised technology based on precast elements, especially in the case of the large-panel buildings of the 70s. For this reason, a new standard was introduced (1972), extending the usable floor space per dwelling and improving the potential for design. Practice soon showed, that even this standard did not allow appropriate arrangement of dwelling ele- ments within the modular dimensioning of widely used large-panel building systems. New stan- dards, taking into account the structural and modular restriction of technology, were introduced in 1974, enlarging the total usable floor space. The significant advantage gained from the appli- cation of this new standard was the increase in the floor area of kitchens and other rooms. For most standards the designated living space was for a minimum occupancy of 1 person. The kitchen was designed for use in the preparation meals only and was too small to include a dining area.. In the 1960s some designs even incorporated “blind kitchens”, without external windows. The small bathroom included the lavatory, only in the bigger dwellings completed in the late 70s, for which large-panel technology was used, were they separated. 1.1.2 Post-war period: 1947-1956 Up to mid 50s, housing was based on the use of traditional brick-walls, with concrete slabs on steel girders and ceramic or concrete filling. During this period there was little significant tech- nical development. Gradually, improved transport equipment led to greater use of precast wall elements and also the first of the typical designs were elaborated, making possible more effi- cient building processes. However, this also led to more uniform architecture. Gradually, as a result of the thoughtless execution of what would have been reasonable designs for cost-saving building, bearing in mind the limited technical possibilities and required standardisation, it was necessary to place. more limitations on the designs. 1.1.3 First stage of prefabrication: 1956-1967 It can be observed that in this period many new industrial centres arose, and older centres were also growing rapidly. As previously indicated, the dwellings were strictly limited to a standard floor area (valid to 1987), but architects tried to follow modern trends. The construction of typi- cal residential blocks was based on a crosswise configuration of the structure with the wide use of large-block precast elements for walls as well as the use of slabs and the introduction of new materials: lightweight and cellular concrete. But traditional technology is still used, especially in smaller towns. Even in these traditional buildings precast floor, roof and stairway elements are used. This construction method demanded modular dimensioning of the entire building and of its parts. Typical residential blocks consisted of 2 to 6 stairways and 4 and 5 storeys, or higher blocks (up to 11 storeys) with elevators. The number of dwellings and the floor areas varied, depending on the size of the families which were to occupy them. 1.1.4 Era of large-panel building The first large-panel multi-occupancy residential buildings were constructed in 1957, and from 1967 onwards this technology became standard for use in residential buildings. Two central large-panel systems were elaborated: OWT-67 and WUF-T and were used country-wide. After this a competition led to the selection of two methods (Szczecin and W-70) and numbers of local systems came into use. Large-panel systems can be divided into two groups: - Closed systems: older systems in which most of walls are structural bearing walls, leading to the need for fixed floor-modules. With this system uniform dwelling units are arranged according a to uniform structural mesh. The largest floor-module is 540 x 480 cm, so all the dwellings in vertical rows are identical, and small.. The examples are OWT-67, WUF- T and Szczecin systems. - Open systems (W-70, OWT-75): These systems, designed according to the dwelling stan- dard of 1974, have a more flexible structural mesh and limited number of structural walls, which provides for greater flexibility in the layout of the dwellings units. Pressure on production capacity and the limitations of the standards requirements strictly limited flexibility in the size and layout of dwelling units and of the architectural design of the entire building. Entire neighbourhoods composed of almost similar buildings make a gloomy impression. Various types of construction and layout are presented below: State of the Art: Poland 75 1.2 Description of main non-traditional technologies 1.2.1 Large-block technology One of the most popular large-block building systems is the era – brick: Z-system (Fig. 5). Because of the relative freedom in building the spatial shaping and dwelling arrangement the system is very flexible. It is popular in small towns, for single buildings and also for social util- ity buildings such as schools and health clinics. Typically it incorporates external and internal wall blocks of storey height and hollow-core slabs, with spans ranging from 240 to 600 cm, with steps of 60 cm. The precast elements of the main system are hollow-core 24 cm thick panels made of plain concrete B20 class. External wall panels have a 12 cm thick thermal insulation layer made of cellular concrete. The main width of wall and slab elements is 120 cm. This system allow con- struction of buildings up to 11 storeys high, typically with a transverse structure. Figure 5. Structure of era-brick large block system (Bilinski & Gaczek, 1982) 1.2.2 Large-panel technology There are a number of popular large-panel systems. The common feature of these is that wall elements are storey-high, and their maximum length extends to 6 m, which is the maximum for a single room. Ceiling slabs have a corresponding span – up to 6.0 m. External walls are precast as three layer sandwich panels, with an internal structural concrete layer, central thermal- insulating layer and external surface quality layer. Wall openings are fitted with assembled win- dows and doors. Foundations: In all systems there are usable single storey basements, which are used for resident’s store- rooms and technical-rooms. Depending on local soil structure and conditions, shallow founda- tions were usually used, with concrete or reinforced strips under the basement walls, while for soils of poorer bearing quality reinforced concrete slabs were used. Exceptionally, deep founda- tions were made. Sometimes system-built precast basement walls (thickness of concrete walls 14-20 cm, cellular concrete walls 26 - 30 cm), were used and in-situ concrete were also popu- lar. The plan of the basement walls followed the same as configuration as the structural walls above them. Over ground structure: Three types of structural form can be distinguished: transverse, longitudinal and mixed – de- pending on the construction system chosen for the building. All elements were prefabricated, of standard dimensions (depending on the system used). Bearing internal walls were made of precast concrete with or without reinforcement, of uni- form thickness ranging from 12 to 24 cm. Wall elements with openings had an appropriate rein- forcement system. Bearing external walls for the Szczecin system were made of lightweight State of the Art: Poland 76 concrete of thicknesses up to 40 cm. For another newer system, typically, three-layer walls with an internal bearing layer made of reinforced concrete 12 to 15 thick, thermal insulating (foamed polystyrene or mineral wool 5 to 6 cm (in later years upgraded to 8 cm) and a surface reinforced concrete layer 6 or 7 cm thick with finishing structure. Curtain walls (self-bearing) have the same structure with the thickness of the bearing layer reduced to 8 – 12 cm. Ceiling slabs were made of reinforced concrete as hollow-core (24 cm thick) or solid (16 cm). Flights of stairs and landings were made of precast reinforced concrete elements, as also were the three dimen- sional elements of elevator (lift) shafts. Flat roofs, with slopes inclined to the interior, were separated from the top storey ceiling by a space and constructed from concrete panels supported on brick walls OWT Szczecin W-70 WUF-T Figure6. Structure schematic of large-panel systems (Bilinski & Gaczek, 1982) Facades: Large-block or early large-panel systems provided facade finishing with plain or parging plas- ter. Most typical of large-panel systems was the rough cast finishing of the external concrete layer of the elements, with sealed fronts for the element joints. In some systems, where external longitudinal strip walls were used, spaces between openings (windows or balcony doors) were filled with sandwich panels. These panels with timber frames were made of asbestos-cardboard sandwiching a thermal insulating layer and chipboard. Sometimes precast concrete panels were used. State of the Art: Poland 77 Element joints Typical structural joints are shown below. All were filled with in-situ concrete and in some cases welded connections plates were also applied. Internal joints External joints Horizontal Vertical Horizontal Vertical Szczecin System W-70 System Figure 7. Typical joints of elements Legend: 1 – precast concrete 2a – thermal insulation (foamed polystyrene) 4 – lightweight concrete 5 – in-situ concrete 6 – insulating foil 7 – steel profile sealing strip 9 – mortar 10 – rubber sealing 1.3 Housing policy For residential building the early post-war period (1945-49) was the period during which the dwelling stock destroyed during the war was replaced, this being the quickest way to increase the living area. Simultaneously, the organisational basis for housing policy and economy was prepared and the first newly designed dwelling units were built. The basic legal act directing development of the entire housing policy was accepted in 1947. This incorporated the-above- mentioned obligatory standard of 11m 2 of usable floor space per person, which it was assumed would satisfy needs of every citizen. The next period, including years 1949-1956, called the “6-year plan” is distinguished by the great increase in heavy industry and the migration of people to new industrial centres. Naturally this of led to a dynamic increase of numbers of dwellings constructed, but the need for housing continued to increase relatively faster so there was still a housing deficit. As the beginning of 1949 the mean density was 1.6 persons per room, but by end of the year this had risen to 1.7 persons per room. Beyond any doubt, the technical condition and equipment of dwellings was improved. This phase was characterised by centrally controlled building planning and industry, intended to improve economic and technical actions in situations where there was a lack of qualified and experienced staff. The development of residential blocks for which precast wall technology was used started around 1960. The reasons for this were: - The need to reduce the total labour requirement (lack of manpower due to the demands of the rapid industrialization process), - The concentration of housing requirements in big urban centres. State of the Art: Poland 78 In 1965, under a rigorous policy of cost-minimization, the first stage started with the intro- duction of two central systems based on large-panel technology. Based on the positive results of first applications, the following systems were accepted, and in early seventies production started on some regional systems. The rapid increase in the dwelling stock based on large-panel technology started following the government resolution of 1972 about “Prospective Dwelling Program” which stated: “ ... in the next years the main increase in building production should depend on industrialized tech- nology based on plant producing large size precast elements ...” and “ ... to provide a dwelling for every family by 1985, 4.5-4.8 million new dwellings must be constructed during the years 1971 – 85, and by 1990 the number should reach 6.6-7.3 million dwellings ... “ In the years 1975-1980 significant but uncontrolled increase in the number of large-panel elements production plants occurred. This development was characterized by: - Assuming that the use of large-panel technology was the way to ensure a rapid increase in the construction of dwellings, - Big pressure by local authorities put on the erection of new plant to guarantee an in- crease in the construction of dwellings, or treating new plants as “gifts” from the central authorities, without appropriate economic analyses of local needs, - Imbalanced and too slow development of building material production, especially insu- lating, installation and finishing materials. Simultaneously, there was a regression in large-block technology and very small increase in the use of precast-frame and in-situ concrete building technology In the eighties, as result of the political end economic crisis, the programme was only par- tially fulfilled, with a decelerating increase in new dwellings. The end of the large-panel era, which affected ca 4 million dwellings in residential blocks that were mainly located in brand new districts in growing towns, was accompanied by the above-mentioned crisis, when the state withdraw from its responsibility for the provision of dwelling housing. This ended with the po- litical transformation of nineties, followed by the implementation of energy-saving requirements for buildings and reduction of central financing for dwelling production. Omitting the direct post-war period, the repair of buildings was only a marginal part of build- ing production. During the decade of 1961-1970 only 18.7 thousand dwellings were repaired, which was about 0.3% of the total dwelling stock. This situation is continues up to the present day owing to the permanent financial deficit.Topics 1.4 Physical aspects 1.4.1 Thermal insulation Centrally controlled energy production, based on the use of hard and brown coal did not provide energy saving solutions for problems relating to the heating and thermal insulation of buildings. The heating systems were based on big central heat-generating plants. Moreover the cost of heat production was not based on individual heat consumption. For these reasons the reduction of energy consumption was not considered until 1982. Thermal insulation requirements for walls and solid roof ceilings valid to 1984 (with slight changes in 1974) were simply the result of assumed principles of excluding vapour condensa- tion on internal surfaces and snow melting on roofs. They were based on experience in tradi- tional brick-wall building (Table 3). Table 3 Standard requirements of heat transfer coefficient in Poland Partitions heat transfer coefficient, W/m 2 K PN-64/B-03404 PN-82/B-02020 PN-91/B-02020 valid to 1984 Valid from 1984 valid from1992 Walls 1.16 0.75 0.55 Roofs 0.87 0.45 0.30 State of the Art: Poland 79 Traditional buildings constructed in the 50s and 60s complied with the requirements men- tioned above, which assumed that a wall thick (one-and-a-half-brick wall was appropriate for mild climate zones I and II, two-brick walls for another zones). In non-traditional systems only the structures of external walls were designed to satisfy the heat insulation conditions. It should be noted , that there were no thermal insulation require- ments for windows. Typically, compact two glass-panel timber frame windows were fitted but their quality was very poor. Heat losses through windows and joints were not considered, so the mean heat transfer coefficient of total wall areas was much bigger than required. Additionally, errors in production technology (incorrect setting of insulating sheets, overheating during curing processes) and in assembling (damage of insulation on the edges of elements, omission of addi- tional insulating strips in joints, careless window assembly), compounded this situation. Calcu- lations including all parts of external walls (panels, windows and joints) showed that the mean effective heat transfer coefficient was bigger by about 0.2 to 0.3 W/m 2 K. System modifications carried out in the 80s slightly improved thermal insulating properties. 6 c m 5 c m 6 c m 6 c m 3 6 c m 7 c m 6 c m 8 c m 7 c m 8 c m 8 c m 4 0 c m 0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 Szczecin* W-70 Wk-70 OWT-67 OWT-75 W / m 2 K Figure 4. Evaluation of tested heat transfer coefficient of wall-panels due to increase of insulation layer thickness (* - solid lightweight concrete wall) It should be noted that as a result of state financial policy in recent decade thermal insulation has been improved in large proportion of the total residential buildings by the addition of an in- sulation layer on external walls and by the replacement of windows. 1.4.2 Protection against moisture In traditional residential buildings both pitched and flat roofs were used or concrete tiles were used on pitched roofs, while for flat roofs or those with a smaller slope, two layers of roofing paper were pitched onto to a concrete deck. Roofs in non-traditional residential buildings systems were flat, so two layers of tarred roof- ing paper were used, but owing to the poor quality of the material used and the poor quality of the workmanship in applying the coal tar pitch, these very often very often leaked. Only the de- fective parts were repaired and this was done by patching them with coal tar pitch paper. Leak- age in the external joints of elements (Fig. 7) also often caused problems. Defects in the precast elements (edges), and omitting appropriate insulating elements in joints (sealing strips and tar mortars) permitted the penetration of rain water into the internal layers and even to the inside walls of the building. This impaired thermal insulation and led to the corrosion of the steel ele- ments of joints and layer connections in sandwich walls. Poor quality windows often caused similar problems. In recent years thermal renovation and the replacement of windows in the majority of build- ings, has effectively protected external walls against rain water penetration. State of the Art: Poland 80 1.4.3 Noise insulation (Szudrowicz, 2003) Factors influencing the acoustic quality of buildings can be divided into three groups: - architectural, - material and structural - installation and technical equipment Before 1970 acoustic parameters of buildings were not considered important. The mandatory standards introduced in 1970 are given in Table 4: Table 4 Standard requirements acoustic insulation index in Poland Partitions Acoustic insulation index, dB PN-70/B-02151 PN-87/B-02151 PN-B-02151-3: 1999 Walls 53 52 50 Roofs 53 53 51 Architectural factors results from the layout of dwellings . Very often “loud rooms” (bath- rooms, lavatories, elevator shafts) are in contact with “quiet rooms” (bedrooms, living rooms). Small dwellings concentrate “habitat” noise in small area. These problems are common to both traditional and non-traditional residential buildings. Iin non-traditional systems too, the main structural material – concrete – transmits more noise than the masonry walls used in traditional technology, although the acoustic insulation is insufficient in both technologies. Common to the technologies mentioned is the problem of ceilings. An inadequate acoustic insulating layer or the lack of such a layer results in even worse noise transfer through ceilings that through walls. Installations, located in shafts without any insulation and directly connected to the building structure are the sources of noise transfer to rooms in contact with these shafts. External walls, especially windows, also have insufficient acoustic insulation. Usually in the past, owing to the dominant unsatisfied demand for dwellings, little attention was paid to the noise problem. Today it receives more attention. Some action and research work on this subject is in progress. 1.4.4 Ventilation Even in buildings up to 16 storeys high, a gravity ventilation system was installed. This ventila- tion served only bathrooms, toilets and and kitchens. In tall buildings, ventilation channels from the rooms of every third or fourth storey were connected to a single ventilation shaft. Some- times, due to improper construction works on a single level there were problems arising from smell penetration. The circulation and exchange of air in the remaining rooms was by means of indirectly en- sured ventilation through small opening lights. In cold seasons, these openings were usually closed to ensure that a comfortable air temperature was maintained. Because external walls were relatively cold, water vapour condensed on walls. 1.5 Structural aspects No typical or important structural problems were noticed. Although there were some cases of gas explosions in non-traditional building it was shown that the structures used, even when there were many defects in consequence of the poor quality of materials or workmanship, were suffi- ciently strong and rigid (Lewicki, 2003). This is a very positive conclusion, resulting from changes that led to the improvement of these buildings. However special problems arose owing to the nature of the sandwich wall structure of the large-panel systems. Owing to moisture pene- tration caused by insufficient insulation of the joints of the elements, steel hangers connecting external (facade) and structural layers could be subjected to corrosion. There was an incident in which the facade fell off a building, but fortunately no one was hurt. This problem is being solved by installing additional hangers Konieczny, 2003). State of the Art: Poland 81 1.6 Health aspects (Dohojda, Jaworska & Prejzner, 2003) Direct influences of buildings on the health of the residents can be divided into two groups: - Material influences - Internal climate influences Material influences leading to problems arise as a result of the use of noxious agents in fin- ishing, impregnating and insulating materials, which penetrate into the air inside the building. These materials include: - asbestos used in external partitions, - substances used to impregnate ceilings, acoustic insulating millboard (chlorophenol, naphthalene, chloronaphthalene), - water-based insulating materials containing naphthalene, methylnaphthalene, phenol, toluene, xylene, The influences of on the internal climate include mildew formatting on walls in spaces that are poorly ventilated and heated. 1.7 Functional aspects Owing to the high demand for dwellings, for a long time the functional aspects were often ne- glected. However increasing expectations in relation to the quality of accommodation have brought this aspect to the forefront. In the past the dwellings were generally small, with ex- tremely small rooms, kitchens and bathrooms. The functional changes can be achieved as fol- lows: - in a single dwelling unit space can be gained by joining rooms and rearranging the lay- out, - adjacent dwellings or the parts of these can be joined (with layout changes). Additionally, new balconies can be installed or existing balconies can be extended. 1.7.1 Safety The result of the poor economic situation of the major part of the urban population and lack of sites for individual houses is that residential building blocks will continue to provide the basic kind of family housing in towns with a low mobility rate. This situation is unlikely to change in the foreseeable future. However, we can suppose that gradually the more affluent members of society will escape from the multi-dwelling districts (this trend has already been observed). The social phenomena of vandalism and criminality that are typical of anonymous neighbourhoods are frequently encountered. Of course appropriate administrative action is taken, but only social evolution can change this situation. The residential districts are called dormitories (sleeping rooms) for the urban population. These districts have few cultural or rec- reational facilities and they fail to satisfy the growing needs. Another problem is the lack of appropriate car parks. The town planning brief did not provide for sufficient car parks and in the past designs never incorporated car parks in the basements of buildings or in separate buildings. Radical changes in the planning are necessary to make dwelling block districts more “user- friendly” to the residents. The limited funding for investment leaves this problem unsolved. 1.7.2 Accessibility In all post war buildings, dwellings on the first floor (ground level) are always located at ca 1.5 m above the level of the entrance, so there are always problems of accessibility for persons with limited mobility. Buildings of up to 4 or even to 5 storeys do not have lifts (elevators) and because the stair- ways are so narrow it is usually impossible to install them inside the building. This solution is not even under consideration. Accessibility for disabled person is provided by locating the low- est residential dwellings at ground level, often with a separate and specially equipped entrance. For higher buildings, which are always equipped with elevators, problems of accessibility concern only the entrance to the building. State of the Art: Poland 82 1.8 Architectural aspects In Poland, prefabricated building technologies were used in order to meet the requirements for social dwellings and to keep costs low. The simplest solution was to mass-produce dwellings. The preparation of the typical building elements in advance speeded up the time needed for their assembly and increased the quantity of dwellings that were available. These were the most im- portant limiting factors. Prefabricated building technologies were focused on quantity rather than on quality.Low standards were set for the materials used and the equipment for the flats. The plans of buildings were very simple; the facades simply reflected the internal configuration of the building. The apartments were often laid out with an inside staircase serving 2-3 apartments on each floor. Many of the dwellings were small; although a balcony was standard in nearly all apartments this was usually also very small. Between 1950 and 1990 the layout of the housing schemes conformed to the ideas on town planning generally accepted in the 1930s. Typical blocks of buildings, were preferably placed running north to south and at equal distance from each other to give all apartments the same ac- cess to a maximum of light and air. The residential function dominated these settlements: other functions were conspicuously absent from these areas. In all the cities in Poland huge assemblies of blocks of flats were constructed. Elements of an accompanying program were designed, but because of lack of funding were never built. Nowa- days it is necessary to change this situation. Little attention was paid to the treatment of the open spaces in the residential areas, apart from the provision of roads, parking space and sometimes small playgrounds. The areas between blocks of flats are left as lawns with few trees and bushes. In Poland as many apartments as possible were built as quickly as possible, therefore only in- dispensable elements were included in housing estates so that people could at least live there. From the architectural point of view it was possible only to implement the main structural ele- ments of the settlements and the full architectural concept was never competed. The public util- ity structures, which determine the social content of the estate were lacking. This situation was most obvious in the huge estates where is has not changed since they were constructed. The de- sign of an estate did not include a social scenario for its development. It was impossible to an- ticipate what people would need and when they would need it. The contractors had to act spon- taneously, as dictated by the economics of the machine use. Pressed by the housing needs, they allowed the tool to master the person to using it. The investors intention was permitted to be dic- tated by the constructors. The designs of mass housing were made for anonymous users. Stan- dardised plans were used for the flats and the designing of housing complexes that were too large was big mistake. Sometimes these complexes could house up to 40 or even 80 thousand people. The residents in these estates were critical of this situation. Nowadays special attention is paid to the thermal renovation of these buildings. This solves thermal problems, but the problems relating to constructional mistakes and to the creation of more architecturally satisfying facades remain. Changing conditions inside the dwellings and improving the facades demands an almost total change. It seems to be possible to replace the outer walls of buildings by new structural materi- als which will simultaneously change their architectural appearance and permit the adaptation of the layout of the building. As most of the multi-storey buildings were constructed with load- bearing partition walls and non-bearing facades it will be rather easy to convert the former poor facades to new ones with much better architectural appearance. The conclusion is that the aesthetic aspects related to the facades can be a problem, but this is a problem which can and must be solved. State of the Art: Poland 83 REFERENCES Bilinski T., Gaczek W., 1982. Industrialised building systems, PWN Warsaw Dohojda M., Jaworska K., Prejzner H., 2003. Large-panel buildings – basic requirements. Health and hygiene problems in large-panel buildings, ITB Warsaw Konieczny K., 2003. Large-panel buildings – basic requirements. Additional connectors of facade layer in Sandwich wall-panels, ITB Warsaw Korzeniewski W., 1981. Housing designer guide-book, ARKADY Warsaw Lewicki B., 2003. Large-panel buildings – basic requirements. Methodology of technical condition evaluating of large-panel buildings, ITB Warsaw Pogorzelski J. A., Kasperkiewicz K., Gerylo R., 2003. Large-panel buildings – basic requirements. En- ergy saving and thermal insulation of partitions, ITB Warsaw Szudrowicz B., 2003. Large-panel buildings – basic requirements. Acoustic protection in large-panel buildings , ITB Warsaw 1981. Review of large-panel systems. Final Report, COBPBO Warsaw 2002. Statistical yearbook of Poland GUS Warsaw This page intentionally left blank Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW ON THE HOUSING STOCK 1.1 Data related to building periods Hungary’s population is approximately 10 millions, 65% living in towns. The number of hous- ing units: is over 4 million. The number of families is approximately. 3,3 millions. In some areas (in the countryside, mainly in agricultural areas) there are empty flats and housings, but in other parts of the country one can find a shortage of flats. The average size of flats: 68 sq.m, the average size of households: 2,7 person/family. The percentage of a one-person households is increasing. Also increasing the percentage of the single parent – one/two children family. The homes number related to different building periods: The post-war housing in number: pre-cast concrete homes built 1960-69 41.000 pre-cast concrete homes 1970-1979 275.000 pre-cast concrete homes 1980-1989 227.000 pre-cast concrete homes 1990-1992 8.000 other homes built with highly industrialized homes: 237.000 homes built with brick and other more traditional method: 3.292.000 1.2. Description of main typologies The housing stock has three main type of dwelling buildings: Buildings for one/two families: - detached houses (mainly private owned): in all villages, in suburbs of towns and in out- skirts of the cities. One can find easily a 100 years old earthen building or a decorative art- novae villa, or more simple designed cube-forms from the ‘60-ies. This first part is: 1.914.000 units, 58% of the total (170.156 units, 21% in Budapest). Buildings for 4-30 families: - tenement houses (private or state owned): 4-8-12 to 30 dwelling units in a same building, mainly 2-4 stories, most of them were built before II. WW, in historic parts of the cities. Usually damaged during the war and ’56 revolution, and not renovated in the last 40 years. State of the Art: Hungary Ágnes Novák Budapest University of Technology and Economics, Faculty of Civil Engineering, Department of Building Construction ABSTRACT: This paper gives an overview of post-war housing in Hungary. The problems, needs and solutions described in the text give detailed information on the housing estates and buildings. Also the problems and offered solutions show the possible way of a new urban de- sign. The technical background and other information help to have on overview on the special problems related to post-war housing. New technologies and urban aspects suggested in the pa- per will show the new solutions for these housing estates. State of the Art: Hungary 86 Small amount of tenement houses was built during the ’60-ies and ’70-ies. In the last 10 year new generation of tenement houses emerged partly in green areas, partly in detached housing areas. This second part is: 786.000 units, 24% of the total (349.937 units, 42% in Budapest). Housing estates, big-scale buildings: - units of housing estates (private or state owned): 5 or 11 story buildings, built with rein- forced concrete panels or light-concrete blocks, or in-situ concrete (i.e. No-fines). This third part is: appr. 600.000 units, 18% of the total used flats. (257.163 units, 33% in Bu- dapest). This document works with this third part of housing-stock, and from these only with the large- panel system. 1.2 Description of main technologies The large panel system was established after the ’56 revolution. The original idea was captured from the Soviet Union, and later from Denmark (Larsen-Nielsen factory). First generation of large-panel buildings (1960-1969) The first generation of large-panel buildings had the following characteristics: - Number of dwelling units: 41.000, - Percentage: 7,4 % (of large panel units) Years of construction: 1970-1979, - Number of dwelling units: 275.000, - Percentage: 49,9 % (of large panel units) Other characteristics: - Small flats: the average built up area of the flats for four persons were 48 m 2 , with two bedrooms and there was also a sleeping place in the living room. - Simple layout of flats was small kitchen, no dining area, and no storage area in the flat. - Simple facades: no terraces, no loggias, and no shops on the ground floor, flat roof, and small entrances. In many cases the same elevation was for north and south direction. - Simplified town-planning: Long, straight buildings and streets, no connection with other parts of the city, also destructed existing urban context, high-rise buildings even in small settlements. - Pure technical background: Very bad insulation (U value for external walls: U=1,25- 1,8 W/m 2 K), no sound insulation, any summer shading for windows, bad heating and sanitary systems. Second generation of large-panel buildings (1980-1989) The second generation of large-panel buildings had characteristics as follow: - Number of dwelling units: 227.000, - Percentage: 41,2 % (of large panel units) Other characteristics: - Slightly bigger flats: The average built up area of the flats for four persons were 54-63 m2, with two or three small-size bedrooms and no living room. - Simple layout of flats: Only in the late eighties changed a bit adding dining and storage rooms for the flats. - Slightly improved facades: Loggias or balconies, coloured ground floor elements, small amounts of buildings had pitched roof or built-in attic, some garages for the tenants on the ground floor. - The improved town-planning created small squares and streets, little connection with the other part of the city, bad public transport, and half of the buildings were high-rise build- ings (mainly with 11 stories). - Improved technical background: little heat insulation (U value for external walls: U=0,85- 1,1), with no sound insulation, no summer shading, bad heating and sanitary systems. State of the Art: Hungary 87 1.3 Description of main technolgies 1.3.1 Structure, foundation All the above described buildings were built on in-situ cast-concrete, regarding to earth-xxxx regulations. The basement level was created with 20 cm of wall thickness, and created rooms for cars and other locally need areas.The outer walls had 27 cm thickness, 5 cm outer layer of reinforced concrete, 7 cm of polistirene heat-insulation, usually damaeged during construction, and 15 cm inner reinforced concrete wall structure. Slabs are concrete of 15 cm thickness, without any sound insulation. Double glazed windows, bad quality sun-shading. The cold bridges are common. 1.3.2 Roofs Almost 98 % of these block were built with poor insulated flat roofs, no terraces or green roofs were built. 1.3.3. Facades The flates were extended usually with narrow balconies, the facedes usually was poorly insulated, enormous thermal bridges are common. Figure 1, Figure 2 1.4 Housing policy During the communist political aera, three main type of ownership was creates. Main part of the new homes in town were owned by state, and rented by families with 2 or more childremn, or families who were priviledges on the basis of political background (About 80 % of the flats). Families with no children, or families with better income had to buy thirt homes from the National Bank (About 10 % of the flats). The third part of the group was formed by associations, which were organized by local municipalities (About 10 % of the flats). After the changes of post-soviet times, the state-owned flats homes were sold for tenants under the“Right to buy„ law, the tenant had the “right” to by their flats for a very cheap price (10% of a market-price). This resulted an opposite structure of ownership. Now only 4 % of the flats are rented, the other is owned. The families with low income bought their flats for a cheap price, but they got all the problems to solve too. That is the reason of the frozen structure of the housing estates. During the last 30-40 years the pipes, wires, windows, carpets, floor covering had no change. Within 5-10 years in spite of the main structure, almost all the element off the building must be replaced or refurbish. The single parent families, or retired couples are not able to accumulate enough money to solve these prob- lems. They are not able because of the very high running cost of the under-insulated buildings. The families must pay a monthly sum for reparation works (leaking roof, damaged elevators) but is enough for the works. An average family must pay 50 % of an average salary for the cost State of the Art: Hungary 88 of an average (54 sqm flats.) The management has no high-standard education, and no real help from professionals, partly they have any financial background to pay for professionals, partly they not realized the necessity of that. Hungarian government started to introduce different solutions in order to save energy and cost. The buildings that applied for the financial help from the sate have to make an application to show the estimated work and cost. Than the estimated cost is divided for three: - One part is the task of tenants, - Second part is the task of local municipality and - The third part is the task of government. During the last 3 years 12.000 fats (2%) could use the help from the state. - There were financial help to change windows to plastic more airtight windows. (Problem of mould emerged very soon.) - In some cases heating system was changed. - In some cases local heating system were introduced. - In some cases boilers were introduced to every flats. (Problem of mould emerged very soon.) - Few buildings got outside thermal insulation (usually 5 cm thick). New financial method is necessary to promote good solutions in order to prevent building- physic and health problems. 2 TOPICS, QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK 2.1 Architectural and urban aspects 2.1.1 Planning aspects After the II. WW big parts of Budapest and other towns were damaged or partly destroyed. Also industry was destroyed, and factories emptied by the soviet army. It was a real economic- miracle to build up thousands of dwelling units and industrial estates within a few years. From early ‘50-ies the communist party ruled the country, using the Stalinist ideas about the town- planning, industry and transport system. Lots of problem has occurred, and some of those con- nected to housing problems. (For example: bigger flats were divided into 2-4 small units for dif- ferent families, using one kitchen and bathroom. The normal size detached dwelling buildings were occupied by state, and it located 2-3 families in order to create a massive heavy industry in towns. Lack of comfort and private life was usual.) The ’56 revolution was the reaction of people from urban areas. But Soviet tanks repressed it. The revenge started. The basic political idea was punishing people after the ‘56 revolution. Planning regulations were created specially for these housing estates. The rooms, kitchen and storage facilities were mini- mized in term of area and height. The tenants from destroyed buildings were moved to other ci- ties (new industrial cities were founded) or the other part of the city, far away from their origi- nal homes. The easy controlled site was necessary the layout of the buildings and streets helped to keep a check on buildings and people. Huge housing estates (8-16.000 flats) were common. Bad site and land use, windy, noisy boring streets has occurred. No useful communal places and meeting points were created. The public transport, shopping fa- cilities and places for family activities were underestimated or neglected. Schools and kinder- gartens were overcrowded. All the members of the families had job, mainly far from their homes. Bed lighting on the street, unsafe environment destroyed the communal life. At the end of the ‘80-ies better ideas find their roots. The new housing estates have street domi- nated layout, more focused on sun and natural environment. Also smaller group of buildings helped communal life to strengthen their roots. Key tasks in order to improve planning: - good sociological survey must be done; - establishing better public transport possibilities; - establish good connection with the surrounding plots, villages and green areas; - establishing work-places in order to create proximity between home and work. State of the Art: Hungary 89 2.1.2 Land use aspects Bad landscape design was common. The new housing estates were laid down mainly on agri- cultural site, but it was common to destroy old villages and detached houses in order to built huge amount of flats in a single row, 11-storey buildings. (Fig.3) Figure 3 No natural resources, water-flows, green belts, parks were taken into account. The windy, dusty dirty streets were vandalized during the last decade. These streets, parking lots and garages were designed for 1car/20families. Today the average car/family ratio increased 1/2. Streets are overcrowded; no parking places and lots for this ten times more traffic. Because of this parks and green areas are vandalized by parking cars. Almost all big housing estates had and have this problem. In 70's and 80' the background idea was softened, but still effected urban planning. In some cases the added built-in attic were planned. Today situation is same as 30 years ago, no changes happened. Key tasks in order to improve land use aspects: - good sociological survey - good environmental survey to help green ideas and solutions, - create more flexible land-use for the housing estates, - conserve the green areas, create parks, garden, activity areas for different groups from tod- dlers to retired people - create lower building height and density to help the communal work, and cohesion of dif- ferent group members. 2.1.3 Architectural aspects Simple designed flats, monotonous function. Flats for families with 3 member. The units have no family room and dining area. Social segregation happened during the last 15 years. The tiny flats caused noise problems, summer overheating because of the underestimated air-change ra- tio. The average size of the flats: 60's 48 sq. m 70's 54 sq. m 80's 63 sq. m The weakest point of the flats: lack of maintenance in term of pipes and electric works, tiny kitchen with no dining area lack of storage facilities lack of washing-drying facilities State of the Art: Hungary 90 Conclusions and key-tasks: - The tenants and owners need financial help from the government to invest into their homes in order to improve their homes. - Case studies, and good-practice must be shown by the government after choosing the typi- cal building and flats to improve. - Flag-ship projects must be create by local municipalities working together with local NGO- s. - Local help and advise have to work-out in term of renovation and rehabilitation work of the units (advisable materials, solutions for bathroom, kitchens). - In order to accessible homes there is a need for new converted homes for people with spe- cial needs. - In order to environment-friendly, healthy building new design approach is necessary consi- dering the materials, ventilation, passive-solar ideas in practice. 2.1.4 Aesthetic aspects The buildings from the ‘60-ies have painted surfaces. Colors used for 4-storey buildings: gray, light-blue, terra-cotta, ochre, English-red. For today all are gray due to air-pollution. The buildings from later years have the concrete surface untouched; the washed surfaces show the pebbles. The color is always yellowish with some gray cement. The façade has the square windows are in a strict order. Sometimes the window-frames were painted in red. Conclusions and key-tasks: - When outside insulation is necessary is the time for aesthetic changes too. - Green façade is especially a good solution for short and long time. - Added balconies or sunrooms helps to change the monotonous view. - If there are more solar devices (PV panels for electricity, or collectors for domestic hot wa- ter) careful design helps to improve the elevations. - In some places new architectural ideas can be proven and test (i.e. “Parasite”). 2.1.5 Environmental aspects – regarding to built environment Natural resources and wider environmental aspects never were taken into account. The areas and open plots between the buildings are remote, vandalized, dirty, dusty, polluted. Only advan- tage: there are open public areas, with trees aged 30-40 years. The built-up density concerning to this housing estates are not high, so we can find possibility to create new parks using local materials, rainwater and surface water, or other natural resources. Key tasks in order to improve environmental aspects: - natural resources must be determined clearly - good environmental survey must be done to help environmental ideas and solutions - using rainwater is a new solution for better environment - noise reduction with green areas is effective - Effective lighting system on outdoor areas to create safe and friendly environment 2.2 Social and cultural aspects The new housing estates do not create a real vivid life of a town. There is a big discrepancy between the high technical standard and the level of the communal activity. These new settle- ments usually have no central area, no real market places, no churches, nothing but dirty streets and polluted parks. There are no movies, no swimming-pools, and no good restaurants. The only changes in the last decade happened: new shopping mails were introduced. Normal- ly a shopping mail is not best place in a middle of poor people, but the site was extremely cheap, and local municipalities were happy to entertain the with shiny shop-windows and heated halls. In some area this new box-style shopping-mail has the only cinema in a district of 90.000 people. Vandalism is common, segregation started. Conclusions and key-points in order to improve the cultural aspects: - Good survey of the local sociological situation is basic. - Local NGO-s must be helped; the communal facilities must be subsidized. - Creating smaller neighborhood is helpful for local community. State of the Art: Hungary 91 After the political changes radical changes started. Families with low-income had two options: to sell their homes and buy a very cheap home near the town in a village, with lower technical standard, but with garden or field to work on. In that case the lower comfort is cheap to run, the family can live on one salary. The other very common scenario is: the poor family staying in their flat with high comfort (heating, hot water etc.) but during the years it was more common, that they could not pay their bills. So they can have some help from the municipality to live on, and not for bills. This group (huge group) of families – very often single parent families, or families with unemployment parents – have a very low level of life. The other families left this block of flats, and segregation started. Conclusions and key-points of social aspects: - Good survey of the local sociological situation is basic. - Local NGO-s must be helped; the communal facilities must be subsidized. - Creating smaller neighborhood is helpful for local community. - To create a more different or various scale of flats helps to solve the problems. - In some cases to involve new groups can add more life to the community. (For example a dwelling building converted to student dormitory creates more activity, cafes, bars, library; Internet cafes will have more guests.) - Considering local natural environment: botanic garden, nursery garden, small zoo or farmstead can help the elderly or handicapped people to have closer life to nature, which help them a lot. - Few buildings got outside thermal insulation (usually 5 cm thick). New financial method is necessary to promote good solutions in order to prevent building- physic and health problems. 2.3 Structural aspects Report from structural aspects shows good picture on the construction. In some cases gas explo- sion happened, one panel flight away from the 5 th storey, and no more damage happened. In other case fire was on the first floor of an 11-storeyed building without any more damages. Some pictures of thermo-vision survey show critical temperature at the vertical and horizontal joints. Conclusions and key-tasks: - Green roof can be design for almost every buildings. - It is advisable to protect the structure, and energy with well calculated outside insulation. - In some case part of the buildings or inner walls can be eliminate. - For 5-storeyed buildings new elevators are necessary. 2.4 Functional aspects 2.4.1 Building typology Simple building layout: 3-4 units on each floor in a typical building with 2-4-6 staircases (long buildings) with 5 or 11 stories. Ground floor with garages or storage rooms for waste and bikes. (Often vandalized.) The waste-chute is noisy and smelly. During the last 10 years big part of the garages were converted into tiny shops or pubs. The biggest problem with the buildings as whole: lack of continuity between the flats – com- munal areas – urban areas. Conclusions and key-tasks: - On the one hand: this is a good sign because the small flats fit better for smaller families. - On the other hand: this is bad sign, families with higher income moved to the suburb, and low-income families stayed (in housing estates the one-parent family is two times more than the average). Necessary to create a mixed-ownership, mixed-use, and wider palette of flats in term of size: architectural solution must be work out: State of the Art: Hungary 92 - creating new more comfortable and complex flats from 2 or 3 smaller (connecting flats to- gether horizontally or vertically) working with the building as a whole, - finding appropriate number of buildings to destroy partly (higher levels) or fully, - focusing to local natural and cultural environment, - cultural activities must be raised higher working together with local NGO-s, - new added levels, flats are not welcome. - other type of extensions can help to give some color and functions to the blocks. - existing building structure must be used, but not extended en term of using to much con- crete. - special designed facades, new balconies, sunrooms are welcome. 2.4.2 Accessibility In Hungary the people living with special needs are the group of the population have one of the lowest income. Main part of this group of people has no job, and the level of social help is very low, meantime all the expenditure is very high for them. The large block of flats has no special room for people with special need. Reflecting the poor housing estates areas, there group is represented higher in these flats, than in oterh part of the towns. There is a real need to ipmprove the outsidde areas, the staircases and elevators, and the flats according to these group of people. The Hungarian low and building code and regulation help to solve these technical problems.The main problem is, that these group has the lowest capability to fight for their rights. 2.5 Building physics 2.5.1 Dangerous materials The presences of dangerous materials are common. The biggest problem (for 40% of the build- ing) is the presence of asbestos. Asbestos was used as insulation material (in cellars, corridors, pipelines), and in other cases as fire-protection material. The asbestos itself was covered with textile and painted by oil-painting. During the decades the surfaces were damaged, and asbestos emerged to the surface, which is even more dangerous. The buildings, carpets, solvents, glues usually contain formaldehyde and toluene. If there was any renovation work during the last decades, it is sure, that the applied new floor-coverings, wall-painting, wall-papers were more dangerous. Reduced filtration ratio raised health prob- lems, asthma and allergy common. Conclusions and key-tasks: - When any refurbishment happens it is advisable to use natural materials. - “The good-practice” must be work-out and shown for the tenants. - Well established PR activity in term of “Healthy Building” can help for the tenants. - Local workshop and workers must have better knowledge about the “Healthy Materials”. 2.5.2 Thermal insulation The necessity of added thermal insulation is out of question now. All the refurbishment must be based on a well designed outside thermal insulation. The new insulation layer must be placed outside (to decrease cold-bridges). It is advisable to use mineral-wool or glass-wool instead of foam insulation materials, regarding the fire-safety problems. The new materials can be proven too: flax, wool, cellulose could be good solutions after it has fire-checked. A well designed outside insulation helps the thermal comfort in summer and winter. (The sur- face temperature is higher; the comfort is better in winter.) Summer cooling could be a problem, ventilation helps, shading (windows) and green facades help, and also the outside natural area helps a lot in summer. Conclusions and key-tasks: - Outside thermal insulation on facades: 10 cm as a minimum, 16-18 cm for passive-house. - Good insulation on flat roof: 20 cm as minimum, 30.35 cm for passive house. - Green roof is advisable to help summer comfort. - Specially designed new windows, three layers of glasses for north facades, and with shad- ing devices for the south. - Local workshop and workers must have better knowledge about the “Healthy Materials”. State of the Art: Hungary 93 2.5.3 Noise insulation Acoustic problems are very common in these type of buildings. The outside area usually noisy doe to the traffic noise. In some area not only the traffic of the local people and public transport exist, but transit through traffic. The inner noise is common too. The noise from the elevator, from the shafts and staircases are usual. Also the slabs have no sound-insulation, and due to lack of insulation the flats are noisy. Conclusions and key-tasks in order to reduce the noise problem: - Improved windows and terrace doors to reduce the outside noise. - Green facades help to reduce the outside noise from traffic. - To reduce the noise from the flat above, sound-insulation is necessary as an underlay of new floor coverings. - To show the good-practice good PR activity and local workshop is helpful. 2.5.4 Lighting Lighting performance is usually good. Geometric parameters of buildings help good day- lighting in rooms and kitchen. Because of the standard design, north and south facades have same window sizes. Literally all the bathrooms and toilettes have no natural daylight. There are buildings (about 10 %) where the inside staircase and inside kitchen are without natural lighting. Key tasks in order to improve lighting aspects: - using appropriate size of window during energy-conservation refurbishment - using solar PV system to help energy conservation in areas where artificial light is neces- sary during daylight period 2.5.5 Ventilation performance Buildings with 5 stories have natural ventilation for inner toilettes and baths. In most cases it is inadequate. Smell and vapor remain in the building. Using airtight windows mold occurrence is common. Where mold occurred, asthma and allergy emerged. Buildings with 11 or more stories have electric fans to ventilate bathrooms and toilets. Usual- ly the solution was using one big ventilation fan on the top floor, added to the flat roof. Bad de- sign caused noise problems, so the tenants (who live near the fans) use to switch it off. Key tasks in order to improve ventilation performance: - using appropriate proposed heat-recovery ventilation system when energy-conservation re- furbishment happen, - using special ventilated windows in kitchens, regarding to gas-cookers and small areas, - using time-switchers for dark areas, - using electric dryers as communal facilities, to help reduce moister content of flats, - light selves in staircases, and communal areas, 2.5.6 Energy performance As the building envelope has a pure design in term of energy consumption, this is one of the main problems of housing estates. (The families pay for heating 25 % of their income. And that is high!) District heating system works inefficiently (30% of the generated energy utilized in the buildings itself, huge amount of energy wasted during procession and transport.) The average required energy: 310 kW/m 2 /annual – for building from ‘60-ies 240 kW/m 2 /annual – for building from ‘70-ies 200 kW/m 2 /annual – for building from ‘80-ies Heat requirement is very high due to the low U-value of facades, the high air-change ratio, and cold-bridges. Bad thermal comfort during winter and summer. High cost in winter for heating, and in summer for cooling. Social problems occurred. State of the Art: Hungary 94 Key points in order to improve energy performance: - well designed outside insulation (min. 10 cm) - insulation against cold-bridges (where possible) - insulation of flat roofs (min. 25 cm), creating green roofs when possible, - improved windows with 3 layers of glass to the north façade, - decrease the size the north facing windows where possible, - improved windows with 2 layers of glass to the south façade, - increase the size the south facing windows where possible with shutters - built in glazed loggias as sunspaces - new system for heating, - solar devices: PV panels for electricity, solar collectors for domestic hot water, sunspaces, sunroofs where possible. CONCLUSIONS The huge number of flats from this period need a special care from government, politicians, architects and urban designers. The energy performance and environment conscious solution is very important, in order to lower the costs for tenants and community. In the meantime the arc- hitectural cultural and social questions have to be considered, and the solutions must be fit for the tenants and the settlements. The expensive skeleton of buildings and infrastructure with high embodied energy must be used in a new way, to offer better life and circumstances for all the users. The architects can sketch the possibilities; the politicians and tenants have to make the decision. REFERENCES Novák, Á., 1998, Paneles lakóépületek felújítása, Budapest, SZIE-YMMFK Csoknyai, T., Zöld, A. 2001, Surface conductance, fabric protection and heat loss. Proceedings of the PLEA 2001 Conference Csizmady, A., 2003, A lakótelep, Gondolat – Budapest Novák, Á., 2001, Kaland a ház körül, SZIE-YMMFK Novák, Á., 2005,Újpalota – Zöldváros, Újpalota közösségi ház Novák, Á., 2005, Eco-city concept for Budapest, Budapest, MUT Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. State of the Art: The Netherlands Marie Therèse Andeweg, Frank W.A. Koopman Delft, University of Technology, Department of Architecture ABSTRACT This paper gives an overview of the status of the post-war apartment stock in the Netherlands. It starts with an overview of the rebuilding of the housing stock since 1946 in which the progress of the production is recorded and the urban principles are described according to which the multi-family housing neighbourhoods are erected. This survey is followed by a description of the used technologies and typologies in relation to the date of completion and the applicable housing policy. The second part focuses on the problems and shortcomings of the Dutch post- war apartment stock as experienced over the last decade in relation to changes in the demand. 1 OVERVIEW OF THE HOUSING STOCK After WW II, the Netherlands experienced, as many European countries, a huge housing shortage. The main reason for this shortage was the fact that over 500,000 houses of the 2.2 million Dutch dwellings had been damaged or destroyed during the war. The repatriation of 97,000 Dutch citizens from Indonesia, which was at that time a Dutch colony, and the fact that large numbers of people got married now the war was over, contributed also considerably to the high demand for housing. The shortage was encountered by a rapidly increasing, large scale housing production. In the first year after the war only 1600 dwellings were built. In 1949 this number had already increased to 43,000 (10). New neighbourhoods of up to 5000 dwellings were planned and developed on the outskirts of the city centers. About half of the production was multi-family housing, and according to the CIAM principles, these building blocks were erected in parallel or perpendicular building blocks divided by green areas, meant for common use. In the first two decades after WW II, over 350,000 small 3- and 4-bedroom apartments have been built in the Netherlands according to these principles (13). 1.1 Data related to building periods The first post-war building program dated from 1946 and aimed for a yearly production of 12,500 houses. This number was rapidly surpassed. In November 1955 the completion of the 500,000 th post-war dwelling was celebrated (10). In 1960 the Dutch housing stock amounted to a total of 2.5 million dwellings. During the sixties one million dwellings were completed, and another 1.4 million between 1970 and 1980. In 1990 the Dutch housing stock added up to a total of 5.8 million and in 2000 it amounted to 6.6 million dwellings. Considering these numbers, the State of the Art: The Netherlands 96 Dutch housing stock is fairly young: 55% has been built after 1965, another 20% has been built between 1945 and 1965, and only 25% dates back to the period before WW II. With 68%, the single family home is the most common type in the Dutch housing stock. The remaining 32% is apartment stock. In 2000 some 35% of the Dutch housing stock consisted of dwellings with at least five rooms, excluding the kitchen and the bathroom, another 35% four rooms, 20% three rooms, and only 10% was a one or two room dwelling (10). In 1960, the Netherlands had a population of 9 million people and a housing stock of 2.5 million dwellings. In the year 2000 the population had increased to 15.9 million while the housing stock has expanded to 6.6 million dwellings (12). These figures show that the average number of persons per household has decreased over the last forty years from 3.6 to 2.4 persons. The average space used per person has increased over the same period of time from 25 m 2 to 55 m 2 . By combining the figures mentioned above, we can derive, that the total floor space of the Dutch housing stock has increased in forty years time with a factor 3.9. Figure 1: Social housing represents an exceptional large part of the Dutch housing stock (7) With 54% just over half of the Dutch housing stock is nowadays occupied by the owner. This number has been growing continuously over the last few decades. Approximately 11% is privately owned rental stock and the remaining 35% of the stock is social housing. Compared to other European countries this last percentage is exceptionally large. See figure 1. In the Dutch social housing stock the early post-war apartment stock as well as the high-rise apartment stock dating from the sixties and seventies is largely represented. 1.2 Description of main typologies The Dutch multi-family post-war housing stock can be divided into two major types of dwellings. The first two decades after the war multi-family housing was realized as what is now called in the Netherlands the ‘early post-war apartment stock’. Starting from the mid-sixties multi-family housing was mainly realized as high-rise apartment blocks. Below a short description of the main characteristics of these two types of apartments. State of the Art: The Netherlands 97 Figure 2 (left): Façade of a typical Dutch early post-war apartment block with basement for storage. Figure 3 (right): typical Dutch early post war floor plans of a two- and a three bedroom apartment. Early post-war apartment stock The early post-war apartment stock is realized in apartment blocks, three or four floors high, with flat or sloping roofs. A building block could contain up to 8 staircases, resulting in a minimum of 24 and a maximum of 64 apartments per building block. See figure 2. The building blocks are composed of symmetrical structures with a staircase hall in the middle, which gives access to two apartments per floor. See figure 3. The majority of these apartments was realized as 2- and 3-bedroom apartments with modest technical and functional quality. The average area for a 2-bedroom apartment – originally meant for a family with up to two children and an average income- is 58m 2 , and the average area of a 3-bedroom apartment, considered to be appropriate for a family with up to four children, is 68m 2 (1). According to the building code in force at that time, the living rooms had to take up at least 16m 2 with a minimum width of 3.5 m (2). In the living room a coal burning stove was fitted, being the only source of heat in the home. These apartments were poorly equipped and fitted with very small bathrooms and tiny balconies. There was often a basement present, used to provide fairly large storages. See figure 3. Sometimes parts of the basement were added to the apartments on the ground floor in order to create 5-bedroomapartments, meant for families with up to eight children. The presence of a basement meant that the ground floor had to be raised up to 1.2 meters above street level. High rise building blocks of the sixties In spite of the production of 1.2 million dwellings, some 20 years after WW II the housing shortage still existed. This was partly due to slum clearance and partly due to the population growth, the decrease of the number of people per household, and the increasing space consumption. In 1965 a new building code with higher technical and functional standards came into force. About the same time, in the northern part of the Netherlands the exploitation started of huge natural gas supplies. This enabled a large scale production of gas burning central heated dwellings. Finally, newly developed concrete slab floors with wider spans enabled architects to design new floor plans. As a result of these simultaneous developments, large numbers of fairly spacious high-rise apartments with elevator access and central heating were realized. One building block could contain up to several hundred apartments. See figure 4. State of the Art: The Netherlands 98 Figure 4 (left): façade of typical Dutch high rise building block from the sixties and seventies. Figure 5 (right): typical floor plan of a high-rise apartment block from the sixties. Compared to the early post-war apartment stock the functional quality of these high-rise apartments from the sixties is much higher. The average area for a three-bedroom apartment went up to 85 m 2 , balconies and bathrooms became larger and the apartments were supplied with a non-individually burned central heating. In general, there were three bedrooms, one double and two single. See figure 5. These apartments were designed for the most common type of household at that time, being a family with two children and an average income. The building blocks dating from the sixties are on average up to 10 storeys high and have flat roofs. There are a few examples known of 18 storeys high. On the ground floor there are no apartments situated, only storages. There is little or no differentiation in size or floor plans. The gallery-access results in a very economical use of the elevator. Generally speaking, there is one elevator present on every eight apartments per floor. This amounts to one elevator being shared by 80 apartments. These types of apartment blocks are always realized with in situ concrete. 1.3 Description of main technologies, traditional building materials and methods. Approximately 70% of the early post-war multi-family housing stock in the Netherlands has been completed with traditional building materials and methods (1). The traditional Dutch building principles are discussed below. 1.3.1 Structure/foundation For centuries the traditional Dutch way of erecting building structures has been to construct with brickwork load bearing transversal walls. On average, in house-building the spans between the load bearing walls measured up to 4 meters. Façades were never load bearing. In the western and northern part of the Netherlands, building blocks had to be founded on pile work, due to the poor bearing capacity of the peat and clay-soil. Until WW II, the common material for this pile- work was deal. The above mentioned building principles refer also to the traditionally built early post-war apartment stock. Some aspects, however, changed after the war. Instead of using deal for pile work a transition was made to concrete (14). In the eastern and southern part of the Netherlands, where the soil structure has a sandier compound, there was no need for pile-work. In these areas the apartment blocks could therefore been founded on a direct bearing slab foundation. State of the Art: The Netherlands 99 After WW II, the common building material used for floors gradually changed from deal to concrete. The most frequently used floor system in the early post-war housing stock is the Cusveller floor. It consists of prefabricated no-reinforced concrete beams. The reinforcement is placed between the beams and incorporated with in situ concrete. See figure 6. Figure 6: Section through a Cusveller floor (Jellema, 1958). The load bearing capacity as well as the sound-deadening capacity of Cusveller floors has proven to be limited and inadequate to nowadays standard. Redesign of these building blocks by joining existing apartments vertically, is hampered by the poor quality of these floors. Making an opening in this type of floor to fit in a staircase, for instance, is virtually impossible. 1.3.2 Roofs In the early post-war multi-family housing stock, both flat and inclined roofs occur. Generally speaking, roofs are constructed with the same materials as used for the construction of the floors. Steeper roofs constructed with a deal rafter are therefore to be found in apartment blocks with wooden floors. These roofs were finished with roof tiles. Flat or slightly inclined roofs were made of concrete slabs and finished off with two layers of asphalt felt and 4 cm gravel. During the first decade after the war, there was no thermal insulation whatsoever applied in the roof construction. Starting in the late fifties, cork or Schewil sheets were added to provide some form of thermal insulation. Since there was no damp proof course in the construction incorporated, and there was practically always a lack of ventilation, moist problems caused by condensation in the insulation sheets frequently occurred. The same form of thermal insulation was used for steeper, deal roof constructions, causing here even more severe problems, because now the condensation took place in the deal roof construction itself. The fact that the extra space under the steep deal roof was meant for drying laundry aggravated the situation. It took until 1970 before the first physical sound roofs were constructed. Condensation in roof structures is therefore a widespread problem in the Dutch post-war housing stock. 1.3.3 Façades Traditionally façades were made of brickwork and constructed as single layer walls or as cavity walls. Often, single layer walls had a clamp-layer added on the inside to improve its water impermeability. The impermeability of cavity walls could be improved by applying a mortar layer on the outside of the inner layer. There was no thermal insulation incorporated in the outer walls. For window frames the most common material was deal. All parts of the Dutch housing stock dating from before the first oil crisis were originally completed with single paned deal window frames. In contrast with most European countries, in the Netherlands the windows open to the outside, thus transferring the risk for leakage to the upper side of the windows, where the inclining brickwork can provide shelter from the rain. State of the Art: The Netherlands 100 Non-traditional building systems Because of the shortages in traditional building materials and skilled labour, the Dutch government provided in the first decades after the war additional quota for building with labour saving non-traditional certified building methods. To acquire certification, savings on skilled labour of at least 40% were required, as well as a guarantee for the same technical quality as could be obtained with traditional building. As a result, many non-traditional building methods have been developed over the first two decades after the war. In large cities 5-year contracts were given to contractors who built with a certified building system. The idea behind these contracts was that continuity would limit cost and lead to cheaper dwellings. The early postwar building systems can be divided into three groups: block unit building systems, large panel building systems and building systems using in situ concrete. Together they count for 30% of the Dutch early post-war apartment stock. The main characteristics of each group are discussed below. Block unit building systems This category contains all systems using large concrete building blocks with a weight of up to 25 kg, which made them movable by one man only. The most successful representative is the Muwi-system with over 30.000 completions between 1951 and 1968, (3). Structure The Muwi-system was originally designed for low-rise building. When used for building blocks more than five floors high, additional reinforced in situ concrete columns were applied in the outer walls to ensure sufficient stability. The building principle is that of a stacked construction of load bearing transversal walls. The building blocks were made of concrete with dimensions of 490 mm long, 210 mm wide and 194 mm high. For buildings over four floors high, building blocks with a width of 250 mm were used. Each block had two cavities in horizontal section of 160 x 177 mm, and after dry stacking the blocks in an alternating pattern, the blocks were joined together by filling the vertical open shafts with mortar, thus forming the load bearing wall. See figure 7. Figure 7: Dry stacking of Muwi building blocks (5 ) Figure 8: typical look of an early post-war building block completed in the Muwi building system with visible belt courses (14) In the early years non-bearing separations were made of small bricks of lava-split and cement, light-weight concrete or gypsum blocks. Later on, large panels with the same height and width of the rooms could be used with the help of small site cranes. These panels were 70 mm thick, existing of a core of 50 mm of slag concrete (wherein a netting of rebar’s Ø5-ç200mm, steel quality QR40) covered on both facings by 10 mm sand-cement mixture. State of the Art: The Netherlands 101 Floors The Muwi-floor system consists of supporting reinforced prefabricated concrete beams and matching concrete filling blocks. See figure 9. The dimensions of the beams were indifferent of the span. Wider spans were realized by decreasing the distance between the beams. The dimensions of the filling floor units varied therefore from 390 mm to 500 mm (5), resulting in a centre distance between 490 mm and 600 mm. Figure 9 (left): filling block in Muwi floor system. Figure 10 (right): incorporation of Muwi floor system in the structure. Muwi-floors were incorporated in the structure with in situ concrete beams. The rebar of the concrete floor beams was longer than the beam itself, thus anchoring the beams to the walls. See figure 10. At the connection of the floors with the façade an in-situ concrete lintel was poured to support the outer leave of brickwork. These lintels appear as belt courses in the outer walls and give the Muwi-building blocks a characteristic appearance. See figure 8. These belt courses cause thermal bridges, which still prove to be one of the major technical problems with this system. For buildings with more than four storeys the load bearing wall ends with an in situ poured concrete column on the connection with the façade. In this way the structure transformed into an in situ concrete framework, giving the additional stability required for higher building blocks. The gaps between the beams and filling blocks were covered by a 15 mm layer of vermiculite concrete (1 pc:1 vermiculite: 3,5 sand). On the downward facing side, there was a difference of 15 mm between the floor beams and the filling blocks in which electricity ducts were placed. For electricity ducts perpendicular on the main bearing direction slits were made in the lightweight floor blocks. Roofs The roofs of Muwi-apartment blocks are usually flat, and constructed with the same elements as used for the floors. There is some thermal insulation incorporated in the roof construction, but compared to nowadays standards absolutely inadequate. The roofs were finished off with two layers of asphalt felt and gravel. Façades The outer walls were carried out as cavity walls with on the inside a stacked building block layer as mentioned above, then a cavity of 5 cm and a traditionally built brick outer layer. In the façades there was no thermal insulation applied whatsoever. Panel building systems As a representative of this category, the BMB building system (Simplified Brick Construction). This system originated from England, where it was developed by a Mr. Henri Dyke. Originally this system was designed for low-rise building, but can be used for building blocks up to 12 floors by adapting the dimensions and the composition of the concrete. It was certified in the State of the Art: The Netherlands 102 Netherlands in 1952 (9). For the composition of the concrete crushed brickwork emanating from houses destroyed in the war was used. BMB is therefore an early example of sustainable building. Almost every element was prefabricated, since over 10.000 dwellings have been built with this system, it was fairly successful, the last completions dating from 1969. With this system, the savings on skilled labour can be up to 70%, which is much higher than the minimum of 40% which was required for certification. Structure Both load bearing and separation walls were made of prefabricated concrete elements with a maximum length of 3130 mm and a height of 1450 mm, which is half a storey high. Wall elements are 70, 100, 140 or 200 mm thick, depending on the use as a separating wall or as a load bearing wall. The composition of the concrete is adapted to the required strength. For load bearing walls the composition in parts by volume is 1 part Portland cement: 1 part sand: 2 parts gravel: 8 parts of crushed brick. This results in a volume weight of 1700 kg/m 3 and elements with a weight of up to 2400 kg (9). All wall elements are finished off with a thin layer of plaster. Floors/Roofs The floor system used with this building system was also made of prefabricated concrete slabs with a width of up to 1600 mm. The flat roofs are constructed with the same elements as used for the floors and finished off in a similar way as described with the block unit building system. Some older BMB building blocks are completed with inclining deal roofs. Façades The outer wall elements were carried out as cavity wall elements. The inside layer being a prefabricated concrete panel of 10 or 14 cm thick, the outside layer made of mechanically laid bricks. This is done by fitting the loose bricks in a mould, and afterwards this mould is filled with mortar. The two layers were fitted together before transferring the finished elements to the building plot. There is no thermal insulation incorporated in these elements. See figure 11. Figure 11 (left): Cavity wall elements of the BMB building system with concrete inside layer and an outside layer of mechanically laid bricks. Figure 12 (right): Typical façade of an early post-war building block completed in the BMB building system. The dimensions of the outside wall elements equal the dimensions of the load bearing elements. The joints in the façades give these building blocks their typical appearance. See figure 12. State of the Art: The Netherlands 103 In- situ concrete building systems As a representative of this building principle Korrelbeton (No fines concrete). The system was invented by the Dutch architect W.Greve (8). The original idea dates back to several decades before WW II. In 1921 there was a try out with this system, when the still famous ‘Betondorp’ (Concrete village) was built near Amsterdam. The system was therefore ready for production straight after the war, and the first apartments were completed in 1946. Figure 13 (left): Korrelbeton, standardized shuttering for outer wall (5). Figure 14 (right): façade of a building block completed in Korrelbeton with a single layer concrete façade. The in situ concrete used in the Korrelbeton building system was mixed with broken brick coming from buildings bombed in the war, which made this system very suitable for the early post-war period (3). The shuttering used for the moulds was standardized to such dimensions that all parts could be handled by one man only. See figure 13. The system has been used for single family houses as well as for low-rise multifamily housing. Structure Since this building system was based on the reuse of old building materials the walls had to be fairly thick. For low-rise building blocks the walls were either 200 mm or 250 mm wide, depending on the load and height of the building block. For high-rise building blocks the system provided wall elements of 300 mm thick. The standard composition of Korrelbeton concrete in parts per volume is: 1 part Portland cement: ¾ part fine sand: 10 parts of broken brick, resulting in a weight per volume of 1300 kg/m 3 . When needed for constructive reasons a higher density is used. For low-rise building blocks, Korrelbeton concrete does not need any reinforcement. In these cases the risk of corroding rebar does therefore not occur. When used for the production of high-rise building blocks, reinforced concrete columns are added on the joints of the outer walls and the load bearing walls. Floors/Roofs The floor system used in this system consists of two layers of concrete with a different composition. On top of a 30 mm thick layer of concrete with a composition as described above, a top layer of high density concrete was poured. The composition of this top layer is: 1 part Portland cement: 3 parts crushed bricks (0-5 mm): 3 parts crushed bricks (5-10 mm), resulting in a total weight of the floor construction of 1850 kg/m 3 . As a result of the high density of the concrete, the sound-insulation between vertically adjacent apartments is in this system better than average. The roofs were completed according to the same principle, but with a thin layer of thermal insulation incorporated between the two layers. Due to a lack of ventilation this layer could end up staying damp. State of the Art: The Netherlands 104 Façades Originally the outer walls were 200 mm thick and monolithic. The composition of the concrete is similar to the description above. These façades were finished off with a layer of plaster. See figure 14. In later days an outer layer of brick was added to give the walls a more traditional appearance. As a result, the thickness of the concrete inner layer of the façade could be reduced to 150 mm. High-rise building blocks The high rise building blocks dating from the sixties and seventies are always realized with in situ concrete. During the seventies this building principle became the new traditional building in the Netherlands for the apartment stock as well as for single family dwellings. It allowed a rapid production of large numbers of dwellings that finally solved the post-war housing shortage. Structure The load-bearing walls of the high-rise apartment blocks are made with traveling formwork. The formwork could be either tunnel moulds or wall formwork. The tunnel moulds allowed the floors to be poured at the same time with the load bearing walls. Depending on the height of the building block, these in situ concrete walls had to be at least 180 mm thick. The non-bearing separation walls were made of light building blocks. Gypsum blocks or gas concrete blocks or the most commonly used materials. Floors In the sixties and seventies there were two systems in use for creating the floors in high-rise apartment blocks. In the first method the floors were created by pouring concrete on 50 mm thick prefab wide-slab flooring elements. With this method the prefab elements were used as a mould for the in-situ concrete. The other option was to pour walls and floor at the same time, using a steel tunnel as a mould. These tunnel moulds were supplied with a heating system, to speed up the hardening of the concrete. Thanks to this heating system the moulds could be removed after 24 hours. Usually these high-rise apartment blocks had a gallery-access. The galleries were made of prefabricated and pre-stressed concrete elements. These were attached to the building block by consoles. The balconies were created according to the same principle. Façades The formwork for the in-situ concrete structure was standardized, to enable the use of prefabricated outer wall elements. The most common way of forming the façades in the longitudinal walls was the use of storey-high prefabricated timber frames with the windows incorporated in the structure. An alternative was a façade with an inner layer of gas concrete blocks and an outer layer of brick. 1.4 Housing policy The first two decades after the war there was a large shortage of skilled labourers and traditional building materials. To speed up the building production, the government subsidized the use of standardized floor plans (6). To assure a fair distribution of the building production, every municipality was awarded a yearly quota, which proved to be quite insufficient. In addition to this quota, supplementary building permits could be obtained for building with a non-traditional certified building system. Certification was granted if, compared to traditional building, savings of at least 40% on skilled labour could be obtained, and the method resulted in houses of equal technical quality as traditionally built houses. As a result of this policy, many non-traditional building systems were developed in the first two decades after WW II. The main characteristics of representatives of the various building principles have been discussed above. State of the Art: The Netherlands 105 Over the years the Dutch government has created various subsidies to stimulate both the housing production and to improve the quality of the existing stock. The first large-scale operation to improve the quality of the existing stock took place in the seventies and was aimed at the pre-war housing stock. The purpose of the ‘Beschikking Geldelijke steun Rehabilitatie 1972’ (Decree Financial Support Rehabilitation 1972) was to stimulate joint ventures on improving the technical quality of the private prewar rental stock. It was not successful. Individual subsidies proved to be only successful with private homeowners who didn’t really need it. Not until 1990, the focus has been on improving the postwar housing stock. Since the first oil crisis, improvements on the energy consumption of the existing stock have been stimulated by the government. Over the years, various subsidies on energy saving have been introduced. These subsidies were all in force only temporary, and could be obtained for measures taken to improve the thermal insulation of a dwelling as well as for the purchase of economical heating systems or active solar systems. Thanks to the regularly revision of the requirements concerning the energy performance, the energy consumption of new completions has much improved over the years. In principle, the latest requirements are only valid for new completions. Dwellings realized in redeveloped building blocks however, are to a certain extent required to meet the present demands. 2 TOPICS. QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK Directly after WW II, in 1946 the government issued a preliminary building code. Revisions aiming for technical improvements came into force in 1951, 1965, and again in 1976. The revision of 1965 focused on adaptations of the minimum required areas, causing a significant higher functional level of newly completed dwellings. In 1992 the building code was more radically changed. This new Building Code has been revised in 1996, 2003 and 2005. The most significant changes from the last decade concern the increasing demands on thermal insulation. Every five years the Dutch government conducts a random check survey to establish the quality of the housing stock. This survey is called the KWR or ‘Kwalitatieve Woning Registratie’ (Quality of Dwelling Registration). The latest survey dates back to 2001. According to the data obtained in that survey the technical quality of the Dutch housing stock as a whole is considered to be very good (4). Compared to the previous survey the situation has substantially improved. 2.1 Physical aspects Before the first oil crisis, there was hardly any thermal insulation being applied in the Dutch housing stock. The first requirements concerning thermal insulation date back to the building code of 1965 and apply to the roof only. Since then the requirements have been steadily increased. Over the last few decades the original single paned deal window frames of the post- war apartment stock have been replaced by new double paned window frames. This is the only type of thermal insulation that has been widely installed. Thermal insulation of the rest of the envelope is not yet done on a large scale. Many early post-war apartments are not yet supplied with central heating. Because of the poor heating facilities, tenants cut back on ventilating. This results in condensation, dampness and mould, and may easily lead to health problems. 2.1.1 Thermal insulation Since the eighties the government has created several subsidies to stimulate thermal insulation for the existing stock. The requirements for newly built dwellings have been increased ever since. Nevertheless, in the existing stock built before 1970 the level of thermal insulation is still considerably lower than nowadays standard, which is a Rc-value of 3m 2 K/W for the total State of the Art: The Netherlands 106 construction of façades and roofs of newly built dwellings as dictated in the Dutch building code dating from January 2003. The same kind of problems can be noticed with the high rise building blocks dating from the sixties. These types of apartments are often supplied with a collective central heating system. In practice, this proves to be less efficient in energy consumption and it is less popular with tenants than an individually burned central heating system. In some cases housing associations have already replaced the original collective central heating systems by individually burned central heating systems. 2.1.2 Protection against moisture Protection against moist is not a big issue in the Netherlands. In the past, there have been some problems concerning the impermeability of single layer brick façades in the early post-war apartment stock, but these problems have been long solved by adding an impermeable layer on the façade. As a rule, since the sixties all outer walls are constructed as cavity walls. Since the eighties there has been thermal insulation incorporated in the cavities. Condensation due to thermal bridges is a widely spread problem, that is usually tackled with the application of outer wall insulation. 2.1.3 Noise insulation In both the early post-war apartment stock and the high rise building blocks dating from the sixties and seventies, the noise insulation is definitely not up to nowadays standard, which is +5 dB between adjacent apartments according to the building code dating from January 2003. The previous standard dated from 1962 and was set on 0 dB. Before that date there were no specific requirements at all. Improvements on noise insulation have proven to be difficult to achieve. Obvious solutions, like adding double ceilings or floor insulation take up several centimetres of the height of the rooms. The rooms in the post-war apartment stock are generally only 2.4 meters high. Since the minimum height for new completions is presently set on 2.6 meters, this is not an option with this part of the housing stock. As a rule, housing associations try to minimize the problem by prohibiting floorboards, floor tiles or parquet floors in the lease. Although more improvements on thermal insulation are essential in all post-war apartment stock, it is save to conclude that the main problems we are experiencing with these parts of the housing stock are not caused by a lack of technical quality. 2.2 Structural aspects According to the latest KWR survey conducted by the Dutch government in 2001, there are no serious structural problems with the Dutch post-war apartment stock (4). 2.3 Functional aspects The functional shortcomings of the early postwar apartment stock are numerous. With an average area of less then 70 m 2 , the lack of space is a major problem. Especially the size of the living room, the bathroom and the balcony is not up to nowadays standard. The equipment of bathrooms and kitchens is insufficient and the layout of the floor plans, with the bathroom being off the kitchen, is out of date. According to modern standards, the high-rise apartments of the sixties are quite spacious and reasonably well equipped. The functional quality can easily be further improved with the fitting of new kitchens and bathrooms or by adding bigger balconies. 2.3.1 Safety Over the last decade, both the early post war areas and the high rise stock built dating from the sixties and seventies are socially and economically in decline. Although the features of the early post-war neighbourhoods and the high rise areas dating from the sixties are quite different, in State of the Art: The Netherlands 107 both areas similar problems occur, like high crime rates, filthiness, vandalism, a deteriorating reputation, and a high mobility rate. Since the social problems in these two very different types of neighbourhoods are of a different origin, the solutions to solve them have to be also different. In early post-war neighbourhoods, one of the main problems with the housing stock seems to be the high concentration of cheap, small apartments. Due to their size, early post-war apartments are nowadays only acceptable for singles or couples with a very low income, which denies them any choice. People hardly ever choose to live in these types of apartments and feel no attachment to the neighbourhood. They leave the area as soon as they can afford a higher rent. Solutions therefore, need to aim for a reduction of the high mobility rate by adding more high quality housing. Since these areas are close to the city centres with all the facilities, and generally speaking well connected by public transport, as a location, these neighbourhoods are quite suitable for more upmarket dwellings. More differentiation of the housing stock can be realized by demolishing the original building blocks and replacing it by new dwellings or by the renovation of the existing stock. Dutch early post-war building blocks are quite suitable for this last approach, since they prove to be very versatile. Three-bedroom apartments can be easily transformed into two-bedroom apartments creating a sizable living room and bathroom. With a more radical approach apartments can be renovated by joining them horizontally or vertically to form spacious one or two floor apartments or even single family houses. Since town plans tend to develop in concentric expanding circles, the areas developed in the sixties are situated at a larger distance from the city centers than the early post-war neighbourhoods. As a result, they have a fairly low level of facilities. The sheer size of these areas contributes to the lack of atmosphere. The mass-production and one-sidedness of the building blocks has resulted in a lack of identity which leads to insufficient social control. Considering the above, renovation of the high-rise apartments dating from the sixties requires adding identity to the building block as a whole and giving it a more up market look. This is done by adding architectural quality to the entrance halls of the building block. Mural paintings and the application of coloured thermal insulation may also help to give eye-candy to the building blocks. Adding extra elevators and dividing the long galleries into smaller parts scales down the size of the building blocks. Although this kind of measures may help, on there own they have proven to be insufficient for large scale areas. 2.3.2 Accessibility Accessibility is a major problem of the early post-war multifamily housing. The ground floor is usually raised up to 1.2 meters above street level, resulting in even a poor accessibility for the ground floor apartments. As a rule, the staircase halls are too narrow to put in an elevator, and even if you manage to put one in, it will only give access to two apartments per floor, because of the staircase hall-access. This means an elevator can only be used by six or eight apartments in total, which doesn’t make it very cost-efficient. In principle there are two options to reduce the cost for elevator-access. The first one is by adding an extra floor to the building block and giving this floor a gallery-access. The pile work foundations used in this part of the stock can cope with an extra weight of 10%, which means one extra floor can be added using lightweight building materials (11). The other option is to replace the original staircase hall-access by a gallery-access. This requires a revision of the existing floor plans shifting the entrance door from the center of the building block to the front. This option is often combined with adding a new addition to the building block, containing more spacious apartments and an elevator. The accessibility of high rise apartments can be considered to be excellent in every way. The building blocks have elevator-access, the apartments are spacious, the spans are fairly wide and all rooms are situated on one floor only. State of the Art: The Netherlands 108 Over the years, many action-plans have been developed to deal with the problems mentioned above. A simple updating of the housing stock, to improve the technical and functional quality as has been done in the eighties, has proven to be insufficient. For a good chance of success, renovation programs should also involve economical improvements and social changes, provide for improvements in infrastructure and public transport, and include the restructuring of the green areas. 2.4 Architectural aspects Among Dutch architects there is a difference of opinion whether or not the early post-war apartment stock has a certain architectural quality. Some architects try to keep the original features intact while renovating the interior. Others try to alter the appearance of the building block as much as possible and in order to give these building blocks a more upmarket look. In many early post-war building systems there are thermal bridges caused by belt courses. Thermal insulation applied on the outer walls results not only in a lower energy consumption, but it also solves problems caused by these thermal bridges at the same time. This kind of insulation seems therefore particularly suitable for renovating apartments completed in one of these building systems. When some colour is added to the thermal insulation, it has a helpful side-effect in giving eye candy to the building block and hiding bad spots in the brick work. Among Dutch architects, the application of thermal insulation on the outside of the building block is one of the main points of dispute. Some believe the original brickwork to add to the architectural quality of this part of the stock. CONCLUSIONS Since 75% of the stock has been built after WW II, the Dutch housing stock is fairly young. The majority of the stock is realized as single family housing. Only 32% of the dwellings is multi- family housing. With 54% just over half of the Dutch housing stock is occupied by the owner. About 11% is privately owned rental stock and the remaining 35% is social housing. This last percentage is compared to other European countries exceptionally large. In multi-family housing dating from the period after WW II, there can be distinguished two major categories: the early post-war apartment stock which consists mainly of small two- and three-bedroom poorly equipped apartments, and the more spacious high rise apartments dating from the sixties and seventies. Both categories are largely represented in the social housing stock. From a technical point of view, the quality of both categories has substantially improved over the last few years and can now be considered to be good. In both categories, however, further improvements are needed on the energy performance. As a result of inadequate heating facilities and insufficient thermal insulation tenants cut back on ventilating. This results in dampness and mould and may lead to health problems. From a functional point of view, the quality of the early post-war apartments is poor. The overall space is limited, the dimensions of living rooms, bathrooms and balconies are not up to nowadays standards, and the apartments are poorly equipped. The staircase hall- access without elevator makes this part of the stock not suitable for elderly people. High-rise apartments dating from the sixties have a much higher functional quality, are reasonably well equipped, and can be considered to be accessible for senior people in every way. Although the features of the early post-war neighbourhoods and the high-rise areas are quite different, both areas struggle with similar social problems like filthiness, a high crime rate, vandalism, a high mobility rate and a deteriorating reputation. Partly, these problems are caused by the accumulation of cheap housing. Therefore, more differentiation by adding more State of the Art: The Netherlands 109 upmarket dwellings is necessary. Early post-war apartment blocks are quite versatile and can be redesigned into spacious apartments or single family houses. The functional quality of the high- rise apartments dating from the sixties is acceptable. The social problems in these areas are partly related to the lack of identity and the sheer size of the building blocks. Here the focus has to be on scaling down the size of the building blocks by adding elevators and dividing the long galleries into smaller parts. Adding identity to the building block as a whole is usually done by giving a more upmarket look to the entrance hall. The application of thermal insulation on the outside of the building block improves the energy performance of the individual apartments, as well as adding identity to the building block as a whole. REFERENCES (1) Battum, M.T. van: Enige (on) mogelijkheden van portieketagewoningen bij herstructurering van vroeg naoorlogse wijken, (bouwkunde TU Delft), Delft (2) Dutch Ministry of Housing and Urban Planning, 1951: Voorschriften en Wenken voor het ontwerpen van woningen, The Hague (3) Elk, R.S.F.J.van en H.Priemus, 1970, Niet-traditionele woningbouwmethoden in Nederland, Stichting Bouwresearch, The Hague (4) Dutch Ministry of Housing, Urban Planning and the Environment, 2001: Kwalitatieve Woning Registratie 1999-2001, The Hague (5) Groosman, E.F. 1960, Nieuwe bouwsystemen voor woningen, Cement 12, nr 8, pages 666-670 (6) Haan, H.de, en J. Haagsma, 1983, Een onderwerp van voortdurende zorg, het naoorlogse bouwen in Nederland, Utrecht (7) Oxley, M. and J. Smith, 1996, Housing policy and rented housing in Europe, London (8) Ratiobouw, 1951, Systeem korrelbeton, The Hague (9) Ratiobouw, 1952, Systeem BMB, The Hague (10) Siraa, H.T., 1989, Een miljoen woningen, SDU, The Hague (11) Stuurgroep Experimenten Volkshuisvesting, 2001, Optoppen, Rotterdam (12) Social and Cultural Planning Office, kerncijfers 2004 (13) Thijssen, C.C.F. and C.J. Meier, 1988, Bouwconstructieve analyse van naoorlogse meergezinshuizen in de non-profit huursector 1946-1965, Delftse Universitaire Pers, Delft This page intentionally left blank Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW ON THE HOUSING STOCK (*) Multi storey family housing represents only a limited part of the total existing housing stock in Belgium. Large neighbourhoods with single housing predominate the multi storey housing buildings as, even in the so called ‘social housing’- sector, people preferred living at the coun- tryside and, when possible, in a individual house with private garden. Neighbourhoods with more than 200 such houses are no exception! Due to the lack of efficient and/or clear govern- ment policy in the field of urban planning and land use in the 1950’s and 1960’s, several social neighbourhoods were implemented in between existing private housing developments. This might be different from neighbouring countries where social housing estates were mainly con- centrated in large uniform compounds at the edge of the city. For that reason, speaking on “post-war multi storey family housing” in Belgium, is speaking on a quite small part of the existing housing stock. By “multi storey” housing, we understand low rise (3 to 5 levels), middle high (5 to 10 levels) and high rise (11 and more levels). In popular language one speaks about “apartment housing“ and according to recent data, this type of hous- ing takes about 20 % of the total housing stock in our country (public and private together). State of the Art: Belgium André De Naeyer Associate Professor, University College Antwerpen, College of Design Sciences Henry vande Velde, Antwerp, Belgium ABSTRACT: The housing market in Belgium is strongly determined by national policies since the late XIXth century. The post war housing developments depend mainly on two laws, these being the ‘De Taeye Law’ and the ‘Brunfaut Law’. Their targets were, and continue to be, to of- fer financial contributions to individual builders and to give subsidies to cities or building socie- ties to built new housing. The main part of the housing market consists of houses for one family occupancy, and only a very small percentage of the market involves multi-storey buildings from three to over eleven stories high. The structural and architectural characteristics relate to urban aspects, architectural models, load bearing structures and the level of prefabrication. The mayor part of the overall housing stock (about 70 %) is in good condition. Problems that demand atten- tion are the urban concept, safety and comfort, and building physics. This contribution will highlight some aspects concerning the buildings envelope. State of the Art: Belgium 112 Fig. 1: Households by tenure status (%) in EU countries in 1996. (source: http://www.stat.fi/tk/el/ echp_national_characteristics_remain _in_housing.pdf) Compared to other countries, this is indeed a quite small sector, but it can be explained histori- cally. From the creation of Belgium in 1830, real estate and private property has always been considered as a very important index for wealth and social success. Living in his/her private owned house, preferable with small garden, was (and still is!) considered as the main economic objective in ones life! This is also illustrated by the statistics: in 2001 77 % of all Belgian fami- lies (excluding Brussels) was living in their private owned single house with private small (or big) garden. In the Brussels Region on the contrary, only 34 % of the families lived in their pri- vate house with garden (as the capital city of the country, the demographic and economic pres- sure since 19th century has been the most important barrier for the same level of ownership as in the rest of the country). The other 66% in Brussels had to be divided in owners without gar- den (= apartments) and renters! (1). As in the whole of Europe, after World War I also Belgium had an acute housing shortage up to about 100 000 units. Idealism about a new society and new ideas on architecture and urban planning, brought realizations following ‘Functionalism’ and ‘Garden city’ models already be- fore World War II. However, the scale of those Belgian projects was usually not that great as in other European countries. This had also to do with the fact that at the national level there existed a dilemma: on one hand, some were stimulating private property to be obtained just outside the cities or in the countryside; on the other hand, there were those who wanted to promote social housing for renting in the city centres. Because of the growing strength of socialism as a reac- tion on the very poor housing and living conditions of the labourers, the Russian revolution of 1917 and the right to vote for all male inhabitants, the government decided to promote private property which resulted in the law ‘De Taeye’ (1946) and the law ‘Brunfaut’ (1948). This first law attributed considerable financial help from State to every individual building his first new house. The second law attributed subsidies to cities or building societies for equipping new urban housing developments with public roads, sewage systems, public lighting, etc.... Both these laws are still valid - and were later (i.e. in 1975) extended to renovation works on ex- isting houses. Since the l980’s, many other political and financial initiatives were taken to pro- mote and incentive all kinds of housing renovation (e.g. the VAT reduction to 6 % instead of 2l % for new buildings) and recently special ‘revitalization subsidies’ for new (or renovation of) housing in the old and decayed city districts. All this favourable conditions, together with a, up to ± 10 years ago, very lax town planning pol- icy, made the Belgian urban town- and landscape as it is, i.e. very individual, poorly homogene- ous, full of contrasts and not always community minded! Owner-occupied dwellings Rental dwellings, public sector (incl. voluntary or non-profit agen- Spain Ireland Greece Belgium Italy Luxemburg United- Kingdom Portugal Finland F 0% 20% 40% 60% 80% 100% State of the Art: Belgium 113 1.1 Data related to building periods Belgium has a total population of 10 500 000 people and a housing stock of 3 992 982 units of which 68 % (2 715 228) is in private ownership. The Flemish and Walloon region both have 72,6 % private owned houses (1 668 886 in the Flemish region and 883 328 in the Walloon re- gion) while the Brussels region only has 41,3 % (163 014). (1) The Flemish region (northern half of Belgium) has a total population of 6 000 000 inhabitants and a total housing stock of 2 150 000, being individual houses (78,5 %) and apartments (21,5 %). About 70 % is used by a private owner and 30 % by renting tenants, to divide in 25 % pri- vate renters and 5 % social renters. A 35 % of the houses are build before 1945, while 54 % are built between 1945 and 1980, and after 1981 about 11 % of the housing stock was raised. A good quality label is given to 68 % of the housing stock, meaning there are no visual de- fects and there is a minimum equipment provided such as bathroom, heating, electricity, etc. About 20 % is of medium quality and needs a renovation with cost estimation of less than 20 000 €. The remaining 19 % is in a bad shape and needs renovation with a cost exceeding 20 000 €. From the 300 000 units in this condition 55 % is used by the owner and 45 % is rented. 1.2 Description of main typologies (2) The present Belgian multi housing estates must be divided into two groups: the single storey row housing estates and the multi storey housing ones. The first group (and maybe the most frequent one) are estates with single family dwellings, some of them still inspired on the ‘garden city’ idea from the 1920 – 1940 (i.e. with detached single houses), but most of them are lines of rows of houses with small private garden disposed according different street patterns. 1.2.1.1 Multi housing developments Although this first group of single row housing estates is not within the direct scope of this COST C16 action, it is interesting to see that the development of the architectural plans of those single storey houses can useful be compared to those of the multi storey housing models, espe- cially within the low-cost (social) housing projects. Semi-public housing societies such as NMGWW (‘Nationale Maatschappij voor Goedkope Werkmanswoningen’ = National Society for Low Cost Laborers Housing) presented in 1948 so called ‘reference plans’ for labourers houses. The central Government promoted the creation of model ‘villages’ and avant garde ar- chitects were asked to develop low cost prototypes. The aim was to give every family the possi- bility to live in their private owned house ! Well known but poorly successful in practice was the semi prefabricated so called EGKS (Europese Gemeenschap voor Kolen en Staal) house, created by W. Van Der Meeren and L. Palm in 1954. Also for high rise building, prefabrication and standardization was a very important issue at that time. This is one of the reasons that the present technical problems concerning future improvement are quite similar in most estates. State of the Art: Belgium 114 Fig 2: Reference plan of a row house of the NMGWW (1948). This plan already shows the chaining of spaces as currently still favoured Fig. 3: Island Malem in Gent. 150 social row-houses were build in several phases. In combination with the reference plans, the NMGWW also defined a package of minimum re- quirements regarding implantation and surface. According to these minimum standards, a fam- ily with one child needs 51 m² habitable space while families with four children require 95 m². No further specifications were elaborated, but the fact that these reference plans and the mini- mum standards were defined, shows the growing concerns for the social environment and living conditions. This was in 1947 a necessity as more than 1/6 of the city-populations lived in too small buildings to house their families. From 1948-1949 the NMGWW also required that the orientation towards the sun had obligatory to be taken into consideration by the architects, and the east-west orientation of the front of the house was recommended. Fig. 4: Ground floor of ‘galery’flat of two levels de- signed by Van Der Meeren for the multi storey resi- dences in Evere (Brussels) The analogy with the archi- tectural floor design of the EGKS house is obvious. Fig. 5: Prototype house (EGKS), by W. Van Der Meeren & L. Palm from 1954 Partly prefabricated and conceived for se- ries of 50 houses, each of them to be built in 1 month time. The architects of the EGKS house started from the idea of an ideal volume of 250 m3 with a base of about 7 x 7 m and two times 2,5 m height. Within this compact volume, the most eco- nomical and comfortable layout was pursued. The modular construction is assembled starting from the metal skeleton in which the openings for doors and the space for the living rooms are already provided. After which the brickwork common walls (20 cm) are made in combination with the floors and the roof. The interior walls are placed in metal structures and have a high State of the Art: Belgium 115 degree of finishing thus avoiding time consuming and expensive plastering. For the floors and ceilings, the architects make use of completely finished plates to reduce manual labour. All ele- ments are made in the factory and only need to be assembled on-site. In co-operation with the NMH (National Housing Society) and the NLM (National Land Soci- ety) model village were built in each region, named ‘Villagexpo’; in 1972 one was realised in Limal by the NLM and in 1973 one in Knokke-Heist by the NMH. In spite of clear differences regarding target audience (buyers or renters), different type of construction companies, and the local social housing companies, the NLM and even more the NMH, had one common goal: get acquainted with and get convinced of the benefits of prefabrication and industrialised building techniques. A solid, reliable, fast and cheap building technique, linked to an excellent organisa- tion of grouped buildings was the focus. Therefore those constructors already experienced in prefab buildings, were selected to build such “model villages”. In despite of the noble aim of these realisations, many considered it being an instrument for public relations for the building firms, rather than a solution for the post war housing needs. 1.2.2 Apartment housing After world war II this housing needs were very acute, and thanks to the experiences with the single row housing systems, the theoretical flexible plan-model units, and the (small) experi- ences with standardisation and prefabrication, everything was in place to tackle the problem by going for the CIAM ideas and multi storey housing estates. Models were setup to define the po- sitioning of the units and the space around them. Unfortunately, the planned open green space (90 % of the available space) was often seen by the local builders as lost space to be filled in for practical use. Belgian examples of modernist architecture are Plain Droixte (Luik), Modelwijk (Brussel), Kiel (Antwerpen), St. Maartensdal (Leuven), CIAM (Mechelen), Watersportbaan (Gent). Fig 6: ‘Luchtbal’ in Antwerp. The concentration in monoto- nous buildings (more than 150 apartments in each one) of mainly low income groups, causes today great feelings of un- safety. State of the Art: Belgium 116 Fig 7: Liège, social housing at Plaine de Droixhe, designed by Groupe EGAU (C. Carlier, H. Lhoest, J. Mozin) 1951-1970 (Photo: Ghent University, Dep. Architec- ture & Urbanism) These projects gave direction to the ideal view on the new building style in Belgium, in spite of the poor overall city planning. Still they define the shape, the skyline of the city. However, these high-rise buildings had their problems. It was not easy to fit the individual units into the puzzle. The positioning of the apartments wit a vertical grouping of the ‘wet cells’, the linking of simi- lar rooms, limit noise hinder, the use of standardised building blocks resulted in unexpected problems, not to be solved easily. To reduce costs, the choice of staircases (the number and the position), had to be considered carefully. The models with only one elevator or staircase serving the highest number of apart- ments were the most favoured. As a disadvantage of those types, one got often dark and unsafe corridors, uniform like struc- tures and a far from optimal orientation of the apartments. This contributed to the negative feel- ings about these apartment-blocks. To overcome this, alternative solutions were worked out for the internal circulation with the purpose to create an identical orientation for all units. Another option was to have an own vertical circulation-zone per two or four apartments. On the positive side, it has to be said that these living units all were equipped from the begin- ning with a bathroom, central heating an elevators for accessibility. Till the 70’s the concept remained inspiring but due to lack of interest in creating an appeal- ing environment, green zones, around the buildings this was never a satisfying solution for the massive housing needs. (3) State of the Art: Belgium 117 Fig. 7: facade and section of social housing development 1949-1958 at ‘Kiel’ Antwerpen, by arch. R. Braem. (Photo Ghent University, Dep. Architecture & Urbanism) 1.3 Description of main technologies 1.3.1.1 Structure/foundation The architectural model was low-rise as well as middle-high and high with a central staircase, lateral corridor, with or without split-levels. Mostly traditional brickwork was applied, concrete precast or on-site (very little steel constructions, no wood at all). The outside walls were dou- bled (10/5/14 cm) with inside air space (humidity protection) an no thermal insulation. 1.3.1.2 Roofs/floors Mostly traditional woods (rafters and board), concrete on site, prefab floor slabs or concrete beams and concrete or brick floor tiles are used. Roofs are flat (bitumen) or inclined (tiles or slates) with limited use of zinc or copper plate. 1.3.1.3 Façades/doors and windows Prefabrication of façade elements with different types of fixation and sealing up were applied with different levels and qualities of industrialisation and standardisation. Window and door frames were in wood or aluminium with single glass. 1.4 Social housing policy 1.4.1. The mission. The mission of an economical, social, political or governmental organisation is the very essence of the task to be realised. It therefore needs to be very well described and intensively discussed with all parties involved. From 1945 till 1980, the mission for social housing was to build non-expensive houses for indi- viduals and families with a low income in replacement of the unhealthy environment they were living in. In the period of 1980 till 1995, a recommendation was added to realise appropriate liv- ing for everyone encouraging the quality of houses and environments for a decent price. State of the Art: Belgium 118 1.4.2. The strategy The strategy to realise this, changed over the years. After World War II, the first necessity was to rebuild the country. The loan conditions were adapted to facilitate the building of a new house or renovating an existing one, also for the poorer social class. In a later period (1961-1974), economical expansion is planned and housing is seen as a pre- condition for an increased quality of life and a balanced growth. Unsuitable houses are system- atically demolished and other renovated as a preventive approach against the decay of city cen- tres. During the later period (1975-1990), still priority is given to the unprivileged to assure so- cial housing for them, further improve the quality of the houses and start a selective territorial steering. Fig. 8: Louvain, Social housing development ‘St. Maartensdal’, designed Braem, De Mol, Moerkerke 1957-1966 (Photo Vermeir 1971) 1.4.3. The laws In the period immediately after World War II, the way to implement the strategy was defined in three major laws: provide a bonus to encourage private initiative; organise financing of infra- structure and grouping of social houses; grant financial advantages for projects demolishing un- suitable houses. Later (1960-1975), more specific initiatives were added: the National Housing Company could build houses for employees of expanding firms; five pilot cities were selected for renovation of the centres; a first national enquiry was held on the topic of quality of housing. Between 1975 and 1990, a first attempt was made to have a global vision on renovation in Flanders and the lo- cal constructors were obliged to keep lists of candidate-renters to allow objective selection. In the five years after that, a great number of additional decisions were taken to increase and strengthen the projects. Private investment in social housing was stimulated, renovation of no longer used factories started, decent housing became a part of the constitutional law. 1.4.4. The actors. The main actor in this housing policy is for sure the average Belgian citizen, he buys, builds, renovates and maintains his house mainly with own financial means. But four more actors par- ticipate in the social housing structure: the credit companies, the national company for housing, State of the Art: Belgium 119 the national land-company, and the housing-fund for large families. The government set up their own institution for administration, finance, investigation and recommendations. After the energy crisis in the beginning of 1971, a period of unemployment, savings, reorganisa- tions starts and the poverty-issue becomes more stringent again. A number of organisations are set up to improve housing facilities for handicapped people, elderly, homeless and refugees. 1.4.5. The finances. Between 1945 and 1995, a budget of 17 thousand million Belgian francs was reserved for hous- ing means. The participation of the private sector increases drastically between 1960 and 1975. The ASLK grants individual loans for about 59000 million francs. Due to the energy crisis, in the period 1975 – 1990, the focus is more on thermal insulation and the use of rain water. From 1990 till 1995 a program for 10 000 new social houses is set up with a workable formula of alternative financing. Public investments are done for 35 % for rental houses and 65 % for private ownership. 1.4.6. The results. The results of all of these efforts are measured with relation to output (number of houses, num- ber of people benefiting from this,…) and outcome (targets reached, social effects,…). Between 1950 and 1995 about 2 125 882 new houses were build in Belgium of which 83 % was private initiative. The purpose to increase private ownership was achieved. With about 65 % of the houses individually owned, Belgium ranks in the middle compared to other European countries. Still, about 50 % of the houses are over 50 years old and about 15 % are in a bad shape. There- fore, in the quality ranking, Belgium scores bad with only 57 % of the houses in a real good state, with bathroom, heating and other comfort. Did all there initiatives provide appropriate housing for the target group, first of all the really needy? Not for all of them, about 300 000 families still live in very poor living conditions, half of them are elderly people. And last but not least, buying land or house, building and renting increasingly became more expensive from 1970 onwards. In 1976, about 7 % of the families had to spend more than 20 % of their income on housing; in 1992 this was already 18 % of the families. 1.4.7. Conclusion As a conclusion, one can say that it was difficult to find the required policy-mix between num- ber of available houses, acceptable quality level, suitable living environment and appropriate pricing level. And as similar concerns and policies were present in the neighbouring countries, it must be said that the Belgian Societies looked only in a limited way to what was happening in other countries. One could have taken more benefit from each others experience ! The government continued stimulating private ownership for years and as a result, today 72 % of the Flemish families own their own house. This is a very strong point and the government still supports financial arrangements, bonuses for renovation projects, social loans, the right for a social renter to buy the house he rents, assurance you can keep living in the house assigned to you by social housing and providing sufficient parcels for building houses at a reasonable price. Some people do not have the financial means to buy a house and need to rent a house. But be- cause of their low income and the increasing prices to rent, there is a real problem in the private rental market. State of the Art: Belgium 120 Certain parts of the private rental sector are scoring significantly lower than the social renting of private ownership in terms of quality of living, security and affordable prices. The government wants to improve this inadequate quality-price relation with financial aids, warrantees, alterna- tive financing, increase offer of social conditions, and official rental associations. The social housing sector scores notably better than the public rental sector with an average rental price of 246 euro. The need for social housing is much higher than the availability due to the low rental prices and the adequate quality of the social houses offered. Investments of the VHM increase yearly, realising about 2500 additional houses for rent. And on top of this, sev- eral initiatives for renovation of existing social houses are realised as well. By targeting a social mix in social housing, the local living problems are tackled. Real participation of the inhabitants can also improve the living environment in social housing neighbourhoods. 2 QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK The quality of the end-product (= house and/or estate) depended in great extend on the type and size of investment and of the promoter. Obviously, the greater the investment per m², the better products could be delivered and the longer they lasted in good condition (of course, also the de- gree of maintenance is of primary importance)! In this regard, difference can be made in three groups: private individuals (resulting in different degrees of quality): from very best to average private promoters (building contractors or companies): usually good quality public societies (mostly within the system of social housing societies with financial help from government): mostly reduced to the minimum standards and qualities to keep prices for selling or renting as low as possible. 2.1 Physical aspects 2.1.1 Thermal insulation After the oil crisis’s of the 70’s thermal insulations was applied as well in new buildings as in renovations and double glass was installed instead of single glass. (3) 2.1.2 Protection against moisture Sometimes the humidity problems were solved by insulating the building, although most of the time condensation increased because of incorrect placement of the insulation. Other causes of humidity are ‘cold bridges’, surface infiltrations, and different kind of roof problems and rain- water drainage. 2.1.3 Acoustic insulation Until 1970 there was no concern for acoustic insulation. The experienced problems are caused by the applied construction systems with mainly contact noises as result. Inadequate choice of materials is also a cause for acoustic problems. 2.2 Structural aspects Special attention needs to be given to the structural safety: concrete rot, corrosion of metals, cracks because of shrinkage, extension of overload. State of the Art: Belgium 121 2.3 Functional aspects 2.3.1 Safety New safety regulations on fire protection, electrical and hydraulic equipment make changes necessary. To comply to the new standards and quality requirements on health in the building, the use of specific materials (e.g. asbestos) and problems with HVAC leading to sick building syndrome are to be banned. 2.3.2 Accessibility The urban aspects considered are the orientation, green and public spaces, traffic facilities, pri- vate and public services. 2.4 Architectural aspects Looking at defects in the initial urban concept, we can identify as problems: Splitting of functions and banality of public space. The CIAM idea promoting the splitting of functions (living - working - leisure - traffic) is based on a too simple living pattern and cre- ates great social discomfort and personal dissatisfaction. This is the case on urban level (e.g. shopping services,) as well as on personal level (e.g. somebody with a small private activity can not exercise this in his house). Generally with ‘social’ housing blocks, very few invest- ment went to the organisation and quality of the open public spaces (in the ‘normal’ housing blocks this was sometimes better!) Uniformity and monotony because of the limited use of industrialisation; these were ‘very dull’ sites, full of impersonal (and non individualised) housing units. Lack of continuity with the existing urban tissue (morphological and visual disconnection between the existing structures and the new developments). Houses are not adapted any more at the modem architectural safety and comfort requirements. The strict demands on structural uniformity was translated in the creation of rigid structural cells, which made it very difficult or even impossible to change those cells in case of family evolution, change of personal needs or new technical or functional requirements. The average types in social housing of the 60’s are a studio (= one room without separate bed- room for 1 or 2 persons) of max. 29 m², a two bedroom apartment of 49 m², a three bedroom apartment of 65 m² or a four bedroom apartment of 84 m². (2) Most evident problems in this regard are the lack of architectural flexibility in the use of spaces, insufficient hygienic conditions, a too small kitchen, insufficient canalisations, lack of garbage facilities (cfr. separate collection) and maladjusted common spaces (staircases, elevators, corri- dors, deposit room,...). As to the aesthetics, many new materials were developed (e.g. special tiling, cladding, paints) and new techniques in cleaning were applied. 3 POSSIBLE INTERVENTIONS ON THE BUILDING ENVELOPE Different levels of interventions are possible: substitution (complete or partial) of the outside envelope (conserving the bearing structures) (use of different kinds of panels such as glass, modern products,...) cleaning and ‘refreshment’ of the envelope (cleaning, re-pointing, painting) (eventual with limited ‘restoration’ interventions such as concrete repair, substitution of altered stone,… superposition with new (not bearing) materials, fixed on the existing structures combinations of the above mentioned interventions. State of the Art: Belgium 122 Improvement of the ‘envelope’ is also a great catalyser for the development of new materials and new fixing techniques: different types of glass and fixing methods (e.g. ‘spider’-glass / glass montage / structural glass) ceramic tiling special renders (lime, cement, plastics) combined with thermal insulation all kind of cladding panels (concrete, plastics, ceramics) and adapted fixing techniques wood techniques (using tropic woods because of resistance to humidity and heat !) protective paints or similar products Each intervention can be done with or without changing the outside volume! Such volume- change happens frequently, as it gives the architects the possibility to give also better identifica- tion of the building. Sometimes decisions and methods become more complex because of emotional, aesthetic, ar- chitectural and urban motivations, economical considerations or necessities such as e.g.: necessary improvements in the field of architectural quality or comfort of the inner spaces (e.g. high rise building is not acceptable any more / Brussels proposition to ‘cut off’ the top of buildings which have more then 15 levels - e.g. ‘Martini’- tower in Brussels). avoiding existing (new) building regulations (e.g. when a high rise building is taken down - because this might be the most economic method -, it may not be allowed to reconstruct the same quantity of square meters) - e.g. ‘Pidpa’-building in Antwerp The further study of the mentioned possibilities, their feasibility, the optimal application meth- odologies and assessment of technical and architectural qualities together with the maintenance aspects will be the main task for the further activity of this COST C16 Action. Fig. 9: Antwerp, ‘Silvertop’ towers – ongoing improvement of the envel- ops 2004-2006 State of the Art: Belgium 123 4 REFERENCES * This ‘State of the art’ is based on the analysis and comparison of only a small number of housing estates (i.e. 3 low rise, 3 middle high rise, 3 high rise and 3 row housing estates, or 12 cases in to- tal). For this reason the representativity of the study is limited, but the author tried to give a reli- able overview of the situation. Some documentation for this paper was collected by arch. Sara LAMBRECHT in her Masterthesis “Architecturale en bouwtechnische kenmerken van sociale woningbouw-projecten van 1950-1980 met het oog op hun renovatie”, University College Antwerpen, College of Design Sciences; Ant- werpen, juni 2006 – promotor of the study: prof. André DE NAEYER. (1) Ministerie der Vlaamse Gemeenschap: “Een uitwendig onderzoek naar de kwaliteit van de wonin- gen in Vlaanderen - verslag survey 1994-1995”, Brussel 1996 en Nationaal Instituut voor de Sta- tistiek “Resultaten van de socio-economische volks- en woning tellingen 2001” Internet: http://statbel.fgov.be. (2) Selected bibliography: G. BEKAERT, F. STRAUVEN:”Bouwen in België 1945 – 1970”, Nationale Confederatie van het Bouwbedrijf, Brussel, 1971 A. DESBULLEUX, Sint Lucas Werkgemeenschap: “Sociale woningbouw in hoogbouw 1960- 1975 bouwopgave voor beleid en architecten” in Vademecum voor Architecten, Afl. 27, pp. 87- 123, Brussel 1999 M. DE KOONING (Ed.): “Horta and after – 25 masters of modern architecture in Belgium”, Ghent University, 2001 (3) Vlaamse Huisvestingsmaatschapppij: “Bouwstenen van sociaal woonbeleid ’45-’95; De VHM bekijkt 50 jaar volkshuisvesting in Vlaanderen. Deel 1”, Brussel 1997. (4) http://www.stat.fi/tk/el/echp_national_characteris tics_remain_in_housing.pdf (5) http://www2.vlaanderen.be/ned/sites/regering/beleidsnotas2004/keulen/ vlaams_woonbeleid.pdf This page intentionally left blank Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW OF THE HOUSING STOCK The population in Metropolitan France reaches 59.342.000 people in 2002. From 1946 to 1986, the population increases with more than 15.000.000 people, almost 400.000 per year. Between 1986 and 2002, the increase is only about 250.000 per year. Labour force is composed of 4% in agriculture, 18.2% in industry, 5.8% in construction works, and 72% in tertiary sector. In France, the land area is 550000 km2, of which 13% are urbanized zones, 28% are woods and forests and the remainder, agricultural areas. The total number of dwellings/apartments was, in 2002, 24.505.000 in main homes (apartments and houses); about 5.000.000 are second homes and unoccupied dwellings (Insee 2004). More than 90% of the main homes are equipped with toilet facilities and central heating; less than 10% have no central heating and only a very small percentage have no sanitary equipment. The total floor area of the main homes stock is about 2450 km2. The estimated average size of primary dwellings/apartments is about 90 m2 and 108 m2 for houses, that is to say a mean value of 100 m2. The average number of persons per dwelling/apartment is 2.39. The average floor space in dwellings/apartments is thus around 42 m2 per person. The mean number of rooms by dwelling is 4. 1.1 Data related to building periods The housing construction in France is very closely related to the historical situation and to the public housing policy. Six periods (Ministère de l’Equipement, des Transports, du Logement, du Tourisme et de la Mer, 2004) can be observed: State of the Art: France Dominique Groleau, Martine Chazelas CERMA, UMR CNRS 1563, Ecole Nationale Supérieure d'Architecture de Nantes, France Francis Allard LEPTAB, Université de La Rochelle, France Gérard Guarracino DGCB, Ecole Nationale des Travaux Publics de l’Etat, Vaulx en Velin, France ABSTRACT: The total number of dwellings and apartments in France is about 25 Millions in main homes. But the building periods are closely related to the public housing policies and his- torical contexts. Thus, it appears that, from 1955 up to 1975, a large amount of buildings, espe- cially in social housing, was built in mass production in order to reduce the dwelling claim, and, since 1975 up to very recently, the housing construction decreases continuously, and one-family house constitutes a new and important demand. So, at the present time, the housing stock pre- sents different characteristics and qualities according to the period they were built, the technical solutions used, the people that live into these buildings and the urban context in which dwellings are built. Consequently, to maintain and to rehabilitate this important stock of buildings, solu- tions have to be fit strongly to the individual situations, taking into account not only technical and functional problems of buildings but also economic, urban and social aspects to adapt build- ings and districts to today issues. State of the Art: France 126 1944-1953: the period of the rebuilding At the end and after the World War II, there is a critical housing problem in France. Dwellings are in very bad conditions, more than 400.000 dwellings are in ruins, 1.900.000 are harmed and the dwelling deficit is estimated to about 4 millions. From 1948 up to 1953, the Ministry of the Reconstruction launches, according to the Athens Charte's principles, a policy for constructing massively new buildings. Thus, from a mean amount of 40.000 dwellings at the end of the war, they are more than 180.000 dwellings that are built in 1953, of which about 18.000 are low cost housing. 1954-1964: the priority to the social housing The social housing becomes a national priority. The "Courant Plan" aims to build 240.000 dwellings per year, then from 1958 up to 300.000. Decolonisation wars (Indochine, Algeria) produces an important migration that increases the dwelling claim. Due to the restructured pro- duction facilities, the loan facilities in favour of the low cost housing HLM movement, the ra- tionalisation of building sites and active participation of architects, linear and tower buildings are produced in series. It is the "Grands Ensembles" period that enables to build in 1956 more than 300.000 comfortable dwellings (72.000 in low cost housing). In 1962, 25% dwellings only are equipped with toilets. 1965-1975: the ZUP period Building effort goes on and with the definition of large zones to urbanize (ZUP, priority deve- lopment area) , buildings are built rapidly according to an "high rise and linear buildings" urban- ism; public facilities are under the municipal authority's responsibility. Nearly 200 ZUP are cre- ated that represents about 2.200.000 new apartments with air, light and central heating. In 1973, the record year, 556.000 dwellings were built. In 1975, 65% dwellings have toilets and bath. But, very quickly, serious critics are expressed about that type of urbanization. 1975-1985: the rehabilitation days At this period, against this mass-production construction and the unfavourable image of the so- cial housing, the slum, the degradation of urban centres, quality becomes a priority and a strat- egy to improve construction is defined. In 1975, the Nora report establishes that more than 15.000.000 of people are yet poorly-housed. The creation of new towns, the promotion of de- tached houses, the help to the accession to a comfortable dwelling and to the ownership and the social rehabilitation of degraded living conditions (especially in "Grands Ensembles") modify the building policy. The number of new buildings decreases. In 1984, only 295.000 dwellings are built (whose 55.000 in HLM), and 69% of these are detached houses; 85% dwellings have toilet and bath. 1985-1995: the urban re-qualification and a "policy of the town" The number of people that benefit help for accessing a decent apartment increases strongly. Households with resources leave HLM apartments; politics to favour the ownership of dwelling by people are proposed and only people with poor income stay in social housing. The increase of "social exclusion" leads to underline social and economic dimensions in the re-qualification of housing and districts. In 1993, 256000 dwellings are built whose 72.000 in HLM. 1996-2004: the social housing and the town; the urban renewal The right for a dwelling stays a priority. The increase of rents, the deficit of dwellings and sites to build and the weak income of many people make difficult the access to a decent dwelling. According INSEE, to answer to the demand, it would be necessary to build 320.000 dwellings per year. In 2003, the recorded amount is of 314.364 dwellings, in increase in relation to 2002, with 57970 in HLM (Equipement Magazine, 2004), but with 13.000 demolished dwellings. Af- ter 15 years of town policy, the housing renewal and the restructuring of districts become a pri- State of the Art: France 127 ority (SRU law, solidarity and urban renewal, ANRU, national agency for the urban renova- tion). The political ambition is to demolish and build 40.000 dwellings per year and to open a new period for the social housing. From the INSEE 2002 dwelling census, the total number of main homes is 24.505.000 (are ex- cluded second homes and unoccupied apartments that represent about 5.000.000 apartments); from this amount, 57% are in single houses and 43% are in block of flats. Around 50% of these apartments are located in more than 100.000 inhabitants dense urban zones. In 1946, 4% of the dwellings were equipped with toilet, bath and central heating. Today, only 4% are not equipped. Table 1 Number and percentage of dwellings related to building periods and kind of buildings (Insee 2004): houses apartments Total % Before 1915 3225600 1665800 4891400 19.96 1915 - 1948 2061000 1192900 3253900 13.28 1949 - 1967 1827900 2557200 4385100 17.89 1968 - 1974 1404900 1990300 3395200 13.86 1975 - 1981 1809000 1177500 2986500 12.19 1982 - 1989 1776800 774200 2551000 10.41 1990 - 1999 1294500 940100 2234600 9.12 2000 and after 504800 302500 807300 3.29 Total 13904500 10600500 24505000 100.00 More than 56% of the dwellings are owned by the tenants; 15.6% are rented by HLM social tenants, 22.3% rented by non HLM tenants (private sector), the others are sub-tenants, share- croppers or free of charge occupants. More than 90% of the dwellings are equipped with toilet, bath and central heating; just a very few percentage have no toilet equipment or no central heating. 1.2 Description of main typologies The main typologies that can be encountered in housing correspond typically to the historical evolution in architecture and urbanism. Illustrations of the proposed typology are constituted from representative buildings taken in the city of Nantes and in its suburbs. . 1950-1975 The principles of the "modern movement" in architecture in conjunction with the housing crisis leads to organize the city and to build dwellings in a very different way, with the extended use of concrete. Three types can be underlined: The buildings of the reconstruction (fig 1), in urban centres, that respect traditional urban morphologies and volumes (several storeys) organized in blocks and streets often according to a grid layout. The façades have generally a stone facing. The several experimental buildings like the "cité radieuse" of Le Corbusier (fig 2) that pro- poses a new layout of the dwelling with loggia and sun breakers. The buildings of the 1955-1965 "grand ensembles" (fig 3) and of the ZUP (priority devel- opment area) period from 1965 (fig 4). They are built in peripheral zones of the city, in open space environment and on enough wide sites to accommodate a large amount of dwellings with several facilities. Designed to be self sufficient and generally poorly connected to the urban centre, they have become in reality dormitory towns. The typical buildings of this pe- State of the Art: France 128 riod are flat roof "barre" (linear building) and "tower" (high buildings), with often beyond 10 or 12 storeys in the ZUP period, built up, according to a formal geometrical arranging, over an open green public space. As soon as 1975 Severe critics of the modern movement involve a feedback in order to reconsider the city and to create a more attractive and human-scale urban development, in reference to the town classical model. Since 1980, new urban settlements (through ZAC operations, concerted extension urban zones), again propose apartments blocks (fig 12) with a limited number of floors and a tradi- tional pitched roof, arranged around squares, streets and avenues. In the end of 1980's and up to nowadays, this urban respect and the necessity to integrate buildings and people in the framework of the city are still relevant today. Without changing deeply in their structure, buildings take over time and according to geographical and historical context a particular style that reflects cultural and architectural debate or fashions but also new way of life, technical progress or new environmental constraints. It can be mentioned, as exam- ples only, the very sunny buildings resulting of the "banlieue 89" social housing program (fig 13) or the around 1995 recent buildings like the 1930' architecture (fig 14) for the private hous- ing sector or still the contemporary apartment block (fig 15) proposed inside a traditional hous- ing and warehouse district currently in a rehabilitation and restructuring phase. fig 1, 2 fig 3, 4, 5 Fig 6,7 Figures 1 until 7: Buildings from Nantes, representative of the historical steps of housing State of the Art: France 129 1.3 Description of main technologies The traditional apartment block is specific of the "Haussman period" and of the 1900's period, with heavy construction with stone or brick walls, wooden floors and pitched roofs, located in historical urban centres. The number of storeys is up to 4 or 5. Just after the Second World War, the urgent necessity to build rapidly and economically makes it necessary to introduce industrialisation. As soon as 1952, various experiments are launched whose results are the growth of concrete system with large panels and formed concrete and their large use in residential building. After in 1964, an effort in favour of light weight industrialisa- tion with open system of components, accompanied by politics of models, tries to open a new way for building. Applications were mainly devoted to build schools but without true success in comparison to concrete competition. And finally, a third try in favour of industrialisation was at- tempted through detached houses concourse. Only, the Phoenix constructor has proposed pre- fabricated houses. In definitive, the main building systems used remain mainly based on con- crete technologies. The more common used system especially in multiple dwelling is a load bearing structure com- posed with reinforced concrete shells arranged according to a parallel layout grid and concrete slabs. This system enables reusable forms and, used with a fixed grid width, the tunnel form- work enables the simultaneous concreting of walls and slab. This tunnel formwork system was frequently used in the period 1955-1965 in the building of "grands ensembles". Generally, at this period, the roof was a concrete flat roof. A variant of these systems consists in replacing concrete walls by concrete blocks walls and the concrete slab by a floor made with beams and filler blocks. It is largely used, actually, for low rise buildings up to 5 floors and in the buildings of individual houses and pavilions. The roof is then either a flat roof or a traditional pitched roof. The system with load bearing façades of sandwich panes and spine wall was used, but at a smaller scale during the industrialization period starting from 1965, in apartment blocks but mainly in facilities building like university or public services. A more flexible system uses columns and beams that support a concrete floor and enables a lar- ger flexibility in layout and in façade. This system is mainly applied to office buildings and pub- lic facilities buildings. 1.4 Housing policy The different public policies can be examined relatively to the six periods mentioned previously. The role of the State is quite important, at the same time, in defining specific public policies and in favouring a corresponding behaviour of the people to put them into effect. Then, the State has mobilized important statutory and financial means in a true public policy as it can be seen through main actions and key dates in housing policy (Insee 2004). 1944-1953: the period of the rebuilding. The immediate post-war is very critical for housing and building activity and the dwelling claim is enormous. Main key dates are the following: 1944, with the creation of the MRU, Ministry of Reconstruction and Urbanism; 1947-1953, the First Plan, with the main objective to reconstitute the production facilities and answer to the urgency of housing demand by building provisory dwellings; 1950 with the HLM movement that has the responsibility to organize the massive construction of social dwellings and 1953 with the Cou- rant Plan that creates a favourable framework to facilitate the construction of dwellings. 1954-1964: the priority to the social housing. In 1953, a decree improves loan conditions to HLM organisms and, during this period, the Second Plan aims to build each year 240.000 dwellings; new experiments with new techniques are encouraged in building (large use of con- State of the Art: France 130 crete and standardisation) to build rapidly and at low cost. The Third Plan 1958-1961 increases the number of dwellings to be built to 300.000. 1965-1975: the ZUP period enables to increase the building effort. Around 3.000.000 dwellings are built and this constitutes an important stock without the thermal today standards. But, al- ready, during the end of this period, starts a significant rehabilitation oriented policy. It is also the start of an intensive promotion for the individual house. In 1969, Albin Chalandon, Housing Minister, launches a famous one-family houses concourse that initiates from this time the still large demand for this kind of dwellings and 1971 sees the creation of the Construction Plan that promotes experiments about housing. During 1971 to 1975, the Sixth Plan aims an ambitious program of 510.000 new dwellings per year, but also plans the slum clearance and urban centres restructuring. The renovation and modernization of the housing stock constituted from the be- ginning of 1950 starts in this period. From 1974, the oil crisis leads to take the first measures in favour of energy efficiency, mainly with the promulgation of the first thermal regulation of buildings that aims to reduce the energetic demand by insulating the buildings. 1975-1985: the period of the "rehabilitation" is launched and will continue until today in differ- ent forms. Between 1976 and 1980, the primary objective of the Seventh Plan is the housing improvement. In 1977, the creation to the PLA (loan for renting) and APL (dwelling personal help) aims to give personal loan to help people to find a dwelling; and HVS (housing and social life) operations are launched for re-qualifying districts in difficulties. Then, in 1979, the DSQ (social development of districts) procedures offer an operational framework to rehabilitate de- graded dwellings. 1985-1995: the urban re-qualification and a "policy of the town" plan to integrate social, eco- nomic and cultural dimensions in housing building and rehabilitation. Private investment is en- couraged by Mehaignerie Law in 1986 to increase renting facilities. In 1994, a law encourages renters to buy their HLM apartments, and in 1995, the PTZ (zero rate loans) helps people to buy their own dwelling. 1996-2004: Needs for dwellings remain important but are more various. The property and rent- ing market is difficult and it is always necessary to answer to the French aspiration for the home ownership. A new equilibrium is to be found between State, HLM organisms and local authori- ties, between public and private investments. With the new environmental and sustainable pre- occupations (health, energy, life quality), the restructuring of social dwelling district and the renovation of existing buildings become a new priority. The new urbanism law (SRU 2000) aims to introduce more social interaction and orders to reach a percentage of 20% of social dwellings in each city. And, from now on, the urbanism and building sector, with a specific pol- icy about towns, participates strongly to the research of a harmonious social, cultural and eco- nomic life. The very recent creation in 2003 of the ANRU (national agency for urban rehabilita- tion) announces a decisive step in the urban and social development of districts. Steps of the French public policy of rehabilitation The fact (Foret & Porcher) that it is preferable to "build the city upon the city" instead of build- ing new buildings comes from the 1970's where rehabilitation becomes a plausible alternative to the demolition-reconstruction process (used in urban renovation operation to eradicate the un- healthy dwelling engaged from 1958) of the post war period, with population moving. The State plays also an important role in this movement that inspires and animates the public policies lead since 1980, taking into account town-planning, economic and social considera- tions. As soon as 1962, with the Malraux law, appears the "safeguard sector" that recognizes the urban and architectural interest of ancient districts and will enable to save historical urban cen- tres. In 1970, in order to reinforce this new orientation the ANAH (national agency for the im- provement of dwelling) is created, to help private owners to the rehabilitation of their ancient dwelling. The publication in 1975 of the Nora report (against urban renovation) leads to texts State of the Art: France 131 and laws in favour of rehabilitation of existing dwellings and social help that stops the renova- tion process. In 1977, the creation of OPAH (planned operation of dwelling improvement) is an incentive tool to promote rehabilitation in the private ancient dwellings at the district scale, under the town authority, with the help of PACT-ARIM associations. The State, with the FAU (Fonds Amenagement Urbain) enables public actions in the public space. The help "to the stone", the owners then "to the person", the tenants, and, more recently the zero rate loan for the social ac- cess to the ownership contribute also largely to the renewal of the important private locative pat- rimony and to maintain a locative offer at low-cost housing. In 20 years (1977-1997), more than 3000 OPAH have been created with a total of over 600000 dwellings involved. This rehabilitation politics applied to historical districts were rapidly extended to the post-war building stocks, especially the "grands ensembles" that represent an important part of the loca- tive social public offer, via the HLM (low cost housing) organizations (around 1000 in France) that administrate 50% of the whole locative dwelling stock in France. In 1977, in concluding an agreement with these organizations to fix the rent threshold, the owner organization benefits a prime (PALULOS, to improve dwelling for social rent) to improve its apartments for social oc- cupancy; a corresponding grant is then dedicated to the tenant (APL) that compensates the in- crease of the rent after improvement. This modernisation of the HLM has mainly concerned, due to the crisis of energy, the thermal insulation and the heating. Most of the dwellings are now heated by natural gas or electricity. Since 20 years, around 200000 dwellings have been rehabilitated each year, with public help presenting 65% of the whole investment. At the same time, but from 1980, public actions for the urban social development have been car- ried out to face the crisis of "banlieues". Social degradation accentuated by the unemployment and weakness of urban forms have lead to departures of people and to unoccupied dwellings. These critical social districts have benefited several public operations like Dwelling and Social Life (HVS) in the last 1970', Social Development of districts (DSQ) from 1981 or the mission "Banlieue 89" that mobilized architects to guarantee the urban quality of these rehabilitations. In this last operation, 250 urban projects are presented for the embellishment and the reorganisa- tion of districts. This process that associates social, economical and urban problems is enlarged up to the crea- tion of the Ministry of the Town in 1990 that consecrates the policy in favour of the city. Today, more than 1300 districts are objects of specific urban operations, with convention with local au- thorities and the State, such as "Contrats de Ville" (130 districts) or "Grands Projets de Ville" (50 sites). It concerns about 6 Millions of people and 300 towns. The main objectives are to pre- serve national solidarity and fight against the urban segregation and social exclusion. As it can be seen, the notion of rehabilitation has considerably changed in France to include to the comfort dwelling improvement, social, economic, cultural and urban preoccupations. Urban insertion and social diversity of districts are priorities of the policy of urban renewal (SRU law, Solidarity and Urban Renewal, 2000) that can lead simultaneously to demolish buildings, reha- bilitate some ones and build new ones. State of the Art: France 132 2. TOPICS: QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK Physical aspects Thermal aspects Before the present thermal regulation (RT2000), successive rules published from 1974 to 1998 have modified considerably the way to consider energy in buildings. In 1974, the first rule K was a direct response to the oil crisis in order to save energy by reinforcing thermal insulation of buildings. Immediately follows the G rule that aims to reduce heating load by limiting the ther- mal consumption of buildings. G characterizes the whole building in terms of volume thermal losses. Various means are proposed for reducing air renewal, infiltrations, using performing windows (double pane) and recuperating solar energy in different ways. Thus, in 1982, the BV rule took into account the thermal impact of the solar radiation as a passive heat gain in build- ings and therefore as a mean to decrease the heating demand (mitigating the only thermal losses). In 1988, the C-calculation rule was introduced to assess the thermal performance of the building enabling to evaluate more precisely the heating load of the dwelling, considering the heating system, heating consumption, and the hot tap water production. Various quality labels were pro- posed to encourage the improvement of building energy performance, and several solar experi- ments and concourses were launched to promote solar renewable energy in buildings. It can be observed important improvements in the thermal design of buildings, but also errors or secon- dary negative effects were noticed, mainly concerning ventilation and humidity due to air tight- ness and internal insulation (thermal bridge) but also relative to the indoor summer comfort. It appears that almost the two third of the building stock were designed before these thermal regulation, therefore without any performing insulation. It is why, very early, rehabilitation were carried out with external insulation for multi-storey buildings mainly in the HLM building stock. But it still remains an important stock to improve thermally. Very recently, following Rio agreements and the necessity to reduce emission of greenhouse ef- fect gas, but also due to harmonization with European rules and the lack of regulation relative to office buildings, a very important and new thermal regulation RT2000 was developed and im- posed to the new buildings. It aims to reduce drastically the energy consumption (20% in dwell- ings, 40% in office buildings) but also to take into account summer comfort and daylight condi- tions. Two main ways are proposed to apply the regulation: Using calculation tools (methods Th-C and Th-E) to verify that, firstly, energy consump- tion of the building is less than that one obtained by a reference building and secondly, that the temperature in summer is less than a reference temperature. Using technical solutions that are certified and proved that the regulation is respected. Minimum standards are required for a set of aspects such as isolation, ventilation or heating sys- tems; for example U values of 0.40 for vertical walls and of 2.00 for windows are required by the present thermal code. This thermal regulation has to be update regularly. In 2005, the RT2005 building thermal regu- lation has reinforced required performances, opening also perspectives for a bioclimatic design of buildings; existing buildings will be partly subject to that new regulation and, by the fact, it will impose serious constraints on the rehabilitation of dwellings. Moisture A recent householders survey from INSEE shows that humidity is one of the most frequent de- fault mentioned in dwellings. Three reasons can be proposed to explain this situation. The first one is technical and can result of a deficient component of the building such as a bad state win- dow that is not watertight, a not performing flat roof like those built in the 1960's or simply a porous external wall. It can be also observed a rising damp from foundation. The controlled flat State of the Art: France 133 roofs execution, the quality of impervious blanket and the performance of windows reduce con- siderably this type of risk. The second one can result of thermal improvement of the dwelling by integrating an internal in- sulating layer, but creating, depending of the constructive system, a thermal bridge, for example at the concrete floor slab extremity, and producing air condensation; it can also simply result of a cold wall effect on a single glass window that condenses air water vapour. The third reason is generally due to a ventilation default that does not irrigate sufficiently the rooms and produces moisture. It results generally from a too important reduction of the new air change flow, especially in simple flow ventilation system, when, for example, air inlets are, for comfort reason, occulted by people. Sound Dwellings built before 1970 are not submitted to a sound insulation statutory. And still today, no requirements are eligible in case of rehabilitation of that building stock. For dwellings built between 1970 and 1996, the 1969 acoustic statutory gives maximal values of sound level for floors, separation walls and equipments, but nothing relatively to windows. It was stipulated, for a 80 decibels emission, a sound level of 35 dB(A) in main rooms and 38 in kitchen and bathroom, or that the sound produced par any building equipment does not overpass 35dB(A). This regulation does not correspond to nowadays requirements. Acoustical comfort is from now a very important constraint for French people and is the subject of numerous complaints. Since 1994, the New Acoustical Statutory (NRA), applicable to new dwellings built after 1996, imposes serious conditions as regards to the protection against sound and noise pollution, especially for residential buildings. This code was updated and, since 2000, applying European normalization, it gives for each sound type the required sound insulation. Thus, the indoor airborne-sound insulation is required to be 53 dB in between apartments and between apartments and common areas of the building. The equipment-sound insulation (venti- lation device, lift, garbage chute) has to be 30 dB(A) in living rooms, 35 in kitchens. For sound coming from outdoor, the façade is required to reduce the sound level with a minimum of 30 dB(A). The impact sound level is imposed to walls and floors in order to have a perceived sound in main rooms that does not exceed 58 dB. May be its can be an occasion to use much more largely than in the past the floating slab. For buildings adjacent to roads or railways, the required minimum reduction of 30 dB(A) is not always applicable. Roads with traffic greater than 5000 vehicles per day have to be classified according to the traffic rate (number of vehicles). Five classes are proposed with a reference sound level varying from 60 to 81 dB(A) for the day time and from 55 to 76 for the night time; at each class corresponds a distance that determines the zone affected by the sound traffic and the insulation level required inside this zone can reaches 45 dB(A) in very exposed situation. In airport sectors, the urbanism code defines three air-traffic sound exposition zones (PEB sound exposure plan) that are part of the various urbanism statutory documents. In these noisy zones, building dwellings is prohibited or subject to very restricting precautions. In France, around 300.000 dwellings are exposed to a problematic noise level and 7 Millions people to external sounds greater than 65 dB(A). Many buildings built in peripheral zones in the 1965-1980 period are today surrounded by heavy traffic roads. Solutions have been proposed with the installation of sound proof walls or double windows but much work have to be done to improve appreciably the sound environment and to rehabilitate buildings and apartments to offer an acceptable sound comfort level. State of the Art: France 134 Structural aspects Reports about structural and construction pathology do not mention critical situations in the sta- bility of buildings. The ground and the quality of foundations are surely the main sources of se- rious construction problems, but fortunately there are very registered cases. In fact, land subsi- dence always occurs but, the protection against its effect consists in applying strong safety factors; that explains the scarcity of accidents. However, to correct afterwards instability of the ground the subsoil injection technique can be used. The large use in the 60's of formworks for concrete walls and floors with bar bending leads to a very monolithic and heavy construction that, with reduced span, reinforces the structure of buildings. In stability calculation, in this same period, aero dynamical effect and additional loads are integrated to insure, by over design, stability and security. In façades however, some degradations can be observed, due to the weak protection and fragil- ity of the external surfaces or coating elements. But, the thermal requirements have imposed very quickly important transformations of façades to reduce the heating energy consumption that represented a considerable part in the building maintenance cost. In existing buildings built before 1974, very often an external insulation layer was applied to these façades. Functional aspects The way of life is continuously in evolution and requirements of people relatively to their dwell- ings change also. But depending of the type of occupation, owner or tenant, the freedom and the means to adapt his dwelling are radically different and it is very related to the freedom to choose its apartment or house and the district accordingly to its interests and tastes. Particularly in the social housing, but not only, inhabitants are totally dependant of the state of their dwelling and of the environmental conditions. And, often architectural and urban problems are interconnected with critical social situation (level of income, education level, job, security, accessibility, mobility...). It can be mentioned actually an important effort to improve, in social housing areas dating from the 60'S or 70's, the common spaces in the buildings like staircases, public spaces, hall entrance, but also the outdoor spaces for a re-qualification that provide a bet- ter and more friendly environment. This kind of transformation needs to be carried out at an ur- ban level with intervention of local authority in order to insure a better connexion between these districts and others parts of the city and to give a global response to that social problem. In the private rental sector, the rents are very high and not necessarily related to a corresponding quality (number of rooms, area, equipment...) of the dwelling. Due to an unfavourable balance between the dwelling offer and the social demand, owners are not specifically disposed to main- tain and improve their dwellings. Architectural aspects Accordingly to the analysis of the different steps of the housing construction in France made previously, two main tendencies can be observed. The first one from the 1950's up to 1975 cor- responds to the necessity, due to the critical lack of dwellings, to produce a great quantity of dwellings in order to accommodate people. It was the period of a mass-production of dwellings based on the application of several principles that give to this buildings stock the appearance it has today. These principles, largely inspired by the architectural modern movement, are mainly: a open site generally located outside the town centre, an industrialized construction process, a type layout for the different living cells, large use of concrete and slip formwork, repetitive buildings arranged according a geometrical figure that enables air and sun to penetrate inside rooms, several typical equipments and service buildings and a very poor open area design. This rapid urbanization has left an impression of repetition and uniformity, representative of the eco- nomical construction. The architectural image is thus not very positive and the various rehabili- tations have often not changed radically this image of public and social housing. It explains the important attention today in favour of a global improvement (architectural and urban) of such buildings and environment. But, can we apply to these buildings an architectural treatment in State of the Art: France 135 accordance with the economic value of these buildings? Recent regulations about thermal or acoustical requirements may be an opportunity to operate such architectural transformations. The second period, as soon as 1980, opens a new period that underlines the importance of the architectural quality. Housing operations offer then more diversity but also leads to operate at a smaller scale in various places in town or in suburbs. Buildings have a limited number of sto- reys. The size of building site are considerably reduced. Buildings are designed by different ar- chitects in different contexts and programs, giving thus, due to the freedom of forms, materials but also of construction ways and the use of innovative products, a more attractive architectural aspect. However, this building production is not always free from defaults (quality of the con- struction and components, assembly detail...) and has to be observed over time. CONCLUSIONS Until today and since the 1970's, rehabilitation of dwellings in France has always been a major preoccupation and has taken different forms with more or less intensity according to the periods, the housing conditions, the type of buildings or ownership, the targeted population and mainly the economical or social problems and political priorities with which France has been con- fronted. At each period, specific politics were applied and, they have concerned finally today an important amount of dwellings or buildings. But it appears that changes and adjustments have to be made continuously or periodically to be in phase with the actual requirements and standards of the way of life. Many existing technical norms make obsolete equipments and technical de- vices or comfort level in the ancient stock of building and the urban environment is also the frame of important transformations. For example, thermal regulation, noise regulation, climatic program, savings energy program, society changes, economic or social problems related to technical evolution imply to adapt the actual stock of buildings. From now, rehabilitation cannot be reduced simply to technical or architectural changes in order to repair or refit the physical defacements of buildings and insure the stability and safety of the buildings. It becomes a global process that interests the various components of the buildings, construction elements, devices, layout, but also of its urban environment, and the social and economic dimensions that play a determinant role. This global approach, that mixes building and urban scale, social, economic and environmental aspects, is encouraged. The creation of State/town conventions that enables to manage complex urban operations on urban districts in- clude the various dimensions, integrating renovation and rehabilitation operation, re-designing public spaces, integrating new population, varying public/private programs or improving trans- portation and integration within the city. Inhabitants become true partners and actors of theses rehabilitations; they are the first interested by the modification of their environment and of their living conditions. Participation programs and procedures are then explored to associate inhabitants to the design of their environment. Between 1949 and 1975, one third of the dwellings was built by private organisms in apartment blocks; it represents a apartment stock more important than the whole HLM stock. Many of these buildings are defaced or damaged and the necessary refitting is difficult due to the private co-ownership. Another problem is the bottom-of-the-range detached houses that are still ignored today but can become very nearly a main preoccupation for the rehabilitation. The Bouché re- port (Bouché, 1998) draws attention of authorities to the unhealthy buildings that do not respect security norms and to unoccupied dwellings. As we can see, this permanent question of adapting buildings and districts to today requirements would imply to carry out a precise and global building inventory and to develop specific tools like an housing observatory, enabling precise analysis of living conditions and building state in order to help to the dynamic transformation of the housing stock in accordance with the chang- ing requirements. For private housing, atlas are already constituted by the ANAH agency with the help of public and private statistics, but identification and qualitative description forms at- State of the Art: France 136 tached to each building could be a convenient way to manage the whole stock of buildings and to prepare adequate strategy and politics. According to a report of the French national assembly, in 2050, 60% of the floor area of the dwelling stock would be already built today; that is to say the importance of the rehabilitation issue and the urgency, from now on, to take into account this question to modify and adjust in a continuous way housing and its urban environment. REFERENCES [1] Annuaire statistique de la France. INSEE, 2004, [2] « Le logement en France, 60 ans en images ». Exposition 2004. Dossier de presse[online]. Min- istère de l’Equipement, des Transports, du Logement, du Tourisme et de la Mer. 2004 http://www.logement.equipement.gouv.fr/actu/logt_60ans/ (consulted on 2004-07- june) [3] Equipement magazine. Mars 2004 [4] Buttenwieser Isabelle et Chevet Hélène. Panorama des techniques du bâtiment : 1947-1997.Paris : Centre Scientifique et Technique du Bâtiment, 1997 [5] Foret C. et Porcher F. La réhabilitation urbaine. Note de synthèse[online]. Ministère de l’Equipement, des Transports, du Logement, du Tourisme et de la Mer. : Centre de Documentation de l'urbanisme. http://www.urbanisme.equipement.gouv.fr/cdu/accueil/bibliographies/Bibliogf.htm (consulted on 2004-07- june) [6] Annuaire rétrospectif de la France. Série longue 1948-1988. INSEE 1990 [7] Cimbéton. Construire avec les bétons. Paris : Le Moniteur. 2000. (Collection techniques de concep- tion) [8] Turaud J. Construction de bâtiment : Technologie de gros œuvre et de second œuvre. Paris : Le Moniteur 1981 (Formation) [9] Birraux Claude et Le Déaut Jean-Yves. Rapport sur l’état actuel et les perspectives techniques des énergies renouvelables.[online] Paris : Office Parlementaire d’évaluation des choix scientifiques et technologiques ? Assemblée Nationale. 2001 (rapport n° 3415 de l’Assemblée Nationale et n094 du Sénat) http://www.assemblee-nationale.fr/rap-oecst/energies/r3415.asp#P51_857 (consulted on 2004-07-june) Rapport citant une étude de J-P. Traisnel. [10] Traisnel J. P. « Habitat et développement durable » Bilan rétrospectif et prospectif » Cahier du CLIP Avril 2001, n°13 Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 INTRODUCTION Portugal is constituted by the mainland and 2 Atlantic archipelagos (Azores and Madeira Is- lands). The mainland is located in the south-western Europe bordering the North Atlantic Ocean at west and south and Spain at north and east (Fig. 1). The mean geographic coordinates of the mainland are: Latitude - 39º30’ N and Longitude - 8º00’ W. Climate in the mainland is classi- fied as maritime temperate, being cool and rainy in north and warmer and drier in south. Figure 1 – Europe map. Figure 2 – Portuguese territorial units for statistical purposes. State of the Art: Portugal Luís Bragança, Manuela Guedes de Almeida and Ricardo Mateus Civil Engineering Department, University of Minho, 4800-058 Guimarães, Portugal ABSTRACT: The aim of this paper is to give an overview of housing in Portugal, presenting the building stock characterisation, the related Portuguese legislation and the socio-economic aspects. For this purpose, the main housing building technology used in Portugal is described and the problems related to multi-storey family houses are identified. State of the Art: Portugal 138 Table 1 lists the general data obtained from the Census 2001 (INE - Portuguese National Statis- tics Institute) that actually characterizes the country. Table 1 – Portuguese general data (Census 2001) Total Area (km 2 ) 92 141.5 Number of Councils 308 Number of Parish 4 243 Resident Population 10 356 117 Population Density (In- hab/km 2 ) 112.4 Resident Population – Man 5 000 141 Resident Population – Woman 5 355 976 Number of Families 3 654 633 Number of Family Dwelling 5 046 744 Number of Buildings 3 160 043 For statistical purposes, Portugal is divided in 7 territorial units. The mainland includes 5 territo- rial units (North, Centre, Lisboa e Vale do Tejo, Alentejo and Algarve) and the other 2 units correspond to the Azores and Madeira Islands (Fig. 2). 1.1 Data related to different building periods Table 2 lists the chronology of constructed buildings since 1919. The building stock grew al- most 11 times during the period between 1919 and 2001. Figure 3 shows that the period of ma- jor growth of the building stock was between 1971 and 1990. Table 2 – Constructed buildings (Census of 2001) Before 1919 297 713 Between 1919 and 1945 335 280 Between 1946 and 1970 740 495 Between 1971 and 1990 1 187 423 Between 1991 and 2001 599 132 Total 3 160 043 Figure 3 – Constructed buildings (Census of 2001). 9,4% 10,6% 19,0% 23,4% 37,6% Before 1919 Between 1919 and 1945 Between 1946 and 1970 Between 1971 and 1990 Between 1991 and 2001 State of the Art: Portugal 139 Table 3 and Figure 4 show the distribution of the existing dwellings and buildings by the Portu- guese territorial units. 0 1.000.000 2.000.000 3.000.000 4.000.000 5.000.000 6.000.000 P o r t u g a l N o r t h C e n t r e L i s b o a e V a l e d o T e j o A l e n t e j o A l g a r v e A ç o r e s M a d e i r a Dwelling Building Figure 4 – Dwellings and buildings (Census of 2001). According to the Census 2001 there are almost 5.1 millions of residential units in Portugal for a total of 3.7 millions of families which represents a ratio of 1.34 residential units per family. From this, 18% correspond to seasonal residences while 11% are unoccupied. This means that Portugal has about 3.9 millions of permanent residential units. Table 3 – Existing dwellings and buildings (Census of 2001). Territorial Units Dwelling Building Portugal -Total 5 054 922 3 160 043 North 1 613 781 1 100 329 Centre 1 254 701 992 321 Lisboa e Vale do Tejo 1 295 832 394 520 Alentejo 423 641 349 946 Algarve 278 418 160 543 Açores 95 241 87 585 Madeira 93 308 74 799 The building sector in Portugal is very active with a strong bet on new buildings. 20% of the ex- isting buildings have less than 10 years and, between 1991 and 2000, the average rhythm of construction reached 84 000 new buildings per year. In 1999 and in 2000 this number raised till 100 000 new buildings per year. This means that, in the same period, were built 8.4 buildings per one thousand of inhabitants while in Europe this ratio is just of 5.5. In Portugal, 80% of the new residential buildings are single-family buildings. However, the re- maining 20% of apartment buildings represent 70% of the total housing units as it can be seen in Figure 5. State of the Art: Portugal 140 % apartments as residential units 0 10 20 30 40 50 60 70 80 before 1980 1980-1990 after 1990 built in 2000 % Figure 5 – Percentage of apartments as residential units. 1.2 Description of main technologies In Portugal the first high oven for Portland cement industrial production was installed in Al- handra (a village near Lisbon) in 1894. Since then, the building technology slowly started to change, taking advantage of the potentialities and versatility of the new building material, the concrete. However, it was only after 1930 that the great development of concrete building construction took place. The change started in the pavements through the replacement of the wooden floors by reinforced concrete slabs. Afterwards, reinforced concrete porticos replaced the load bearing walls. These changes led to the building technology actually used in housing buildings in Portu- gal (Guerra 1995). Since 1950 the building technology in Portugal is based on a steel reinforced concrete beams and pillars system. Although there are few exceptions to this general rule, it can be assumed that 99% of the housing buildings have the following pattern: - Foundations: superficial pillar shoes made of reinforced concrete (depending on the soil load capacity) (see Photo 1); - Bearing structure: reinforced concrete porticos forming the building skeleton (see Photos 2 and 3). Steel reinforced concrete pillars (see Photos 4 and 5) and steel reinforced concrete beams (see Photos 6 and 7) compose the resistant structure of this solution; - Floors: reinforced concrete slabs in the southern part of Portugal and/or pre-strengthen beams and ceramic (or concrete) molding blocks slabs in the north (see Photo 8 and 9); - Roofs: tilted roofs and/or flat roofs (especially in the south). Usually the pendant of the tilted roof is made of pre-strengthen beams and ceramic molding blocks slab, constituting a non-ventilated attic (see Photos 10 and 11); - Exterior walls: single or double leaf hollow brick walls (see Photos 10 and 11); - Interior partition walls: single leaf hollow brick walls; - Fenestration: after 1990 (because of the introduction of a building thermal regulation), most of the windows have double glaze (6+12+6 mm). The glass is clear on both sides in all the facades. Most of the windows frames are made of aluminum since the 70’s (since the middle of the 90’s appeared in the market PVC windows frames). Before the 70’s the windows frames were in wood (see Photo 14); - Shading devices: due to the intense solar radiation almost all windows are protected with exterior roller shutters mostly made of plastic since the 70’s (see Photos 15 and 16). State of the Art: Portugal 141 Photo 1 – Superficial foundations of housing building. Photo 2 – General view of the typical housing bearing structure. Photo 3 – Partial view of the typical housing bear- ing structure. Photo 4 – Definition of the pillar location. Photo 5 – Mounting of the pillar moulding panels. Photo 6 – Preparing the mould of a beam State of the Art: Portugal 142 Photo 7 – Steel reinforcement of a beam. Photo 8 – Preparing a beam and pot slab to receive the concrete. Photo 9 – Concreting a beam and pot slab. Photo 10 – Typical tilted roofs. Photo 11 – Covering the roof slab with ceramic tiles. Photo 12 – Double leaf hollow brick wall with in- sulation State of the Art: Portugal 143 1.3 Housing policy 1.3.1 Construction codes The principal Portuguese legislation that is applicable to the housing buildings is the following: - General Regulation for Urban Construction (RGEU) - Executive Law nº 38382/51, of Au- gust 7, and subsequent alterations (now in the process of revision); - Technical Recommendations for Social Housing - Ministerial Order nº 41/MES/85, of Feb- ruary 14; - Regulation on the Thermal Behaviour Characteristics of Buildings (RCCTE) - Decree-law nº 40/90, of February 6 (now in the process of revision); - Safety Regulation against Fire in Residential Buildings (RSIEH) - Decree-law nº 64/90, of February 21; changed by Decree-law nº 66/95, of April 8; - General Regulation on Public and Building Residual Water Distribution Systems - Regu- lated Order nº 23/95, of August 23; - Regulation on Building Acclimatisation Power Systems (RSECE) - Decree-law nº 118/98, of May 7 (now in the process of revision); - General Regulation on Noise (RGR) - Decree-law nº 292/00, of November 14; - Regulation on Buildings Acoustic Requirements - Decree-law nº 129/02, of May 11. Photo 13 – Single leaf hollow brick wall without insulation. Photo 14 – Double glazing in an aluminium win- dow frame. Photo 15 – Roller shutters used as shading de- vices. Photo 16 – Balconies and roller shutters used as shading devices. State of the Art: Portugal 144 1.3.2 Economic aspects In Portugal the prices of the housing rent were frozen for more than 2 decades. After the democ- ratic revolution of April 1974, the housing rent froze was extended to the entire country, leading to the almost total extinction of the rental market and to a significant decay of a large portion of the housing stock. This situation ended during the 80’s and led to some distortion in the housing market. Before 1980 the total number of non-owned dwellings represented 42% of the housing although after 1980 this percentage decayed to 21%. Figure 6 shows the property status of the occupied dwellings, according to the INE Housing Project, “Housing Inquiry – 1998”. The Portuguese housing policy that kept the rental prices frozen last for over than 2 decades and led to the lack of dwellings to rent. In that period, the people that needed a new dwelling had to buy it. According to the IV General Housing Census (INE 2001) in 2001 the percentage of dwelling occupied by proprietary and renters remain almost the same as it was after 1980 (Fig. 7). 0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0 Purchase and Construction Purchase and Recovery Own Home - Other Rented Free Grant and Other % Bef ore 1980 1981 - 1990 Af ter 1990 Figure 6 – Property status of the occupied dwellings (1998). Figure 7 – Percentage of dwelling occupied by proprietary and renter (2001). According to the INE Housing Project, "Housing Inquiry – 1998", the main way to achieve the dwelling property is by the purchase, immediately followed by the construction of new homes. Figure 8 shows the distribution of the different ways of accessing to the dwelling property. Although the expenses with the property of the own dwelling are more than two times the ex- penses with the rented dwelling, the Portuguese prefer to purchase their own house instead of rent it. Figure 9 shows the average expenses with dwellings for all the Portuguese territorial units (2001). State of the Art: Portugal 145 Nowadays, the prices of the building construction are approaching the average European level and the Portuguese government is trying to develop the rental housing market, in order to be possible to renew the existing buildings and to promote people’s mobility. The prices of dwelling construction depend on the location of the building and quality of the construction itself. According to data supplied by the Portuguese Northern Builders Association the construction costs per m 2 were between € 430 and € 460, for current housing, and between € 300 and € 330, for social housing. 0,7 3,6 5,4 5,4 32,9 43,6 0 10 20 30 40 50 Other Donation Heritage Purchase and Recovery Original Construction Purchase (%) Figure 8 – Ways of access to the property in Por- tugal (1998). Figure 9 – Average expenses with dwellings (2001). 1.4 Rehabilitation and maintenance cluster In Portugal, the conservation/rehabilitation activity represents a market share of about 7% of the total civil construction and public works sector, while in the rest of the European countries this activity is near 35% (Bragança, 2003). Figure 10 shows the weight of building conservation and rehabilitation activities in the construction market. The lack of investment in building conservation and rehabilitation justifies the high degradation level not only of the facades but also of the other building elements (Piedade, 1995). Figure 11 shows the Portuguese investment in the construction sector by types of activity. 0% 10% 20% 30% 40% 50% 1997 1998 1999 2000 2001 2002 2003 Portugal West Europe Central Europe Figure 10 – Weight of building conservation and rehabilitation activities in the construction market (2001). State of the Art: Portugal 146 Figure 11 – Portuguese investment in the construction sector. It must be noticed that the data shown in Figure 10 also includes the investment in the conserva- tion and rehabilitation activity promoted by public institutions in order to preserve the historical patrimony. This very low investment in the conservation and rehabilitation actions is not caused by the lack of need in this kind of works. According to data from 1996, the Portuguese housing stock needed at that time an investment of approximately € 25,000,000 in the building rehabili- tation and maintenance areas, although in that year it has been invested only a little bit more than € 1,450,000 (Afonso, 1998 and INE 1998). Table 4 and Figure 12 also shows that the number of housing rehabilitation interventions is reducing since 1975 and that the new construc- tion is continuously increasing. Table 4 – Types of housing intervention (INE 1998). Year New Constructions Rehabilitation Total Nº of Dwelling (%) Nº of Dwelling (%) Nº of Dwelling (%) 1975 31967 90,7 3271 9,3 35238 100 1976 30028 90,7 3073 9,3 33101 100 1977 34893 92,6 2771 7,4 37664 100 1978 34379 93,8 2262 6,2 36641 100 1979 36430 93,7 2437 6,3 38867 100 1980 38231 93,6 2631 6,4 40862 100 1981 38597 94,2 2365 5,8 40962 100 1982 39791 94,7 2211 5,3 42002 100 1983 38127 94,4 2278 5,6 40405 100 1984 41250 93,6 2834 6,4 44084 100 1985 35475 92,5 2870 7,5 38345 100 1986 37274 93,2 2708 6,8 39982 100 1987 38833 92,8 3024 7,2 41857 100 1988 45974 93,7 3098 6,3 49072 100 1989 58152 94,4 3465 5,6 61617 100 1990 62081 94,4 3655 5,6 65736 100 1991 - - - - - - 1992 52185 94,2 3200 5,8 55385 100 1993 63199 95,5 2970 4,5 66169 100 1994 59353 95,9 2536 4,1 61889 100 1995 65304 96 2695 4 67999 100 1996 65607 96,9 2133 3,1 67740 100 1997 68599 97,3 1916 2,7 70515 100 30% 23% 7% 40% Residential Non Residential Conservation and Rehabilitation Public Works State of the Art: Portugal 147 In Portugal, the low activity in the conservation and rehabilitation areas can be explained by several facts of recent history, where the old building rental policy plays the major role. This, together with the high inflation rates occurred during the 70’s and 80’s, made economically un- viable the execution of maintenance works by the owners. According to data published in the 2001 Census, almost 33% of the Portuguese buildings, built after 1946, require some kind of reparation. Figure 13 shows the level of the required interven- tion. The others 67%, at that time, do not need any reparation because those buildings have been object of more or less recent intervention by the owners in order to keep the housing units in good conditions of habitableness. The need of intervention in façades, including walls and windows, is slightly higher than the need of intervention in the buildings themselves and is approximately 40% of the total buildings built after 1946 (see Fig. 14). The façades deterioration is closely related with the coating materials used. The results of the 2001 Census show that the most common used coating materials can be classified in 4 types: stone, concrete, plaster and ceramic tiles. The most common is the stone (38,2%), immediately followed by the concrete (31,6%) and the plaster (24,1%) and finally the ceramic tiles (5,8%). Only 0,3% of the building stock haven’t any of these type of finishing (see Fig. 15). 0 20 40 60 80 100 120 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 (%) New Constructions Rehabilitation Figure 12 – Types of housing intervention (INE 1998). 67% 21% 8% 3% 1% No need of repairing Small reparation Medium reparations Great reparation Highly degraded Figure 13 – Level of required building interven- tion in Portugal. 60% 22% 12% 4% 2% No need of repairing Small reparation Medium reparations Great reparation Highly degraded Figure 14 – Needs of intervention in façades. 31,6% 5,8% 38,2% 24,1% 0,3% Concrete Ceramic tiles Stone Plaster Others Figure 15 – The most common used finishing materials. 2 QUALITY OF THE HOUSING STOCK 2.1 Architectural and urban aspects 2.1.1 Aesthetic and social aspects The architectural aspects can be divided in three main periods, marked by two important dates: 1) 1949-1974. Portugal did not participate in 2 nd World War, so, the war period didn’t have a so huge impact on the territory as in other countries. The post-war period was characterized by a dictatorial regime that has already been implemented in 1933. New Constitution delayed the State of the Art: Portugal 148 come out of consumerism, differentiating Portugal, from the very beginning, from the industri- alization and technological development that took place in other Western-European countries. This somehow pushed Portuguese architects towards intense adaptation work. The industrializa- tion on construction processes was rather difficult to implement. The 50’s period would be marked by an irreversible transformation of the territory and, above all, by altering the scale of intervention. Stripped of its original content, that of a democratic architecture oriented towards the wellbeing of its users, a skin-deep functionalism was propagated as a formal model at one with the International Style, imposing itself in huge real-estate interventions, mainly in Lisbon. “Bairro das Estacas” in Lisbon is an example of these interventions, as it is shown in Photo 17. Portuguese Architecture from this period has a defined and centralized “Style”, called the “Por- tuguês Suave”, especially in Social and Public buildings, but with some contributions from Modern Style, as the architects were present in the major interventions and regulations. The hil- liness and dead of the Regime Prime Minister, Salazar, during the 60’s and the Ultramarine Wars, led Portugal to some controversy and difficult period that culminated in a Revolution in 1974. However, the 60’s period was already a transitory period, where some social housing was built, and punctual interventions were inspired on the “Athens Letter”. 2) 1974-1986. The revolution of 25 th of April 1974 marked the beginning of a Democracy in Portugal. Some housing dwelling initiatives were undertaken, especially in the two major cities, Lisbon and Porto, where the major transformations took place, both for the best and for the worst. In order to meet the social dwelling requirements, several medium scale urban interven- tions were done, mainly in central areas of major cities, and some Cooperatives were created. An example of this is the SAAL interventions in Porto, as the “Bairro das Águas Férreas” de- signed by the architect Siza Vieira (Photo 18) or the intervention of another architect, Pedro Ramalho, in Guimarães, as it is shown on Photo 19. Photo 17 – Bairro das Estacas in Lisbon (International Style). Photo 18 – Bairro das Águas Férreas in Porto (Cooperative of Housing). Photo 19 – Cooperative of housing in Guimarães. In spite of the existence of some problems related with the quality of construction, with actual consequences, the quality of the Architecture was one of the main concerns in these interven- tions. But, in this period, private promoters also found a fertile soil for speculation and disor- dered construction and non-regulated urban areas grown up, mainly in the suburbs of the major State of the Art: Portugal 149 cities but also in the city centres. In most cases, Architects were not involved in this process, and this contributed to the mischaracterization of Urban and Rural Landscapes. The constructive aspects didn’t change from the previous period, as some inertia on the introduction of new sys- tems did not allow a significant change, and the relatively low cost of the hand labour was still a reality that permitted the maintenance of traditional constructive systems. 3) 1986-till now. 1986 was the date when Portugal joined European Economic Community. EEC cohesion funds gave a huge contribution to the economical and socio-cultural development of Portugal, but, at that time, there were many problems that could have not been solved, and some of them have even been aggravated. The consciousness that the kind of transformation that took place after 1974, should have been carried out at an urban level, with intervention of local authorities in order to assure a better connexion between these quarters and other parts of the urban landscape, only took place in the middle 80’s, when it was already too late. Errors that took place in the previous period, due to the lack of urban regulation, led to some incrusted problems that are now very difficult to undertake, namely the lack of green and leisure areas, the creation of urban “ghettos” in the middle of big cities and the difficulty of absorbing all the im- migrant population that are now continuously arriving. In what concerns the infra-structural transport subject, European funds were mainly conducted to improving road transports. The majority of the funds were used to build new highways. But this strategy led to an excessive car dependency that aggravated environmental problems and mainly cities accessibilities. This period, after 1986, performed a significant improvement in the building sector, regarding architectural quality. However, the interventions are always operating in a small scale, as urban re-qualification interventions at large scale become much more difficult due to the previously identified urban errors and also to the saturation of the housing market. In this context, some buildings are now conceived by architects, because of an increasing demand of aesthetic and functional quality, but only in very discrete cases. In spite of this, some problems are still occur- ring, namely constructive problems, regarding the introduction of new materials, not yet very well tested. Renovation and re-qualification of existing buildings are now giving the first steps in Portugal as construction reached the saturation point and the Population is diminishing. Improving and creating some leisure and green areas are also a growing concern, with some City Parks re- qualified or being created in many Cities. 2.1.2 Functional aspects Portugal has four main differentiated soil occupancy geographical areas: littoral and interior, North and South. North interior territory is mainly composed of dispersed housing, mainly sin- gle-family type, with small partitions of land associated to them. On the contrary, in the interior South, the individual family houses are surrounded by large extensions of land and the urban ar- eas are scarce, small and concentrate. In the littoral areas, both in Southern and Northern terri- tory, the soil costs are very high so, the housing stock is mainly composed of Multi-Dwelling buildings concentrated in urban areas. Social problems are aggravated by the contrast between Littoral and Interior Areas. Interior areas are becoming deserted, while Littoral Areas are over- populated, with increasing criminality and economical and cultural contrasts. This is more evi- dent in the North than in the South. The lack of public transport infrastructures is only now being mended and citizens are still ex- cessively dependant on individual transports. It has been very difficult to convince people to use public transports since they are no more used to do it and there isn’t yet a satisfactory transport net in the territory. Portuguese regulation on Functional aspects is enough to maintain minimum conditions of in- habiting, in living areas, circulations and basic commodities. Projects are done regarding some acoustic comfort conditions and some minimal thermal comfort conditions that are only possible because of the mild climate in the majority of the Portuguese territory. Due to this low thermal State of the Art: Portugal 150 quality of the envelopes, occurrence of condensation is one of the major concerns in Portuguese buildings. Another general main problem is that buildings are built not taking into account maintenance costs. These costs become a major concern of their inhabitants after 15 or even 10 years of use, as promoters don’t take this issue seriously. Even if the promoter is the state, namely in Social Housing, this aspect is neglected. There is a main aspect that determines now the functional aspects of urban houses: the owner- ship. Housing owners that inhabit their houses are free to adapt and make the changes they con- sider necessary and, in many cases, they were even participating in their conception. In these cases they are more concerned and involved in their maintenance and they care for their good conditions. In central and historical urban areas and in Social Housing, where tenants pay very small rents, owners very hardly preserve their dwellings, as they sometimes pay more of mu- nicipal taxes than they earn on rents. Sometimes, are the tenants that make some urgent refur- bishments, but, as they are not investing on their own property, they don’t do major reconstruc- tion works. Changing the policy of rents is now one of the major concerns of the government, namely after some accidents that took place recently, where some buildings ruined, in some cases even with casualties. 2.2 Structural aspects 2.2.1 Safety Reports related to construction pathology in national buildings do not mention critical situations about the structural behaviour. The main reason for the scarcity of accidents at this level is the application of strong safety factors in the structural design. The reinforced concrete bearing system is the structural solution in the majority of the buildings built in the second half of de 20 th century. The first regulation about the structural safety of this structural system was published in 1967. In the structural design, beyond the static loads and the additional effects, some dynamic loads are considered (wind and seismic). The poor quality of the foundation works is the main source of the majority of structural prob- lems, but fortunately there are very few registered cases. The main reason of this reality is the tradition of not performing tests to the subsoil before the foundations’ design. The most applied technique used afterwards to correct the subsoil resistance is the injection technique. In façades and balconies, some problems could also be observed. The steel bars corrosion is a frequent problem in the façades’ structural elements, what can, in a short period, compromise the buildings’ structural stability. The insufficient protection of the steel bars and the fragility of the external surfaces or coatings are the main reasons of this problem. 2.2.2 Earthquake Portugal, mainly at the South and at the Azores islands, has seismic related problems. Since 1755, with the Great Earthquake of Lisbon, some questions related to its seismic behaviour are considered in the design phase of buildings. Nowadays, according the safety and loads statutory, the seismic loads are considered in the de- sign phase, according to the seismic risk of each local. The buildings in the mainland and Madeira Islands do not suffer considerable seismic loads along its life span. So, there is a very small number of buildings with problems. On the contrary, at the Azores islands the earthquakes are very frequent and, sometimes, strong. The last strong earthquake occurred in 1998 and had great social and economical impacts in the islands of the central group, destroying a big quantity of buildings. The majority of the buildings destroyed had load bearing stonewalls. The rehabilitation processes of those buildings respected the origi- nal architecture and improved its seismic behaviour. State of the Art: Portugal 151 2.3 Physical aspects 2.3.1 Thermal insulation The first legal document concerning the building thermal performance was published in 1990. Its name, RCCTE (Decree-Law 40/90 from the 6th February) is the acronym for the Portuguese name “Regulamento das Características de Comportamento Térmico dos Edifícios” that means Regulation of Thermal Building Behaviour Characteristics. This document had the general aim of promoting the general quality of the buildings and assur- ing better hygienic and comfort conditions, especially in residential buildings. This regulation had also the purpose of controlling the energy consumption for thermal (heating and cooling) and visual (lighting) comfort. This document intended to impose the improvement of the thermal quality of the buildings en- velopes as a strategy to improve the indoor comfort without increasing the energy consumption. To improve the buildings behaviour during winter, the reduction of the overall thermal coeffi- cient (U) of walls and roofs was imposed through the definition of a maximum U-value. Since that time, the use of insulation materials and double glazing in widows started to become com- mon in building construction. The most common insulation materials used in the envelope are the expanded polystyrene, the extruded expanded polystyrene and more recently the rock wool and the polyurethane foam. Besides the thermal insulation improvement, it was also promoted the use of efficient solar en- ergy collection strategies through south oriented glazing, protected during night time by shutters or equivalent devices that can contribute to reduce heat losses during that period. During summer, the strategy to avoid the energy consumption was the encouragement of the use of shading devices in all windows, mainly in the south oriented glazed areas to prevent over- heating, and the use of cross natural ventilation strategies as a way of removing the heat gains from the interior. In Portugal there is also another regulation concerning the building thermal comfort. Its name is RSECE (Decree-Law 118/98 from the 7th May), which is the acronym for the Portuguese name “Regulamento dos Sistemas Energéticos de Climatização nos Edifícios”, meaning Regulation of the Energetic Systems for Building Acclimatization. This regulation, published in 1998, is tar- geted to buildings with significant energy consumption for heating and/or cooling. It is applica- ble mainly in office, commercial and residential buildings where the acclimatization energetic systems have more than 25 kW installed. This regulation envisages mainly to avoid the exaggerated over sizing of the acclimatization systems and therefore reducing the corresponding energy consumption. As the previous regula- tion (RCCTE), RSECE also imposes a set of measures for rationalizing energy consumption, like the heat recovery, the passive cooling, the energy management systems, the power fraction of the cooling and heating equipments and its respective minimum efficiency, the good mainte- nance practice and the liability of the designers and installers, among others. As nearly 80% of the building stock was built before the publication of the RCCTE, therefore without any thermal demands, its thermal performance is inadequate in almost all cases. In spite of this reality, thermal rehabilitation is not yet a common practice. Therefore there is still a great effort to be done in this context in Portugal in the near future. In 2001, following Rio agreements and the necessity of reducing greenhouse gases emissions (Kyoto protocol), but also due to the European Directive 2002/91/CE of the European Parlia- ment and of the Council of December 16, 2002 on the energy performance of buildings, the Por- tuguese government is revising the RCCTE regulation to improve the quality level of the build- ings. State of the Art: Portugal 152 The new regulation envisages the reduction of the building energy consumption in nearly 50% and the main changes are the following: - improve the reference thermal characteristics of the building envelope; - double the envelope insulation thickness, in general; - mandatory use of double glazing in the coldest zones and for the orientations without sig- nificant solar gains; - take into account the contribution of passive solar systems; - take into account the energy spent for lighting purposes and the energy spent in heating the sanitary hot water. 2.3.2 Protection against moisture The protection of buildings against moisture is always done at three different levels: the roof, exterior walls and elements in contact with the soil. At the roof level, the most common protection is carried out by tilted roofs using ceramic tiles as covering. However, in recent buildings the use of flat roofs is becoming more and more popular. In these cases, the protection against moisture is achieved through the use of bitumi- nous sheets. The protection against moisture of exterior walls is usually obtained by the use of a mortar layer with low porosity (rich cement mortar). The most common exterior wall technology is the dou- ble wall without any contact between panes, which is an important contribute to avoid the mois- ture penetration through the vertical envelope. It is common the use of bituminous paints to waterproof the elements in contact with the soil (foundations and retaining walls). To avoid rising damp through the foundation elements it is current the use of waterproof additives in the concrete mixing. Humidity inside buildings is one of the most frequent defaults mentioned in the Portuguese building stock. Three main reasons can be pointed out to explain this situation. The first one is technical and it is connected to an inappropriate design or to a faulty construction of a building component. At the roofs, the major defaults are found in the flat roofs, mainly due to the bad quality of waterproofing sheets and/or (mostly) due to its bad application. The most common problems are found in the interception of these sheets with the vertical elements (chimneys and roofs cross bands). Humidity in the envelope walls (exterior and interior surfaces) is becoming a common problem in recent construction buildings, mainly due to the bad quality of the finish- ings (high porosity) and to the recent architectural fashion of designing roofs without eaves. The eaves used in the traditional Portuguese buildings are a way of protecting the exterior walls from the rain water. The second one is a result of the thermal improvement of the buildings envelope with the inte- gration of insulating layers in the exterior components. This situation leads frequently, depend- ing on the construction system, to the occurrence of thermal bridges with consequent air con- densation on those areas. This is very common in the surfaces in contact with the structural elements and at the windows borders. This is a frequent default in recent buildings, mostly built after the publication of the Thermal Regulation Code (1990). The third reason is generally due to ineffective ventilation in the rooms where moisture is pro- duced (mainly in bathrooms and kitchens). In Portugal it is seldom the adoption of mechanical ventilation systems. This reality worsens the air condensation at the thermal bridges and con- tributes to the low quality of the indoor air. This anomaly is frequent in buildings built after 1990 due mainly to the adoption of low leakage windows. 2.3.3 Noise insulation Acoustical comfort is now a very persistent problem for Portuguese people and it is the subject of frequent complains. Buildings built before 1987 were not submitted to any sound insulation regulation code. Between 1987 and 2000, there was an acoustic regulation code but, in general, State of the Art: Portugal 153 it was not applied. Since 2001, a new code is in force which imposes serious requirements re- garding the protection against sound and noise pollution. According to the Portuguese Building Acoustics Legislation, partition elements must meet some acoustic requirements as shown in Figure 16. Figure 16 – Sound insulation levels required. The high mass of the conventional construction systems contributes to the satisfactory sound in- sulation of the vertical partition elements. The majority of complains is related to the horizontal partition elements, normally between commercial areas and dwellings, due to an insufficient airborne sound insulation level. The low impact sound insulation index observed between dwellings is another cause for complains. Floating slabs and suspended ceilings are the most common solutions used in the horizontal elements to solve these problems. 3 CONCLUSIONS The existing building stock erected between 1946 and 1991 represents 61% of the entire build- ing stock in Portugal. Therefore, there are a big number of envelopes to be improved. The rehabilitation and maintenance will replace the new construction. Therefore more and more interventions in the buildings and mainly at the level of the most exposed construction elements (roofs and façades) will take place in the near future. D 2m n w - Airborne Sound Insulation Index of the facade D n w - Airborne Sound Insula- tion Index of partitions L’ n w - Impact Sound Insulation Index Dwelling D n,w = 50 dB Commercial area Dwelling Dwelling Dwelling D n, w = 50 dB L´ n,w = 60 dB D n, w = 58 dB L´ n,w = 60 dB D n, w = 50 dB Commercial area D n, w = 50 dB L´ n,w = 50 dB D n, w = 58 dB Garage D 2m, n, w = 30 dB D 2m, n, w = 30 dB D 2m, n, w = 33 dB State of the Art: Portugal 154 4 REFERENCES - Afonso, F. et al (1998). O Sector da Construção – Diagnóstico e Eixos de Intervenção, IAPMEI, Lisboa, Portugal. - Bragança, Luís, et al. (2003). Anomalias Mais Comuns nas Fachadas de Edifícios do Concelho de Guimarães. Paper presented in the PATORREB – 1º Encontro Nacional de Patologia e Reabilitação, Porto, Portugal, April. - Guerra, Franklin (1995). História da Engenharia em Portugal. Author Edition, Porto Portugal. - INE 2001. INE (Instituto Nacional de Estatística), Recenseamento Geral da Habitação – Censos de 2001. - INE 1998. INE (Instituto Nacional de Estatística), Inquérito à Habitação – 1998. - INE 1997. INE (Instituto Nacional de Estatística), Estatísticas da Construção – 1997. - Piedade, A. (1995). Competividade Industrial e Técnica na Construção de Edifícios, Jornada sobre Competividade da Indústria da Construção, Lisboa, Portugal. - Portas, Nuno & Mendes, Manuel (1992). Portugal Architecture 1965-1990. Editions du Moniteur, Paris. - Tostões, Ana (2001). The legacy of the “verdant 1950s’ .pp 131-143 in 2G, International Architec- ture Review, nº 20. Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW ON THE HOUSING STOCK After the second World War many reasons caused an intense building activity: the huge destruc- tion of most cities, the migration of people from country to town, a significant population growth. These factors caused a great demand for dwellings, especially in the biggest cities with industrial centers. A fundamental role for the reconstruction was developed by Public Housing Institutes (IACP, INA-CASA, GESCAL) by the promotion of several public and half – public building interventions. By the promulgation of the law n. 43/1949, that instituted the National Plan INA-CASA, the government promoted a building activity articulated in two periods of seven years, financed by obligatory contributions from workers and building firms in addition to public contributions. The main objective of the plan was to resolve housing and work problems, involving public administrations, professionals and artisans who operated in every town. This action, which realized more than 350.000 dwellings, constituted the most important public in- tervention in the subsidized housing during the second post-war period. 1.1 Data related to building periods The most part of the whole building stock in Italy has been built after World War II (Fig.1- Tab.1). Due to the war, near 1.900.000 dwellings were destroyed and about 5.000.000 were se- verely damaged of more than 30.000.000 which were present in Italy before the conflict. The first act of public interventions in the house-building was the promulgation of the law n. 43 28/02/1949 that instituted the National Plan INA-CASA: by this law the government promoted the setting up of a building society aimed to build up houses intended for the tenancy or the lease option of the state employers. The plan was articulated in two periods of seven years, second of which was activated with law n.1148 26/11/1955, and financed by an obligatory con- tribution from workers and building firms, in addition to public contributions. This operation, which realized more than 350.000 dwellings, constituted the most important public intervention in the subsidized housing. The INA-Casa Plan was directly enacted from Law 43/49 and from 1949 to 1963 it guided a large output of plans and realizations, from isolated types to an urban State of the Art: Italy Roberto Di Giulio, Silvia Brunoro University of Ferrara, Department of Architecture Eugenio Arbizzani University of Rome “La Sapienza”, Department of Architecture ITACA ABSTRACT: This paper illustrates some aspects of the housing developments built during ‘50/’80 which represents the main part of the Italian building heritage. The main housing build- ing typologies and technologies diffused in Italy are described, furthermore problems related to the multi-stored building blocks, which is the most common building type used for the housing settlements, are analyzed. State of the Art: Italy 156 scale with entire neighborhoods or urban centers that were independent. Public residential hous- ing has been managed since the beginning of the twentieth century by institutions with limited territorial importance such as the I.A.C.P. (Istituto Autonomo Case Popolari/Independent Public Housing Agency). Between 1946-1950 a number of 216.000 dwellings was produced for a total of 1.084.916 rooms. Between 1951 and 1976 an improvement of the building activity can be recorded, reaching a total of 1.334.871 rooms in 1976. From 1972 to 1980 approximately 50,000 homes were produced annually, and from 1980 to 1986 the building of new residential homes appears cut by half in comparison with the previous decade, approximately 26,000 homes having been legally produced per year. Year Dwellings 1946 33.618 1947 27.453 1948 36.515 1949 45.675 1950 73.422 Total 216.000 Figure 1: Age of dwellings in Italy; Table 1: number of dwellings built between 1946-1950 [2] 1.2 Description of main typologies Italian post-war building stock is characterized by the use of multi – storey building blocks, that were considered the most suitable for a multitude of needs and adaptable to every situation. The building activity can be divided in three main periods: INA-CASA Plan, divided in two seven – year periods from 1949 to 1963, and GESCAL Plan from 1965. First seven-year period (1949-1956) The building stock of this period is still characterized by the use of traditional technologies. Buildings are less extended and includes little apartments with simple schemes. The line – guides of the first INA-CASA post – war production can be listed in [11]: The definition of the minimum areas of 30, 45, 60, 75, 90 m 2 , for respectively flats with 1, 2, 3, 4, 5 available rooms; The separation from living and sleeping area; The use of loggias and balconies. Building blocks are generally composed with two or three apartments for floor and contain be- tween twenty and seventy apartments, with a medium high (from four to seven floors high). Staircases are generally in the middle, and there is no elevator installed. The majority of these apartments have a little kitchen open in the living - room and two bedrooms with a whole area of 50-60 m 2 (Fig.2). Many quarters were realized with mixed typologies, with the use of ter- raced buildings as the most suitable typology for a limited range of users (numerous families, ancients). State of the Art: Italy 157 Figure 2: Building block of the first seven year period. Cà Granda, Milan, 1955 [5] Second seven-year period (1957-1963) In the second seven year period began the first prefabrication era. The tentative to improve technical and functional quality of apartments oriented the production in [2]: The realization of fairly spacious apartments: minimum areas were fixed in 50,70,90,110 m2 for respectively flats with 1, 2, 3, 4, 5 available rooms; The separation between kitchens and living rooms; The use of separated entrances and the enlargements of service areas (e.g. storerooms); The realization of public activities in the ground floor instead of apartments, or the reali- zation of apartments in the ground floor only if elevated of 60 cm. Building blocks are more extended and have spacious apartments, generally ranging from 80 to 90 m 2 . The number of flats is higher, about 10 to 19 floors and there are elevators on every staircase (Fig.3). This period is characterized by the large use of tower typology: high and nar- row buildings including 1 to 5 apartments for floor, assembled in various ways as regard as the staircase and generally 6 to 14 floors high. Tower buildings are completely free on all the sides and it enables a near boundless view: for this reason they are generally provided with large log- gias and balconies. In this period the typologies with few floor and low numbers of apartments for floor, 1or 2, prevailed (Fig.4). Figure 3: Building block of the second seven year period. Via Arno, Bologna, 1964 [5]; Figure 4: Tower building of the second seven year period: Via Porro, Rome, 1959 [4] 1965 – 1980 period From 1965 the State intervention was committed to GESCAL by means of zone - plans carried out in several Italian cities [10]. The residential districts, built up with the partnership of the pre- fabrication manufactures, were planned by using a different grade of intervention, in order to achieve a building rationalization: the mean size of the buildings becomes larger, an average the loading measurements decrease and the house typology become standard. Sizes of 64, 80, 96, 112 m 2 were stabilized, respectively for apartments formed by 2, 3, 4, 5 rooms. The use of large State of the Art: Italy 158 panels and industrialized tridimensional modules produced the levelling and unanimity of choice also in front of very different typologies. Quarters built in this period are generally formed by different typologies combined, mostly building blocks with high tower buildings used as signal (e.g. by the four sides or at the centre). Building blocks of this period are generally very complex and extended: they are on average up to six floors high, and contains from two to four apartments for floor. Usually there is an eleva- tor on every staircase. Tower buildings grew in height, following the principles of the “low ri se-high density”. Height ranges between eight to nineteen floors, with more than two apartments for floor. 1.3 Description of main technologies Up until the reconstruction planning was worked out, the appeal for industrialized technologies and prefabricated components was rejected: the ideological justification was poor adaptability with the Italian construction methods and the repetitiveness of the finished building products. Therefore, in the first post-war period the use of traditional technologies prevailed. Starting from the second half of the 60’s, when new urbanization caused a frenetic growth in the request for housing, the resorting to innovative building technologies (at that time) appeared as a forced choice. The need to create quickly new dwellings incremented the use of industrialized methods and technologies, based both on the use of concrete casting on site and prefabricated elements. Industrialized building technologies needed to be imported from beyond the Alps, where im- proving the most useful realization aspects in order to speed up construction site stages began fairly early. 1.3.1 Structure/foundation The main technologies, in relation to building period and typology, can be listed as follows. Table 2: Typical technology for building period in Italy Period Type of dwelling Technology First seven – year 1949-1956 Building blocks 4-6 floors high Terraced buildings 1-2 floors Load – bearing masonry Concrete frames on site Second seven – year 1957-1963 Building blocks 10-15 floors Terraced buildings 1-2 floors Tower buildings 6-9 floors Complex formworks (Tunnel) Prefabricated concrete frames 1965-1980 Building blocks 8-15 floors high Terraced buildings 2-4 floors Tower buildings 8-19 floors Complex formworks (Tunnel) Prefabricated concrete frames Prefabricated concrete panels Tridimensional elements In all cases foundations are continuous column foundations or raft foundations. Tunnel and half-tunnel Tunnel is a re – employing formwork technology, formed by a complex static system that al- lows the realization of tridimensional structural elements by spout technology installed. The standard elements are 125x250 cm, but larger dimensions are possible (between 280-420/400- 620 cm) because beams are telescopic. Modules, pre - assembled in building site, form a whole reed to unite installed. For economic reasons the technology of complete tunnel, that imposes strong constrains on the design and a careful building yard organization, was generally used for building of more than 100 dwellings (Fig.5-6). In many cases were used half–tunnel formworks: modular elements “L” overturned that, joined in longitudinal and transversal sense, formed a tunnel element deep as the whole building. This technology was applied to resolve structural and dimensional problems with more flexibility. State of the Art: Italy 159 Fig.5: Tunnel realization; Fig.6: Half tunnel elements [16] Prefabricated concrete framework This technology, generally utilized for tower buildings, is based on structural concrete frames realized by prefabricated elements, transported and assembled on site: Prefabricated pillars, one floor high, joined by tubular profiles, with dimension ranging from 25x25 to 40x40 cm; Prefabricated beams formed by a trestle frame; Prefabricated floors “Predalles” formed by 4 cm of concrete with trestle frame and les- sening layer in polystyrene; External concrete panels and other prefabricated integrated elements (e.g. staircases). After the connection between pillars, beams and floors, a concrete casting is realized to connect structural elements (Fig.7). A variation is represented by the use of vertical continuous elements and horizontal plates. Pillars are generally tree floors high and the plates, deep as the whole sur- face included by four pillars, are connected to vertical elements by steel cables. Plates dimen- sion ranges between 240x300 cm to 540x700 cm with a minimum thickness of 22 cm for a plate of 420x420 cm (Fig.8). Figure 7: Pillar/beam concrete frame: the “K” system; Fig.8: Pillar/plates realization [16] Prefabricated concrete panels and tridimensional elements These technologies had an experimental and limited diffusion in Italy during ’60/’70 years, im- ported from the East Europe production, principally due to the limited possibility of design and to the poor information and practise of the Italian building industry. The systems, suitable for the rapidity of the assembly operations (structural panels were produced with integrated win- dows and plants and dry - assembled), were mainly used for the realization of block and ter- raced buildings. The standard dimensions strictly limit design of dwellings, modulated on panel State of the Art: Italy 160 dimensions, and this is also legible in the facades (Tab.3). Tridimensional elements can be open systems (L, T) based on the aggregation of two structural elements or closed systems based on the aggregation of four or more plans (Tab.4). Table 3: Principal prefabricated large panels: basic data System Type of building Basic parameters Single layer panels Block buildings 8-12 m high Walls thickness = 14 cm; Module mesh 250x500 cm Plates thickness= 21 cm; L= 250-400 cm Storey height 270 cm Multi layer panels Block buildings Over 12 m high Walls thickness = 23 cm (internal layer 12-16 cm; insulating layer 3-5 cm external layer 6-8 cm); Module mesh 200x400 cm; Plates thickness = 15 cm; L= 360-400 cm; Storey height 300 cm Hollow section panels Block buildings Over 12 m high Walls thickness = 20-28 cm; Module mesh 20 cm (40 to 600 cm); Plates thickness = 21 cm; Module mesh 60 cm (60 to 240 cm); Sto- rey height 270-300 cm Table 4: Tridimensional elements: basic data System Type of building Basic parameters O P E N Block, terraced, tower buildings Maximum 100 dwel- lings 5-12 floor high Modular mesh 60 cm Width max 240 cm thickness = 25 cm Height 280-360 cm Length 240 – 600 cm C L O S E D Block and terraced buildings 5-14 floors high Modular mesh 30 cm thickness = 25 cm standard dimensions 270x270x450 cm State of the Art: Italy 161 1.3.2 Roofs Multi-store housing stock in Italy is realized both with flat and pitched roofs. Generally flat roofs are used in the south of Italy, due to the rare incidence of the rain while pitched roofs are realized in the North of the Italy. The structure is generally the same used for the floors: trestle floor beams and hollow floor blocks or prefabricated concrete panels. Flat roofs are usually fi- nished with two layers of asphalt paper and 4 cm of gravel. Slope roofs are finished with roof tiles. 1.3.3 Façades Facades are generally realized in perforated brickwork or prefabricated concrete panels. Brick walls are single or, rarely, double layer with 4 cm air cavity. Dimensions ranges between 27 (single) to 32 (double) cm. Sometimes there is thermal insulation incorporated in the air cavity. External and internal layer is, for the most part, plaster. Panels are single or multi layer (Tab. 3) and finished by gray smooth concrete or white or yellow marble chips. The most common mate- rials used for window frames are aluminum and plastic. The most part of housing stock was built before the first petrol crisis in 1973 and the consequent law n. 373/1976, so have single glazed window panes. 1.4 Housing policy The Public residential housing policy has been managed both by national public agencies (INA- CASA, GESCAL) and by regional agencies such as the I.A.C.P. (Istituto Autonomo Case Popo- lari/Independent Public Housing Agency – now Azienda Territoriale Edilizia Residen- ziale/Territorial Residential Housing Company) with provincial jurisdiction. By analyzing the regulation about public residential housing since the beginning of second post – war period from 1980 it’s possible to distinguish two main periods, characterized by different housing poli- cy actions [2]. The immediate post - war period was characterized by Law n. 43/1949 which determined the conditions for beginning a substantial public residential housing plan destined for the less well- to-do classes – but self-financed by the workers themselves – whose motive was to revive pro- grams which would encourage reintroduction of the jobless workforce. During this period the main actions were: Direct contributions by State for the construction of social housing for employers realized by existing or created for the scope public agencies (INA CASA, GESCAL) with long – terms plans of interventions (Law n. 43/1949 and Law n. 60/1963); Tax facilities, granting of loan or state contributions based on payment of interests to pub- lic agencies for building activity (IACP; INCIS) or to housing associations to improve construction and purchase of social dwellings. In this case the contribution of the State was indirect (D.Lgs 399/7947; Law n.408/1949; Law n. 715/1950; Law n. 622/1959; Law n. 195/1962; Law n. 218/1965; D.L. n. 1022/1965; law n.422/1968); The building of social housing totally State - provided, for temporary events such as natu- ral calamities: war destructions (D. Lgs n.261/1947), people who lives in insalubrious places (Law n.640/1954), flooded people (Law n. 687/1957). In the second period, the promulgation of Law n. 865/1971 that delegated housing management to Regions. Social housing policy was regulated by a more organic regulations package both in terms of planning and use of money facilities. This law provided for a unique utilization of every funds promoted by public housing interventions: the building of dwellings for workers, for people who lives in insalubrious and decaying dwellings; the building of dwellings for re- gions stuck by natural calamities, of host – dwellings for students, workers, immigrate, indigent and old people. Next to the public social housing plans (regulated by the IV article of the Law) the programs about building with agreement were promoted, to help the building activity that couldn’t be based only on direct public funding. The measures promulgated after the Law were helpful to clarify and divide competences between different agencies (IACP, Regions, Munici- State of the Art: Italy 162 palities, etc…) and to transfer and de-centralize competences about public building interven- tions to Regions. Furthermore, building activity was increased by the promulgation of Law n.167/1962 (Facilities for the purchase of building areas for public and economic housing) that allowed the purchase of low – prices areas in the surroundings of the city centre. In the recent years, many actions concerning the refurbishment and upgrading of non – tradi- tional buildings were promoted: The new Italian laws on Urban Refurbishment (L. 179/92, and L. 493/93: “PRU – Urban Refurbishment Programs”) commit to the category of “Rehabilitation” the bulk of the building activity. The Act on “Contratti di quartiere” (“Neighborhood Contracts”), D.M. 22.10.1997, which is dedicated mainly to the regeneration of town districts heavily affected with social, eco- nomic and physical decay, points out the paramount role of rehabilitation of the existing housing estates, rather than that of overall renewal. The objectives of D.M. 22.10.97 fo- cus on four general issues: Morphological Quality, Eco-systemic Quality, Use Quality, Quality System. 2 TOPICS, QUALITY OF THE POST – WAR MULTIFAMILY HOUSING STOCK 2.1 Architectural and urban aspects Urban districts built during the second post war are the representation of the rationalist thought of that period, based on industrial production and use of machines. Therefore, in the most cases, technologies were imported and normally materials didn’t come from the local context: the re- sult was that residential typologies became general and undifferentiated. The principal reasons for the negative image of the post – war quarters are the size and the colours. Normally the multi - storey family houses were built in dark colour, which gives the sensations of pessimism. The extended dimension of the buildings, often being as big as a traditional dis- trict, gives the image of a greatly inhomogeneous and poorly arranged stock. Uniformity and monotony, because of the limited opportunities offered by industrialized systems, caused imper- sonal and not individualised units. The lack of architectonic solutions couldn’t give an architec- tural identity to the various parts of the site and increase the alienating character given by the repetitiveness and anonymity of the buildings. Another factor that influences negative impact in terms of aesthetic quality is the decay of elements and part of the buildings, due to realization errors or lack of maintenance. 2.1.1 Functional aspects The use of industrialized technologies, as tunnel, forces to the use of modular dimensions and limited the internal flexibility. Most of the units built in this period have internal spaces inade- quate to support any modern and changed comfort requirements because of the creation of rigid structural cells which made very difficult or even impossible to change them in case of family evolution, change of personal needs or new technical requirements. In general, spaces are cha- racterized by a low flexibility that makes difficult the adaptability to new user or temporary con- figurations. Apartment area, in the most cases, ranges from 50 to 70 m 2 , so the lack of space is a relevant problem. Especially the size of bathrooms and kitchens is insufficient and not corres- pondent to nowadays standard. State of the Art: Italy 163 Table 5: Exit of a questionnaire promoted by IACP about user requirements [1] Motivation of the disease Requirement Percent % Overcrowding – lack of rooms in rela- tion to number of inhabitants Extension of livable space, separation be- tween day and night zone 73,54 Lack of storerooms, service spaces Creation of wardrobes and storerooms 37,97 Single bedrooms too little Rebalancing of bedrooms (e.g. reduction of double room) 45,11 Kitchen not livable Extension of kitchen with glass balconies 48,37 Less lighted access and corridors Creation of open spaces (e.g. union between access and living room) 54,88 2.1.2 Accessibility In the majority of the post-war multifamily buildings, accessibility for disabled is not guaran- teed, because of the lack of elevators or ramps. According to Italian standards (L.13/89; D.M. 236/89) about architectonic barriers, the elevator box must be minimum 1.30x0.95 m, the space in front of the elevator must be 1.50x1.50 m and the entrance door 0.80 m, positioned on the short side of the box. Only in few cases the staircase is large enough to insert an elevator, consi- dering also that it’s necessary to have an extra-run room and an engine room in the underground floor or in the garret. 2.1.3 Environmental aspects Environmental impact during the management phases of the building is in particular related to heating systems. During the second post-war period the principle of managerial autonomy wasn’t adverted because of the disposition of low – cost energy, so most of the buildings were realized with central heating, and a lot of people are served by a unique power station. This is cause of: Low security of the most part of the systems that wasn’t constructed according to law; Low thermal efficiency that means maximum consumption and maximum pollution emis- sions in atmosphere; Thermal discomfort for the residents. 2.2 Social and cultural aspects 2.2.1 Urban/neighbourhood/planning/facilities In the most important cities the policy of the self – sufficient districts was carried out [13]. By analyzing the new INA CASA interventions, it’s possible to identify two lines of town planning scheme: the first one linked to the experiences of the European functionalism and the second one prompted by the Scandinavian and Anglo – Saxon realizations. The quarters built under the influence of the rationalistic movement are characterized by some typical elements: orthogonal lay – outs, plan volumes and flat facades (Fig.9). The planning rules according to the Scandinavian and Anglo – Saxon models generally take into consideration various forms, redis- covering architectural elements and styles peculiar to the Italian historical small towns. For ex- ample S.Giuliano quarter in Mestre was planned with low house centres which form small squares, following the minor Venetian style (Fig.10). Fig. 9: Tuscolan residential district in Rome; Fig.10: S.Giuliano residential district in Mestre, Venice [2] State of the Art: Italy 164 The difficulty of finding, during the expansion phases, cheap areas in the proximity of the urban center forced INA CASA to realize the intervention in suburban areas lacking of urban services. Consequently a policy of settlement that justified the realization of a new urbanization was elaborated. That means the realization of self – sufficient areas gifted of services and collective facilities that permitted the develop- ment of social, cultural and commercial activities, that “limited the density of dwellers at 500 for ha, with various and articulated composition, able to create comfortable rooms” [12]. In the reality, life of the dis- tricts was quite different from planning intention: most of them grew with negative characteristics that compromised the correct development. In first place, they were too far from the center of the city and from first suburb services. This caused discomfort and marginalization for the residents and considerable costs for planning operation that caused building speculation, favored by the raising of prices of next areas. Furthermore most of collective facilities, that represented the indispensable condition to the self – sufficiency, weren’t realized. 2.2.2 Social anonymity/lack of identity/ownership City planning performed in that period was mostly characterized by empiric and random choices linked to the necessary solutions of incidental problems. In many cases these solution conse- quently caused an exponential growth of the decay factors: urban districts built during this pe- riod are normally unable to offer forms of sociality and communal life, due to the degradation of the communal spaces. The new city suburbs are not evidence of human and social values shared by people, but only the effect of profiteering: therefore they are elements of deep disagreement in the social community. One of the most problem was the minimum attention to social and cul- tural background of people and to their tradition. An example of cultural distance from local tradition was the realization in many buildings in the South - Centre of Italy - where streets and open squares are the traditional places for socialization and community life - of a middle plan destined to collective activities. These areas become unused, degraded and empty. Lack of ser- vices and of urban standards encourages micro criminality and alienation character given by the repetitiveness and anonymity of the buildings. The social disadvantages of the multi - storey family houses are also connected with the feeling of communion where high buildings have li- mitations: people are many and it is difficult to know them, spaces of aggregation are lacking, and it is difficult for the parents to control the children playing outside. This favored juvenile delinquency and micro – criminality. Table 6: List of Principal problems related to urban districts built between ‘70/’80 in Italy - comparison between year 2000-1997 [7] 2000 List position (1 to 15) 1997 List position (1 to 15) Juvenile delinquency 37,1 1 24,8 4 Unemployment 36,4 2 46,6 1 Urban traffic 27,3 3 25,1 3 Drug 24,8 4 26,7 2 Immigration 21,9 5 15,9 8 Lack of social – sanitary services 21,4 6 21,2 5 Lack of structures for sports and leisure 19,5 7 19,1 6 Public administration inefficiency 16,9 8 16,3 7 Pollution 13,9 9 14,8 9 Lack of formative structures 10,4 10 14,2 10 Suburbs degradation 9,4 11 7,5 13 Lack of infrastructures 8,3 12 6,6 11 Micro criminality 7,4 13 8,7 12 2.2.3 Social structure of neighbourhood/building By the end of the ’60 the massive building activity caused the formation of big popular “ghetto” quarters for the most part occupied by immigrants and old people. Socio – demographic charac- teristics of the residents configure a significant area of social discomfort. The most common State of the Art: Italy 165 family unit is formed by singles, young couples and hybrid families with new partners com- posed by 4 or 5 members. Singles are mostly old people (medium age 69,94 years) who lives in solitude condition [1-14]. Table 7: Structure of inhabitants in IACP buildings [1] Number of components % Family composition 1 2 3 4 5 6 7 8 9 mor e tot Single 52,19 52,19 Couple 12,91 12,91 Complete family 5,02 3,2 2,24 10,46 Incomplete family 5,80 3,35 0,97 0,45 0,17 0,06 10,80 Extended family 1,65 4,62 4,59 1,65 0,85 0,23 0,06 13,65 total 100,0 Significant indicators about discomfort of families are work and income. The prevalent figure is on pension, then a low percent of occupied people, in the category of worker, ranging from 33- 34% to 37%. Another diffused condition is worker on one’s own, that in the most cases means work off the books. About income 61% of family composed by head of the family over 65 years is included in the sector ranged from 65.000 to 75.000 Euro, that shows the relationship be- tween low income and old families. The image of this headquarters is of a massive concentra- tion and segregation of poor social groups or high – risked of poverty, that goes to old people to adolescent and numerous family: for example 33% of people who turns to “people in difficulty” office lives in IACP houses. 2.3 Structural aspects 2.3.1 Safety/Earthquakes There are no serious structural problems noticed in Italian post – war apartment stock. About earthquakes, Italy presents a large seismic area defined in three zones. All the multi- storey building stock built before 1974 don’t care about seismic regulations (L. 64 2/02/1974, D.M. 16/01/1996, Circ. 10/04/1997). Therefore, framework concrete structures and complex formworks don’t represent a problem: the height of the buildings is not restricted, the technolo- gy is monolithic and represents a solid framework that can work in seismic zones. Problems are relevant for large panels buildings (maximum height is fixed in m. 32, 25 and 16 depending on thickness) and in the distance between buildings in relation to streets dimension that, in most cases, are too narrow. 2.4 Physical aspects Building sector account for the most energy loss waste on earth, owing to the low thermal insu- lation level of the envelopes, high thermal dispersions and minimum exploitation of the climatic resources [8]. 2.4.1 Thermal insulation In the last years the regulation about thermal insulation and comfort in working and living units has become more restrictive, due to the intervention of the “Energy saving law” (originally L.373 30/04/1976 then L.10 9/01/1991, and DM 27/07/2005). The D.P.R. 26/08/1993 defines six Italian climatic zones, based on categories of degree-days and the recent decree 192 18/08/05 “Energy efficiency of buildings” defines the energetic requirements for a building State of the Art: Italy 166 (W/m 2 year) in relation to the different climatic areas, expressed in function of the S/V value (V = volume of the heated building defined by his external surfaces - m 3 ; S = external surface that defines volume V - m 2 ) (Tab 8). Table 8: Energetic requirements of a building in winter season according to the Decree 192/05 A B C D E F Degree-day <600 >600<900 >900<1400 >1400<2100 >2100<3000 >3000 S/V Energetic requirements (kW/m 2 year) _ 0.2 10 10 - 15 15 - 25 25 - 40 40 - 55 55 _ 0.9 45 45 – 60 60- 85 85 - 110 110 - 145 145 According to this decree, standard transmission values (U – value) for opaque façades and win- dows are fixed (Tab.9). These values will be more restrictive since 2009. Table 9: Standard U values for façades and windows according to the Decree 192/05 Climatic Zone Opaque Façades Windows U (W/m 2 K) Since 1/01/2006 U (W/m 2 K) Since 1/01/2009 U (W/m 2 K) Since 1/01/2006 U (W/m 2 K) Since 1/01/2009 A 0,85 0,72 5,5 5,0 B 0,64 0,54 4 3,6 C 0,57 0,46 3,3 3,0 D 0,50 0,40 3,1 2,8 E 0,46 0,37 2,8 2,5 F 0,44 0,35 2,4 2,2 The housing stock built in the second post – war period generally doesn’t respect insulating standard values. For perforated brick or concrete panels facades, global thermal transmittance (U value) ranges between 0.6 and 1.5 W/m2 K. Windows are in the most cases single – layer, and sometimes the parts under the windows are thinner. Building deterioration increase negative consequences both in terms of the health of the residents and greater wasting of energy. Table 10: Thermal transmittance coefficient (U-value) of most typical post – war building facades Facades Thickness (cm) U – value (W/m2 K) Single layer perforated brick wall with plaster 27 1,5 Double layer perforated brick wall with air cavity (14/4/8). External and internal layer: plaster 28 1,1 Double layer wall: brickwork, air cavity, perforated bricks. External and internal layer: plaster 32 1 Single layer concrete panel 20 0.8 Multi layer, concrete panels as “sandwich” 25 0.6 2.4.2 Protection against moisture Protection against moisture is a big issue in Italy. Humidity inside buildings is one of the most relevant phenomenon in multi housing stock. Humidity in the exterior and interior surfaces of the walls is a common problem in recent construction buildings, mainly due to the bad quality of the finishing and to the ineffective ventilation in the rooms where moisture is produced (mainly in bathrooms and kitchens). State of the Art: Italy 167 The most causes of decay are related to: The horizontal penetrability of single layer façades caused by rain, fog, snow; The breaking of waterproofing layers; The difficulty of removal of rainwater (due to the absence of drips or covers) The condensation due to thermal bridges. These factors, are the principal responsible of different states of decay: The crumbling of plaster because of infiltration of humidity that causes swellings; The attack of biologic moulds that creates micro – organism patinas; The phenomenon of efflorescence due to the presence of salt in bricks; In the case of concrete panels, the breaking of final layer and corrosion of reinforcing steel bars; The removal of the cladding elements; The corrosion and malfunction of wood and steel window frames. Crumbling of plaster Attack of biologic moulds Efflorescence Steel bars corrosion Removal of cladding Corrosion of window frames Figure 11: Most common states of decay 2.4.3 Noise insulation The Italian set of rules about noise insulation is regulated by L.447/1995 and DPCM 5/12/1997 n.297 that defines noise standards for building and their elements in decibel degrees (Db). Table 11: Noise insulation standards for residential buildings according to DPCM 297/97 Description Value (Db) RW Soundproof power index for walls between two rooms, to calculate ac- cording to UNI regulation 8270 (1987 part 7, chapter 5.1). R is defined by EN ISO 140-5 (1996) 50 D2m,nT,W Standardized noise insulation index for facades to calculate as Rw 40 Ln,W Tread noise index, to calculate according to UNI regulation 8270 (1987 part 7, chapter 5.2). Ln is defined by EN ISO 140–6 (1996) 63 LASmax Maximum level of sound pressure considered A with slow time - constant 35 LAeq Continuum equivalent value of sound pressure, considered A 35 State of the Art: Italy 168 In the most part of post – war building stock noise insulation is definitely not up to standard. The lack of acoustic quality is mainly related to: Structure and materials of the building; Assembly defects of the components; Installations and plants, considering that the sound emits from plants has to be contained between 3 Db for bedrooms and 5 Db for other rooms during the day (6-22) and 3 Db during the night. The most problem is represented by noise throughout floors and internal walls because of the minimum thickness of the elements. In the most cases, the interventions for the improvement of the soundproof power like double ceilings or floor insulation are difficult to achieve, due to the minimal high of the rooms, generally 2,4 meters. The external walls also show insufficient acoustic insulation: they are in the most cases thin (e.g. the standard of 40 Db would be obtained with massive walls with a thickness of more than 25 cm) and especially careful in windows and parapets. In particular, the rigidness of prefabricated concrete systems (panels, modules) in- creases acoustic conductivity between the elements of the structure. 2.4.4 Daylight/sun and Air Quality The building policy during the second post – war involved the occupation of any available land and the consequent overcrowding. For this reason in many cases there aren’t the conditions for a correct day - lighting. Buildings are generally too much close, so people living in the lower level get very little sun and fresh air comparing to those living in higher floors. Rooms are too deep, especially in tower buildings with more than 2 or 3 apartments for floor, so the light permeabili- ty in internal areas is very difficult. Another problem is represented by the absence of solar shading systems that, mostly in South of Italy buildings, causes summer overheating. The most part of the dwellings have a bad inner climate, and the people living in them are re- ported to be not healthy. Principal reasons are the distance between buildings and the depth of the rooms. Many studies have demonstrated that the best results for internal ventilation are reached when the distance between buildings is more than 2.4 times the height of the building and this is less respected. Moreover, the change of air is fixed in 0.25V/h for each type of build- ing by DM 27/05/05. In many cases the relation between windows and room area is not res- pected (windows area _ 1/8 floor area) and sometimes rooms are too deep in relation to modern standards (room length _ 2,5 window height). Lack of sun and fresh air and overheating of the houses causes what is called “sick building syndrome”. The pollution of the inside climate of the house, causes diseases like asthma, allergy and headache. REFERENCES [1] AA.VV., 1992, Trasformazioni sociali e demografiche e nuove esigenze abitative, IACP Emilia Romagna, Franco Angeli, Milano [2] Acocella A., 1980, L’edilizia residenziale pubblica in Italia dal 1945 ad oggi, CEDAM, Padova [3] Cambi E., 1980, Di Cristina B., Steiner G., Tipologie residenziali a schiera, BeMa, Milano [4] Cambi E., Gobbi G., Steiner G., 1981, Tipologie residenziali a torre, BeMa, Milano [5] Cambi E., Di Sivo M., Steiner G., 1984, Tipologie residenziali in linea, BeMa, Milano [6] Cerasi M.,Ferraresi G., 1974, La residenza operaia a Milano, Roma, Officina [7] Censis, Fondazione Bnc, 2000 [8] ENEA, Energy Environment Report, 2001 [9] Giovanna Franco, 2003, Riqualificare l’edilizia contemporanea, Franco Angeli, Milano [10] GESCAL, 1964, Norme tecniche di esecuzione delle costruzioni con speciale riferimento alla progettazione, Roma, [11] INA CASA, 1949, Suggerimenti, norme e schemi per l’elaborazione e presentazione dei progetti, Roma, [12] INA CASA, 1952, Suggerimenti, esempi e norme per la progettazione urbanistica, Roma [13] Libera A., 1952, La scala del quartiere residenziale, in: Esperienze urbanistiche in Italia, Roma, INU, , pp.130-147 [14] Mingione, Zajczyc, 1992, Le nuove povertà urbane in Italia: modelli a rischio nell’area metropolitana milanese, Milano [15] Pierini R., 2001, La città distante: piani e progetti di edilizia residenziale pubblica, ETS, Pisa [16] Zaffagnini M., 1981, Progettare nel processo edilizio, Ed. Parma, Bologna Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW ON THE HOUSING STOCK Due to the historical and political environment, the building activity in Greece is gradually increasing from the beginning of the 20 th century until the 1970s. After 1922 Greece had to accommodate many repatriates, who left Turkey after World War I. Later on, political unrest and civil strife that followed World War II hampered the development of reconstruction in the fifties. Unlike the western European countries, governmental housing programmes in Greece were limited during that time both in number and in scale. These programmes were only directed toward particular areas, such as reconstruction in upcountry regions, which suffered heavily in the civil war, reconstruction of islands shattered by the disastrous earthquakes of that decade and construction of a few housing projects for refugees and workers. As a result, the housing problem passed into the hands of private businessmen, first in Athens and then in other cities. These entrepreneurs, working with little capital and with the system of floor ownership and “contracession deals” - land acquired from the owner in exchange for one or more apartments in the finished building - began reconstruction in the central districts of Athens and later in the outlying districts and provinces. The wave of migration to the cities, the growth of industry, the tendency to imitate foreign patterns, the discovery of a source of profitable occupation for a large number of engineers and contractors, combined with a rapid rise in urban land values, a preference by the public for apartments as an investment and the social status conferred by ownership created an unprecedented boom in the building industry, which continued until the mid sixties [8]. As a result, many buildings were demolished in the centre of the cities and were replaced by multi-storey buildings, the construction of which was often governed by the achievement of the highest possible exploitation of the building provisions and the maximisation of the profit for the construction parties. State of the Art: Greece Lambis Baniotopoulos, Dimitris Bikas, Katerina Tsikaloudaki, Kostas Chatzinikos Dept. of Civil Engineering, Aristotle University of Thessaloniki Ted Stathopoulos Dept. of Civil Engineering Aristotle University of Thessaloniki & CBS, Concordia University, Montreal ABSTRACT: This document provides information regarding the state of the art of the building construction in Greece. At first, the overview of the building stock is presented, including detailed analysis about the evolution of building construction, as well as statistical data and the government housing policies. Special attention is given to buildings erected during the period 1950-1980 with reference to their typology, technology and pathology. State of the Art: Greece 170 1.1 Data related to building period The present illustration of the country’s evolution in the sectors of building construction during the last century is shown in Figure 1 [3]. As Figure 1 demonstrates, more than 50% of the building stock was erected during the period 1946-1980 and under the particular provisions of law, meaning that their age ranges between 25-60 years. A decreasing trend of the building activity is evident after 1980, which is attributed to the crisis in Greek and international economy, as well as to the decline of intense urbanization. 0 100 200 300 400 500 600 700 800 900 1000 b e f o r e 1 9 1 9 1 9 1 9 - 1 9 4 5 1 9 4 6 - 1 9 6 0 1 9 6 1 - 1 9 7 0 1 9 7 1 - 1 9 8 0 1 9 8 1 - 1 9 8 5 1 9 8 6 - 1 9 9 0 1 9 9 1 - 1 9 9 5 a f t e r 1 9 9 6 x 1 0 3 Chronology N u m b e r o f b u i l d i n g s Building stock Urban areas Rural areas Figure 1. The building stock of urban and rural areas of Greece according to the period of erection. only ground f loor 57% 2 storey-buildings 30% >7 floors 1% 4-6 storey buildings 5% 3 storey buildings 7% Figure 2. Number of floors for the building stock in Greece. 77,0% 1,7% 4,6% 2,2% 0 1.000 2.000 3.000 Residence Public Tertiary sector Other uses x10 3 Number of buildings Main use of buildings with single use 76,5% 1,0% 13,2% 9,4% 0 100 200 300 400 Residence Public Tertiary sector Other use x10 3 Number of buildings Main use of buildings with mixed use Figure 3. Main use of buildings designed for single and mixed use. State of the Art: Greece 171 The effect of urbanization on building construction activity is also presented in Figure 1. In urban areas the construction activity reached its maximum during the period 1961-1980, while for rural areas the erection of new buildings started to decline after 1960; previously, the rural areas were developed and reconstructed after the wars. The vast majority of the constructions (90%) are designed for specific uses, while multi-use buildings account for only 10%. Figure 2 indicates the distribution of the number of floors appearing in the building stock of Greece. Although more than half of the buildings appear to consist of only ground floor, it must be mentioned that one- or two-storey buildings are more common in rural areas or have special uses (i.e. factories, schools, etc). In urban areas the majority of the contemporary constructions have 3-5 floors above the ground floor. The distribution of the categories of main use in single- and multi-use buildings is presented in Figure 3. Most of the single and multi use buildings (77.0% and 76.5% respectively) refer to constructions built for residential purposes. The tertiary sector (offices, hotels, factories) occupies the 4.6% of single use buildings and the 13.2% of multi-use constructions. The proportion of buildings with public use (hospitals, churches, educational buildings) is lower for both single- and multi-use buildings (1.7% and 1.0% respectively). 1.2 Description of main typologies In Greece most of the factors determining the main characteristics and, consequently, the typical forms of the buildings, usually show no signs of change with time. Specifically in the urban environment this persistence is particularly pronounced and clearly visible. As a result, urban buildings and specifically urban residential buildings display a characteristic uniformity relative to the decade of their erection throughout the country. However, certain changes in legislation and technology are the main factors of differentiation between the typical buildings of each of these decades. In Greece, almost all urban residential buildings erected between 1950-1980 take the form of multi-storey apartment buildings (Figs 4-6). The great majority of these buildings consist of a ground floor and usually three to five floors above it. The floor-to-floor height is approximately equal to 3.0m, which results to a net height of each floor between 2.7m and 2.8m. For the communication of the floors a central stairwell, consisting of an elevator and a staircase, is used. A typical apartment building has a basement, which houses the boiler-room for the central heating system and separate storage areas for the apartments. On the ground floor lie the main - Figure 4. Typical plans of apartment buildings constructed in ‘60s and ‘70s. State of the Art: Greece 172 entrance and either an open-sided parking area for the residents (pilotis) or shops. More rarely, there are apartments on the ground floor, usually positioned higher from the ground level. An analysis of building statistics for the period 1991–2002 shows that the average volume of private buildings in Greek towns is in the order of 1500m 3 [3]. This volume accounts for about 120–200m 2 per floor. On each floor there are usually one to four apartments with net floor areas ranging between 40m 2 and 100m 2 . These apartments, depending on their size, contain 1 to 3 bedrooms of approximately 10m 2 each, a living room, a kitchen and a bathroom/WC. An essential feature of all residential buildings in Greece is the balcony. Every apartment above ground level has at least one balcony in the form of a projection. Specifically, apartments with a larger number of balconies, or even buildings where continuous balconies occupy most of the external surface areas, are much easier to find. Balconies vary in width from a minimum of 0.5m to almost 2.5 m. Figure 5. Apartment building in Athens, erected in 1954-1960 [8]. Figure 6. Residential complex of luxurious apartments built in Athens in 1973-1975 [7]. 1.3 Description of main technologies In general, the building construction techniques depend upon a group of factors, which are either geographical (climate, earthquake behaviour of the site, availability of raw materials or traditional practices) or are imposed by building regulations and developments in the technological sector. State of the Art: Greece 173 Stone masonry was used widely at the beginning of the century, but its use declined after 1919, when the use of bricks for the construction of bearing walls started to expand, due to the development of the clay industry. The emergence of concrete (at the end of 1920) changed the scene: the use of reinforcement concrete became very wide, mostly for urban areas. The main materials used for the bearing structure of the building stock during different construction periods are presented in Figure 7. Nowadays, 67% of the building stock in the urban areas is built with reinforced concrete (Fig. 8). 1.3.1 Structure/opaque elements The bearing structure of the majority of the building stock consists of slabs, beams, pillars and foundations, all made of concrete. The construction is carried out on site with ready-mixed concrete produced by special units and transported to the building sites in special concrete mixers. Greece is one of the most seismically active countries in Europe, accounting for more than half of the continent’s seismic energy release. It has been hit by many destructive earthquakes 0 50 100 150 200 250 300 350 400 450 500 b e f o r e 1 9 1 9 1 9 1 9 - 1 9 4 5 1 9 4 6 - 1 9 6 0 1 9 6 1 - 1 9 7 0 1 9 7 1 - 1 9 8 0 1 9 8 1 - 1 9 8 5 1 9 8 6 - 1 9 9 0 1 9 9 1 - 1 9 9 5 a f t e r 1 9 9 6 x 1 0 3 Chronology N u m b e r o f b u i l d i n g s reinforced concrete wood brick masonry stone masonry Figure 7. The building stock of Greece according to the main material of its bearing structure and the period of erection. URBAN AREAS wood 1% brick masonry 21% stone masonry 11% reinf orced concrete 67% RURAL AREAS wood 0% brick masonry 35% reinf orced concrete 31% stone masonry 34% Figure 8. The building stock of Greece in urban and rural areas according to the main material of its bearing structure. State of the Art: Greece 174 throughout the centuries and, consequently, the structure and the form of the buildings are significantly influenced. During the last two decades, the Greek Seismic Code has been revised extensively twice, after strong seismic events, namely the Thessaloniki earthquake in 1978 and the Athens earthquake in 1999. Researchers and engineers have currently in their disposal more data, tools and techniques for the study of the structural response of buildings under seismic events and those parameters such as soil conditions, types of foundation, etc. that usually affect the buildings performance significantly. This knowledge has been taken into account for the revision of the Seismic Code and led to the imposition of new stricter requirements and more reliable design practice regarding the structural assessment of reinforced concrete and steel structures in earthquake-prone zones, as are almost all Greek territories. Moreover, improvements of the construction materials set higher requirements concerning the quality and durability of any structure. The aforementioned recent evolutions and the updated design criteria necessitate the enhancement of the structural performance under seismic excitation of those buildings that were erected during the period 1950-1980 or even earlier. These buildings or perhaps their majority, do not comply with the recent requirements of seismic performance. From an economics point of view, it would not be a good practice to initiate strengthening all these buildings in order to comply with the provisions of the recent editions of Structural Codes. However, it has been decided recently that it would be really essential to reinforce constructions of high societal interest, such as schools, hospitals and other public buildings. This latter rehabilitation activity has already started in all major Greek cities for such public- interest constructions through pilot projects on selected schools. The structural capacity of these buildings is analysed by means of appropriately chosen software. After evaluation of the analysis results with respect to compliance with the Codes, a variety of rehabilitation techniques and interventions, such as adding steel X-bracing, concrete reinforcing mesh and others, may be applied. Consequently, buildings designed according to a rather low level code environment are now rehabilitated with reference to the most updated code provisions, so that they can exhibit a better structural response, mainly with respect to integrity and serviceability, during an event of exceptional loading (windstorm, earthquake etc.). Both interior and exterior walls are almost always constructed with bricks. Reinforced concrete and bricks are produced from local resources. Manufacturing units supplying ready-made concrete and bricks lie scattered throughout the country and cover local needs. Most of the other building materials and elements which are required in different parts of the structures, are also produced by domestic manufacturers from native raw materials, while special and luxury materials are usually imported. The walls between the concrete frames are constructed with brick masonry, plastered on both sides. Exterior walls and the walls between adjacent apartments are generally constructed as double brickworks (Table 1). The interior walls within apartments are constructed in a single row of bricks 9 cm thick. Apart from the changes in the Seismic Code, a regulation for thermal insulation was introduced in 1979, in order to serve as a basic tool for establishing energy and environmental considerations into building construction in Greece. According to this Code, the country is divided into three climatic zones and for each zone a maximum average heat transmission rate is provided, ranging from 0.616 to 1.553 W/m 2 K, in relation to the ratio between the volume and the envelope surface area of each building. The implementation of the new regulation has changed the way of construction for external building elements (pillars, beams, roof, floors), since thermal insulation is required (Table 1). The thermal insulation is usually positioned on the exterior side of bearing elements made of concrete, while core insulation is typically used for double brick-walls. In order to fulfil the criteria of the regulations, double-glazing is required for windows and balcony doors. Floors above ground, non-heated basements or open-sided open areas should also be insulated. The most common materials used for thermal insulation are extruded polystyrene and glass wool. 1.3.2 Roofs The roofs of apartment buildings are usually flat; they are also communal and accessible from the central staircase. This is where the room housing the elevator machinery is located, as well as TV aerial installations, solar water heaters, water tanks, chimneys, etc. Flat roofs are usually State of the Art: Greece 175 finished with cement tiles, while most of the constructions built before the regulation for thermal insulation lack thermal and moisture protection. Rarely, in areas with more adverse climatic conditions, apartment buildings may be found with inclined roofs, usually resting on sloping concrete slabs. Pitched roofs are usually finished with ceramic tiles. 1.3.3 Internal finishes Prior to 1980, the most widely used material for internal floors used to be terrazzo. In more “luxurious” constructions, wood was used for bedrooms, and either wood (in the form of parquet flooring) or marble for the living room. Terrazzo was also used for balcony floors. Since the 1970s, however, this material has ceased to be used and it has been replaced mainly by ceramic tiles. Even so, wooden floor boarding continues to compete with tiles in bedrooms, while marble continues to dominate in living rooms. Interior doors are usually made of wood. 1.3.4 Facades The external surfaces of the buildings are usually simply plastered and painted with emulsion paints. Light colours are more common, usually ochre, blue, beige, orange or green. More rarely, some sections of façades are covered with ceramic tiles (usually in the shape of bricks), natural stone or, in luxurious buildings, marble. Exterior doors (balcony doors) and windows are usually two-leaved and single glazed. Initially, the frames were made of wood, but aluminium started replacing it after the 1970s. However, at that time aluminium frames were made by small firms, which could guarantee neither quality of construction nor acceptable standards of performance. Wooden frames contained shutters of the French type, while aluminium frames contained either external synthetic sliding panels or blinds with synthetic slats that could be rolled up. Table 1. Construction details for various structural elements appearing in buildings erected before and after 1980. It must be mentioned that after 1980 buildings are erected in accordance to the Thermal Insulation and the New Seismic Code. Before 1980 After 1980 State of the Art: Greece 176 1.4 Housing policy The responsibility for housing construction in Greece is almost totally relegated to the private sector. Public housing accounts for barely 2% of the total volume of housing units produced after the war. During this period several government agencies were created with the purpose to correct the fact that the production of the private sector was unable to cover the needs of the lower income bracket of the population. The Worker’s Housing Organization (OEK) has been the only one of these agencies with a fair record in creating housing projects in large urban centres, as well as in most of medium and small towns across the country. Several of the projects built in the ‘50s and ‘60s seem to be poorly located within the urban context; land scarcity has been the main reason. Many of these areas are frequently surrounded by incompatible land uses and in many cases far from social infrastructural services. Their small size, on the other hand, seldom allowed the creation of local services. In an effort to reorient itself towards a new model of development at the end of the 80’s, OEK adopted land use standards providing social infrastructure facilities within every large project and developed housing standards which are at least competitive if not higher than those offered by the private sector for middle income housing (Figs 9-11). Two representative types of public housing projects are mentioned below: The Menidi I, in Attiki (Fig. 11): housing development, design 1983, construction 1985-88, plot area 505,000m 2 , coverage 11%, building coefficient 0.25. The settlement comprises of a total of 974 units in two-storey single- or two-family houses and three- storey block of flats. A network of pedestrian streets and open spaces links the settlement’s neighbourhoods with each other, as well as to the central facilities, schools and playgrounds. Figure 9. The housing development project in Menidi, built in 1985-1988 [1]. State of the Art: Greece 177 The Solar Village 3, in Pefki, Attiki (architects: A. Tompazis and Associates): Built for 435 families, the settlement is organized in neighbourhoods with a network of pedestrian streets leading to the village centre (Fig. 10): The larger residential units of 100m 2 have been assembled in two-storey row houses, while the 80m 2 and 60m 2 units have been arranged in blocks of flats, from two- to six- storeys high. In total 34 residences, grouped in one three-storey and three two-storey buildings, were designed to be heated solely with passive solar systems. Similar activities of housing projects have been undertaken by banking organizations, as for example the Komotini project (Fig. 11). Figure 10. Axonometric drawing, plan and sections of the Solar Village in Pefki, Attiki [1]. Figure 11. Plan and view of a housing project in Komotini, built in 1978-1983 [6]. 2 TOPICS, QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK 2.1 Architectural aspects The building activity in Greece developed spontaneously during the first half of the 1950s. At that time, urbanization was excessive, unchecked and was accompanied neither by a parallel planned expansion of the infrastructure nor by the industrialisation and rationalisation of building components. Considering the above situation, it is not surprising that the freshness of approach and humanistic attitudes of the post-war reconstruction projects of other European countries can not be found in Greece. Instead, a decline in the overall quality of the built environment in spite of a considerable improvement in the quality of the individual buildings was present. The most conscious designs of this period are carried out by conservative architects educated before the war. They provide technically successful solutions, but seen as cultural State of the Art: Greece 178 statements, the buildings appear to have no content. They aimed at satisfying a small group of entrepreneurs or industrialists and a handful of professionals who succeeded not only in surviving the crisis, but also in coming out of it with some profit. Details of the past were dismembered, dislocated and deformed [2]. New architectural ideas were not easy to be introduced in Greece at this time. The generation of the 1920s with few exceptions is too conservative in its background to understand the problems and attempt such a leap. The generation of the 1930s attempts, in the framework of the social, political and cultural radicalism of their time, to create important avant-garde work. The generation of the 1940s, students during this period of confusion in institutions deeply damaged by the repression of the times, involve themselves in political activities. A decade after the end of the civil war, the institutional innovations in the field of architecture are limited. The government planning still mostly channels building opportunities into the private residential domain. This leaves hardly any chances for the public sector to develop either interesting schemes for tourist facilities or for social housing, educational projects or government offices. Despite all difficulties, the new needs and aspirations slowly find their expression in architecture through two movements: the functional-rationalism and the critical-regionalism [2]. Functionalism-rationalism tries to create icons, which express the aspirations of Greece to overcome the misery of prejudice and privilege through objective science and progressive technology. It employs the elements of post and beam structure organised in either a rectilinear prismatic or grid pattern. Critical-regionalism on the other hand tries to express the ideal of community and independence censoring the libertarian materialist attitude of the past-war era and the mentality of dependence. Main characteristics are the geometrical and topological devices found in the organisation of passages and places of Greek vernacular architecture, colour and material also cited from the Greek vernacular, as well as the rectilinear prismatic grid pattern [2]. The generation of the 1950s turned their attention to the rehabilitation of the apartment house of its recent past. A new conception of the facades emerges in these apartments. The concrete prism and grid pattern are dominant. At the same time, a generous continuous balcony space is projected between the front wall and the street [2]. As in most other cultural activities, the period of 1967-1974 dictatorship produced very little in the way of architecture. The younger generation had opportunities to build, but the architectural statements were few and mostly indifferent [2]. Nevertheless, the mass of buildings, the changes in building construction, the introduction of a large number of functionally sophisticated buildings, the emergence of coherent stylistic trends and the international awareness of architecture are indeed achievements of the post-war period [2]. It must be mentioned, however, that many problems still remain unsolved. The integration of post-war buildings with their environment is their weakest point, with some exceptions. The urban infrastructure is underdeveloped, while the largest number of the inhabitants live and work in areas, where unfavourable environmental conditions prevail. 2.2 Social aspects Greece has a high proportion of property ownership: 75% of the dwellings in Greece are privately owned and only 20% are rented (Fig. 12). This may cause problems concerning potential refurbishment, since the various owners of apartments in building blocks do not often share the same opinion for renovating actions. The present condition of the dwellings regarding the provided amenities is at a relatively good level (Figure 13). Almost all have indoor kitchen and bathroom and are connected with electricity and water supply networks. The majority of buildings have central or other heating system installations, while more than 60% of the dwellings are connected to the public sanitary system. However, problems related to water or heat installations are very common and are attributed mainly to the age of the buildings. State of the Art: Greece 179 Figure 12. The status of ownership of the building stock in Greece. 33,4% 66,2% 94,1% 95,3% 98,9% 94,1% 99,4% 99,5% 100% 0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0 3 5 0 0 4 0 0 0 Total Dwellings with kitchen Dwellings with electricity Dwellings with indoor bathroom Dwellings with indoor hydraulic installations Dwellings with central or other heating Dwellings with indoor bathroom & hydr. instal. Dwellings connected to drainage system Dwellings with other type of drainage system x10 3 Number of dwellings Figure 13. General description of the amenities offered by the building stock of Greece. 2.3 Structural aspects It is well known that the Aegean and the surrounding area, which includes mainland Greece, the Aegean Sea, Albania, S. Yugoslavia, S. Bulgaria, W. Turkey and part of the Northern Eastern Mediterranean, is seismically the most active region in the entire Mediterranean and in the West Eurasia. This region is a part of the collision zone between the Eurasian and the African lithospheric plates (Fig. 14), but its present tectonic activity is much higher than in other regions of the same zone. The most prominent morphological features of tectonic origin in the Aegean and surrounding area from south to north are the Mediterranean ridge (or chain), the Hellenic trench, the Hellenic arc and the northern Aegean trough. On the basis of the Greek Seismic Code (1999), the country is divided into four zones of seismic risk. Seismic ground acceleration rates for the design of earthquake-proof building range from 0.12g to 0.36g. On average, the construction of an urban residential building of typical (average) size in Greece lasts between 12 and 18 months. The most suitable time for starting construction is before autumn, in order to avoid rainfalls and the low temperatures of winter that make outdoor work difficult and may also cause problems to the concrete quality [5]. State of the Art: Greece 180 Figure 14. The main morphological features of tectonic origin in the area of Greece [4]. 2.4 Physical aspects Due to the age of the buildings of the 1950-1980 construction period, many problems related to their functional aspects are observed. A large number of the pathological symptoms is attributed to the total absence of damp proofing and thermal insulation. Therefore, damp regularly appears in several elements of the buildings, causing surface stains, appearance of humidified and watered surface, colour weathering and peeling, detachments, material decay, ruptures and cracks, oxidation of unveiled steel bars and mold formation (Fig. 15). The absence of thermal insulation, apart from being responsible for high energy consumption, often results in the appearance of vapour condensation on walls. Poor or lack of water-proofing of the roof and the basement envelope is not the only factor of damp appearance. Problems with hydraulic installations are also very common. Aging of materials also causes problems in heating and electricity installations. In this respect, the problems appear to be related both with the materials and the used construction methods, which are generally carried out without the use of suitable insulation and without adequate observance of the building regulations. The building elements, which over the course of time first display deterioration symptoms, are mainly doors, windows and floors, or rather coverings in general. Causes appear to be connected with age, poor workmanship and inadequate observance of the building regulations [5]. An indication of the pathological problems that buildings display is the fact that apartment blocks built in the 1950s and the early 1960s have begun to reach the end of their life duration and some have already been demolished, while those that are still in use have undergone or require serious and extensive repairs or renovations. Figure 15. Problems caused by dampness in building elements. State of the Art: Greece 181 A problem connected with the pathology of buildings is their maintenance. The low-cost maintenance of the communal areas and installations in urban apartment buildings in Greece, as well as other administrative matters, are entrusted by the residents to an elected administrator on the basis of a residents’ charter for the building concerned. In cases where maintenance costs are higher, the agreement of all the residents is required in practice. This system, which often encounters difficulties even in simple administrative matters, often proves to be unwieldy and ineffective in the case of serious repairs or maintenance work on the building [5]. REFERENCES [1] Caranicas, J. 1986. Public housing in Greece. The case of Worker’s Housing Organization. Architecture in Greece (20): 181-199. [2] Doumanis, O, 1984. Post-War architecture in Greece. Architecture in Greece Press, Athens. [3] General Secretariat of National Statistical Service of Greece 2001. Census 2001. Ministry of Economics, Hellenic Republic, http://www.statistics.gr. [4] McKenzie, D.P. 1972. Active tectonics of the Mediterranean region. Geoph. J. Astron. Soc. (30): 109-185. [5] Papamanolis, N. 2005. The main constructional characteristics of contemporary urban residential buildings in Greece. Building and Environment (40): 391-398. [6] Phillipides D. 1985. Two housing schemes in Trace. Physical planning and design aspects. Architecture in Greece (19): 174-186. [7] Tombazis, A. 1980. Residential complex at Psychico, Athens. Architecture in Greece (11): 138-140. [8] Tzakou, A. 1978. The apartment house: Its post-war development in Athens. Architecture in Greece (12): 131-143. This page intentionally left blank Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW ON THE HOUSING STOCK Cyprus is a very small country, covering only 9.251 km 2 . It is the third largest island in the Mediterranean after Sicily and Sardinia. The island gained its independence in 1960 and was proclaimed a Republic. At the period 1960-73 Cyprus went through a fast and almost uninterrupted growth. Despite the breakdown, in the years 1974-75, due to the Turkish invasion and the occupation of 38% of its territory by military forces, the economy recovered soon after and a substantial growth has been achieved. Between 1975-93 Cyprus once again witnessed additional economic growth, accompanied by an expansion of social services. Today the people of Cyprus, who live in the Government controlled part of the country, enjoy a high level of education, low unemployment and a good standard of health care. Crime is maintained at low levels. The 69% of people is living in urban areas, which cover 9.6% of the island. By 1st of May 2004, Cyprus became a full member-state of European Union. Approximately since 7000 BC, until the mid 20 th century AD, construction methods have varied only slightly. The same building material such as wooden beams, straw, clay mixtures and stones were used in approximate methods. In most of the architecture there is much wisdom in the method of construction and for the most part, the solutions found and utilised are both ingenious and economic. Although many Cypriots participated in the 2 nd World War, the war period did not have a huge impact in Cyprus since the island was not a main battlefield. Before the Cypriot independence in 1960, specialised building tradesmen constructed dwellings. In particular, the existence of travelling building teams is very important because as they moved from place to place, they learned a lot from local architecture and influenced the method of construction and building types in other regions. Furthermore, local people began to travel abroad and influence construction by bringing prototypes from many countries. The huge housing problem created after 1974 was immediately dealt with by government’s initiative and action, beginning with the reconstruction of destroyed areas to alleviate the housing shortage in the cities. As a result, the housing problem passed into the hands of private State of the Art: Cyprus Petros Lapithis Intercollege, Design department, Lefkosia Christos Efstathiades Aristotle University of Thessaloniki, Faculty of Engineering, Institute of Steel Structures George Hadjimichael Ministry of Interior, Town Planning and Housing Department, Lefkosia ABSTRACT: The worst housing problem ever faced by Cyprus appeared after the invasion of 1974 when 38% of its territory was occupied by Turkish military forces. 36,2% of the housing stock was lost and 200.000 refugees had to be housed in their own country. Until 1986 the Government of Cyprus managed to house nearly 50.000 of these people in various refugee estates carried out by the Town Planning and Housing Department. Out of this number, approximately 30% have been housed in small three-storey family houses. Some thousands of refugees have been housed in multi-storey family houses built by the private sector. Today, due to the specific technical, environmental and seismic conditions in Cyprus, as well as the change of the quality of the available building materials, many of these multi- storey buildings face a variety of problems. The solutions decided vary from complete State of the Art: Cyprus 184 businessmen. In fact, because of the absence of other investments, the building industry began to play a determining role in shaping the Cypriot economy. The new government took measures towards regulating of the urban space with the purpose of stabilising the regime. Many image- driven public building projects began and several laws were passed making construction policies less strict. Consequently although the first substantial reductions of some plot ratios (above 200%) were enforced in the main towns, many new development zones were created in order to set the ground for new structures. As a result, private building construction especially focused on tourism and housing industry boomed during this period. A series of reforms was introduced to the new constitution that specifies that the protection of the physical and cultural environment is an obligation of the state. All the reforms reflect the necessity for an adequate planning mechanism in the field of housing and environmental and land use planning. However, the Cyprus government has not yet established many implementation procedures and reserves for itself (4 out of 33 Municipalities) the right to act on any problem by highly centralising the decision-making process on all these fields. Contemporary life and the building industry in Cyprus are greatly affected by the proliferation of apartment blocks in the large urban centres. The apartment house became the symbol of the final stage of urbanisation. And since urbanisation is for certain reason a preferable way of living for the contemporary Cypriot, the apartment model is extensively adopted even in medium size settlements in the countryside. Cyprus employs a lot of housing systems. Within the context of the housing policy for the refugees, the government of Cyprus has introduced various schemes and programs like the “Low Cost Government Housing Scheme” that provides houses, free of charge, to low-income families. Until 2001, more than 12.500 families (or 5,6% of the total number of households) were benefited from this scheme in 71 housing estates. In addition to that the government provides the “Self-help Housing Program on Government Land” (where 9.000 families, or 4,1% of the total number of households, have already been housed in 321 estates of this type), the “Self-help Housing Program on Private Land” and the “Purchase of a House /Apartment Scheme”. In the private sector, development and construction companies offer in the free market various types of housing units and mainly apartment or terrace houses. This type of development satisfies nearly 30% of the total demand (Fig. 1). A substantial number of families however, choose to build their own detached or semi-detached house, on an individual plot of land, which has an average surface of 520 m 2 . It is worth mentioning that in 2001, 68,2% of the total number of households in Cyprus had their own private housing units. Three categories of construction financing have been developed. In the first, a contractor undertakes the construction of the building. In the second, the owner of the property decides to play the role of the contractor-entrepreneur and undertakes the responsibility of constructing and financing the project. He usually sells or rents most of the apartments keeping one or two for him. In the third (the gradual method of construction), the owner of the property builds one housing unit for the present needs of his family, allowing for the possibility of constructing additional apartments in the future to cover the needs of the growing family or merely for investment reasons. State of the Art: Cyprus 185 Fig. 1: Multi-storey family buildings on regular plots built by the private sector The results of this practice in the form of the city are the following: - Housing areas close to industrial or other areas, dangerous for public health - Very limited green and open spaces within the housing areas - Bad relation between street width and building height. - Different housing types even in the same street-large apartment blocks adjacent to low houses. - Unplanned and often unhealthy interaction between the built and natural environment. In an analysis of the built environment of the city area, it was concluded that the negative points of the housing environment are not due to the lack of adequate housing units, but to the high cost of the housing units, the lack of big organised complexes, the domination of individual developments in small building plots and the uneven drops of adjacent plot ratios (building area to site area). This results in the lack of open spaces and to the quality of the immediate environment around the houses with restricted ventilation, solar access etc. 1.1 Data related to building period. The Statistical Service of Cyprus provides basic demographic data approximately every 10 years. The last two census of population were carried out in 1992 and 2001. Housing data are given for the last decade at varying intervals of one to two years. The total number of persons enumerated in 2001, in the area controlled by the Cyprus Government, was 689.565. The population pyramids for the same year are shown in Fig.6 (Graph 1 and 2). The increase of the dwelling stock is shown in Fig.6 (Graph 3). The total number of units was 286.000 in 2000. Almost 85.000 of these units were built in the period from 1960-1980. Out of the total number of units, nearly 60.000 are apartment blocks and 125, 000 are detached or semidetached houses. The number of new dwellings completed over the last 15 years is shown in Fig.6 (Graph 4), 5.000 dwellings in 2000, the average dwelling area in Fig.6 (Graph 5), 189 m 2 for 2000 and the average construction cost in Cyprus Pounds, in Fig. 6 (Graph 6), 334 Cyprus Pounds or 568 Euros per m 2 for 2000. From the above data it can be derived that the average number of persons per dwelling, was 3,23 for 1992 and 3,06 for 2001. In addition to that the number of square meters per person, was 49,5 for 1992 and 61 for 2001. Basic economic data according to Statistical Service, stipulate that in 2000 the Cyprus economy registered a growth rate of 5%, unemployment rate less than 3,3%, inflation of 4,1 % and fiscal deficit of 3,5%. The per capita income was more than 7.500 C.P. (12.825 Euro) for 2000. State of the Art: Cyprus 186 Fig. 2: Demographic and housing data 1.2 Description of main typologies In general the typical housing construction system in Cyprus, is based on the conventional construction system, quite common in this part of the Mediterranean Sea. Typical plans and elevations of multi storey housing buildings from the public (Fig. 7) and private sector (Fig. 8). The system comprises the use of reinforced concrete for the load bearing part of the building, which is completed by masonry walls. Prefabrication systems have rarely been used in the past, mainly by the Government in the construction of some low cost refugee estates in the late 70´s. So reinforced concrete, from foundations to the roof applies for the vast majority of the housing constructions. It has to be mentioned however that preliminary regulations concerning the calculation of seismic loads, were issued in the late 80´s and that detailed construction regulations were adopted in the beginning of the 90´s. Thus all the buildings built before, may sometime in the future, face possible seismic failure. The typical filling of multi-story family houses comprises of brick walls (20 or 25 cm for the outer walls and 10 cm for the inner walls) that are plastered with 2-2,5 cm on either side. The finishing surface is usually covered by sprits or paint. GRAPH 1. FEMALES 0 10 20 30 0-4 10-14 20-24 30-34 40-44 50-54 60-64 70-74 80+ GRAPH 3. DWELLING STOCK 0 50 100 150 200 250 300 350 1 9 8 0 1 9 8 5 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0 5 D W E L L I N G S I N T H O U S A N D S GRAPH 4. NEW DWELLIGS COMPLETED 0 1 2 3 4 5 6 7 8 9 1 9 8 4 1 9 8 6 1 9 8 8 1 9 9 0 1 9 9 2 1 9 9 4 1 9 9 6 1 9 9 8 2 0 0 0 2 0 0 2 D W E L L I N G S I N T H O U S A N GRAPH 6. AVERAGE COST IN CP / S.M. 1 CP = 1.7 EURO 0 50 100 150 200 250 300 350 400 1 9 8 0 1 9 8 5 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0 5 S Q U A R E M E T E R S GRAPH 5. AVERAGE DWELLING AREA 0 50 100 150 200 250 1 9 8 8 1 9 9 0 1 9 9 2 1 9 9 4 1 9 9 6 1 9 9 8 2 0 0 0 2 0 0 2 S Q U A R E M E T E R S GRAPH 2. MALES 0 10 20 30 40 0-4 10-14 20-24 30-34 40-44 50-54 60-64 70-74 80+ % FOR 2001 State of the Art: Cyprus 187 Fig. 3: Typical 2 and 3 bedroom flats in a Government refugee estate. Respective elevations and section Fig. 4: Typical plan from the private sector. Respective typical elevation (shops on the ground floor and flats on the floors) 1.3 Description of the main technologies. In most of the cases the whole of the load bearing structure, including the foundations, consists of a reinforced concrete frame. This method of design is a must for the buildings in Cyprus, due to the seismic excitations that the structures undergo during their life. The surface of the concrete is either “fair face” or “typical” depending on functional, aesthetic etc. criteria (Fig. 5). There is a variety of foundations types according to the type and size of the structure. The most popular are the separate foundations with connecting beams and the general (whole) foundation (Fig.6). The outer skin of a structure, is usually created by the reinforced concrete parts (for the load bearing structure) and a single layer of bricks, (200mm), both coated with three layers of plaster (20-25 mm) and a finishing layer of paint or sprits. The roofs are usually flat concrete slabs, which are covered with light concrete or screed of 50-100 mm for thermal insulation and on top with an asphalt layer of 2-5 mm, for humidity insulation. Fig. 5: A typical structure. “Fair face” reinforced concrete for the ground floor parking and “typical” for the rest of the building Fig. 6: Foundations State of the Art: Cyprus 188 The final touch is given by the use of reflective paints. The last 5-10 years some multi-story family houses appeared to form a different top finish with a complete or partial pitched roof. It is believed that this is used not so much for insulation reasons, but rather for sales promotion reasons since it gives a touch of more domestic or more humane housing buildings. As far as windows are concerned, the vast majority of them are single glazed (4-5 mm) with aluminium frames whereas a considerable proportion of multi-story family houses, especially after 1980, used double glassed windows. 1.4 Housing Policy Administrative structure Cyprus is a presidential parliamentary democracy and administratively is separated into Districts (6 altogether) that are managed by the District Officers appointed by the Government. In addition there are two types of local authorities, the Municipalities (33) and the Communities (352), which are governed by separate laws. Municipalities form the core of the local government structure in urban areas and in tourist centres, whereas Communities constitute the local government structure, in rural areas. Communities with a population of over 5.000 inhabitants or smaller Communities with sufficient economic resources to function properly and independently have the opportunity to become Municipalities. The Mayors and the Municipal Council of the Municipalities, as well as the Presidents and the Community Councils of the Communities, are elected directly by the citizens for a five-year term. The Municipalities and the Communities have their own budget. They are responsible for the construction, maintenance of streets, provision of local services and the appearance of public areas, the protection of public health etc. The main sources of their revenues are state subsidies, taxes and fees. Development Plans The planning system is highly centralised. The Minister of the Interior is the Planning Authority and is responsible for the preparation and publication of Development Plans. As such are the ‘’Local Plans’’ and the detailed ‘’Area Schemes’’ for the urban areas and the ‘’Policy Statement for the Countryside’’ for the rural areas. The General Development Plans contain a set of land uses including public facilities and zoning maps as well as policies, provisions and regulations to guide the development. The major advisor to the Minister is the Town Planning Board. The Department of Town Planning and Housing provides technical assistance and expertise. Authorities responsible for issuing Planning and Building Permits The Town and Country Planning Law has been enacted, as a whole, on the 1 st of December 1990. The responsibility of issuing Planning Permits rests with ten distinct Planning Authorities, which are the Director of Town Planning and Housing Department, all five Divisional Town Planning Officers in the districts, as well as the four main Municipal Councils of the island. In cases of urban complexes made up of several Municipalities and Community Councils, a new proposal of establishing a joint Planning Authority for the whole conurbation area (covered by each Local Plan) is currently under consideration, by the Ministry of Interior. Building Permits can be issued by the 24 Municipalities (since 9 out of the 33 are under occupation) for the Municipal Areas and the five District Officers, for the rural areas. Application drawings and inspections The Law, considering the kind of development, specifies the appropriate drawings and any other documents, certificates etc., which they have to be submitted with the application form to the Planning Authority. Three main issues can be mentioned here: State of the Art: Cyprus 189 - There is not any legal obligation to submit designs or calculations for thermal, acoustic, light and fire performance of a conventional building within the application form. - Although civil engineering calculations have to be submitted at the building permit application process, these drawings are roughly checked and the responsibility for any structural failure remains on the civil engineer’s side. - According to a recent regulation of 2000 all new constructions, renovations and generally any structure, have to be inspected by authorized engineers. Therefore inspections are compulsory for freelance practitioners, though are not compulsory for Responsible Authorities. For this very reason the enforcement of the Planning and Building laws, is not so effective. Legal framework concerning modifications and improvements All building modifications require a ‘’building permit’’ and moreover, the modifications that are regarded as ‘’substantial’’ require an additional ‘’planning permit’’ in advance. The specific provision is unclear and therefore depends on the discretion of the respective Town Planning Authorities, to judge whether a modification is substantial or not. The painting of a building for example does not require any permit, simply because is not regarded as a substantial modification. Therefore designers are not obliged to ask for approval of any drawing concerning painting. There are no specific data concerning maintenance, renovations, modifications, etc. of building envelopes. Indicative data however suggest that the average Cyprus family does not pay a lot of attention on these matters, that people extent as long as possible the various works needed and that they proceed to the necessary works, only when the performance of their building is intolerable, or dangerous looking always for the absolute minimum expense. In the vast majority of the cases improvements are related only to the painting of the buildings. 2 QUALITY OF THE POST-WAR MULTIFUNCTIONAL HOUSING STOCK 2.1 Architectural and urban aspects 2.1.1 Legislation handicap. No specific legislation was ever passed before 80’s concerning incentives for organized housing complexes. The only regulatory tools were the commonly used town planning restriction which concern plot ratio, plot coverage, maximum height, maximum number of stories, a general aesthetic framework and some indirect density standards, concerning the minimum surface in relation to the size of housing units. This is actually the very reason that multi-story family buildings were very few till 80’s. Some sort of incentives for organized housing complexes up to three stories, were introduced in the revised statutory local plans in 2003. There are no specific regulations concerning architectural and functional aspects. The authority that is responsible for issuing the Planning Permit, decides whether a certain development rests within the environment of the surrounding area. There are however indirect density standards, concerning the minimum size of housing units. Practice however is much different especially as far as the aesthetic control is concerned. Problems also arise when dealing with the incorporation of small but vital structures, like solar panels, antennas etc. 2.1.2 Accessibility There are specific rules and regulations for new buildings and public uses according to which accessibility to people with special needs, including access ramps and larger toilets in the ground floors, must be provided. State of the Art: Cyprus 190 2.1.3 Architectural aspects. No tremendous changes can be seen in the aesthetic appearance of the government owned estates. The only differences are related to colours and to the variety of plasters and sprits areas combinations. On the contrary bigger changes on architectural aspects can be seen on the multi- stories buildings built by the private sector. The bigger change concerns the use of new materials (stones, concrete fair face and pinched roofs) and new designs. 2.1.4 Management problems. Although multi-storey buildings are covered by a specific law and regulations (Chapter 224 of Lands and Surveys Department) Cyprus is still facing specific management problems. These are related to the ambitious extensions, illegal advertisements, the distribution of maintenance and renovation costs, the insurance of the housing units, the resolving of differences and the management of pets. 2.2 Social and cultural aspects Different social problems appeared in multi-story family houses in Government refugee estates and individual building plots. It is obvious that the major problems arise from the absence of adequate public open spaces, of community uses, as well as from the close proximity between buildings. People in these areas seem to lack privacy, but on the same time they are not given enough opportunities for social interaction. In the first case the bigger problem is some sort of ‘’isolation and identity problem’’ that is due to the non-penetrated road network of the estates and the patterned morphology of the buildings. Some of the first estates built in the 70’s, present some sort of anti-social youth behaviour Government owned settlements built during 70’s created somewhat the image of isolated estates, partly because of their locations at the periphery of the towns. Nowadays, all the settlements were overtaken by the new town planning zones, new neighbourhoods and detached houses, which are allowed even outside the development boundaries. 2.3 Structural aspects Cyprus falls in a very active seismic zone due to its position between the Asian and the African plates (Fig.7). That’s why seismic excitations are very common events, especially in the southern part of the island (Fig.8). For this reason, for civil engineering calculations for structures, five seismic zones (with different acceleration values, from 0.75 m/sec 2 to 1.5 m/sec 2 ) have already been established. Fig 7: Tectonic plates around Cyprus Fig 8: Epicentres of 674 earthquakes registered during the period 1905-1996 State of the Art: Cyprus 191 The vast majority of ‘’multi-story family houses’’ in Cyprus were built according to classical conventional methods (reinforced concrete for the bearing system, brick walls and plaster finishing). A prefabricated system based on preheating molds was used in a very small proportion of some Government own estates. The system proved very efficient and many of the housing units built with this system are still in a better condition than those built with conventional methods. Although a considerable number of seismic excitations appear during the life of all the structures in Cyprus only a very small number of buildings showed serious damages. All the multi-storey family houses of the chosen, by Action 16, period were built before the adoption of any seismic regulations. Therefore their seismic behaviour is rather unknown and only special studies can reveal aspects of their performance 2.4 Physical aspects 2.4.1 Thermal performance Cyprus shares an intense Mediterranean climate with extended hot, dry summers and rainy rather changeable winters, which are separated by short autumn and spring seasons. Basic meteorological data for the capital Lefkosia (o) and Prodromos village (A), 1900 m above sea level are shown in Fig. 9. TEMPERATURES FOR NICOSIA (0) AND PRODROMOS() STATIONS 1991/2000 0 5 10 15 20 25 30 35 40 J A N F E B M A R A P R M A Y J U N J U L A U G S E P O C T N O V D E C D E G R E E S C E L C I O U S MEAN RELATIVE HUMIDITY AT 1300 0 10 20 30 40 50 60 70 80 90 J A N M A R M A Y J U L S E P N O V % MEAN DAILY SUNSHINE DURATION 0 2 4 6 8 10 12 14 J A N F E B M A R A P R M A Y J U N J U L A U G S E P O C T N O V D E C h o u r s / d a y MEAN DAILY WINDRUN AT 2 m 0 20 40 60 80 100 120 140 160 180 J A N M A R M A Y J U L S E P N O V K m / h Fig 9: Basic meteorological data Rainfalls vary a lot. The average annual total precipitation is about 500 mm. The last 15 years however Cyprus faced some very difficult dry seasons and this is the very reason that more than 100 water dams and reservoirs, of a total capacity of 300.000.000 cubic meters, as well as two desalination plants, have been constructed so far. The thermal performance of contemporary buildings is discussed below in relation to the climate and in terms of the main aspects necessary for an understanding of such performance (Table1) (Kolokotroni 1985). These aspects are: Architectural design: Innovations and advancement in building design and technology have made any form of building possible to create with materials such as glass, metal and building panels of every kind characterizing the new architecture. These features of contemporary buildings have also created many problems in the Mediterranean countries by being unsuited to the climatic conditions. Constructional materials and methods: The above-mentioned materials are normally incorporated in semi-heavy-weight constructions inappropriately designed. The roof and external walls are seldom provided with sufficient thermal insulation. They are also not thick enough to compensate for such loss of insulation by having high thermal capacity. Occupancy patterns: Residential buildings are usually occupied continuously or intermittently. It is however normal to find more than 90% of the occupants at home by 3.00 p.m. in summer. State of the Art: Cyprus 192 As the structure of contemporary buildings is with a short time-lag of the order of 2 to 3 hours. The maximum temperature of the internal surface appears about 3.00 or 4.00 p.m. Heat emission into buildings therefore takes place during the resting time of the occupants, when the outdoor shade air temperature is still high and such heat cannot be removed by ventilation. Moveable fans are widely used. But with little effect on improving the indoor conditions because the draught of external air is already of a high temperature and the distribution of air movement is non-homogenous. The overall result is physiological and psychological dissatisfaction. As many contemporary residential buildings are comprised of apartments normally designed with a specific function for each space, the occupants are obliged to carry out their activities in the specified zones regardless of the daily and seasonal change in weather conditions. Alternative spaces, which can be used to avoid the overheating effects at certain times of the day, seldom exist. Table 1: The thermal performance of contemporary buildings in relation to the climate and in terms of the main aspects necessary for an understanding of such performance Building aspect Characteristics related to contemporary building Architectural Design -Outward looking -Free plan form -Multi-storey blocks -Small balconies -Vast glazed windows -Flat or pitched roofs Constructional materials and methods -Materials are mostly imported or locally made with poor qualities -Frame structures -Simple constructions -No insulation -Non-load bearing walls Occupancy patterns -Unchanged in residential buildings because of the design restrictions of contemporary buildings Planning -Incompact planning. No courtyard -Zoning problems Thermal performance -Unsatisfactory during the times of overheating and under heating. Non-thermal comfort problems -Weathering problems -No adequate building regulations -High influence of the building contractors -Acoustic problems Demand -Increasing because of social and economic changes and contemporary life 2.4.2 Current housing habits (thermal comfort) In an attempt to evaluate some of the current housing habits in Cyprus, a questionnaire was compiled (Lapithis 2003). The results of the questionnaire were taken from contemporary residential buildings, with mostly four or five residents, in urban areas of Lefkosia. Upon examining the outcome of the detailed questionnaire, certain interesting observations are deduced. - A high percentage (69%) of the survey participants experience bothersome noises from the outside, probably as a result of single glazing and poorly insulated wall surfaces which not only allow heat enter and exit freely, but also allow noise to penetrate with little difficulty. - A high percentage of the participants frequently felt cold in the winter (80%) and an even greater number feel warm in the summer (87%). - There were also complaints about bothersome cold surfaces (70%). - Another problem area, which can be minimized by proper passive design, is the need for artificial lighting (64%). State of the Art: Cyprus 193 - It also transpired that many participants experience drafts from windows and doors (86%), an element of ventilation that can be exploited in a passive system, if it is designed properly. - There is a need for a more widespread use of double-glazing windows in order to minimize moisture condensation on windows (65%) and for a better thermal and noise control. - An interesting fact deduced from the survey is that the overwhelming majority of Cypriots feel safe in and around their house (91%), which makes it easier for a passive solar designer to arrange for ventilation systems requiring frequent openings especially for nighttime ventilation. From the outcome of the questionnaire, it transpired that most dwellings in Cyprus are constructed with little or no insulation and this is the most likely cause for the high percentage of summer and winter discomfort as well as noise complaints. Most other complaints stated (e.g. poor natural lighting) are the result of unsuccessful bioclimatically orientated design. All this suggests the need for better, more bioclimatically appropriate constructions, with adequate insulation and proper orientation with respect to the sun. 2.4.3 Technical recommendations Technical recommendations are compulsory for the prefabricated buildings according to Order 2/2001 issued by the Minister of Interior, who is in charge for Town and Country Planning Law. The order specifies the characteristics shown in Table 2. Table 2: Technical recommendations issued by the Minister of Interior Thermal Insulation (U value in W/ m 2 °K) Walls 1,7 Roof 2,0 Slab between floors 2,0 Noise insulation (for 500Hz in dB) Walls 45 Roof 45 Slab between floors 50 In addition to the above the Order specifies that the bearing structure and any stair of a prefabricated building should provide at least 1/2 an hour fire resistance. The ´´Cyprus Organization for the Promotion of Quality´´ chaired by the Ministry of Commerce Industry and Tourism plans to establish more quality standards and enforce them as compulsory. It can be mentioned that this Organization has already specified some recommended thermal insulation values for conventional buildings, which however are not compulsory. Cyprus has already adopted five compulsory standards concerning the quality of cement, sand, gravel, concrete and brick. The enforcement of these standards lies on three Government bodies, which are, the Mines and Quarries Department, the Public Works Department and the Competition and Consumers Protection Service. Inspections are carried out based on selective processes. Furthermore it must be noted that in cases the consumer finds any discrepancies from the standards, he has to claim his rights through the detail provisions of his contract. It is worth mentioning that by the 1 st of May 2004, Cyprus became a full member-state in European Union, and therefore all the relative European standards (Euro-codes, etc.) have to be established in the respective case-law. State of the Art: Cyprus 194 2.4.4 Insulation problems. The existing legal framework does not incorporate any objective criteria and indices concerning the technical characteristics (like the thermal conductivity (K), the thermal transmittance coefficient (U), the sound reduction index (SRI) etc), the performance of the building materials and the whole structure of conventional buildings. Therefore in most of the cases the free market, especially the local one, does not provide the necessary technical specifications of the relevant advertised products. So only practice can show the real fire resistance and the thermal, acoustic and light performance of any housing unit. 2.4.5 Networks and equipments. In the majority of the cases these networks are treated as the annoying part of multi-storey family houses for the very reason that no specific water, electricity, heating and cooling studies are carried out by the respective engineers. In most of the cases the architect involved or some practical technicians, carry out the job. CONCLUSIONS From all the above the following preliminary conclusions can be drawn. The legal framework concerning the issuing of permits as well as the management of multi-story family houses need to be amended so that all sorts of building interventions will be easily perceived and managed by all the stake holders. The responsible Authorities should proceed with the establishment of technical and performance criteria for all the raw materials and structures used in the building industry. Evaluations have to be undertaken by established teams of professionals, supported by groups of interests and individuals, depending on the case. REFERENCES Government of Cyprus 1996. Streets and Building Law (Cap. 96). Lefkosia: Government of Cyprus Government of Cyprus Immovable Property Law (Tenure, Registration and Evaluation – Chapter 224). Lefkosia: Government of Cyprus Government of Cyprus 1972 . Town and Country Planning Law (Law 90/72) Lefkosia: Government of Cyprus Government of Cyprus 1985. Municipalities Law (Law 111/85). Lefkosia: Government of Cyprus. Kolokotroni, M. 1985 The Thermal Performance of Housing in Greece: a Study of the Environmental response to Climate. London: Bartlett School of Architecture, UCL Lapithis, P. 2003. Solar Architecture in Cyprus. ISES 2003 Conference Proceedings. Gothenburg: ISES Meteorological Service 2000. Climatological Data of Cyprus 1991-2000. Lefkosia: Government of Cyprus Ministry of Commerce 1998. CYS 98, Cyprus Organization for Standards and Control of Quality. Lefkosia: Government of Cyprus Statistical Service 2001. Population Census. Lefkosia: Government of Cyprus Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW ON THE HOUSING STOCK Republic of Macedonia occupies the land area of 25.713 km 2 with population of around 2 million inhabitants. It declared its independence in 1991 after the breakdown of the former S.F.R. of Yugoslavia. According to the Constitution Republic of Macedonia is a parliamentary democracy and multiethnic society where 65 % of the population are Macedonians, 22% Albanians and 12-13 % other minority groups (Serbs, Romeos, Turks…) Due to relatively good planning of urban centers, traffic infrastructure and economy capacities in last 50 years it made remarkable progress in term of urbanization (59%) Building industry and existing housing assets present a good base for further development of the real estate market. According to the 2002 census in the country there are: - 2,030.257 inhabitants; - 564.296 households; - 697.529 dwellings with total of 49,671.709 m 2 of which 94% (662.249) built after 1945 Due to the process of privatization and denationalization 99% of the total dwelling stock in mid 90s, (690.961) is private and 1% of it (5420) are still in the government possession. According to the census statistics, 83 % (579.184) of the total dwelling stock is occupied, 17% (65.096) is available or put on real estate market. Within the dwelling stock there are 24.745 summer or weekend houses of different type. Figures also indicate four basic planning parameters for future housing and living consideration: a) Republic of Macedonia is a comfortable country (79 residents per km 2 ); b) Relatively new dwelling stock (70% built after 1970 and still in a good condition); c) Positive rate of dwellings versus household’s number (697.529 / 564.296); d) Good basic social capacity, infrastructure and natural goods. State of the Art: F.Y.R. of Macedonia Tihomir Stojkov University of Ss Cyril and Methodius, Skopje ABSTRACT: Republic of Macedonia is a small country in the core of the Balkans. From 1945 until 1991 it went trough intensive urban development within the Yugoslav socialist system where 85-90% of present dwelling stock and residential buildings were built. Significant part of it built in 70s and 80s is still in good condition. The rest of it built in 50s and 60s (until 1963) needs to be subject of serious professional and institutional consideration in order to establish applicable methodology and management of reconstruction to offer different options of choice and possibilities both for their present tenants and future customers. After the break down of former S.F.R. of Yugoslavia,. Republic of Macedonia is going again through dynamic process of transition coping with complexity of problems and necessary reforms on the way to join EU. State of the Art: F.Y.R. of Macedonia 196 1.1 Data related to building periods According to the statistics, in 1948 there were around 1,152.986 residents and 218.819 dwellings (mainly of average or pour quality), in 1953 there were 1,303.906 residents and 248.730 dwellings (of which around 140.000 government flats) and in 1961 there were 1,410.000 inhabitants and around 300.000 dwellings.(Figures 1-2) Figure1: architecture from ’50s and ’60s Figure 2: architecture from ’70s and ’80s Table 1 Number of dwellings built in Republic of Macedonia after the II WW Period Number of dwellings 1947 - 1960 73.688 1960 - 1970 136.418 1970 - 1980 181.969 1980 - 1990 151.434 1991 - 2002 118.740 Total 662.249 It can be also said that 70% of the present dwelling stock (built after 70s) is still in a good shape with market value of 400-1200 € m 2 1.2 Description of main typologies The 2002 census also indicates that of the total dwelling stock (697.529) 60-62 % are mainly one or two storey single family houses or double ones, and relatively small percentage of row houses or other types. The rest of 38-40% are multifamily houses of different type built as three to four storey buildings (65%), seven to ten storey (30%) and ten to sixteen storey (5%). It can be also mentioned that 95 % are one level flats and the rest are two level or so called “duplex” flats. Table 2 Basic typology of existing dwellings Studios 54.529 (8 %) One bedroom 196.536 (28 %) Two bedroom 216.895 (31 %) Three bedroom 146.784 (21 %) Five bedroom 85.791 (12 %) State of the Art: F.Y.R. of Macedonia 197 2 5 38 25 BRICKWORK 38cm (25+1+12) INTERNAL PLASTER 1.5cm BRICKWORK 25cm BRICKWORK 25cm BRICKWORK 25cm INTERNAL PLASTER 1.5cm EXTERNAL PLASTER RENDERING 2.5cm DETAIL "B" DETAIL "A" BRICKWORK 38cm (25+1+12) INTERNAL PLASTER 1.5cm CEILLING FLOOR 2 0 - 2 5 5 - 6 6-7 RIB R.C. STRIP (SERCLAGE) 38 INTERNAL PLASTER 1.5cm FLOOR TIMBER BEAM BRICKWORK 38cm (25+1+12) CEILLING R.C. STRIP (SERCLAGE) 38 1.3 Description of main technologies Building technologies in 50’s In 50s there were used extensive classic masonry building systems based on massive solid brick structural walls thick 25-38 cm. and slab construction based on three construction systems: a) Cast reinforced concrete thin-ribs slab system (Figure 3); b) Semi-prefabricated thin-ribs slab system “Avramenko”, stiffened with perimeter and internal reinforced concrete strips cast over the structural walls. Within structural walls there weren’t vertical R.C. supporting pillars or strips. (Figure 4); c) Timber slab construction over the solid bricks structural walls. (Figure 5); Figure 3: Cast R.C. thin-ribs slab system. Layout Figure 4: Semi - prefabricated system “Avramenko”. Section Figure 5: Timber slab construction. Section Later, at the begging of the 60s (until 1963) the first larger and better planned complexes of multi-storey family houses were built, unfortunately without significant structural improvements. In that time, beside above mentioned slabs the new, semi-prefabricated ceramic “Monta” slab-system” was introduced mainly for the 4-5 storey residential blocks. Due to pour seismic performances, lot of buildings suffered vide range of damages or collapsed implicating serious casualties during the 1963 earthquake. The rest, beside some damages, were subject of structural rehabilitation and strengthening by means of inserting new extra horizontal and vertical R.C. strips and throw-in supporting pillars within massive structural walls. State of the Art: F.Y.R. of Macedonia 198 However, this was a painful but very important new experience for Macedonian architects and engineers to later improve the quality of building structure. Building technologies in 60’s Immediately after the 1963 earthquake new rigorous seismic regulations and building standards were introduced by means of use the high quality R.C. skeleton building systems with high security coefficient (Cs=3). In addition to this, a new, fully prefabricated, pre-cast R.C. heavy- panel system “Karpos” (donation of USSR government), was introduced. In the period of 15-2o years the new R.C. heavy-panels factory built in Skopje produced around 15.000 flats of total of 760.000 m 2 . This building stock, together with some newly introduced light-weight systems of individual residential houses of different type (donations from other countries), were important contribution to Skopje in such a urgent situation: In six months period around 70.000 inhabitants of Skopje got new flats. It was very important achievement in the critical efforts to sustain the local economy and life of the Capitol city in such a misfortunate circumstances (70% of all buildings in the town of 200.000 were damaged and almost 25% ruined implicating the most gloomy statistic index of Skopje earthquake of around 1200 casualties). In that respect, the building stock of multi-storey family houses built after 1963 performed very good during the last seismic activities in the region.(Figures 6-7). As far as “Kapos”-system concerns, there were four different flats’ size. (Table 3) Figure 6, 7: The building stock of multi-storey family houses built after 1963 Table 3: Basic typology of dwellings based on “Kapos”-system Studios 31-42 m 2 One bedroom flats 48-52 m 2 Two bedrooms flats 70-71 m 2 Three bedrooms flats (Fig. 8-9) 84.00 m 2 State of the Art: F.Y.R. of Macedonia 199 3 2 0 3 2 0 19 2 6 0 3 2 0 3 2 0 3 2 0 3 2 0 3 2 0 2 6 0 3 2 0 3 2 0 19 576 576 15 15 90 90 1 2 3 4 5 6 7 8 9 10 11 12 A B C NS.4 NS.3-6 NS.3-6 NS.4-2 N S .1 N S .2 N S .3 N S .1 N S .2 N S .2 N S .2 N S .1 N S .3 N S .2 N S .1 N S .1 N S .2 N S .3 - 2 N S .2 N S .1 N S .2 N S .1 N S .2 N S .3 - 2 N S .2 N S .1 VS.1 VS.1-2A V S .4 A V S .3 A E K .1 V S .9 V P .3 V P .2 VP.1 V P .6 V P .2 V P .4 V P .7 VS.1-2 VS.1-2A VS.6 VS.6 V P .2 V P .3 VP.1 V P .6 V S .3 A VS.1-2A VS.1 V S .4 A VP.5 VP.5 VS.1 VS.1 V S .4 A VP.5 VS.1 VS.1-2 V S .2 VS.1-2 VS.1-2A V S .3 A VS.1-2A V P .3 V P .2 VP.1 V P .6 VS.6 V P .2 V P .4 V P .7 E K .1 V S .9 VS.1-3 VS.6 VS.1-2 V S .7 A VP.5 V P .2 V P .3 VP.1 V P .6 VS.1-2A V S .2 NS.4-2 NS.3-6 NS.3-6 NS.4 180 - A 3 4 0 0 3 4 3 8 1152 1182 P=17.16m2 - C - B1 -B P=8.00m2 P=3.48m2 P=6.00m2 P=16.18m2 -- 1 -- 1 FLOOR PLAN 0 1 2 3 4 5 m A B C BP1-3 576 576 - F - D - E 0 1 2 3 4 5m 10.72 SECTION BP-1 BP-1 BP-1 BP-1 BP1-3 BP1-3 BP1-3 BP1-3 NS-5 NS3-2 PR-1 PR-2 PR-2 PR-2 BC15 NS-3 NS3-3 NS3-3 NS3-3 NS-3 NS-3 NS-3 NS-7 LM-1 LM-1 LM-1 LM-2 BP-2 5.32 2.62 -0.08 -2.17 8.02 +5.40 +2.70 ±0.00 +8.10 -2.17 +6.75 +4.05 +1.35 -1.01 -1.23 LM-1 LM-1 LM-1 DETAIL "B,B1" 1 5 1 0 5 6 1 4 2 5 INSITU CONCRETE SEALANT INSULATION 1.5cm INSULATION 6cm 6 19 INSULATION 6cm INSITU CONCRETE DETAIL "A" DETAIL "C" 12-14 INSITU CONCRETE SEALANT SEALANT E X T E R N A L R .C . P A N E L E X T E R N A L R .C . P A N E L EXTERNAL R.C. PANEL EXTERNAL R.C. PANEL INTERNAL R.C. PANEL E X T E R N A L R .C . P A N E L EXISTING FLOOR (PARQUET) BALCON ROOM EXISTING FLOOR (TERATZO) R.C. FLOOR PANEL 10cm EXISTING BITUMEN COVER ZINC COVERING SHEET R.C. FLOOR PANEL 10cm SEALANT SEALANT INSOLATION 6cm INSITU CONCRETE R.C. BALCONE PANEL 10cm DETAIL "D" DETAIL "E" DETAIL "F" E X T E R N A L R .C . P A N E L 6 19 6 19 EXTERNAL R.C. PANEL 90 60 25 Figure 8, 9: Three bedrooms flats based on “Kapos”-system. Layout and section. Structurally, the perimeter wall panels, thick 25 cm, consists of three basic stratums; External pre-cast R.C. panel thick 5 cm, internal (structural) pre-cast R.C. panel thick 14 cm and Styrofoam or fiberglass thermal insulation thick 6 cm inserted in-between the panels. External and internal panels are structurally connected with concrete ribs. Horizontal and vertical perimeter wall panel joints are usually visible and sealed with special sponge hose from inside and elastic sealant from outside. Internal structural panels depending on their position are thick 12 and 14 cm. The clean structural height of all wall panels is 270 cm. For slab construction two basic modules of panels were used: 260x576 cm and 320x576 cm. both thick 10 cm. The slab panels were connected to external or internal structural wall panels with special joints of steel framework and metal accessories, sealed later with cast concrete. (Fig.10-11) Figure 10, 11: Perimeter wall panels. Layout and section. State of the Art: F.Y.R. of Macedonia 200 Indeed, at the beginning “Kapos”-system was pretty chip and acceptable for most of the residents interested in buying a new and “safe flat”. Unfortunately, due to both structural inflexibility and limited internal space performances, this system produced problems to the tenants intending later to do some internal modifications The second handicap of “Karpos”-system was its modest standard in term of use of building materials and equipment. Also, the external pre-cast RC walls, besides the built-in Styrofoam insulation of 6 cm, manifested pour thermal comfort as well as some later identified philological syndromes to the tenants living in “concrete flats”. Later, some modifications of external panel-joints were done by making them invisible (by covering and rendering with terranova mortar) but, after certain period of time some cracks appeared again. 1.4 Housing policy Until 70s the planning and building concept in the Country was mainly based on the idea for radical convert of the pre-Second World War tradition of living in single family houses into collective multi-story family houses of socialist type. Although this idea originally was based on good-natured purpose and spread around by well organized propaganda, the consequences we are facing now after 40-50 years, are frustrating because significant part of the dwelling stock built especially in 50s and early 60s (25-30%) is in a pour condition. A serous and comprehensive reconstruction is immanent in order to reuse it properly. According to the statistics, more than 22.000 flats of average size of 50-60 m 2 in multifamily houses were built. Majority of the stock was built in Skopje and the other in a few other bigger towns. This situation imposes to answer two primer questions: a) What to do with it and how to do it? b) How to sustain, reuse and make them dissent place for living with good market value? Before to answer these questions, we have to learn something from that experience. Namely, by braking with traditional memory and neglecting the values of traditional living concept, this radical change normally produced complexity of social and cultural implications. In addition to this, in the last 14 years Republic of Macedonia, going through transitional period, faced specific social, economical and political problems too. In such a situation, the most serious problem is how to convert still on going process of unskilled and elemental building “own way” undertaking done by the tenants them selves out of any control. The pressure to get some “extra space” in existing buildings together with insatiable demand to get (buy) living space in the big towns, stimulate private entrepreneurs to abuse the situation. They focus their interest in building new flats creating an surplus of more than 65.000 flats. By condensed the living environment in the towns sometime by means of demolishing some of the worthy architectural heritage. In such situation very few people are interested in buying (even very cheep) flat in older buildings, primarily because of their neglected condition and appearance beside their external commodity and still comfortable surrounding. (Figure 12,13) State of the Art: F.Y.R. of Macedonia 201 Figure 12, 13 Other serous problem could emerge due to the fact that almost entire fund of so called “government flats” in multi-storey family houses (more than 56.000 flats!) have been sold to the tenants in early 90s for incomprehensible low prices (3-5% of their real value!). With this wrong (and pure political) step the government and the institutions in charge incapacitated the possibility to rise a solid financial resources for a possible reconstruction and maintenance to this significant building stock. They simply didn’t focus their interest toward this important asset and public property even as a possible basic generator for new building reproduction. In the meant time, some of the former tenants and overnight owners of those flats, thanks to their better position in the former socialist society, have already bought second one or built their own house. Now they are selling the gratis government flat (or flats!) for 50-80 % of real market value making fast profit. Later, they invest the money in new building joint venture phenomenon; flats just for rent. This is a kind of magic wand to get rich overnight in the period of transition. This phenomenon produced a kind of new building business out of any control. Thus, the new private investors are not interested any more in reconstructing the existing old buildings, built even in very attractive sites. They focus their interest in usurping the rest of inbuilt land or free space in central urban areas to build new flats creating serous urban problem such as unnecessary condensed space and overpopulation to the exiting urban matrix, and serious disturbances to the living environment. On the other hand, the former tenants, usually ordinary working people now on social welfare or jobless, couldn’t do this machination because the government flats they’ve got were the only satisfaction for their hard labor in the former socialist society. Actually, they are the ones who need bigger or extra flat for their already adult children but can’t afford it. To meet this urgent demand, they are trying to reconstruct or “to extend” some how their tiny flats their own way, out of any control and usually unskilled, to extend the flats they often abuse the regulations at the beginning by adding to their flat an extra balcony. Certainly, later they convert it in an extra room or so. This situation produces later serious problems into the living environment, not only from architectural or aesthetic point of view but from social and cultural too. (Fig.14-15) State of the Art: F.Y.R. of Macedonia 202 Figure 14, 15 Some of the tenants living on the top-floor often make unskilled build up to existing flat roof or hip roofs in order to get more extra space or even an extra flat. But, most serious problem is when they sometime make changes even to the basic structural system unaware of the danger and risk in a seismic region such as Macedonia. Hopefully, the local authorities make some efforts to control this situation but so far the results are minor. (Fig.16-17) Figure 16, 17 Other serious problem will also emerge due to the pour quality of thermal insulation, unskilled use of materials, problematic commodity conditions and quality of the living space and maintenance. (Figure 18-19) Unfortunately, the consequences of such a situation are evident both within the significant segment of existing building stock of multi-storey family houses and newly built ones. Beside this severe reality the situation still offers some opportunities for professional engagement, for research and applicable projects, employment and productive contribution to entire economy of the country. To achieve this goal and to give this buildings a new esprit and reference of decent place for living a specific approach and applicable building and management methodology are to be introduced. Having in mind the fact that some of the buildings today are in important locations, close to the city core area, they can regain on their value and some of them even to convert to good quality buildings. But, in this matter few professional aspects are to be first taken for serious consideration. First of all, it must be establish a new management system, different that the one used before and, more important, to introduce an appropriate financing system in the condition of market economy. State of the Art: F.Y.R. of Macedonia 203 GROUND LEVEL 2.5cm EXISTING EXTERNAL MORATR 10-12cm R.C. SLAB EXISTING MORTAR 10-12cm R.C. SLAB 10mm PLASTERBOARD 5mm SYNTHETIC MORTAR 5cm INSOLATION 3-5cm THERMAL INSULATION 1.5cm EXISTING MORTAR DOUBLE GLAZED WINDOW 2cm PARQUET 5cm CEMENT SLOGH PVC FOIL 2cm STYROFOAM DEMIT FACADE 10mm PLASTERBOARD 3-5cm THERMAL INSULATION 1.5cm EXISTING MORTAR 2cm PARQUET 5cm CEMENT SLOGH PVC FOIL 2cm STYROFOAM 2.5cm EXISTING EXTERNAL MORATR 5mm SYNTHETIC MORTAR 5cm INSOLATION DEMIT FACADE 5cm THERMAL INSULATION DOUBLE GLAZED WINDOW .5cm EXTERNAL MORATR GROUND FLOOR LEVEL GROUND LEVEL .5cm EXTERNAL MORATR 12cm BRICKWORK 1.5cm INTERNAL MORTAR ORDINARY FLOOR ORDINARY FLOOR NEGATIVE THERMAL CONDUCTIVITY (N.T.C.) (N.T.C.) (N.T.C.) (N.T.C.) (N.T.C.) 10-12cm R.C. SLAB 1.5cm CEILLING MORTAR SINGLE GLAZED WINDOW 10-12cm R.C. SLAB 10-12cm R.C. PARAPET 1.5cm INTERNAL MORTAR SINGLE GLAZED WINDOW Figure 18: Unskilled intervention. Figure 19: Proper intervention. Also, the entire undertaking must be strictly controlled and creatively completed in order to offer different possibilities and options of choice both for tenants and for future customers. 2 TOPICS, QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK On the C-16 Meetings in Delft and Ferrara were presented papers focusing the attention on some general information regarding State of the art and some preliminary possible solution to improve the quality of physical and living comfort in the existing multi-family houses built in Macedonia in 50s and 60s. In that respect the interest was aimed to two typical settlements in built in Skopje in that period; the first one called “Prolet” built in 50s and the second one called “Karpos III” built after the earthquake in 1963. State of the Art: F.Y.R. of Macedonia 204 Within this consideration few important questions that could impose certain framework for professional approach and applied methodology were raised in other to analyze specific problems related to architectural and urban aspects, social and cultural as well as physical and structural ones. Some of the above mentioned aspects were subject of consideration at Berlin C- 16 Meeting 2.1 Architectural and Urban aspects Residential settlement “Prolet” This settlement was planned on the outskirts of Skopje as a typical segment of the new residential working class settlement zone planned for workers and their families. The positioning of the settlement was supposed on the idea to be close to the Skopje Tobacco factory to the south-west and to the commercial canning and food processing industry to the east The settlement was planned for around 1000-1200 tenants. Now 50 years after, it is almost part of Skopje central area, close to the new complex of the Skopje Transportation Center (Railway station, Inter-city bus station and Central Post Office. (Fig. 20-21-22) Figure 20: Residential settlement “Prolet, Site Plan; Figure 21: Composition; Figure 22: Plan layout “Prolet” settlement consists of three main special units; a) Collective multi-residential area 312 + 72 flats (Total 384 flats); b) Area of individual residential houses (mainly double houses); c) Public area (schools, playgrounds, services and retail); The urban planning was supposed on a simple scheme of 13 + 2 four-storey residential gable roof blocks arranged south-east north-west alternating between four small parallel service streets connected to a secondary street on the north-west. Within the original urban planning State of the Art: F.Y.R. of Macedonia 205 there wasn’t almost any car-park space for the residents. “Prolet” was planned just for living equipped with basic urban infrastructure: narrow service streets and foot paths, open areas with basic facilities (usually play grounds for children) and modest landscaping. Hopefully, from present point of view “Prolet” still looks considerably comfortable residential settlement with a possibility to be successfully restored and improved. Later, in 60s and 70s some modifications have been done and yet they couldn’t meet the real and permanently growing demand for car-parking. Some of the residents abused the situation and started building their own garages on the vacant land in-between the residential blocks implicating serious damages to the landscape and wider environment. Done poorly and improperly, these provisory now looks ugly and devastating and contributes significantly to the general pour appearance of the settlement. Aside from illegally built garages the rest of the open areas looks deserted and lawns are with few neglected trees and bushes.The north-west corner of the settlement wasn’t realized completely probably because of some problems that appeared with the actual land lords. Only two blocks were built at that time. (Fig 23-24) Figure 23, 24 Residential settlement “Karpos III” “Karpos III” was built 1964-66 on a block of land of around 223.000 m 2 and consists of five basic spatial units:) 1. Two residential block units with arranged north-east and north-west in between the four main and secondary streets and eight small, internal, orthogonal service street (127.500m 2 ) 2. Primary school alternating between the residential units 26.196 m 2 ) 3. Residential block unit built in R.C. Skeleton system 34.800 m 2 ) 4. Kindergarten 12.000 m 2 ) 5. High school (21.800 m 2 ) Residential units were designed and built in a fully prefabricated “Karpos-system” with total of 1344 flats (34.672 m 2 ). Residential blocks consists of one to three bedroom flats of an average size of around 60 m 2 (31,50 m 2 - 84,oo m 2 ). (Fig. 25-26) State of the Art: F.Y.R. of Macedonia 206 Figure 25: Residential settlement “Karpos III”, Site Plan; Figure 26: Layout There were two different types of residential blocks: Type A: Four storey residential block (34.38 m x 11,82 m in layout) consisting of 24 flats of different size or 20 (R. b.) x 24 = 480 flats Type B: Four storey residential block (59.0 m x 11.82 m in layout) consisting of 48 flats or 18 (R. b.) x 48 = 864 flats Beside the fact that “Karpos III” was also designed just for living with modestly urban infrastructure too the original urban planning offered certain percentage (18 %) of two type car- parks: Type A: Separate garage-car-park units (8- 13 cars per R. b. or total of 45); Type B: Open car-parks (around 45 cars) for whole settlement. (Figures 27-28) Figure 27, 28 Certainly, this was far of being satisfying for a settlement of 1344 flats (4500 residents). This problem later produced abuse of open areas and landscaping for car parks. State of the Art: F.Y.R. of Macedonia 207 2.1.3 Aesthetic aspects Residential buildings built in 50s and 60 were of modest design value which is quite understandable. Their general aesthetic expression corresponds to the time they were built. Practically, there is no significant architectural decoration or specially designed details, ornaments or so. They express pure, simple but frank architecture, with no claims or aspirations to be too likable. Usually designed as single four level residential blocks arranged orthogonally with gable roofs, small balconies and staircases, these building nevertheless fit well into the environment. Facades are treated with external mortar, usually white or grey and sometime yellow painted. Roofs are covered with red color ceramic tiles or grey salinity. 2.1.4 Functional aspects These settlements even nowadays look pretty comfortable and functional. Usually built away from big and busy communications, surrounded with small secondary and service streets and lot of footpaths, they still could offer god living quality. However, narrow streets and evident shortage of car parks is serious disadvantage now. Functionally, the flats are based on simple design mostly as one to three bedroom units with strictly integrated kitchen with dining room, usually with one bathroom and small store room. On each floor there are usually two to three flats; two typical or similar ones (50-70 m 2 ) and a smaller one (studio or one bedroom flat). Due to the internal structural walls flexibility is reduced to the certain extend. 2.1.5 Accessibility This settlements are not dense populated and consist of buildings not higher than 12 m with pretty well sized open areas between the residential blocks. Thus, they look quite accessible and simple to communicate 2.1.6 Environmental aspects Due to low density (120-150 residents/ha) and well planned open areas between the residential blocks (25-27m 2 per resident) most of the settlements sustained the quality of their original environmental capacity. Unfortunately, some later interventions (illegally built garages and other extensions) and general negligence for the landscape and urban facilities gave this settlement unpleasant appearance. However, this is relatively easy solvable problem in a future rehabilitation and reconstruction Certainly, the most serious problem is the enormous number of illegal and unskilled extensions done to the buildings both from outside and inside. This will for sure create insolvable problems in a future rehabilitation or environmental improvement. 2.2 Social and cultural aspects 2.2.1 Urban planning facilities It must be said that the settlements built in 50s and 60s don’t satisfy contemporary planning standards. Lack of even an average quality of urban facilities and especially joint facilities such as small shops, art and common facilities, playgrounds, urban signature and so on is one of the most serious problems which needs to be seriously considered before to start with any conceivable and comprehensive rehabilitation and reconstruction. 2.2.2 Social aspects Left on the margins in the society of transition where interest of many individuals, private business’, inert, weak and hesitant institutions are focused on some “instant” projects, the settlements build in 50s and 60s slowly but surely are losing the battle for surviving and transforming into descent places for living. On one side, some strange changes out of control are going on in these settlements implicating serious social, cultural, personal and collective identity decay of their residents within the dynamically transforming society on the other side. This could be the second most serious State of the Art: F.Y.R. of Macedonia 208 problem in a future eventual rehabilitation. Both, cultural and identity rehabilitation could be the most critical one beside the technical one. 2.3 Physical aspects It can be said that thermal insulation in the multifamily houses until 70s (the first global energy crises) in Republic of Macedonia was not a subject of any serious consideration. Practically, within this period all residential buildings (multifamily or single ones) lack thermal insulation which generally implicates some other, more or less, serious physical handicaps such as high coefficient of thermal conductivity (Ct=1-15), significant heating losses, many thermal bridges, moisture, and energy unfits. In regard to this, serious thermal reconstruction projects for proper energy efficiency are to be made and this is going to be the most critical and expensive part in the eventual future improvement of the quality of urban building envelope to the settlements built in 50s, 60s and 70s. First of all, within this projects, contemporary heating systems, local or central, must be introduced beside the new thermal insulation and protection to the buildings (both from outside or inside as well as to the roofs and basements). Also, an inevitable replacement to all windows must be done. Lucky enough, it is not necessary to intervene much in regard to noise insulation because of heavy masonry both of the external walls and dividing ones between the flats. The problem of daylight and sun incomes into the dwellings as very important factors of commodity and health could be improved by window’s replacement as mentioned above. 2.4 Structural aspects The building practice of 50-60’s used two types of structural systems. A) Bearing walls constructed of solid brick without RC belt courses B) Bearing walls constructed of solid bricks with horizontal RC belt courses Bearing walls constructed of solid brick in lime or cement lime mortar were arranged in longitudinal, transverse or both orthogonal directions. The walls are partially inter-connected by timber beams or strengthened and inter-connected by horizontal RC belt courses at the floor level. The structure was founded on strip foundation constructed of stone or in concrete. The slabs were constructed of wood or cast/pre cast RC ribbed type “. The roof structures are made of timber covered with ceramic tiles. The unskilled interventions that later occurred (enlargement, extensions, build up roofs..) can create serious structural problems having on mind that are built in different periods and materials, unskilled structural systems and knowledge. However, the masonry structures are the ones that can suffer large failure and heavy structural damage in case of a possible future earthquake. 2.4.1 Damages Due to the ravages of time, improper maintenance and design/performance defects in the course of time, both types of structures have suffered different extent of damage and require proper maintenance, i.e., increase of seismic resistance to the level compliant with the legislative regulations. This is particularly true for structures constructed prior to the effectuation of the Rulebook on Construction of High-rises in Seismically Prone Areas. 2.4.2 Repair and Strengthening The usual mode of repair of damaged walls is injection, strengthening by use of RC jackets, replacement of timber floor structures by flat RC slabs as well as their interconnection in both orthogonal directions. This gives rise to a quite extensive modification of the characteristics of the structure for the purpose of sustaining external and static and dynamic loads. State of the Art: F.Y.R. of Macedonia 209 Later constructed structures by use of reinforced concrete are characterized by a different degree of safety against expected seismic effects, depending on the level of knowledge of the design engineer. The earthquakes that have occurred and have inflicted heavy structural damage and loss of human lives point out that a step forward should be taken in analysis. This step is consideration of the dynamic response of the structure to actual seismic effects expected at the considered site. CONCLUSIONS Since 75% of the dwelling stock in R. of Macedonia has been built after 60s (1963), it is fairly young and in a relatively good shape. The majority of the stock (60-62%) is realized in a different type of family houses. The rest (38-40%) is realized in multi-family residential buildings. Also, it can be mentioned that 98-99% of the stock is private and owned by the tenants. This situation can later create certain problems in terms of improving or revitalizing the existing urban envelope especially in the settlements built in 50s and early 60s where a serious and comprehensive rehabilitation is immanent Other serious problem can emerge due to specific social, economical and political problems in society going through critical transitional period (since 1991) where dramatic changes occurred. First of all, there is the fact that almost entire stock of so called “government flats” in multistory family houses have been sold to the tenants for incomprehensible low prices. In a situation of pressure to get “some extra living space” the tenants, usually jobless or in a social welfare working class people, started to do unskilled “extensions” and “changes” to the flats creating serious problems into living environment, energy performance, urban planning. All this situations however will limit future possible interventions or improvements. However, this severe reality still offers some opportunities for professional engagement in terms of applicable projects to convert these settlement into decent places for living REFERENCES (1) State Statistic Bureau of Republic of Macedonia, Statistic Catalogue-2002 Census Statistic Information, web-site: www.stat.gov.mk (2) Friedrich Ebert Stiftung, International Conference Book, 1999, Habitat-The Needs, Possibilities and Perspectives (3) Stojkov,T. 1999, Some aspects of transitional housing policy in R .of Macedonia (4) Filipovski, L, .Stojkov, T. 1982; Analysis of thermal insulation in multi residential settlement “Aerodrom”, Skopje (5) Pljakoski, D. Stojkov, T. 1979, Materials in Inherited Architecture (6) Cipan, B. 2005, Tradition and modernity in architecture (7) Stojkov, T. 2004, The housing construction in Macedonia (8) Stojkov, T. 2003, Review of some practical solutions in improving the quality of multi-storey family houses built in R. of Macedonia in 50s and 60s This page intentionally left blank Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 211 1 OVERVIEW ON THE HOUSING STOCK The Maltese Archipelago comprises two inhabited islands and a number of smaller uninhabited ones, the size of a sesame seed on the world map, located in the centre of the Mediterranean. Malta and Gozo having a population verging to 400,000 with an annual increase of around 0.8% per annum [1], classifies the Island State as one of the most densely populated countries in the world. With a total land area of 246 sq. km or a population density of 1.85 persons per sq.km, no wonder land is at a premium in Malta [2]. Land availability, the price of land, a bloated real estate market, distaste for renting, building and development permits, planning policies, social housing policies and public attitudes and lifestyles, all have contributed to the state of the art in housing accommodation as we know it today. Residential accommodation, both private and public, is influenced by parameters beyond the most basic need of a physical shelter. Be it low-cost, low-rent social housing or the elite up- market low-density private property, both extremes are admittedly associated with the family’s income bracket. However the whole residential sector owes its present status to various characteristics. These are principally rooted in social, economic and cultural influences, but moreover Malta’s history, its built form and fabric and its built environment. The basic rational laws of supply and demand apply to almost all sectors of the economy. Housing in the building industry is but one of them. An adequate supply of residential units establishes the price of dwelling units on the market. Such a supply normally comprises units for private outright sale, private renting or social subsidized housing. The stability of self- regulated price control depends on a balanced availability of all such types of accommodation. If the supply in one of these sectors is diminished for one reason or other, then the price in the other allied sectors increases to accommodate demand, stemming an imbalance in the open market [3]. In Malta’s small but highly volatile property market this is constantly happening today due to five prime factors. State of the Art: Malta Vincent M. Buhagiar University of Malta, Faculty of Architecture & Civil Engineering, Department of Architecture & Urban Design ABSTRACT: This paper gives an overview of the present status of residential urban built form since the rebuilding of post-war Malta. It inter-relates various architectural aspects namely the main typologies, evolution of local building technology, housing policy, rent laws as well as the social dimension. An outline of ruling foreign influence on the aesthetic quality of today’s historic edifices is given, also highlighting the transposition from farmhouse to townhouse to today’s’ terraced houses and residential blocks. An emphasis is also placed on the general built environment, proposing a general way forward for improving the thermal performance of the building envelope itself. Although seemingly limited to the physical aspect, however this paper does not stop at the envelope itself. Moreover it gives an overview of past attitudes versus modern trends towards acquiring property in Malta in the context of today’s lifestyle and demographic changes, on the threshold of the 21 st century. State of the Art: Malta 212 The major prime influential factor relates to the rental market. Private renting is based on outdated rent laws where right of tenancy, stemming from a post-war social approach, is still a priority, thus inhibiting landlords from developing and renting property. In most village cores in Malta and Gozo there is a substantial amount of older character houses left derelict and vacant for lack of maintenance and fear of being permanently occupied by tenants. A second factor is the influence of available social accommodation, which has gradually changed polarity over the last two decades or so: Government housing policy is shifting from providing low rent social housing to subsidized freehold sale of apartments. This liberates the Authorities from the daunting task of follow-up maintenance and legal disputes with tenants, which taxes the limited human and financial resources. The cost of land and its development is increasing for the Government too as it has to compensate for requisitioned land at open market prices. Admittedly, according to recent published statistics [4], there is an ever-diminishing number of families living below the poverty line, signaling an improvement in the standard of living. A third emerging dimension is the increase in demand for property in Malta by foreigners, especially since now the sovereign Islands have become a full member of the European Union. Apart from the ever high percentage of British expatriates living in Malta, stemming from strong ties between the two countries, a wider blend of nationalities are interested in property in Malta, today even beyond the new boundaries of an enlarged Europe, from Russia to South Africa and Australia, including returned immigrants. Land availability for development is the fourth factor. Considering Malta’s small size and the limited land resource, combined with tight land development policies and a militating national planning authority, it is no wonder that land offered for development is also diminishing in supply. Hence today we see a shift from the former single plot-owner developer-user scene into a new scenario, where due to increase in land costs (when available), contractor-developer partnerships are forming to build smaller units to maximize land use (& profits), now being sold as maisonettes and apartments in the free-end open property market. With this scarcity of land a new scenario is emerging: old and even relatively new terraced houses, built circa 15-20 years ago are being sold to such entrepreneurs for demolition and redevelopment into smaller units for today’s reality of smaller families, singles’ lifestyles and co-habitation. Loans are another major influence affecting the cost (and affordability) of residential building stock in Malta. Perhaps sparked off by the preceding two factors as well as the internationalisation of banking practices within Maltese shores, local banks have today shifted their loans business from a purely commercial nature in the 1960s and 1970s to a more domestic sector oriented approach. Home loans schemes offering low mortgage interest rates and incentives are being continuously launched with vigorous competitive marketing campaigns between the four local banks. All offer attractive financial packages for young couples, paying the loan over their entire working lifetime, thus pushing “affordable” easy payment terms into an upper price bracket for preferred smaller property but possibly highly finished as modern standards or the ‘Johnsons’ dictate. In some instances the loan facility requires such a high hypothec value (property security) that the couple would have to call up their parents’ residence or other secured capital as bank security for the loan. This fifth factor is - in many ways - verging towards promoting unafforded luxuries [5]. Therefore the influence of this penta-faceted predicament [rent laws, diminishing availability of social housing, foreigners buying Malta, land supply/demand and loan schemes] have all had a significant combined effect on supply and demand for property in the Maltese islands. As a result market prices have increased steadily but more significantly over the last decade. This has in turn diminished supply and pushed down affordability for the average wage-earner in the Maltese community. State of the Art: Malta 213 1.1 Data related to building periods British Colonialism in Malta lasting for over 100 years (1802-1964), left its deep-rooted influence on the way we build today, on the threshold of the 21 st century. British rule in both the West Indies and India lasted over a century, which in turn influenced the way they perceived buildings of utility and comfort in warm climates, particularly housing forms. No wonder the British brought with them a baggage of preconceived ideas on built form. In Malta these were further refined with the influences of the abundant indigenous building material, globigerina limestone and vernacular architecture, in the context of a Mediterranean climate. In fact in Malta colonial architecture compares quite closely with Indian architecture. An evaluation of styles and buildings by Nilson [6] has revealed that European architecture in India between 1750 and 1850 most architects understood the elements of vernacular architecture for climatic control and sieved through them to adopt the most practical ones for an imported European style in the colony. With the termination of the British base in Malta in 1979 these were handed over to the Government of Malta and were converted almost overnight into social housing for low-income Maltese communities. These were not exactly an expected extension of established layouts, with some naïve misconceptions on climatic control and the lack of segregation between pedestrian and vehicular traffic. Figs 2, 3 refer. Figures 2,3: Mtarfa – extension of former British Residential quarters: vehicular penetration 1.2 Description of main typologies Early planning typology was principally dictated by rural lifestyle and basic functionality, also based on cart and mule typology for circulation. Animal livestock, tool shed, crop store and all farming accessories were located at ground floor, all accessible through a central courtyard. The later was used both for leisure as well as work for the odd farming preparation work in after hours (periods of excess sunshine or cold spells). The family’s habitable spaces were located at first floor, overlying the same utility rooms. Therefore the farmer felt secure with all his belongings under one roof, contained in an enclosed more or less square-shaped plot, secure and well sheltered from the elements. There was eventually an organic growth of the farm building, depending on diversity of use, family size, livestock and availability of adjacent land. The traditional Maltese farmhouse was therefore a direct response to the farmer’s way of life. A typical farmhouse layout, isometric view and actual building are shown in Figure 4. The official set-up of Parishes as villages was the first step to mould the change from rural to urban communities. In architectural terms there was a similar gradual transition. In general planning terms the townhouse was an evolution from the farmhouse, although now dictated by strict parallel 3 rd party wall boundary lines, and a more formal façade aligning a street. This was totally contrasting to the freestyle planning, unregulated by property boundaries, since the farmer typically built his own abode on the fringes of his own tilled land, attempting to reinforce his presence on the land. State of the Art: Malta 214 Figure 4: Typical farmhouse layout, isometric view and actual building, Gharb, Gozo. Figure 5: Mdina Cathedral dominating the town square and residential buildings. In the townhouse an attempt was made at emulating an architectural style that was not too dissimilar from the Church, typically Baroque with touches of Neo-Classical architectural styles. This resulted in aesthetic proportions and ornamental décor that were wide and vertical as opposed to the former simple cubic forms. The wealthier members of the rural communities who may have laid down their tools earlier, often moved to prime sites closer to the influential village square. This was typically dominated by the large scale motherly bosom of the church dome, also symbolically beaming down a Catholic maternal protection over its people. Fig. 5 depicts this in an aerial view of Mdina. In the early 20 th century traditional influences further changed radically. Although today’s housing stock is primarily composed of terraced houses, this was only a later development of the townhouse, then governed by different forms of legislation detailed later in section 1.4 in this paper. The terraced house is certainly not representative of traditional Maltese architecture, as it is the direct influence of British Rule in Malta between 1802 – 1964. The evolution form the farmhouse into the townhouse is graphically shown in Figures 6,7 & 8. 1.3 Description of main technologies Vernacular architecture in Malta, as in most countries departed from the basic needs of rural communities, having to struggle for surviving off the land, encountering the elements year in year out, as well as any possibility of piracy or sabotaging their daily simple life, based on needs more than on wants of modern society. Their buildings were truly “architecture without architects” as they made the best use of available knowledge of the climate, terrain topography and available building materials. State of the Art: Malta 215 Figures 6, 7: Typical alleyway and evolving streetscape aligned farmhouse cum townhouse. Figure 8: Evolution of farmhouse to townhouse in three phases In Malta, where there is no forestation to serve as a timber source, or rivers as a transportation mode, early Maltese farmers built their dwellings through wit and perseverance, investing much hardship for excavating, transporting and erecting the local indigenous material, globigerina limestone, commonly called, franka stone. Globigerina limestone was always an abundant indigenous material in the Maltese Islands, although not so much today. It has always been considered to be Malta’s only natural underground (quarried) resource since no other relevant minerals have ever been excavated. It is soft and malleable yet robust and long-weathering, giving it a strong aesthetic appeal through its yellow-ochre to rosy colour and texture. Ever since the Knights of the Order of St. John set eyes on it as an ideal building material it has never faded in importance in the local building industry. Early Monolithic Construction Techniques Malta has very limited natural resources. This is due to its size and geology. The Islands are barren of minerals and natural fossil fuels, as oil drilling has confirmed. Naturally occurring building materials are non-existent, except for its globigerina limestone, locally termed 'franka' stone. This is almost unique in the Mediterranean, except for the Dalmatian coast. It has always been the sole natural contributor to the building industry – and its rich ornate architecture. It is quarried in horizontal bedding planes, using circular saws to cut blocks of 270 x 230 x 610mm. Fig. 9 refers. State of the Art: Malta 216 Figure 9: Quarried stone still in the quarry and the finished product, Grandmaster’s Palace in Valletta The Islands’ lack of other natural resources has contributed towards the development of certain ‘natural’ basic tangent trades, such as structural masonry, flagstone finishes and stone sculpture. Other indigenous trades using the local stone range from fishing to farming, used as anchors and weights respectively. 1.4 Housing Policy The Maltese Islands were subjected to different sets of legislation, formulated under various subjugators and eventually the Maltese Government itself. In consideration of building periods, trends and policies, important contributions in this sector were made by King, M. [7] and Camilleri, A. [8]. These sum up the legislation giving the main thrust to housing policies in post-war Malta. The more important milestones are outlined here: The Maltese Rent Laws, 1947 The rent laws were enacted following the aftermath of World War II (1939-1945) as part of a major reconstruction programme. They were meant to be a temporary measure, enabling government to expropriate any vacant house and allocate it to third parties, primarily for humanitarian purposes. The rent was based on the standard of living prevalent in those job- depressed post-war days. In an attempt to address the dire national need of promoting new families and a stable labour force, housing accommodation was deemed to be a social necessity more than a commodity. Hence the tenant was practically immune to the landlord’s request for rent increase or even re-possession of his own property. Adding insult to injury, any repairs and maintenance were to be borne by the same landlord, with potential claims for a rent increase regulated strictly by the purposely set-up Rent Regulation Board. The Atkinson Report, 1958 Among other items this highlighted deficiencies in the building trade and recommended alternative building methods, including the use of proper stone blocks instead of rubble-wall style of building. This kicked off a new approach to quarrying with novel stone-cutting techniques. It also suggested an increase in the rate of house-building from 1000 to 1500 houses per annum, in the process also recommending that the building industry should be more commercialized, making it more profitable for private enterprise to embark on building programmes too. Perhaps this is in close proximity to what is today being promoted as private- public partnership. State of the Art: Malta 217 Reconditioning of Standard Housing Scheme, 1957 Due a considerable amount of houses considered sub-standard this scheme provided financial support to landlords to improve or introduce sanitary facilities and enhance ventilation modes by enlarging windows. Capital expenditure was also invested to ameliorate infrastructural services of water, electricity and public sewage to replace the cesspit. Special Development Areas Bill, 1956 The move from the improvement of individual dwelling units to special land development was upgraded to a national priority through this bill enacted in 1956. The government of the day felt the need to provide employment for the Maltese labour force by earmarking selected areas for industrial and tourism development among others. Housing Policy & the Housing Census, 1957 In order to sensitize future policies to slum areas, a population census was carried out. A report published in 1957 revealed that Valletta had exceeded all other areas with 755 units, almost double that of the second listed, Birkirkara with 436 dwellings. The report, among other facts, revealed that the rate of growth of the population was slowing down between 1948-1957, typically due to a lower birth rate and a lower mortality rate too. Due to the depression in post war days, emigration was tantamount to loss of the male labour force on the Islands. The population in 1957 stood at just under 320,000. Housing (Decontrol) Emergency Ordinance, 1959 Following claims that the building industry was being clamped down by the unpopular rent restriction, the British Legislators of the day (caretaker government between May 1958- December 1961) drafted a housing decontrol ordinance as an emergency measure. It stipulated that houses built after March 1959 or owner-occupied to that date were decontrolled. This meant that decontrolled dwellings were not subject to requisitioning by Government for any public use, including social housing. The new law classified rented building in three categories: those built prior to March 1939, those built between March 1939 and April 1959 and those built thereafter. Today this is considered as a missed opportunity to revise the Rent Laws to balance landlords’ and tenants’ rights and to achieve better relationships between the two parties, curtailing legal disputes which form the majority of dragging civil court cases. This legislation did however give the required boost to the building industry. It further proved that the private developer had a contribution to make in this respect. This further developed into the building boom of the early 1960s, which eventually shaped the urban built envelope still to come. Between 1980-1986 more than 7,000 plots were given out by Government to prospective engaged couples, under various ‘Home Ownership Schemes’ and ‘Building Development Areas’. The Church authorities followed suite did the same with its own inherited property. On the Threshold of the 21st Century Housing Authority Policy to date is to refurbish dilapidated property possibly to reinstate the same tenants under a new lease agreement with marginal rent increase respecting the annual C.O.L.A. (Cost of Living Allowance), typically standing at 15% per annum. Alternatively if the block is dilapidated it is typically demolished to be rebuilt to modern design standards. These are then sold in the free-end open market by public tender bidding at a subsidized rate. Providing social housing by governments is today generally affected by land scarcity and exorbitant prices, since Government can no longer requisition, but has to compensate at open market prices. Banks have risen well to this situation. Home loans are the prime mover of property deals today, especially for first time buyers, typically young couples. There is constant advertising about an ever-lower interest rate charged by leading banks in an aggressive and volatile competitive loan market for purchased property, since rented accommodation is not so popular as a permanent abode. These discourage savings by newly formed families, binding a good portion of their salary for a good 30-40 years until retirement simply to own the house or maisonette they live State of the Art: Malta 218 in. Loan period is now spreading over offspring’s lifetime. Loan hypothec is now also roping in parents’ property (tied down for a number of years) due to higher property prices and a more up market unit being sought after by the couple. This in turn has a knock down effect on mobility by anchoring a family to one, possibly large abode, discouraging the typical three-phase family rotation: from a single bedroom flat to a two/three bedroom maisonette and back to a one bedroom residence, for young working couples, a growing family and a retired couple respectively. 2 TOPICS, QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK The post-war multi-family (mixed and single unit) housing stock consisted of four main periods, as classified by Camilleri in his review of post-war housing trends. These namely included: The immediate post-war period (1943-1955), the transition period (1955-1962), Post-Independence Malta (1962-1971) and Malta as a Republic (1971-1981). Although seemingly only politico- legislative periods, these cannot be divorced from architectural and urban design aspects, today forming part of our built urban fabric. 2.1 Architectural and Urban Design Aspects Setting the record straight from the onset, Malta has no high-rise residential blocks when compared to European standards. Such housing stock is never in excess of four floors and these were even designed to be part of a mixed development scheme layout, comprising units of two storey houses and flats. The early sixties saw the beginning of such layouts in Santa Lucia, San Gwann and Qormi among others. Fig. 13 depicts such a typical streetscape mix in Qormi. Figure 13: Mix of four and two storey housing in Qormi, Malta. The architecture consisted mainly of good-sized open terraces, either with a setback from the main façade or simply a projection onto the street, as per fig.13, exploiting the summer breeze. Treatment of openings was mainly modest with a general mix of concrete and stone. All walls were load-bearing with no frame structures necessary. On an urban design layout, open spaces were deemed to be the lungs of such communities where they not only breathe fresh air but also interact and mingle, socializing across generations. Planning legislation produced master plans towards this end. In his M. Arch dissertation “Homes and People”, Galea, J.M. [9] highlights the importance of such open spaces where communities are enticed to seek alternatives for, not only ameliorating their abode, but moreover to enhance the quality of outdoor spaces. Galea also emphasizes the importance of a good quality environment beyond the doorstep, focusing specifically on transitional spaces State of the Art: Malta 219 between the streets and the communal habitat, commonly termed the neighborhood. This promoted self-help, self maintained notion of upkeeping open spaces, steering away from vandalism and theft, today known as the ‘neighbourhood watch’. Although some may not have been so successful, in the sense that they intrqoduced concepts of wide spaces for both open visibility and vigilance as well as vehicular access, the latter considered equitable with comfort and material luxury. Today we realize with dismay how negative such open spaces were in promoting car intrusion to almost every area of the neighbourhood, in the process destroying every intimate pedestrian haven of each village core. This was ideal for providing that dash of shelter from solar and wind exposure on regular pedestrian errands downtown. Such examples illustrate this unprecedented destruction of village cores, claiming the step up form village to town (e.g.s: Siggiewi & Zurrieq). In fact today the more sensible communities are reverting to older village cores seeking houses of character with a more introvert lifestyle, away from the former syndicate eyes behind louvered windows. Typical open spaces are shown in figures 14, 15,16 showing ‘broadways’, today replacing the cart and mule typology of ‘remissa’ arched doorways to garage typology for the family vehicle. Today two units per family are considered as just adequate’ in car ownership standards, if not a minimum. This is still a dominant parameter, prevalent to this very day, which has molded our urban built environment. Figures. 14, 15: old and new open urban spaces, making way for the car Figures 16,17: isolated recreational areas on the outskirts of social housing State of the Art: Malta 220 2.2 Social and cultural aspects Urban/neighbourhood planning/facilities No urban core can last long without the existence of stable residential areas in proximity to the town centre or civic spaces. This is true of most towns and villages in Malta where the recipe of unity in the earlier villages was the town square and the facilities it supported, beyond business prosperity into social and cultural unity: it is the civic sense of civilised society which binds it. In turn the binding, if strong enough, also strengthens the individual families themselves. This may be said of smaller earlier Maltese communities, often grounded to one village in both childhood and marital life. Today this has changed considerably especially with the introduction of post-war housing estates, increase in mobility, and not so close family ties. This is perhaps what is causing the loss of what was termed as the friendly neighbourhood. 2.2.1 Social anonymity/lack of identity/ownership The lack of identity was lost with the intrusion of the car in almost all public spaces, often ripping villages apart, for the sake of commodity. Property ownership has become almost synonymous with vehicle ownership, where the car one drives becomes another status symbol – to be seen by all the community. Ball games and informal childhood events in the quasi- pedestrian streets have become history, with the provision of playing fields as ‘isolated islands’ for grandparents and offspring, so typical of multi-family residential building stock in Malta. 2.2.2 Social structure of neighbourhood/building/refurbishment Demographic growth and economic activity are the principal motors behind this rate of increase in built up area [10]. There is also the trend that to demonstrate an improvement in his standard of living (better job, salary increase or other material gain) the bread-winner has to demonstrate this within the social stratum by changing home or possibly building a new one in a more upmarket locality. This contributed to the (severe) surrender of agricultural land in the two building booms of the 1960s and 1980s. Admittedly however, the trend is now shifting to refurbishing old dwellings rather than going for new build, possibly due to the exorbitant cost of land and the hassle of the construction process itself (given the means are available) [11]. Taking account of land-use Malta is over 20% built up. Although as an absolute value this is seemingly low, it is relatively high by European standards, standing between 8% and 12% respectively for northern and southern Europe [12]. Built up area is increasing at an annual rate of 0.5% p.a., (almost equivalent to building up the area of ‘one Valletta per annum’) [13]. Admittedly the last three or four years have seen a slow down of this rate, curbed by the cost of land and more stringent planning norms, regulated by the only planning control mechanism in the country, the Malta Environment & Planning Authority. Some (speculators) view the Authority as a ‘development deterrent ‘ – but not by many. 2.3 Structural Aspects Structural and safety aspects are considered of paramount importance particularly for medium to high-rise apartment blocks. Malta learnt its lesson from post-war reconstruction days when buildings were built more robust and simpler by employing the use of double leaf masonry and reinforced concrete monolithic slab cast in situ. Malta is one of the few countries where the architectural and civil engineering professions are married as one, coined as the ‘Perit’, of Spanish origin. Education and training is such that these two disciplines are not divorced; hence it comes almost natural that the architects designs a safe and sound building to accomplish his own architectural achievement. Hence practically all edifices are designed by the architect and civil engineer en suite, who is governed by a warrant as a license issued by a Warranting Board, now falling under the ‘Periti’ Act. State of the Art: Malta 221 2.3.1 Safety In Malta health and safety aspects have only gained ground in the last decade. However most apartment blocks have always had all public safety measures applied to staircases, general circulation areas and open spaces. Today these are governed by mandatory legislation, in conformity with EU and international safety standards. 2.3.2 Earthquake/mining/underground traffic Although Malta was never subjected to any serious earthquakes, yet the Islands are still on the edge of two dynamic tectonic planes, running just north of north Africa, across the continental shelf of the central Mediterranean. Today, although not yet mandatory to design for seismic loading, the structural Eurocodes are used by most structural engineers for standard loading criteria. No mining or underground traffic exists in Malta. 2.3.3 Accessibility In Malta it is only recently that an ‘access for all’ approach was made mandatory through legislation. Otherwise no public or private housing had any serious consideration for installing ramps and lifts as standard. These were however installed almost overnight once a disabled member of the community was identified. 2.4 Physical Aspects 2.4.1 Thermal performance For an understanding of the fabric response of stone buildings a closer look needs to be taken at the thermal properties of limestone. The Maltese local stone, unlike brick or block, is a natural resource, a quarried material. It occurs in bedding planes, in different strata, namely falling under two general categories, the ‘soft’ and the ‘hard’ type of stone. The former type is also classified as the lower and the upper coraline soft globigerina limestone, which is opaque, yellow ochre in colour and highly porous. There is also the hard coraline layer normally verging to white in colour. This material has the advantage that it is practically impervious to water. It was in fact used for foundations and up to ‘dado’ level in the early 20th century for its high density, load-bearing capacity. Its use was phased out with the onset of the damproof course. It was always more difficult to quarry, found in limited quantities and needed careful quality selection for structural reasons. In-situ concrete ousted its structural use, now only popular for hardwearing surfaces and as crushed aggregate for concrete. Like any other building material, the soft upper coraline globigerina limestone, locally known as ‘franka’ stone, has its strengths and weaknesses. The two basic characteristics influencing its thermal performance are the material density and its moisture content. Density is influenced by its nature of occurrence, varying greatly, dependent on its bedding plane. Its moisture content, also varies, depending on rainfall and wind speed, among other factors: (rendering, mortar thickness & crust when built). Since both parameters are subject to considerable variations, it is difficult to calculate an exact value of the thermal conductivity. However, the IHVE guide [14] identifies variations of ±30% occurring in specimens of equal density. Limestone, with a density of approximately 2,000 kg/m3, for a conductivity k = 1.5 W /m2/ °C , then its thermal resistivity would be 0.67m2°C/W. There is admittedly a lack of knowledge about basic heat transfer mechanisms among stonemasons and owners alike. Under the new upcoming Building Regulations for Malta rigorous measures will be introduced to ensure energy conservation in the building industry. This will be accompanied by an equally important educational campaign, where a ‘guideline’ approach is known to be more effective than enforcement through and ‘authoritative’ methodology. No thermal insulation in cavities or on flat roofs has been the norm in Malta. This stems primarily from the fact that although summers are hot, winters are mild with only nominal need for heating in winter. There was never any need to legislate for insulation so far, but now State of the Art: Malta 222 with the rapid introduction of air conditioning this will be a must, as dictated by the imminent introduction of new building regulations. As a member state Malta will also have to comply with the Energy Directive 2002/91EC, coming into force in January 2006. 2.4.2 Protection against moisture Located in the centre of the Mediterranean, Malta has a typically humid climate with onshore currents also bringing in saline spray into the deeper parts of the Islands, considering their small size. This creates problems in the form of spalling concrete in buildings located within close proximity to the coast. Marine structures require admixtures and more than adequate cover to steel reinforcement towards this end. Rising damp from the limestone and soil terrain is another problem. Buildings, typically built of local globigerina limestone, due to its high porosity, as outlined above, needs adequate protection, especially from rising damp. This is achieved by inserting the now traditional damproof course close to external finished ground floor surfaces. Storm water drains also ensure discharging of water away from the building or into a purposely-built reservoir, as imposed by standing legislation since the 16 th century under the Knights of the Order of St.John. 2.4.3 Noise insulation Malta has no code of practice or legislation that specifically dictates the use of insulation in buildings. This is probably because the heavy monolithic masonry walls provide sufficient mass towards reducing noise between third party walls. Today stringent sound reduction requirements are being introduced for isolating leisure or semi-industrial facilities from residential units. This is primarily done by zoning but still specific dB levels apply for certain trades, including hours of work operations and business hours for entertainment localities. 2.4.4 Daylight/sunshine As a Mediterranean Island, Malta boasts of its long hours of sunshine, averaging 6 hours daily all year round. Hence there is undoubtedly an excess rather than a deprivation of it. This however creates problems of glare and overheating in summer, which is mitigated by carefully designed shading devices or setbacks in the façade in most of the residential building stock (and other building types). 2.4.5 Air quality Although a small Island, once considered pollution free due to quick air dispersion off-shore, today this is no longer the case with increase in CO 2 emissions. The stems from increase in car ownership and two major power stations in the south of the Island. In residential quarters the vehicle is perhaps the only major concern. However families still rely heavily on natural ventilation in most housing estates, even though air conditioning units have mushroomed overnight, over the last decade, with almost every other house owning at least one unit. CONCLUSIONS Today, over fifty years later, the rent laws are still in force. As a result the owners still cannot take possession of their own property, even for their own personal use. The tenants, protected by these laws, continue to pay Lm20, Lm30, possibly up to Lm50 a year (50-125 Euros annually), for houses in prime areas, including Valletta. Today, in many cases the tenants are better off financially than the owners themselves. It is only through a slight modification in 1995 that any property let out to third parties will be governed by a private notarial deed where the landlord could evict tenants should these be in breach of contract for almost any reason. Through a householder survey [15] government has declared that there were over 30,000 uninhabited houses out of the present 800,000 dwellings in Malta, although a mere 0.04%, still significant for a population of over 380,000. Most of these 30,000 are old mansions, passively left to deteriorate by their owners, who know well enough that if they make even the minimal State of the Art: Malta 223 repairs, to let out, they would fall victim to the noxious rent laws. Very often such ‘houses of character’, lying within village cores, possess rich architectural features, which crumble with them as they wither into the ruins of oblivion. With the eventual removal of these archaic rent laws – whenever this crystallizes – such prestigious old mansions could be rendered habitable through refurbishment and re-use, even by possibly sub-dividing into smaller units, to the tune of sustainable development. Therefore for the sake of the entire residential building stock, one way of remodeling the urban built environment is to relinquish the present rent laws and legislate anew in line with today’s modern lifestyle and standard of living. REFERENCES [1] Population Census 2002, Central Office of Statistics, Government of Malta, Valletta. [2] Malta Year Book 2003, De La Salle Brothers Publications, Grima Printing & Publishing Industries, Marsa, Malta, 2003. [3] Camilleri, D.H., Housing Affordability in Malta, Housing Afordability Conference, Chamber of Architects & Civil Engineers and Building Industry Consultative Council, 4 th November 1999, Coastline Hotel, Salina, Malta. [4] Standard of Living Survey 2004, Central Office of Statistics, Government of Malta, Valletta. [5] Domus Magazine, Domus School of Design, Milan, spring 1995. [6] Nilson, S., European Architecture in India, 1750-1850, Faber, London, 1968. [7] King, M. J., Housing in the Maltese Islands, M.Arch Dissertation, University of Malta, 1971. [8] Camilleri, A., Building Trends and Policies 1943 –1981, B.E.& A.(Hons.) Dissertation, University of Malta, 1981. [9] Galea, J.M., Homes and People, M.Arch Dissertation, University of Malta, 1975. [10] Household Survey, Central Office of Statistics, Government of Malta, 1998. [11] Buhagiar V., Mallia E., The Energy Policy Workgroup, An Energy Policy for Malta - Part One: The Present Situation., MCST January 1999. [12] Eurostat, a resume of statistical data of Europe, 1998. [13] Housing Survey Report, part E, Planning Authority, 1992. [14] I.H.V.E. Guide, Book A – 1992. [15] Population Census 1996, Central Office of Statistics, Government of Malta, Valletta. This page intentionally left blank Improving the Quality of Existing Urban Building Envelopes – State of the Art. M.T. Andeweg, S. Brunoro, L.G.W. Verhoef (eds.) IOS Press, 2007. © 2007 IOS Press and the Authors. All rights reserved. 1 OVERVIEW ON THE HOUSING STOCK Two overwhelming reasons can be accounted for the extensive residential construction that was carried out in Slovenia during the post-war period. Firstly, large parts of Slovenian cities were damaged in World War 2. Secondly, after the war, the accelerated rate of industrialization of the country resulted in increased demand of workers close to the industrial objects, and consequently the migration of inhabitants from rural to industrial - urban areas were taking place during that time. During late sixties and early sev- enties, a new wave of economic migration from the less developed parts of former Yugoslavia was taking place. It was caused by economic growth resulting in additional working positions appearing in primary industry as well as in tourism and service industry. After the Yugoslav policy on travelling and emigration was liberalized in the late sixties, a small number of Slovenians immigrated to Western European countries, particularly Germany. This phenomenon, to a minor extent, created additional job opportunities and encouraged the migration within Yugoslavia as well. Large residential neighbourhoods were built in that period. The quality of the residential buildings built in the seventies is fairly good, as the living standard was steadily increasing while state planned economy present at that time was not exclusively profit-driven. A substantial part of present day’s urban building stock was created under these circum- stances. The basic statistical data related to the existing housing stock in Slovenia, i.e. number and size of dwellings, and average number of occupants per dwelling is presented in Table 1. State of the Art: Slovenia Marjana Šijanec Zavrl ZRMK, Building and Civil Engineering Institute, Ljubljana Roko. Žarnic, Jana Šelih University of Ljubljana, Faculty of Civil and Geodetic Engineering ABSTRACT: The period from 1946 to 1980 was the most intensive in residential building con- struction in Slovenia. Thus, 61% of all existing residential buildings are from that time and 63% of dwellings built in that time are located in urban, multi-storey buildings. Roughly half of total number of dwellings in urban areas has floor space in the range of 45 to 74 m 2 . Typical residen- tial buildings in Slovenia have either masonry or reinforcement concrete structure. Envelopes of recently erected buildings are insulated what is not usual case for buildings erected between 1946 and 1980. Residents of dwellings with large open air balconies and terraces tend to enlarge dwellings by closing them what usually harms architectural appearance of envelope. Interven- tions in envelopes in many cases may bring the additional strength and earthquake resistance to entire building. In general, the importance of envelope for aesthetic, structural and functional aspects of residential building should not be neglected. State of the Art: Slovenia 226 1.1 Data related to building periods As already mentioned, during 1945 and 1980, a large percentage of people were migrating to the urban areas, which together with continuously increasing living standard created an in- creased demand for new dwellings. New neighbourhoods with repetitive structures were built in all bigger Slovenian towns. Typically, the residents of a particular neighbourhood were of the same age and social back- ground. A survey carried out by the Faculty of architecture of University of Ljubljana published on web page by Gabrijelcic et al. 2001) shows that even today, in many cases, the »original« in- habitants reside in the dwellings of large residential neighbourhoods built in the post-war pe- riod. The post WW2 migrations from rural to urban areas caused the balance of rural and urban population what is clearly seen from Figure 1 below. Table 1. Building stock in Slovenia. Population of Slovenia 1.964.036 Area of Slovenia (km 2 ) 20.273 Number of residential buildings 463.029 Number of dwellings 777.772 Average number of dwellings per building 1.7 Total floor space of dwellings (m 2 ) 58.031.187 Average floor space of dwelling (m 2 ) 71.3 Average size of private household (persons) 2.8 Share of dwellings in urban settlements 51.6% Share of population in urban settlements 50.5% Occupation of dwellings in urban settlements 89.5% Occupation of dwellings in rural settlements 81.2% Source: Statistical Office of Rep. of Slovenia, Census, 2002 0 10 20 30 40 50 60 70 80 90 0-4 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85 + A g e g r o u p s Number of persons (in thousands) in Urban areas Rural areas Figure 1. Age distribution of Slovenian population in urban and rural settlements (Source: Statistical office of Slovenia, Census 2002). The dwellings were originally property of the state. After Slovenia gained the independence in 1991, and the market driven economy became predominant, a law giving the right to buy the state-owned apartments to their residents well below the market price was introduced. As a con- sequence, today, approximately 70% of the Slovenian families, including the residents of the post-war neighbourhoods, own their homes. The number of dwellings located in urban settle- ments distributed according to their floor space is presented in Figure 2. State of the Art: Slovenia 227 For the majority of residents of buildings built in the fifties and sixties, even the relatively low price meant a fair amount of money. In addition, the »original« inhabitants of these neighbourhoods are today retired, often with small pensions, thus they are not financially able to keep up with the maintenance or even renovation costs of their apartments/buildings. It can be expected that in these neighbourhoods, within the next decade, there will be a change of resi- dents' generation that may facilitate the organization, financial support and execution of the building renovation. The distribution of dwellings in urban settlements by types of buildings by the location and the period of construction is seen in Figure 3. According to statistical data ob- tained from Census of 2002, roughly 18% of dwellings in urban settlements were built before year 1945, 61% in years 1946 to 1980 and 21% in years 1981 to 2000. As can be seen from Figure 3, roughly 63% of dwellings constructed in 1945 to 1980 period are located in multi- dwelling buildings. A survey of the housing stock built in the early post-war period (Šijanec Zavrl 1995) revealed that the residential buildings of that time do not have any thermal insulation. In addition, com- pared to the housing stock originating before WW2 or earlier, the walls are thinner which leads to the fact that even the minimum requirements related to thermal performance are not fulfilled for buildings of this period. The situation improved after 1967 when new regulations defining minimum requirements of thermal insulating performance of the building envelope came into force. The performance requirements became harsher in 1970 which had a positive effect upon the thermal insulation installed in the envelopes of the buildings erected after that year. 0 20.000 40.000 60.000 80.000 100.000 N u m b e r o f d w e l l i n g s U n d e r 1 8 1 8 - 3 4 3 5 - 4 4 4 5 - 5 9 6 0 - 7 4 7 5 - 8 9 9 0 - 1 0 9 1 1 0 - 1 2 9 1 3 0 + Floor space of dwelling (m2) Figure 2. Distribution of dwellings in urban set- tlements by their size (Source: Statistical Office of Republic of Slovenia, Census, March 31, 2002). B e f o r e 1 9 0 0 1 9 0 1 - 1 9 1 8 1 9 1 9 - 1 9 3 0 1 9 3 1 - 1 9 4 5 1 9 4 6 - 1 9 6 0 1 9 6 1 - 1 9 7 0 1 9 7 1 - 1 9 7 5 1 9 7 6 - 1 9 8 0 1 9 8 1 - 1 9 8 5 1 9 8 6 - 1 9 9 0 1 9 9 1 - 1 9 9 5 1 9 9 6 - 2 0 0 0 0 5.000 10.000 15.000 20.000 25.000 30.000 35.000 40.000 45.000 50.000 Semi-detached or row house Detached house Multi-dwelling building Figure 3. Distribution of houses and buildings in ur- ban settlements by their age (Source: Statistical Of- fice of Rep. of Slovenia, Census, 2002). 1.2 Description of main typologies Architecture In the first post-war decade the focus was put on rehabilitation of demolished buildings, settle- ments and industrial premises. All the housing policy was based on administrative decrees for occupation of existing flats. Only a few apartment buildings were built, with very low budget and poor technical capabilities. The first organized construction of apartment buildings began in 1954-55, when the obliga- tory “financial contribution for apartment building” was introduced as a part of personal income deduction. Thus the permanent budget for building of social houses was guarantied. In the same time (1957) the guidelines for residential buildings construction were prepared, where the eco- nomical criteria were combined with the architectural, urban planning and structural rules. The preferable building types were buildings with ground floor + 3 storeys (GF + 3S), ground floor + 5 storeys (GF + 5S) and also higher buildings (skyscrapers), though not many were actually built. The recommended types of dwellings are shown in 5. State of the Art: Slovenia 228 The first post-war apartment buildings were erected as clay-brick buildings, built with mas- sive bricks and later with hollow bricks; the buildings had cellars, comfortable but unheated staircases and corridors, in many cases flat roofs, terraces and common spaces (laundry and dry- ing room). Many of these buildings contained not more than ten to twenty flats per entrance. Table 2. Recommended types of dwellings per number of persons in preferable building types, by the guidelines for social housing from 1957. Type of dwelling Adequate number of occupants Single family house – on a string 5 – 7 persons Multi family house – on a string (GF + 3S) 3 - 5 persons per apartment Multi family house (GF + 7S) and higher 3 persons per apartment and smaller units for 1-2 persons Table 3. Apartment area per number of persons, guidelines for social housing from 1957. Nr. of persons No balcony With balcony Balcony 2 2 x 20,5 = 41,0 m2 2 x 22,5 = 41,0 m2 4,0 m2 3 3 x 19,0 = 57,0 m2 3 x 21,0 = 63,0 m2 6,0 m2 4 4 x 17,0 = 68,0 m2 4 x 18,0 = 72,0 m2 4,0 m2 5 5 x 15,5 = 77,5 m2 5 x 17,0 = 85,0 m2 7,5 m2 6 6 x 14,0 = 84,0 m2 6 x 15,0 = 90,0 m2 6,0 m2 Figure 4. Floor plan of dwellings in a clay brick building GF + 3S, built in 1957 (arch. Umek, Savsko naselje, Ljubljana). Figure 5. Floor plan of dwellings in a cast-in-place concrete building with infills, GF + 15S, built in 1958 (arch. Mihelic, Arnautovic, Savsko naselje, Ljubljana), see also Figure 12. Figure 6. Floor plan of dwellings in a clay brick building GF + 5S, built in 1961 (arch. Šorli, Povšetova, Ljubljana). State of the Art: Slovenia 229 The prevailing type of dwelling was 2-bedroom apartment with a big kitchen including pan- try; the kitchen was used by all family members during the daytime. The apartments were heated with stoves in all rooms and kitchen. Originally there were no elevators, unless the verti- cal distance between the entry and the flat exceeded 14,5 m.. In 1967 the national regulation for apartment design was adopted, where several items were prescribed, like 12 m 2 of minimal floor area for the first room, 6m 2 for the second and 5 m 2 for the third room. The minimum height of apartment of 2,4 m was obligatory. The lavatory was admitted in the bathroom, but in case of more than 6 beds an additional separate lavatory was prescribed. In buildings higher than GF + 4S the elevator became obligatory. Table 4. Floor area of different types of flats, used in design of social building stock in Ljubljana (1973, 1979, 1983). Type of flat Floor area (m2) 1973 decree for Ljubljana Floor area (m2) 1979 guidelines for Ljubljana Floor area (m2) 1983 social housing guidelines for Ljubljana Bachelor room 29 30 - 34 24 - 34 1 bedroom 40 40 35 - 40 1 bedroom + cabinet 50 52 44 - 52 2 bedrooms 56 59 52 - 59 2 bedrooms + cabinet 68 71 63 - 71 3 bedrooms 75 78 68 - 78 3 bedrooms + cabinet 83 87 77 - 78 4 bedrooms 90 94 82 - 94 4 bedrooms + cabinet 100 103 91 -103 In late 60-ties and in early 70-ties the living habits changed and beside the national regulation also new architectural guidelines were created, mainly on municipal level. The classification of apartments was no longer done by the number of beds but by the number of rooms. In Table 4 the floor areas for different types of flats are presented according to the Ljubljana municipal de- cree (1973). The architectural concept was modified; the kitchen became smaller, used only for preparation of food, white the family stayed in the living room. Slightly increased floor area of living room caused reduction of bedroom(s) area. 60-ties and 70-ties were the most flourishing for the apartment building construction, not only social houses were built but also flats for the market were erected. Cast in place concrete buildings (“outinor” system) was used for multi- storey buildings (between 1971 and 1985) besides the of masonry structures for smaller build- ings. The prevailing type became 3-bedroom apartment, mainly as a result of economic growth and criticism of favouring of 2-bedroom dwellings in 60-ties. 1.3 Description of main technologies The housing systems in Slovenia are influenced by geographic location, availability of local ma- terials and Central European cultural environment. Geographically, Slovenia is located in earth- quake prone area where the moderate to strong earthquakes can be expected every hundred years. The most available building materials in Slovenia are coming from exploitation of sediment rock deposits making the prevailing materials clay bricks and Portland cement based materials. Traditionally, majority of Slovenian population lived in brick and natural stone masonry family houses in rural and town areas with some multi family houses in town areas. Although forests cover the vast part of Slovenia the timber structures were used mostly for non-residential build- ings with some exceptions in Alpine regions of Slovenia. However, timber was until sixties of last century also used for floor constructions in masonry buildings. The main building types used in construction of multi-apartment buildings in time period from 1946 to 1980 in Slovenia are summarized in Figure 7. State of the Art: Slovenia 230 In Figure 8 the distribution of multi-storey apartment buildings (from 1946 –1980 period) ac- cording to architectural type and construction system (i.e. structural building materials) is sum- marized. Most of buildings are constructed as multi-apartment houses “on-a-string” (type no.2, see Figure 7) constructed from clay brick masonry without thermally insulated envelope. The next most used systems are those of types no.1 (self standing multi apartment houses with 4 to 6 apartments) constructed from clay brick masonry without thermally insulated envelope. Signifi- cant number of residential buildings was constructed in form of apartment blocks “on-a-string” (type no.4) from either clay brick masonry (earlier period) or cast-in-place reinforced concrete (later period). Reinforced cast-in-place concrete was also used for construction of building types no.2, 3, 5 and 6. Data presented in Figure 9 show distribution of floor spaces located in buildings of different construction types what complete the insight in discussed topic. Most of apartments are located in buildings of type no.4 that are constructed of reinforced cast-in-place concrete. Those build- ings were mostly built in 60-ties and 70-ties of the last century. Significant number of apart- ments is located also in buildings of type no.2 and no.4 built from clay brick masonry in earlier period. Diagram also shows that large number of apartments is located in reinforced concrete buildings of type no.5 and no.6. Those buildings were constructed in the last third of discussed period. 1 brick construction without thermal insulation 2 construction with other (non-brick) materials 3 brick construction with thermal insulation 4 cast concrete construction in lost panelling 5 reinforced concrete frame with infill walls 6 cast concrete construction 7 light prefabricated construction 8 heavy prefabricated construction 9 combined system TOTAL 1 . 1 . 1 . 2 . 1 . 3 . 2 . 0 . 3 . 1 . 3 . 2 . 3 . 3 . 4 . 1 . 4 . 2 . 5 . 0 . 6 . 1 . 6 . 2 . 6 . 3 . 1 2 3 4 5 6 7 8 9 T O 0 1000 2000 3000 4000 5000 6000 7000 Figure 8. Distribution of buildings built 1946 – 1980 according to construction system and building materials. State of the Art: Slovenia 231 1.0 Multi-apartment houses, “self standing” 1.1 No. of apartments 4 or 6 1.2 Villas 1.3 Villa-blocks 2.0 Multi-apartment houses, “on a string” down street houses up to: ground floor + 3 floors 3.0 Apartment blocks, “self standing” 3.1 simple prismatic form 3.2 horizontally and vertically deviated 3.3 special forms (terraces, etc.) 4.0 Apartment blocks “on a string” 4.1 Simple prismatic form 4.2 Horizontally and vertically deviated 5.0 Multi-story buildings - low up to ground floor + 5 floors 6.0 Multi-story buildings – high, more than ground floor + 5 floors 6.1 Simple compact form 6.2 Horizontally and vertically deviated 6.3 Special forms 1 . 1 . 1 . 2 . 1 . 3 . 2 . 0 . 3 . 1 . 3 . 2 . 3 . 3 . 4 . 1 . 4 . 2 . 5 . 0 . 6 . 1 . 6 . 2 . 6 . 3 . 1 2 3 4 5 6 7 8 9 T O 0 20.000 40.000 60.000 80.000 100.000 120.000 Figure 7. The main systems used in construction of multi-apartment buildings in Slovenia during 1946 to 1980. Figure 9. Distribution of dwelling floor space re- lated to construction system and building materials (built 1946 – 1980). State of the Art: Slovenia 232 Typical residential buildings built in the observed period are shown in following pictures. In general, buildings in Slovenia are fairly well maintained although the maintenance costs are relatively high. Therefore, the usual interventions are mostly limited to renovation of renders and concrete surfaces. In some cases more extensive renovation encompasses also replacement of windows and thermal insulation of envelope (Fig. 10). However, there are also rare cases where the earthquake resistance of building is increased by structural interventions in building envelope. The figures (Figs 11-16) represent some characteristic buildings corresponding to the groups defined in Figure 7. Figure 10. Most common techniques used for energy refurbishment of post war building envelopes. 1.4 Housing policy Dwelling provision policy reflects the main characteristics of the political system in the country. In the period between 1945 and 1954 the existing dwellings were administratively allocated to the applicants, many of these apartments were obtained in nationalisation of real estate, and on the other hand many people were forced to live in bad dwellings, sharing the apartments with other occupants. In the period between 1956 and 1972 the federal state ruled the residential buildings area, where the money for investment in new social dwelling was collected on the solidarity basis. The majority of big apartment buildings with rented dwellings and many building plots have been nationalised in 1958. The huge residential building construction project started. Between 1972 and 1990 new residential legislation was adopted, valid only on the area of to- day’s Slovenia. In this period the companies were the main investors of apartment buildings, mainly built for their employees. Also the building of privately owned flats became important in that period. Residents contributed to investments with their money savings when buying the apartment and also when renting it (i.e. financial contribution when the social flat was rented); as well as they contributed with their own work (relevant in case of building of single family houses). The banks offered loans with acceptable interest rate, so that between 1980 and 1987 more than 10.000 dwellings were built per year (14.674 dwellings in 1981). State of the Art: Slovenia 233 Figure 11. Masonry apartment block “on-a- string”; built in the fifties. Figure 12. High reinforced concrete apartment blocks; built in late fifties. Figure 13. Masonry “self standing” block of flats; built in early sixties. Figure 15. Cast in place reinforced concrete “self standing” blocks; wooden, largely fenestrated eastern and western facades; from late seventies. Figure 14. Reinforced concrete “on-a-string” blocks having pre-cast large panel envelope ele- ments, built in late seventies. Figure 16. Reinforced concrete high multi story buildings having pre-cast large panel envelope elements from late seventies. State of the Art: Slovenia 234 After 1991 and independence of Slovenia the number of new dwellings was intensively re- duced (less than 6.000 new dwellings per year). The key problem is that these dwelling are mostly in single family houses (i.e. private investments), there were very few investments made by public bodies, municipalities and also by developers on real estate market. Mainly due to worse economical situation (revalorisation of loans, bad economical situation of companies, low incomes) and due to omission of all social solidarity funds for new residential buildings, the new dwellings erection rate reached the lowest number of only 790 units in 1998. In 1991 new Residential law was promulgated, which enabled privatisation of all social (state owned) rented dwellings, except of those in the buildings nationalised in 50-ties. In 1991, before the privatisation, the overall proportion of privately owned dwellings in Slovenia was 70,2%, while more in particular the proportion of privately owned apartments in multi-apartment build- ings was only 10,9%. After the completed process of privatisation (1994) where the dwellings were sold at up to 10% of their market price, 87% of all building stock is privately owned. Due to the fact that the post war buildings were privatised, today we have to deal with a lot of barri- ers (lack of money for refurbishment, no consensus for investments) for rehabilitation. The residential law from 1991 also committed the municipalities to provide social dwellings and thus stimulated again the erection of municipal social houses. The breakthrough in stimulat- ing the investments in residential building sector was made with establishment of National resi- dential fund (1991), which stimulates the private savings and offers soft loans for buying and re- furbishment of flats. On the other hand the fund affects the reduction of prices for new apartments by being currently the bigger investor in housing sector. It should not be forgotten that in last decade the real estate developers also contributed significantly to the construction of new dwellings. 2 TOPICS, QUALITY OF THE POST-WAR MULTIFAMILY HOUSING STOCK There are no systematic analyses of the quality of Slovenian housing stock available. Different studies focus particular problem areas actual in the local environment. Two most important ar- eas of quality are energy efficiency and earthquake resistance, because Slovenia is rather cold country (3200 DD) and it lies on the earthquake prone area. 2.1 Physical aspects 2.1.1 Thermal insulation Residential buildings in Slovenia built before 1980 are considerable energy consumers because of the poor thermal insulation of the building envelope and therefore offer immense energy sav- ing potential. A series of studies has been done to find out the most appropriate way of activat- ing technical and economically viable energy saving potential and to strengthen apprising peo- ple’s interest in implementation of energy efficiency measures. Buildings form early post war period were built without of thermal insulation. The situation was slightly improved after 1967 when new regulations defining minimum requirements of thermal insulating performance of the building envelope came into force. The performance re- quirements became harsher in 1970 (outer wall U value 1.2 W/m 2 K) which had a positive effect upon the thermal insulation installed in the envelopes of the buildings erected after that year. The first serious thermal insulation regulation (outer wall U value 0.8 W/m 2 K) was put into force in 1980. Since the current situation in building practice in Slovenia may differ from the ideally ex- pected one, i.e. because of the lack of money for finishing the construction (private investors) or insufficient control of building regulation implementation, some relevant data on building enve- lope insulation rate were collected with a pole in a relevant statistic sample (Šijanec Zavrl. and Gruden 1998). In general it can be observed that in 60% of the buildings outer wall U value ex- ceeds 1.0 W/m 2 K. Following the construction period of the buildings from the random sample in the pole one can conclude that poorly insulated buildings ratio is not considerably reduced until 1980, when implementation of rigorous building insulation regulations should intensively reduce proportion of buildings with U > 1.0 W/m 2 K and increase the number of buildings with State of the Art: Slovenia 235 lower outer wall U value. The obtained results may be discouraging. Nearly one third of the buildings from 80-ties still have U value higher than 1.0 W/m 2 K. Detected energy saving poten- tial is now being realised by raising awareness, state subsidies and by making energy efficiency investments interesting for private investors. Approximately 25% of all energy in Slovenia is used in the buildings’ sector. The analysis (Šijanec Zavrl 1995) of 18 typical apartment buildings (according to the architectural type, heavy or light weight building technology, year of construction) in Slovenia built before 1980 has shown that the introduction of energy-efficient technologies currently available on the mar- ket can contribute up to 60% to the lowering of heating energy demand in apartment buildings (Fig. 18). Energy-efficient windows themselves have a technical potential of about 20%. Trans- lated to energy figures this percentages represent a reduction of energy demand for heating from current 350 kWh per square meter of heated floor area to 113 kWh/m 2 for older, thermally not insulated single-family houses, and from 115 kWh/m 2 to 50 kWh/m 2 for larger apartment blocks in the wider Ljubljana area (central part of Slovenia, 3310 DD, thermostat set temperature 20 o C, base 12 o C). Figure 17. Overview of outer walls thermal transmittance U (W/m 2 K) in Slovenian residential buildings. An average payback period for investments in energy renovation of buildings in Slovenia ex- ceeds 25 years if the complete investment in building work is assessed. Some simpler measures have a much shorter payback period, e.g. 3 to 4 years for loft insulation with construction costs included and less than one year with construction costs excluded. The payback period for the additional cost (i.e., for the investment in energy efficiency), when replacing existing thermally inadequate old windows at the end of their life-span (double glazed cast windows, old thermopan glazing) with energy-efficient windows (low-e + inert gas), the pay back period for incremental investment is only about three years, and for external insu- lation about 8 to 10 years, respectively. The feasibility studies and public opinion analysis were the basis for the incentive programme - grant subsidy scheme in residential buildings and households, financed by the Slovenian gov- ernment (Agency for Efficient Use of Energy) in the years 1996 – 2002. Three low cost building measures were subsidized: loft insulation, window tightening and oil burners adjustment in the total budget of 153.000 EUR ('96-'97) and a EE windows and glazing as a medium cost measure were supported in a total amount of 640.000 EUR ('98-'02). Since the beginning of the pro- gramme more than 8000 subsidized measures were implemented and additional positive effects of the incentives programme were initiated. The subsidies are currently available for entire en- ergy restoration of building where annual savings are at least 10.000 kWh. State of the Art: Slovenia 236 57% 66% 76% 70% 68% 65% 74% 60% 62% 56% 70% 63% 71% 60% 55% 45% 64% 69% 0 100 200 300 400 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 sample building k W h / m 2 a savings energy demand after refurbishment Figure 18. Annual heat demand per square meter of heated floor area before and after energy restoration, technical energy saving potential in 18 representative sample buildings. 2.1.2 Moisture Protection against moisture is not very important issue and it is considered to be easily solved using well known techniques and materials. The repetitive difficulties can occur in some cases of flat roofs and terraces. In more rainy areas this leakage has been solved by putting traditional pitched roof on the top of the apartment block. Another typical problem of existing envelopes is deterioration of façade due to inadequate de- tailing of water drainage. Renovation plan beside rendering and solving of drainage usually takes into consideration increasing of thermal insulation following the contemporary codes. Moisture problems caused by interstitial and surface condensation, respectively, immerged in 70-ties due to the implementation of new materials (thermal insulation, covering materials with high water vapour diffusivity), unfamiliar at that time to the traditional builders. The slabs and details have now been repaired for a long time. Cold bridges are the problems of 70-ties and 80- ties, when the cast in place concrete structures were popular. The mould growth on inner sur- faces is prevented by insulation and sufficient heating. More recently, a lot of old windows were exchanged with energy efficient which allow low infiltration. This often cause to high relative humidity and surface condensation on widow frames in the metal edge area. Sufficient air exchange rate through controlled ventilation in old refurbished buildings is a key element of successful restoration and exhibiting of moisture prob- lems in old buildings. Post war buildings usually contain water barrier to prevent capillary raise of ground water, what is not the case in pre-war buildings. 2.1.3 Sound insulation Since the post war building were built with heavy weight materials the sound protection is quite good. The sound protection is lower in buildings built in 70-ties and 80-ties, due to transfer of sound through the concrete structures (the details for prevention of sound transport over the structure were not available). Not many repairs are done in this field. For insulation from the noise outside the building in 80-ties special types of glazing were introduced (SHF gas and glass with different thicknesses). State of the Art: Slovenia 237 2.2 Structural aspects Speaking form structural point of view the period from 1946 to 1980 can be divided in earlier one before 1963 Skopje earthquake and later one after earthquake. Building external walls (i.e. envelope walls) were in earlier period constructed either of clay brick masonry or cast-in-place concrete. In later prefabricated systems were introduced, applying the elements pre-cast by normal or lightweight concrete. In earlier period internal walls were constructed in clay brick masonry mostly as non-load bearing partition walls with some load bearing ones. Learning from the building behaviour during 1963 Skopje earthquake, the number of internal load bearing walls increased giving higher earthquake resistance to buildings. Floor structures of buildings constructed in earlier period were made either from wood or cast-in-place concrete over clay brick blocks. Later floor constructions were made mostly of cast-in-place reinforced concrete. However, in all cases the building envelope plays a major role in providing load bearing and stability of building as well as its earthquake resistance. Therefore, any intervention in envelope including adding of roof construction to flat roofs, have a big influence on load bearing capacity and earthquake resistance of entire structure. This fact can be efficiently used when existing structures undergoes the renovation process. Pre-cast reinforced concrete envelope elements are in many cases deteriorated due to low quality of concrete and surface finishing or inadequate protection of concrete surface (Fig. 19). Corrosion of concrete and steel reinforcement leads to spalling of concrete and propagation of surface damages. More dangerous can be corrosion of metal anchors of pre-cast elements and thus their splitting from the main structural elements of building. This can happen often in case of relatively small pre-cast panels that are fixed to load bearing part of envelope due to freeze – thaw cycles or earthquake or strong wind action. Figure 19. Visible effect of decay of pre-cast reinforced concrete envelope elements and balconies. 2.3 Functional aspects Slovenia did not build many large residential areas also due to scattered population. The resi- dential neighbourhoods offered good environment for inhabitants, new schools, shops, parking areas, public transportation. Private and rented flats were mixed in the same building. The eco- State of the Art: Slovenia 238 nomic power of inhabitants in apartment buildings was relatively unified. There were no low cost dwellings built for poor people. Due to the changed habits of people living in apartment buildings neighbourhoods and aging of the population some typical functional difficulties emerged, like the lack of parking places, accessibility problems in buildings without elevators, lack of living space and subsequently the glazing of balconies. Small floor areas are of course a problem but on the other hand when buy- ing a new flat, due to the high prices, many young families can not even afford a bigger flat. Apartments in post war buildings are competitive on the real estate market, due to slightly lower price. Only rare buildings in urban areas are not centrally heated by now, using either district heat- ing or natural gas. Technically it is possible to increase functionality of the building and apart- ment, respectively, but there are economic barriers and lack of consensus from many new own- ers. The most important investment in the life time of these buildings is the thermal insulation of the envelope and exchange of windows, what contributes to the aesthetics and quality of life in the building. 2.4 Architectural aspects Post war buildings are usually refurbished without preservation of their architectural appear- ance. Only some buildings, designed by established architects, are considered as architectural heritage. Changes of floor plan as a part of retrofit are of course possible if the structural aspect is not affected. Bellow (Fig. 20) there is a theoretical study of possible adaptation of two bed- room post war apartment into a flat corresponding to the quotidian needs of young family (Ši- janec Zavrl et al. 1995). Not many such projects have been realized. Figure 20. Retrofit plan for the residential building in Ljubljana, clay brick structure (Vosnjakova, 1957), existing 2-bedroom apartments (above) could be functionally renewed into small 3 bedroom apartments with sunspaces, closer to the today living habits. State of the Art: Slovenia 239 CONCLUSIONS The existing building stock erected between 1945 and 1980 represents 61% of entire building stock in Slovenia. Therefore, there are a big number of building envelopes to be improved in Slovenia. Roughly half of total number of dwellings in urban areas has floor space in the range of 45 to 74 m 2 . Typical residential buildings in Slovenia have either masonry or reinforcement concrete structure. Envelopes of recently erected buildings are thermo insulated what is not usual case for buildings erected between 1946 and 1980. Existing cases of stochastic approach to envelope alternations shows cases of enlargement of dwellings by closing of open-air terraces and balconies, repairing the deteriorated materials and surfaces, improving the building resis- tance to earthquake action. The economic strength of Slovenian society is fast growing. There- fore more and more interventions in existing envelopes will take place in near future. But the strategy and know how to improve envelope in more efficient and aesthetic way is urgently needed. REFERENCES Boštjancic et al. 1993. Concept of national programme for energy restoration of residential buildings, (in Slovene), Ljubljana: ZRMK, UL FA. Gabrijelcic, P. et al. 2001,. http://www.arh.uni-lj.si/rakovnik/ Gradbeni center Slovenije 1980. Design guidelines for social housing in Slovenia. Ministry of environment, physical planning and energy 2000. National programme of housing. Municipality Ljubljana, 1983. Design guidelines for planning and construction of social housing in Mu- nicipality of Ljubljana, (in Slovene). Ljubljana: MOL. Statistical office of the Republic of Slovenia 2002. Census 2002, http://www.stat.si Šijanec Zavrl, M. et. al. 1995. Concept of energy restoration of residential buildings in Slovenia, Pro- ceedings of International Workshop: Energy Rehabilitation of Residential Buildings in Slovenia, Por- torož, Sept. 19, 1995: pp. 30-40. Ljubljana: ApE. Šijanec Zavrl, M. 1996. Approach to energy refurbishment of residential buildings, De Herde, A. (eds). Building & urban renewal: Proceedings of the thirteenth international PLEA conference, Louvain-la- Neuve, Belgium, July 16-17, 1996: 369-374. Louvain-la-Neuve: Architecture et Climat. Šijanec Zavrl, M., 1996. Expectations and reality in attaining energy saving potential in Slovene residen- tial building stock. Goetzberger, A. and Luther, J. (eds.). EuroSun'96: proceedings EuroSun'96, Freiburg, Germany, 1996: 1131-1135. München, DGS-Sonnenenergie. Šijanec Zavrl, M. & Gruden, T. 1998, Concept of energy restoration of residential buildings in Slovenia, Saving buildings in Central and Eastern Europe : report = rapport = Bericht, (IABSE reports, Vol. 77): 214-215. Zürich: IEMB. Šijanec Zavrl, M et al. 1995. Concept of national programme for energy restoration of residential build- ings, (in Slovene), Ljubljana: ZRMK. Šijanec Zavrl, M., Tomšic, M. & Gruden, T. 2000. Energy-efficient windows and glazing-state subsidies in Slovenia. EuroSun 2000: The Third ISES-Europe Solar Congress, Copenhagen, Denmark, 19- 22June, 2000: 5 pages. Copenhagen: International Solar Energy Society. Šijanec Zavrl, M. & Tomšic, M. 2001. Supporting sustainable restoration of buildings in Slovenia. Žar- nic, R. (ed.), The future of the city: new quality for life: abstracts: 112-115. Ljubljana: UL FGG. Šijanec Zavrl, M. 2002. Approach to energy conscious retrofit of Slovenian building stock, Ed.: A.Zold, M.Lain, S.Petruszko (eds.). Proceedings of Workshops Newly Associated States EnerBuild RTD: 95- 101. Budapest: TU. Zveza stanovanjskih skupnosti 1989. Starting-point for holistic residential reformation in Slovenia, (in Slovene). Žarnic, R. 2001. Building regulations for rehabilitation works and their application in Slovenia. In Carlo Blasi & Luca Giorgi (ed.). The application of existing building regulations in rehabilitation works: Proceedings of the workshop, Florence, 2-3 December 1994: p. 63-76. Luxembourg: Office for Offi- cial Publications of the EC This page intentionally left blank In the last 50 years, society has changed continuously with respect to various factors including age-structure, family composition and the availability of energy. These factors are reflected in building activity, which is gradually shifting from new construction to the reuse and renovation of existing buildings. All over Europe the large housing shortages resulting from World War II have been resolved by constructing large quantities of multifamily housing with a poor technical and functional performance. In order to speed up the building production non-traditional labour saving building methods have been introduced in virtually every European country. As a result, the European housing stock is fairly young with 2/3 of the total housing stock been produced after WW II. The percentage of the housing stock built after World War II varies from country to country. The highest percentage are in The Netherlands (75%), Slovenia, (80%) and FYR of Macedonia (70%). Large similarities in typology can be noticed. The first few decades after the war the prevailing type of building block is three to five stories high and without elevator access. Europe-wide, urban plans for residential areas are laid-out according to the CIAM-principles with parallel or perpendicular building blocks containing small and poorly equipped apartments with an average space of 11-20 m 2 per occupant. By the mid-sixties, in large parts of Europe housing shortages had been finally solved. The focus shifted from quantity to quality and building codes were adapted accordingly. High-rise apartment blocks with elevator access become the prevailing dwelling type for multifamily housing and a sizeable increase in space consumption can be noticed. Europe-wide, the two prevailing building techniques for labour-saving building are a skeleton structure with steel reinforced beams and pillars, and large panel building. The first technique is mainly used in Mediterranean countries, the second one in the northern and eastern parts of Europe. In addition, we find some spine-wall structures, structures erected with in situ concrete and tunnel moulds, and structures erected by stacking prefabricated concrete blocks. Housing policies have greatly influenced the quality of post-war European housing stocks. In the first decades after WW II, many European governments have created legislative frameworks to promote the use of non-traditional, labour saving building techniques. In the seventies, energy savings have been extensively stimulated by granting subventions and by incorporating requirements for thermal insulation in national building codes. Over time, the demands for thermal insulation have continuously been reset on higher levels, although there are large differences noticeable between the various countries in this respect. These differences can not always be explained by differences in climate. Over time, the technical quality of some experimental building techniques proved to be questionable, resulting in moist problems. These problems occur frequently in the post-war apartment stock and can be of various origins. Since any excess of moist may result in health risks for the occupants, they have to be taken seriously and dealt with accordingly. In the first few decades after the war, noise insulation was a topic of little interest. In view of the increasing Conclusions Silvia Brunoro University of Ferrara, Department of Architecture Marie Therèse Andeweg Delft, University of Technology, Department of Real Estate and Housing Conclusions 242 noise levels of heavy traffic, requirements for sound-insulation have been gradually incorporated in the majority of the European building codes. Europe-wide, the demands are nowadays remarkably similar in this respect. Evidently, the post-war European apartment stock is structurally sound. Functionally, however, all over Europe the shortcomings of these parts of the housing stock are experienced in a similar way, although not in every country to the same extent. On an urban scale, social problems like vandalism and high crime rates, caused by the anonymity that results from the size of these areas, are considered to be the major issues. There is also a Europe-wide consensus on the need to improve the poor accessibility of the apartment stock dating from the first few decades after the war. For the refurbishment actions, the experience has been functional to better way of improvement. Time delay was helpful to learn a lesson: a lot of mistakes were made by countries who started many years ago, and nations who started to refurbish later, can learn from the mistakes. In relation to that, a lot of lessons have been learned from countries who could benefit from the experience of countries who started before, such as Poland from Germany. From a technical point of view, the quality of the European building stock has substantially improved over the last few years and, in nations like The Netherlands, the quality can be considered to be good. However, further improvements are needed on the energy performance. From a functional point of view, the quality is very poor, particularly of the early post-war apartments. The overall space is limited, the dimensions of living rooms, bathrooms and balconies are not up to nowadays standards. The staircase- access without elevator makes this part of the stock not suitable for the elderly people in our aging society. High-rise apartments dating from the sixties have a much higher functional quality, are reasonably well equipped, and can be considered to be accessible for senior people in every way. Considering the numerous intervention programs that have been put into action, large efforts have already been made in order to assure that the quality of the European post-war multifamily housing stock keeps pace with the present and future changes in demand. However, post-war apartment blocks form proportionally a large part of the total European housing stock, and there are large discrepancies noticeable between the present demands and the original technical and functional quality of these building blocks. Therefore, further substantial efforts are required in order to assure adequate improvements to nowadays standards. For the last decade, the priority in the intervention programs has been on solving social problems. On a lower scale, the main issues are a further reduction of the energy spill, and the need to obtain better accessibility with respect to changes in the age-profile of the European population. Noticeable improvements have already been achieved on the first topic. Nevertheless, since the demands on energy saving are been reset on ever higher levels, continuous efforts in this respect are required. Although the necessity to improve the accessibility of the early post-war multifamily housing stock seems to be widely acknowledged, so far, the achievements in this respect have been limited. These poor results can largely be attributed to the architectural features of the early post-war apartment blocks. The largest part of the housing stock is multi-family houses, nevertheless there are exceptions, such as in Belgium, where we find public or private rows of file houses developments that find their origin between 1920 and 1940. Tower typology is less diffused, mostly in the centre of Europe (Italy, Germany and France). A particular case is represented by Malta. The definition of the minimum floor areas, suitable for a multitude of needs and adaptable to every situation, is the main cause of the low standards for surface and equipment of flats. The space consumption per person and the number of rooms for apartment varies from country to country according to building regulations, and often in the same country standards has been modified in subsequent periods. In Poland for instance in 1947 a maximum of 11 m 2 of usable floor space per 1 inhabitant (equipped with bath-room, lavatory and kitchen) was indicated, while from 1974 the obligatory dwelling standard for a family of 7 persons was set on a maximum area of 75- 85 m 2 Conclusions 243 In Hungary the average built up area of the flats of the sixties for four persons was 48 m 2 , composed by two bedrooms, small kitchen, no dining area and a sleeping place in the living room. From 1970 flats were bigger, with an average area of 54-63 m 2 for four persons, with two or three small-size bedrooms and no living room. In The Netherlands, until 1960, 2 bedroom (4 persons) and 3 bedroom apartments (up to 6 persons) were the most diffused typology, with an average area of respectively 58 and 68 m 2 , while starting from the sixties apartments comprised in general 3 bedrooms (6 persons and more) with an average area of 85 m 2 . In Slovenia, the guideline for social housing was set on a floor area of 68 m 2 for a family of four in 1957, and in 1983 the guideline for social housing in Ljubljana for a three bedroom apartment was set on 68-78 m 2 . In Macedonia, the building stock of multi-storey family houses built from the sixties varied from 1 to 3 bedrooms with sizes ranging from 48 to 84 m 2 . A larger floor area per inhabitant can be founded in Denmark and France. In Denmark the basic lay-out is formed by a kitchen and 2 rooms. Additions of more rooms to this core gave the bigger ones, with an average size of around 95 m 2 (average number of persons 2). In France, the average size of primary apartments ranges from 90 and 108 m 2 , with an average number of persons per apartment of 2. This means that the average floor space in apartments is around 45 m 2 per person and the mean number of rooms by dwelling is 4. In Italy in the first second post war period, the majority of apartments had little kitchen open in the living - room and two bedrooms with a whole area of 50-60 m 2 From the sixties the floor area was bigger, from 50 to 110 m 2 , depending on the number of rooms (1 to 5). In Portugal, building blocks have two or three bedrooms and a minimal usable floor area ranging from 35 to 134 m 2 . In Greece apartments contain from 1 to 3 bedrooms, a living room, a kitchen and a bathroom with a floor area ranging between 40 and 100 m 2 . As a conclusion, we can say that European post-war apartment stock is characterized by the use of traditional technologies, with small apartments and a few numbers of flats. Usually there is a variable number of staircases for each building, and every staircase has from 3 to 6 flats each level. From the ’60, building technologies are characterized by the large use of prefabricated systems, used in order to meet the social dwelling requirements together with the cost reduction. After the sixties, the interventions become more complex and extended: the village-size buildings are very lacking of public and social spaces, with narrow staircases and elevators, no connection with the surrounding area and little communal possibilities. The technologies used for non traditional post war European housing stock are mainly based on prefabricated construction systems. Looking at the technology used, the European non- traditional housing stock seems to be geographically defined. Main technologies can be synthesized in three typologies which are peculiar of different European areas: - Prefabricated large panels are typical of Northern and Eastern Europe (Sweden, Denmark, Germany, Poland, Hungary); - Load bearing walls technology is largely used in Northern and Central Europe (The Netherlands, Belgium, France). In France and in the Netherlands there are also examples of experimental building systems that made use of stacked prefabricated hollow concrete blocks; - Skeleton structure in situ or prefabricated, in which façades and partition are added are also typical of Mediterranean area; - In addition, we find some outsiders countries, such as Malta, Slovenia and Macedonia, in which the prevalent technologies are brick-wall structures. Also structures erected with in situ concrete and structures based on pre-cast concrete heavy-panel systems are used. Conclusions 244 I group: Northern and Eastern area. Sweden, Denmark, Germany, Poland, Hungary In East-European countries, the development of prefabricated building systems began fairly early in order to speed up the construction process. The previous preparation of the building elements speeded up the time of assembly and increased the quantity of realizations. In this part of Europe, as well as in Sweden and in Denmark, precast large panel technology is the prevailing building technique. Room - sized panels of pre cast concrete were fixed together with in situ concrete or welded steel plates. Light weight prefabricated concrete slabs were used for floors, façades and partition walls. In Sweden, a large part of multi-family houses were built in situ, but in the same decade pre-cast construction became more common. Since 1950 the industrialization of construction started in an effort of large-scale production and minimizing of building costs, started by political resolutions and investments and by the big constructors. Multi family houses built in situ were two to three to four-storey houses, and tower blocks were six to eight storeys high. Prefabrication technique was then rapidly developed during the 1950s and 1960s, and the most common used systems were: room sized slab units, and slab units more than room size. They were used together or combined with in situ constructions. In Poland, the first large-panel multi-house buildings were done in 1957, and from 1967 this technology became as basic for dwelling housing. Two central large-panel systems were elaborated: OWT-67 and WUF-T and provided to country-wide application. Next two (“Szczecin” and W-70) were selected in competition mode. The standard obliged from 1959 didn’t fit modular system necessary for industrialised technology based on pre cast elements. In 1972 new standard was introduced enlarging usable floor space per dwelling and improving possibilities of design. In 1974 a new standard was state, taking into account structural and modular restriction of technology, enlarging total usable floor space. Significant gain of this standard is revision in plus floor space of rooms and kitchens. In Denmark, the typical lay out of apartment blocks in multi-storey buildings is composed by the basic unit of 2 apartments per storey. The smallest of the apartments being just a kitchen and 2 rooms, and additions of more rooms to this core gave the bigger ones. Two ways of construction were dominant: the first was a system with load bearing transverse walls and non- bearing light weight façade elements, the other was a system with load-bearing façades of sandwich type and spine wall. Other systems based on the use of columns, beams, frames etc. are very seldom. Also building blocks with a structure of bearing façades and a spine wall are to be found in Denmark. In Hungary the large panel system was established after the ’56 revolution. The original idea was captured from the Soviet Union, and later from Denmark. Housing estates are mostly composed of 5 or 11 story buildings, built with reinforced concrete panels or light-concrete blocks, or in-situ concrete. Conclusions 245 Table 1: Main typologies in Group I. Northern and Eastern area COUNTRY PERIOD TYPOLOGY FLOOR AREA (m 2 ) Related to rooms N OF FLOORS Sweden 1950-1960 Building block ----- 2/4 Tower ------- 6/8 1950-1980 Building block 72 5/8 and higher Denmark 1946-1980 Building block 95 (3-5 rooms) 4/10-16 Germany 1949-1980 Small multi family ------- 2-4 Big multi family -------- 4-6 1958-1978 High-rising buildings --------- 15 and higher Poland 1947 Building block 11 per inhabitant 4 to 8 1959 Building block 20-71 (1-5 rooms) 4 to 8 1972 Building block 23,5-74,5 (1-5 rooms) 4 to 16 1974 Building block 25-85 (1-5 rooms) 4-5 to 16 Hungary 1960-1969 Building block 48 5-11 1970-1980 Building block 54-63 5-11 Table 2: Main technologies in Group I. Northern and Eastern area COUNTRY PREVALENT TECHNOLOGY Sweden Pre cast large panels; in situ reinforced concrete frame Denmark Pre cast large panels, Building blocks Germany Pre cast large panels, Reinforced concrete frame (on site) Poland Pre cast large panels Hungary Pre cast large panels Whatever load-bearing system is used in these buildings, reinforced concrete slabs is the most diffused technology for floors and roof structure. In Sweden and Denmark, the roof is in general a wooden construction, either as flat or sloped. The most common cladding is in the first case asphalt or gravel, and in the second case tiles or metal. Conclusions 246 Table 3: Floors and roofs in Group I. Northern and Eastern area COUNTRY FLOOR STRUCTURE ROOF STRUCTURE ROOF COVERING Sweden Reinforced concrete slabs Wooden structure Reinforced concrete slabs Sloped: Brick tiles or asbestos cement tiles Flat: Roofing felt Denmark Wooden beams spanning from façade to façade, supported on the spine wall Reinforced concrete slabs Wooden structure Reinforced concrete slabs Sloped: panes of tiles or cement Flat: asphalt felt on boards Germany Reinforced concrete slabs Wooden structure Reinforced concrete slabs Sloped: brick, steel or copper, bituminous material. Flat:, bituminous material steel or copper Poland Pre cast concrete slabs Concrete panels supported on brick walls Flat: asphalt or gravel Hungary For large panels building technologies, façades are the answer of the modular internal configuration of the building. Mostly of the façade surfaces are made by pre cast concrete panels. In Poland, where external longitudinal strip walls are used, spaces between openings (windows or balcony doors) are filled with sandwich panels. These panels with timber frame were made of asbestos-cardboard with thermal insulating layer and chipboard inside. Generally no others cladding or coloring is added, so the final aspect is dark-grey, but sometimes with exposed aggregates or some decorative texture. Other common surface materials are brick, plaster or metal sheets. In Germany, the façade is in most cases fitted with balconies. Table 4: Façades in Group I. Northern and Eastern area COUNTRY FAÇADES Walls Window frames Outside finishing Sweden Brickwork Pre cast concrete panels Wood Concrete, Plaster, Metal sheets Denmark Massive brick masonry Pre cast concrete panels, lightweight panels Wood Plastic, Aluminum Facing bricks Fiber reinforced plaster Germany Massive/perforated brickwork Concrete panels Wood, Metal, Plastic Brick, stone metal or wood coverings Concrete Plaster, Pains Poland Pre cast concrete panels Wood Plaster, Pains Concrete Hungary Pre cast concrete panels Aluminum, PVC Concrete Conclusions 247 II group: Northern and Central Europe area. The Netherlands, Belgium, France In the Northern and Central Europe countries, like The Netherlands, Belgium and France, the main building systems used are mainly based on load bearing walls technologies, built in situ or pre cast. In The Netherlands, the early second post-war period is characterized by small multi family buildings of three or four floors high. Starting from the mid-sixties multi-family housing was mainly realized as high-rise building blocks, containing up to several hundred apartments and up to 10 storey high. Approximately 70 % of the early post-war multi-family housing has been completed with traditional building materials and methods, nerveless the 30% of the Dutch early post-war apartment stock was realized with non traditional building systems, such as: block unit building systems, panel building systems and building systems using in situ concrete. In Belgium, multi storey family housing represents only a limited part of the total existing housing stock. Large neighbourhoods with single housing predominate the multi storey housing buildings: the architectural model was low-rise as well as middle-high and high with a central staircase, lateral corridor, with or without split-levels. Mostly traditional brickwork was applied, concrete pre cast or on-site and very little steel constructions. In France, the average floor space in dwellings/apartments is thus around 42 m 2 per person. The mean number of rooms by dwelling is 4. The more common used system in the mid sixties in multiple dwelling is a load bearing structure composed with reinforced concrete shells arranged according to a parallel layout grid and concrete slabs. This system enables reusable forms and, used with a fixed grid width, the tunnel formwork enables the simultaneous concreting of walls and slab. Although less frequently, this technique has also been used in Italy. Such as in the Netherlands, there are also examples to be found of experimental building systems that made use of stacked prefabricated concrete blocks to form the load bearing walls. Table 5: Main typologies in Group II. Northern and Central area COUNTRY PERIOD TYPOLOGY FLOOR AREA (m2 ) Related to rooms N OF FLOORS The Netherlands 1946-1960 Building block 58-68 (4-5 rooms) 3-4 1960-1980 Building block 85 -100 (5 rooms) 10-18 Belgium 1949-1980 Row houses 51-95 (5 rooms) 2-3 Building Block ------ 4-8 France 1949-1974 Building Block 68-103 (2-4/3-6 rooms) 4-12 1975-1989 Building block 68 -111 (1-5/4-6 rooms) 2-5 Table 6: Main technologies in Group II. Northern and Central area COUNTRY PREVALENT TECHNOLOGY The Netherlands Brickwork, Concrete walls; block unit building systems, panel building systems Belgium Brickwork France Reinforced concrete shells /tunnel formworks/concrete blocks walls Conclusions 248 In general, the flat and sloped roofs are constructed with the same system as used for the construction of the floors. In The Netherlands, the most frequently used floor system in the early post-war housing stock consists of prefabricated non-reinforced concrete beams. Reinforcement is placed between the beams and incorporated in the structure with in situ concrete. Flat and slightly inclined roofs are often finished with two layers of asphalt felt and 4 cm gravel. Sloped roofs are constructed with a deal rafter and finished with roof tiles. In Belgium for floors and roofs structure, mostly wooden rafters and boards, concrete on site, pre cast floor slabs or concrete beams are used. Flat roofs covering is bitumen and sloped roofs covering is tiles or slates, with limited use of zinc or copper plate. Table 7: Floors and roofs in Group II. Northern and Central area COUNTRY FLOOR STRUCTURE ROOF STRUCTURE ROOF COVERING The Netherlands Concrete beams and reinforced in situ concrete (Cusveller floors) Pre cast concrete slabs Pre cast concrete slabs Flat: Two layers of asphalt paper and gravel Slope: Asphalt paper and roof tiles Belgium Wood rafters and boards Reinforced concrete Prefabricated slabs and concrete on site or brick floors Flat: Bitumen cover Sloped: tiles or slates France Reinforced concrete slab Beams and filler blocks Reinforced concrete slab Sloped: tiles In The Netherlands, façades are made of brickwork and constructed as single layer walls, with a clamp-layer added on the inside to improve its water impermeability, or as cavity walls. In Belgium, pre cast concrete façade with different types of fixation and sealing up, were applied with different levels and qualities of industrialisation and standardisation. In France, the tunnel formwork system enables the simultaneous concreting of walls, Also load bearing façades of sandwich panes and spine wall was used. Table 8: Façades in Northern and Central area COUNTRY FAÇADES Walls Window frames Outside finishing Netherlands Concrete block walls Concrete panels Wood Brick Plaster, Concrete panes Belgium Concrete panels Wood, Aluminum Concrete, Plaster France Concrete walls Concrete panels Wood, Metal Stone Plaster, Concrete panes Conclusions 249 III group: Mediterranean area Portugal, Italy, Greece, Cyprus In Mediterranean countries, the main building technology is a bearing structure of steel reinforced concrete beams and pillars of in situ concrete. To this skeleton, façades and partition walls are added, using mostly hollow brick blocks. The floor is usually reinforced concrete slab, but pre-strengthened beams with filling blocks are commonly used. In Italy, starting from the sixties, industrialized building technologies were imported from beyond the Alps and briefly diffused, such as tunnel formworks, pre cast large panels and three-dimensional elements. In these Countries, while the “stone or brick tradition” was still strong, the appeal for industrialized technologies and prefabricated components was initially rejected. In Italy and Portugal, in the first second post war period, buildings are generally small and includes little apartments with simple schemes. In Portugal, for example, the greatest part of the multifamily housing stock of the 50-60 period is building blocks usually composed by two or three dwellings per floor with three or four floors high. In Italy, building blocks of this first period are generally composed with two or three apartments for floor and contain between twenty and seventy apartments, with a medium high (from four to seven floors high). The majority of these apartments have a little kitchen open in the living - room and two bedrooms with a whole area of 50-60 m 2 . After the sixties, when the first prefabrication era began, high rise buildings are typical. The newly developed pre-cast concrete technologies allowed the construction of higher buildings with greater number of floors and dwellings. Building blocks are more extended and have spacious apartments, generally ranging from 80 to 90 m 2 . The number of flats is higher, and generally there are elevators on every staircase. In Italy this period is characterized by the large use of tower typology. In Cyprus and Greece, it is very difficult to find high-rise buildings. In Greece the great majority of these buildings consists of a ground floor and usually three to five floors above it. On each floor there are usually one to four apartments with net floor areas ranging between 40m 2 and 100m 2 . In Cyprus the typical housing construction system is mainly based on the conventional construction system: use of reinforced concrete for the load bearing part of the building, which is completed by masonry walls. A prefabricated system based on preheating moulds was used in a very small proportion of some Government own estates. Table 9: Main typologies in Group III. Mediterranean area COUNTRY PERIOD TYPOLOGY FLOOR AREA (m 2 ) Related to rooms N OF FLOORS Portugal 1950-1960 Multi family 35-134 (4-7 rooms) 3-4 1960-1980 Multi family 60-159 (4-7 rooms) 4 and more Italy 1949-1956 Building block 30-90 (1-5 rooms) 4-7 1957-1963 Building block, Tower 50-110 (1-5 rooms) 6-14 1965-1980 Building block, Tower 64-112 (2-5 rooms) 8-19 and higher Greece 1949-1980 Building block 40-100 (3-6 rooms) Gfloor+3/5storeys Cyprus 1949-1980 Building block ------- 3-6 Conclusions 250 Table 10: Main technologies in Group III. Mediterranean area COUNTRY PREVALENT TECHNOLOGY Portugal Reinforced concrete frame (on site or pre cast) Italy Reinforced concrete frame, Complex formworks Greece Reinforced concrete frame (on site) Cyprus Reinforced concrete frame (on site) The structure of the floors is usually concrete slabs, although in Italy trestle floor beams and hollow floor blocks are largely diffused. In Portugal we find reinforced concrete slabs in the southern part and/or pre-strengthen beams and ceramic (or concrete) molding blocks slabs in the north. Usually the structure is generally the same used for the floors. Flat roofs are usually finished with bitumen or gravel. Slope roofs are finished with roof tiles. Table 11: Floors and roofs in Group III. Mediterranean area COUNTRY FLOOR STRUCTURE ROOF STRUCTURE ROOF COVERING Portugal Reinforced concrete slabs Pre-strengthen beams and ceramic/concrete molding blocks slabs Pre-strengthen beams and ceramic molding blocks slab Slope. Ceramic tiles Flat. Bitumen cover or gravel Italy Reinforced concrete slabs in situ Trestle floor beams and hollow floor blocks Pre cast concrete slabs Reinforced concrete slabs in situ Trestle floor beams and hollow floor blocks Pre cast concrete slabs Slope: Bitumen layer and roof tiles Flat: Bitumen layer or gravel Greece Reinforced concrete Flat. Bitumen layer or gravel Cyprus Reinforced concrete Flat: Light concrete or screed and asphalt. Façades are generally realized in perforated brickwork or, mainly in Italy, prefabricated concrete panels. In Mediterranean countries, when external surfaces are plastered and painted with emulsion paints, light colors are used (white, yellow) mostly in Greece, Cyprus and Portugal. Also ceramic tiles (usually in the shape of bricks), natural stone or, in luxurious buildings, marble are characteristic claddings of these countries. An essential feature of residential buildings in Greece is the balcony, in form of protection. Every apartment above ground level has at least one balcony, generally continuous, which vary in width from a minimum of 0.5m to almost 2.5 m. Also in Portugal and Italy balconies are common. Conclusions 251 Table 12: Floors and roofs in Group III. Mediterranean area COUNTRY FAÇADES Walls Window frames Outside finishing Portugal Single/double leaf hollow brick walls Wood, Aluminum PVC Stone Concrete Plaster, Pains Ceramic tiles Italy Single/double layer hollow brickwork Pre cast concrete panels Aluminum, Plastic Plaster; Paints Cyprus Single layer brickwork Aluminum Plaster; reflective paints Greece Massive/perforated brickwork Wood, Aluminum Plaster; Light color paints or ceramic/stone tiles Outsiders: Malta, Slovenia, Macedonia This part comprehends nations which can’t be gathered in the previous groups, because of their peculiarity. Maltese housing stock represents a particular case in the European outline. Building technology is based on stone tradition, the local indigenous material globigerina limestone, commonly called “franka” stone. All walls are load-bearing with no frame structures, so buildings rarely exceed four floors. The post war housing stock is primarily composed of terraced houses, which are a later development of the typical farmhouse layout of the early planning typology. Apartments are very rare. In Slovenia we find the highest share of apartments, about the 63% of the total housing stock. Typical residential buildings have either masonry or reinforcement concrete structure. The housing systems in Slovenia are influenced by geographic location, availability of local materials and Central European cultural environment. In the early post war period, most of buildings are multi-apartment houses “on-a-string” self standing multi apartment houses with 4 to 6 apartments constructed from clay brick masonry. In late 60-ties and in early 70-ties the living habits changed as did the national building regulations. The prevailing type became the 3- bedroom apartment, the kitchen became smaller, used only for preparation of food, while the family stayed in the living room. A significant number of residential buildings was constructed with cast-in-place reinforced concrete and pre cast technologies. Macedonian building technology of the first post war period is mainly based on classic masonry building systems: massive solid brick structural walls thick 25-38 cm. From 1960 a new pre-cast concrete heavy-panel system was imported from USSR named “Karpos”. Table 13: Main typologies in Malta, Slovenia, Macedonia COUNTRY PERIOD TYPOLOGY FLOOR AREA (m2 ) Related to rooms N OF FLOORS Malta Multi family ----- 2-4 Slovenia 1953-1967 Multi family on a string 63-85 (2-3 rooms) Gfloor+3 floors 1953-1967 Building block 41-63 (3-4 rooms) Gfloor+5/7 floors 1967-1980 Building block 34-103 (3-6 rooms) FYR Macedonia 1949-1960 Multi storey ------- (3-7 rooms) 4-16 1960-1980 Multi storey 31-84 (3-6 rooms) 4-16 Conclusions 252 Table 14: Main technologies in Malta, Slovenia, Macedonia COUNTRY PREVALENT TECHNOLOGY Malta Stone block walls Slovenia Brick walls; reinforced concrete frame, pre cast panel systems FYR Macedonia Brick walls; pre-cast concrete heavy-panel system Floors and roofs technologies are very different, depending on the building technologies. In Macedonia floors are based on three concrete systems: cast reinforced concrete thin-ribs slab system, semi-prefabricated thin-ribs slab system called “Avramenko”, and timber beams over the brick walls. Timber structures are the most diffused technologies for floors and roofs in Malta, and in Slovenia in mostly the early second post war period for masonry buildings. In Slovenia building blocks with concrete technologies have in many cases reinforced concrete slabs floors and reinforced concrete slabs flat roofs. Table 15: Floors and roofs in Malta, Slovenia, Macedonia COUNTRY FLOOR STRUCTURE ROOF STRUCTURE ROOF COVERING Malta Timber structures Timber structures Flat Slovenia Timber structures Reinforced concrete slabs Timber structures Reinforced concrete slabs Sloped Flat FYR Macedonia Reinforced concrete Prefabricated concrete thin-ribs slab system Timber slab construction --------------- Flat. Grey salinity Slope. Ceramic tiles Maltese housing stock façades are characterized by the use of Globigerina “franka” stone in yellow-ochre to rosy colour and texture. In Slovenia masonry buildings of the fifties are generally finished with plaster and paints, while reinforced concrete blocks have in general pre-cast large panel envelope elements. Sometimes dwellings of the seventies are characterized by wooden largely fenestrated façades, open air balconies and terraces. In Macedonia massive solid brick buildings of the fifties have plaster finishing, while pre cast large panels façades are typical after the sixties. Conclusions 253 Table 16: Floors and roofs in Malta, Slovenia, Macedonia COUNTRY FAÇADES Walls Window frames Outside finishing Malta Massive stone walls Wood Globigerina “franka” stone in yellow-ochre to rosy colour and texture Slovenia Massive brick masonry Precast concrete panels Wood Plaster, Pains Concrete FYR Macedonia Massive brick masonry Concrete panels ---------- Plaster, Pains Concrete Housing policies The multistory family houses can be seen as a monument of centralized political resources and power of the post-war period. Interventions were mainly state financed, with great public interest and non profit making associations and builders involved. Building legislation promoted, generally, pre – determined urban plans with pre – figurate volumes, orientation and building dimensions. In most parts of Europe, housing policy laws attributed considerable state financial contribution to building societies for equipping new urban housing developments with public roads, sewage systems, public lighting, etc. Only in a few cases, for example in Greece, interventions were totally delegated to the private sector. By the end of the eighties, the process of privatization of buildings begun: this means that nowadays most of the European social housing buildings are owned by the tenants. Since the 1980’s, many other political and financial initiatives were taken to promote and incentive the housing renovation. Physical aspects A poor physical performance of a dwelling can cause many problems and may even cause serious health risks for the tenants. The problems can be of various origin. Building physics create many problems because of degradation or lack of maintenance, depending on specific climatic conditions and geographical position of different countries. Moisture problems are mainly connected with humidity: condensation on thermal bridges, surface infiltrations, moisture and attack by moulds. They will be discussed according to the subdivision of the format, i.e. thermal insulation, protection against moisture, and noise insulation. Thermal insulation Thermal insulation is Europe-wide a topic of growing importance. This is reflected by the ever higher requirements for the thermal insulation values in the national building codes of the participating countries. The highest demands on thermal insulation values are to be found in Denmark where a maximum U-value of 0,2W/m 2 K is required for outer walls with a weight of less than 100 kg/m 2 . Denmark has a long tradition of saving energy through the application of thermal insulation, considering the fact that in 1961 the maximum U-value was already set on 0,6W/m 2 K for the same construction parts. This last value is lower than the present demands in Mediterranean countries with a hot climate like Cyprus and Greece where U-values of over 1W/m 2 K are still acceptable for new dwellings. Although also being a Mediterranean country, Italy forms a favourable exception, with the maximum U-value presently set on 0.3W/m 2 K. This value equals nowadays demands in Poland, a country with a considerably harsher climate. Protection against moisture Moist problems can be divided according to their origin. Moist problems resulting from insufficient impermeability of façades and roofs, or resulting from poor architectural design are reported from Portugal, Italy, Poland, Greece and France. Moist problems resulting from a lack of ventilation due to the increasing cost of heating can be found all over Europe. In most non- Conclusions 254 traditional building systems as described previously, moist problems caused by thermal bridges in belt courses are fairly common. Thermal bridges may also result from inadequately applied thermal insulation. Finally moist problems may originate from damp rising into foundations and porous walls. Any excess of moist in dwellings results in condensation, dampness and mould, thus causing serious health threats to the occupants of the effected building blocks. Noise insulation Noise insulation is a relatively new topic. The first two decades after the war, demands for adequate sound insulation were not incorporated in the building code of any European country. The first requirements for sound insulation date from 1961 and are to be found in the Danish building code. The insulation for airborne-sound and impact-sound between apartments was here set on a value of 50 dB horizontally and 52 dB vertically. By the mid seventies France, The Netherlands, Poland and Cyprus had similar demands added to their building codes. Portugal followed in 1987. Today, Denmark has the highest demands on sound-insulation with the value for the impact-sound set on a minimum of 58 dB between adjacent dwellings. Insufficient sound insulation may cause a lack of sleep and stress with tenants. Therefore, adequate sound- insulation is nowadays considered to be an important issue for the well being of occupants. In view of the increasing noise levels from heavy traffic and airplanes in densely populated areas, improvements on sound-insulation in the existing housing stock will continue to be a big issue. In the European post-war apartment stock, adaptations to improve its sound deadening capacity are often hampered by the limited height of the living quarters. Structural aspects In general, the European non-traditional post-war multifamily housing stock seems to be structurally sound. In the Portuguese contribution some structural problems are mentioned caused by failing foundations, due to insufficient testing of the bearing capacity of the subsoil. Some structural problems caused by the corrosion of steel bars in the structural elements of the façades have been reported from Poland, Slovenia, and Portugal. Adequate earthquake resistance is only an issue in the south-eastern part of Europe, in Portugal and on the Azores islands. In Greece, most building blocks erected between 1950 and 1980 do not comply with their present requirements for seismic performance. Functional aspects On the scale of the individual dwelling, a lack of space is the main reason for the poor functional quality of the European post-war apartment stock. Solutions are to be found in rearranging floor plans in order to enlarge living areas and bathrooms, or in joining adjacent apartments and create overall larger apartments. In view of the necessity to improve its functional quality to nowadays needs, the building techniques used for erecting the post-war apartment stock are restrictive for the options for its redevelopment. Skeleton structures prove to be very adaptable. Mediterranean countries, where this technique has been used as the main building principle, have little problems in this respect. Spine-wall structures as used in Denmark and France offer also good options for redesign. In East-European countries, where the prevailing building technique is large-panel building with relatively narrow spans, adaptations are far more difficult to achieve. The adaptability of in-situ concrete structures with tunnel moulds as used in France and in the Netherlands from the mid-sixties onwards is also restricted by the width of the spans. These in-situ structures however, have wider spans than the early post-war systems. Safety Europe-wide, for the last few decades living conditions in post-war neighbourhoods have been deteriorating. Social problems like vandalism frequently occur, and crime rates are alarmingly high in these areas. Therefore, on an urban scale a lack of safety seems to be one of the main issues for the wide-scaled renewal of the post-war neighbourhoods. All over Europe Conclusions 255 intervention schemes are focussed on scaling down the size of these vast areas in order to improve social control, on opposing anonymity by adding identity to the individual building blocks and on improving communal life in general with supplementary measures like job schemes. Accessibility In view of the large shift in the age-profile of the European population, as foreseen for the next few decades, adequate accessibility of the apartment stock is an issue of increasing importance. In Malta for instance, recently ‘access for all’ has become mandatory. Poor accessibility is mainly an issue in the European apartment stock that has been produced before the mid-sixties. Improvements on the accessibility are difficult to achieve. The obstacles are numerous and divers. Dimensions of stairway halls are often insufficient to insert an elevator. In Germany, Poland and in the Netherlands, the ground floor in post-war apartment blocks is often elevated half a storey above street level, compelling its occupants to climb at least half a flight of stairs. Due to the high rate of individual ownership, in Slovenia attempts to improve the accessibility of post-war apartment blocks are greatly hampered by a lack of consensus on the investments cost among its occupants. In Denmark adequate accessibility doesn’t seem to be considered as a major issue. Architectural aspects The recognition of the lack of the architectural quality of the post-war apartment stock is unanimous all over Europe. Attempts for improvement are not yet widely spread. From Germany, Sweden, and the Netherlands some examples have been reported. The most common measures for changing the appearance of a building block are by adding mural paintings or coloured plastering on to the façades. The enlargement and glazing-in of small balconies adds functional quality to the individual apartments, as well as making the apartment block as a whole more interesting by embossing its flat façade. The identity of a building block may also be enhanced by redesigning its entrance hall, using expensive materials in striking colours. In many European countries new technologies have been developed, but they have either not yet been translated into practice, or have been only locally used to achieve a higher quality in urban buildings. This results in a limited impact on urban environments. Therefore it is essential to bring all kind of local solutions together, to learn from it and to come to a more general approach that can be used for building systems. To reach best results, it is essential to integrate all the factors influencing urban building envelopes and look at it in a broader scope. This requires the development of new and suitable strategies for local authorities, housing corporations and owners on one hand, and for architects and civil engineers on the other hand, involving a multitude of factors such as: quantitative technical demands, qualitative aspects, social aspects, safety aspects, environmental aspects (including energy use), and modifications in the use of the building. This page intentionally left blank COST C16 Management Committee Belgium Prof. Andre de Naeyer Hogeschool Antwerpen Univ. College Henry vande Velde Design Sciences Mutsaardstraat 31 B-2000 Antwerp +32.3.231 6200 +32.3.231 9604
[email protected] Cyprus Mr. Christos Efstathiades Public Works Department Republic of Cyprus Ministry of Communication & Works Lefkosia +35799597362 +35725332094
[email protected] Cyprus Mr. George Hadjimichael Town Planning & Housing Department Demostheni Severi Avenue 1454 Nicosia +357 22 30 65 92 +357 22 30 65 01
[email protected] Denmark Mr. Jesper Engelmark DTU - Technical University of Denmark Dept. of Civil Engineering Planning and Management of Building Processes DTU Building 118, Brovej 2800 Lyngby +45 45251932 +45 45883282
[email protected] Denmark Prof. Ebbe Melgaard Royal Academy of Fine Arts School of Architecture Philip de Langes Allé 10 1435 København K +45 49147850 +45 32686111
[email protected] F.Y.R. of Macedonia Prof. Kiril Gramatikov St Cyril & Methodius University Faculty of Civil Engineering Dept. of Concrete and Timber Structures UL. Partizanski odredi 24 POB 560 1000 Skopje + 389 2 3116066 ext. 148 + 389 2 3117 367
[email protected] COST C16 Management Committee 258 France Prof. Francis Allard Université de La Rochelle Pôle Sciences et Technologie LEPTAB ave Michel Crépeau F-17042 La Rochelle cedex 1 +33 546 45 82 04 +33 546 45 82 41
[email protected] Germany Mr. Franz Georg Hofmann Federal Ministry of Transport Construction and Housing Merler Allee 11 53125 Bonn +49 228 252500 +49 228 9259 554
[email protected] Germany Mr. Christian Wetzel CalCon Holding GmbH Management Goethestr. 74 80336 Munich +49-(0)89-552698-0 +49-(0)89-552698-75
[email protected] Greece Prof. Charalampos Baniotopoulos ARISTOTLE UNIVERSITY OF THESSALONIKI CIVIL ENGINEERING UNIVERISTY CAMPUS GR-54124 Thessaloniki +302310995753 +302310995642
[email protected] Hungary Dr. Tamás Mezós University of Budapest for Technology and Economics Muegyetem rkp 3 1111 Budapest +36 1 463 2303 +36 1 463 1638
[email protected] Hungary Prof. György Sámsondi Kiss Technical Committee Monitor Szent Istvan University Thököly Str 74 1146 Budapest +36 1 252 1270 +36 1 252 1278
[email protected] Hungary Ms. Agnes Novak Budapest University of Technology and Economics Budapest +36 1 3060 394 +36 27 347 237
[email protected] Italy Prof. Roberto di Giulio University of Ferrara Department of Architecture Via Quartieri 8 44100 Ferrara +39 348 3856993 +39 055 244042
[email protected] Italy Mr. Eugenio Arbizzani Universita degli Studi di Roma "la Sapienza" Facolta di Architettura Valle Giulia Via Gramsci 53 00197 Roma +39 06 49919291 +39 06 49919290
[email protected] Malta Dr. Vincent Buhagiar University of Malta Faculty of Architecture & Civil Engineering Environmental Design Department of Architecture & Urban Design Tal-Qroqq MSD 06 Msida +356 2340 2849 +356 21 333919
[email protected] COST C16 Management Committee 259 Malta Mr. Ruben Paul Borg University of Malta Faculty of Architecture and Civil Engineering Mediterranea, 161, Triq Luigi Billion, Pembroke, Msida, Malta (00356)79055680 (00356)21375185
[email protected] Netherlands Prof. Leo G.W. Verhoef (Chairman) Delft University of Technology Berlageweg 1 2628CR Delft +31.152784179 +31.152781028
[email protected] Netherlands Mr. Frank Koopman (Technical Secretary) Delft University of Technology Faculty of Architecture (room 2.05) Chair Restoration Berlageweg 1 2628 CR Delft +31152784133 +31152781028
[email protected] Poland Prof. Aleksander Kozlowski Rzeszow University of Technology Building Structure Civil Engineering W. Pola 2 Rzeszow Poland 35-959 Rzeszow +48 178541127 +48 178542974
[email protected] Poland Dr. Adam Rybka Rzeszow University of Technology Faculty of Civil and Environmental Engineering Department of Town Planning and Architecture W. Pola 2 35 959 Rzeszow +48 17 8651624 +48 17 8543565
[email protected] Portugal Prof. Luís Bragança Lopes University of Minho School of Engineering Building Physics and Construction Technology Laboratory Azurem 4800-058 Guimaraes +351253510200 +351253510217
[email protected] Slovenia Prof. Roko Zarnic (Vice Chairman) University of Ljubljana Faculty of Civil and Geodetic Engineering Jamova c. 2 1000 Ljubljana +38641777517 +38614250681
[email protected] Slovenia Dr. Jana Selih University of Ljubljana Faculty of Civil and Geodetic Engineering Jamova 2 1000 Ljubljana + 386 1 4768575 + 386 1 2504861
[email protected] COST C16 Management Committee 260 Sweden Prof. Dr. Satish Chandra Gothenburg University Institute of Conservation Box 130 St. Nygatan 23-25 40530 Gothenburg +46 31 7734709 +46 31 7734703
[email protected] United Kingdom Mr. Stephen Ledbetter University of Bath Centre for Window & Cladding Technology Bath +44 1225 826506 +44 1225 826556
[email protected] COST C16 Working Group Members Working Group 1 Cyprus Mr. Petros Lapithis Intercollege Art and Design Department 46 Makedonitissas Avenue Lefkosia CY, Cyprus +357 22 841 571 +357 22 353 682
[email protected] Denmark Mr. Torben Dahl Institute of Technology School of Architecture Royal Danish Academy of Fine Arts Philip de Langes Allé 10 Dk-1435 Copenhagen K, Denmark +45 32 68 62 04
[email protected] F.Y.R. of Macedonia Prof. Kiril Gramatikov St Cyril & Methodius University Faculty of Civil Engineering Dep of Concrete and Timber Structures UL. Partizanski odredi 24 POB 560 1000 Skopje + 389 2 3116066 ext. 148 + 389 2 3117 367
[email protected] France Mr. Dominique Groleau Ecole Nationale Supérieure d'Architecture de nantes Laboratoire CERMA rue Massenet 44300 NANTES +33 2 40 59 21 22 +33 2 40 59 11 77
[email protected] Germany Mr. Christian Wetzel CalCon Holding GmbH Goethestr. 74 80336 Munich +49-(0)89-552698-0 +49-(0)89-552698-75
[email protected] Greece Prof. Ted Stathopoulos Concordia University / Aristotle University Engineering / Computer Science Centre for Building Studies Building, Civil Engineering 541 24 Thessaloniki
[email protected] COST C16 Working Group Members 262 Hungary Dr. Tamás Mezós University of Budapest for Technology and Economics Muegyetem rkp 3 1111 Budapest +36 1 463 2303 +36 1 463 1638
[email protected] Italy Prof. Roberto di Giulio (Chairman) University of Ferrara Department of Architecture Via Quartieri 8 44100 Ferrara +39 348 3856993 +39 055 244042
[email protected] Italy Ms. Silvia Brunoro University of Ferrara Faculy of Architecture via Quartieri 8 44100 Ferrara +39 347 1497462 + 39 0532 293627
[email protected] Netherlands Ms. Marie Therese Andeweg Delft Universiry of Technology Faculty of Architecture Berlageweg 1 2628 CR Delft +31152787912
[email protected] Poland Dr. Zbigniew Plewako Rzeszów University of Technology Faculty of Civil and Environmental Engineering Department of Building Structures ul. W. Pola 2 35-959 Rzeszów +48 602759595 +48 178542974
[email protected] Portugal Prof. Luís Bragança Lopes University of Minho Building Physics and Construction Technology Laboratory School of Engineering Azurem 4800-058 Guimaraes +351253510200 +351253510217
[email protected] Slovenia Dr. Marjana Sijanec Zavrl Building and Civil Engineering Institute ZRMK Dimiceva 12 1000 Ljubljana +386 1 280 8342 +386 1 280 8451
[email protected] Sweden Prof. Dr. Satish Chandra Gothenburg University Institute of Conservation Box 130 St. Nygatan 23-25 40530 Gothenburg +46 31 7734709 +46 31 7734703
[email protected] COST C16 Working Group Members 263 Working Group 2 Belgium Prof. André de Naeyer Hogeschool Antwerpen Mutsaardstraat, 31 2000 Antwerpen +323 231 6200 +323 231 9604
[email protected] Cyprus Mr. George Hadjimichael Town Planning & Housing Department Demostheni Severi Avenue 1454 Nicosia +357 22 30 65 92 +357 22 30 65 01
[email protected] Denmark Prof. Ebbe Melgaard (Chairman) Royal Academy of Fine Arts School of Architecture Philip de Langes Allé 10 1435 København K +45 49147850 +45 32686111
[email protected] F.Y.R of Macedonia Mr. Tihomir Stojkov St Cyril & Methodius University School of Architecture Partizanka b.b. 91000 Skopje
[email protected] France Dr. Gerard Guarracino ENTPE CNRS Department of Civil Engineering & Building Rue Audin 69518 Vaulx en Velin +33472047030 +33472047041
[email protected] Germany Mr. Franz Georg Hofmann Federal Ministry of Transport Construction and Housing Merler Allee 11 53125 Bonn +49 228 252500 +49 228 9259 554
[email protected] Greece Prof. Dimitrios Bikas Aristotle University of Thessaloniki (AUTh) Structural Engineering/Building Construction Dept. of Civil Engineering 541 24 Thessaloniki +(30)2310 995763 +(30)2310 420628
[email protected] Hungary Ms. Agnes Novak Hungary University of Design and Crafts Budapest University of Technology and Economics Budapest +36 1 3060 394 +36 27 347 237
[email protected] Italy Mr. Paolo Civiero Universiy of the Studies of Rome “La Sapienza” Dept. ITACA Via Flaminia, 70 00196 Roma +39 3286223091 +39 0644363083
[email protected] Netherlands Mr. Frank Koopman Delft Universiry of Technology Faculty of Architecture Berlageweg 1 2628 CR Delft +31152784133 +31152781028
[email protected] COST C16 Working Group Members 264 Poland Dr. Adam Rybka Rzeszow University of Technology Faculty of Civil and Environmental Engineering Department of Town Planning and Architecture W. Pola 2 35 959 Rzeszow Poland +48 17 8651624 +48 17 8543565
[email protected] Portugal Prof. Manuela Almeida 23/05/2006 University of Minho School of Engineering Building Physics and Technology Group Civil Engineering Department Azurém 4800-058 Guimarães +351 253 510 200 +351 253 510 217
[email protected] Slovenia Prof. Roko Zarnic University of Ljubljana Faculty of Civil and Geodetic Engineering Jamova c. 2 1000 Ljubljana +38641777517 +38614250681
[email protected] Sweden Prof. Solveig Schulz Chalmers University of Technology Architectural Conservation SE-41296 Göteborg +46(31)7722441 +46(31)7722489
[email protected] COST C16 Working Group Members 265 Working Group 3A Belgium Dr. Filip van Rickstal Catholic University of Leuven Civil Engineering Department Div. Building Materials Kasteelpark Arenberg 40 3001 Heverlee +3216482797 +3216321976
[email protected] Cyprus Mr. Christos Efstathiades Public Works Department Republic of Cyprus Ministry of Communication & Works Lefkosia +35799597362 +35725332094
[email protected] Denmark Mr. Jesper Engelmark DTU - Technical University of Denmark Planning and Management of Building Processes BYG.DTU - Dept. of Civil Engineering BYG.DTU, DTU Building 118, Brovej 2800 Lyngby +45 45251932 +45 45883282
[email protected] F.Y.R. of Macedonia Prof. Kiril Gramatikov St Cyril & Methodius University Faculty of Civil Engineering Dep of Concrete and Timber Structures UL. Partizanski odredi 24 POB 560 1000 Skopje + 389 2 3116066 ext. 148 + 389 2 3117 367
[email protected] F.Y.R. of Macedonia Mr. Zivko Bozinovski (Vice Chairman) St Cyril & Methodius University Institute of Earthquake Engineering and Engineering Seismology P.O.B. 101 Salvador Aljende 73 91000 Skopje +389 2176155 +389 2112163
[email protected] France Prof. Francis Allard Université de La Rochelle Pôle Sciences et Technologie LEPTAB ave Michel Crépeau F-17042 La Rochelle cedex 1 +33 546 45 82 04 +33 546 45 82 41
[email protected] Germany Mr. Claus Asam TU Berlin Institut für Erhaltung und Modernisierung von Bauwerken Berlin +4930399216 +493039921850
[email protected] Hungary Dr. Tamás Mezós University of Budapest for Technology and Economics Muegyetem rkp 3 1111 Budapest +36 1 463 2303 +36 1 463 1638
[email protected] COST C16 Working Group Members 266 Italy Prof. Roberto di Giulio (Chairman) University of Ferrara Department of Architecture Via Quartieri 8 44100 Ferrara +39 348 3856993 +39 055 244042
[email protected] Malta Mr. Ruben Paul Borg University of Malta Faculty of Architecture and Civil Engineering Mediterranea, 161, Triq Luigi Billion, Pembroke, Malta Msida, Malta +35679055680 +35621375185
[email protected] Netherlands Prof. Leo G.W. Verhoef Delft University of Technology Architecture/ Restoration Berlageweg 1 2628CR Delft +31.152784179 +31.152781028
[email protected] Netherlands Ms. Marie Therese Andeweg Delft Universiry of Technology Faculty of Architecture Berlageweg 1 2628 CR Delft +31152787912
[email protected] Poland Mr. Alexander Kozlowski Rzeszow University of Technology Building Structure Civil Engineering W. Pola 2 35-959 Rzeszow Poland +48 178541127 +48 178542974
[email protected] Slovenia Dr. Jana Selih University of Ljubljana Faculty of Civil and Geodetic Engineering Jamova 2 1000 Ljubljana + 386 1 4768575 + 386 1 2504861
[email protected] Sweden Ms. Sonja Vidén School of Architecture Royal Institute of Technology Stockholm Sweden
[email protected] COST C16 Working Group Members 267 Working Group 3B Cyprus Mr. Petros Lapithis Art and Design Department Intercollege 46 Makedonitissas Avenue Lefkosia CY, Cyprus +357 22 841 571 +357 22 353 682
[email protected] Denmark Mr. Torben Dahl Institute of Technology School of Architecture Royal Danish Academy of Fine Arts Philip de Langes Allé 10 1435 Copenhagen +45 32 68 62 04
[email protected] France Mr. Dominique Groleau Ecole Nationale Supérieure d'Architecture de nantes Laboratoire CERMA rue Massenet 44300 NANTES +33 2 40 59 21 22 +33 2 40 59 11 77
[email protected] Germany Mr. Frank Ulrich Vogdt TU Berlin Institut für Erhaltung und Modernisierung von Bauwerken Berlin +4930399216 +493039921850
[email protected] Germany Mr. Christian Wetzel (Vice Chairman) CalCon Holding GmbH Goethestr. 74 80336 Munich +49-(0)89-552698-0 +49-(0)89-552698-75
[email protected] Greece Prof. Ted Stathopoulos Concordia University / Aristotle University Engineering / Computer Science Centre for Building Studies Building, Civil Engineering 541 24 Thessaloniki
[email protected] Hungary Mr. András Zöld
[email protected] Italy Ms. Silvia Brunoro University of Ferrara Faculy of Architecture via Quartieri 8 44100 Ferrara +39 347 1497462 + 39 0532 293627
[email protected] Malta Mr. Vincent Buhagiar University of Malta Faculty of Architecture & Civil Engineering Environmental Design Department of Architecture & Urban Design Tal-Qroqq MSD 06 Msida +356 2340 2849 +356 21 333919
[email protected] Netherlands Mr. Christoph Maria Ravesloot Faculty of Civil Engineering and Geo Sciences Department of Design and Construction Section Design and Construction Processes PO Box 5048 2600 GA Delft 31 15 2781472 31 15 2787700
[email protected] COST C16 Working Group Members 268 Poland Dr. Zbigniew Plewako Rzeszów University of Technology Faculty of Civil and Environmental Engineering Department of Building Structures ul. W. Pola 2 35-959 Rzeszów +48 602759595 +48 178542974
[email protected] Portugal Mr. Ricardo Mateus University of Minho Civil Engineering Department Azurém 4800-058 Guimarães +351 253 510 200 +351 253 510 217
[email protected] Portugal Prof. Luís Bragança Lopes (Chairman) University of Minho School of Engineering Building Physics and Construction Technology Laboratory Azurem 4800-058 Guimaraes +351253510200 +351253510217
[email protected] Slovenia Dr. Marjana Sijanec Zavrl Building and Civil Engineering Institute ZRMK Dimiceva 12 1000 Ljubljana +386 1 280 8342 +386 1 280 8451
[email protected] Sweden Prof. Dr. Satish Chandra Gothenburg University Institute of Conservation Box 130 St. Nygatan 23-25 40530 Gothenburg +46 31 7734709 +46 31 7734703
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