CORTENs STEELReseaRch PaPeR aDRIaNO cLaUDIO scaRFO 547503 abPL 90301. aRchItectURaL FINIshes. 2011 23rd DecembeR 2011. INDIvIDUaL assIgNmeNt + cONteNts cORteN steeL ReseaRch PaPeR_ 02 03-04 05-08 09-12 13 14 abstRact INtRODUctION case stUDY 01 (australian centre for contemporary art) case stUDY 02 (sidney myer asia centre. University of melbourne) DIscUssION bIbLIOgRaPhY .01 PG No _ /16 ___ . JPg therefore when studying corten steel and the differences in appearances of recrystallised oxide which may form.02 PG No _ /16 ___ . the purpose of this report is to provide some basis for conservators to use in considering possible treatments for the care of corten steel structures. lack of drying. all flat surfaces experience more drying (blue. If the steel is not allowed sufficient drying time. red and diffusely reflecting. the appearance of corten steel depends on the extent to which re-crystallisation has occurred and controls the extent to which the barrier layer is formed. . with its use in local and international architecture. and since its appearance will change over time there must be care taken in designing and caring for the material. the early rust forms in isolated crystallites that are fine. INtRODUctION cORteN steeL ReseaRch PaPeR_ corten steel has become a popular façade treatment of recent. the layer which has re-crystallised appears to be blue and reflective. the wetting to generate the rust. cOR-teNb is actually a trade name for the product being discussed in this report. the weathering of corten steel is due to many factors within its environment. as a general note. run-off and so they appear more red. such as the australian centre for contemporary art (acca) and sidney myer asia centre. gloss appearance) and the vertical surfaces experience more wetting due to condensation. the formation of the protective layer requires alternating wetting and drying cycles. almost similar to that of mineral form of iron oxide (specular hematite shown below). and it is once they re-crystallise that they can form into a sealed layer of rust. as it is actually a corrosion resistant low-alloy steel that forms a protective coating of rust (hydrated iron oxide) when exposed in many natural atmospheres. http://earth2geologists. like iron oxide. the cause for such differences stems from the amount of wetting and drying that occur. the rust layer on corten steel is only able to form a protective layer once the fine crystallites of early rust re-crystallise. and the drying to allow it to re-crystallize. most notably in local architecture there has been a celebration of the material in two iconic buildings in melbourne. the resulting continual rusting will cause the partially crystallized outer layer of rust to be shed and will prevent a barrier film from forming.net/grandmanangeology/ mineralPhotos/specular_hematite. the appearance of corten steel can also be affected by other factors. including graffiti. the problems will be reported and solutions proposed. variances in the appearance of corten used in the built environment will be affected by one or a mixture of the weathering factors described previously. chemical cleaning treatments such as acids can convert the hydrated iron oxide to other iron compounds of different colour or appearance.staticflickr.com/6031/6323749257_28 04d2cc9f_z.jpg . In atmospheres with significant content of sulphur oxides deposits of white to yellow ferrous sulphate may appear in the rust on weathering steel. http://farm7. If this material is coloured it will contribute to the appearance of the rust. In some climates organic growth such as moss may be present and affect the appearance of the rust. analysing the case studies and determining the causes of corrision will form the basis of this report.03 PG No _ /16 ___ . In discussion. During re-crystallisation the rust will trap particulate matter on the surface. ephemeral and digitally projected work. case stUDY architects: Wood/marsh PtY LtD architecture Location: victoria. chunky move and Playbox. steel frame and taut metal skin. australia Project Year: 2002 create a strong presence and express with optimism. the predominant vocabulary of the architecture is that of the shed. 01_ australian centre for contemporary art (acca) completed in 2002.com/images/fabio-ongarato/acca-building.jpg . the bold form and materiality of the façade is intended to http://identitydesigned. acca. australia. the australian centre for contemporary art (acca) is a multiuse facility built for the victorian state government in melbourne. to create a unified major presence in the arts precinct surrounding the existing malthouse theatre. coupled with the single dominant cladding material (large insulated trays of corten steel) the sculptural form simultaneously alludes to the industrial age and natural landforms. Pragmatically. the building is designed to make reference to its primary function. Openings in the external fabric are kept to a minimum to support a broad array of installations. the combined wall structure achieves the necessary thermal performance to protect art works in the event that the mechanical equipment fails.04 PG No _ /16 ___ . the project combines the existing infrastructure of three organisations. Referencing the past industrial occupation of the site (warehouses). which is located on the adjacent site. it is a sculpture in which to show art. by disturbing the drying/wetting process the creation and re-crystalisation of rust is missing in the damaged section. 04_engraving of graffiti When engraving the material. 02_Uniform panel (No Damage) With no apparent damage to these panels shown in this image. this image was taken from above head height as below this height there is graffiti and other types of damage.05 PG No _ /16 ___ . 03 04 01 03_chemical Damage the damage shown to this panel is obvious in the colour change of the protective layer formed over the steel. damage to the buildings facade is barely visible. it may serve as a guide to what the original state of the material was intended to be. From a distance. 01_North Facade Overall view of the building with overcast lighting conditions. 02 . which is either a product of cleaning. or liquids being spilt accidently. which the building is meant to be viewed (as a monolithic sculpture). the protective rust layer is removed and will only regenerate with the creation and recrystalisation of rust. 08_graffiti (coloured spray Paint) to remove coloured graffiti a number of layers of the protective coating must be removed. the material is colored so it will affect the appearance of the rust. 05_Panel Join Detail Where the cor-ten panels join. 07_Narrow Panels Design considerations must take into account the narrowness of panels and the affect that this will have on the weathering of the panels. 05 07 06 08 06_graffiti from 0-2 metres (engraved) by locating the material below a reachable height the affects can be seen through the occurence of graffiti.06 PG No _ /16 ___ . . there appears to be a more dramatic removal of the protective layer through weathering. Weathering is more severe in these sections as shown. Where joins occur on the facade this is common. as during recrystallization the rust will trap particulate matter on the surface. 09_covered areas the appearance of the protective layer of rust differs in the two locations shown. and it is the natural formation of rust which will transform the material to its intended form (Which is occuring on this wall. 12_constant damage When items such as the bin in this image are constantly rubbing against and removing the protective layer of rust from the same area. Designation of these items within a site must be located appropiately to avoid such damage. must be considered in the design at an early stage to avoid unwanted variations of colour. although at a slow rate). 10 . then there is no time lapse between damage and repair by the wetting/drying process.07 PG No _ /16 ___ . the second is covered and would receive little if any weathering from water or sunlight as is seen in the colour difference between the two. 10_as above (09) close up view 11 12 09 11_concentration of graffiti Layers of graffiti are seen here. the first is not covered and suceptible to the elements (water. sunlight) which allows the rust process to occur. which might have been an error on the construction or design team.08 PG No _ /16 ___ . or the ponding of water. 13 15 14 16 14_adhesive Damage close-up of damage (16) 16_adhesive Damage Using adhesive tape or other products to attach items to the material will inevitably remove sections of rust and may occur more damaged in sections closer to the join of two sheets of steel. as stated previously. . 15_Water Damage the occurence of water damage in this section may have been caused by internal water leaking. the angle of the material may affect the ability to shed water. and has further discoloured the cor-ten steel by spreading the white paint to other areas previously unaffected. 13_attempted graffiti Removal the use of chemical solvents has not been able to remove the graffiti shown below. the paint will penetrate deep into the rust layer. the sidney myer asia centre is a multipurpose building that responds to a range of functions to serve the needs of both University teaching and exhibition space and the headquarters of an education/ business group. the five simplified houses refer to the five continents. Defined as the sum of makigawa's sculptural career. the creation of the basement theatre provided an opportunity to create a landscaped ramp connection diagonally through the site from a new major grassed open spaced to connect to University buildings to the south that previously were isolated. In this. australia Project Year: 2001 02_ sidney myer asia centre. monumental in its vision. seed pods and buds represent birth and growth. spirit wall draws together symbols he often used.jpg .700 m2 has five levels on swanston street with the theatre located in the basement below. carlier makigawa). created from rusted corten steel by the Japanese-born australian sculptor akio makigawa. University of melbourne Wrapping around the north-eastern corner of the façade at street level is spirit wall.au/__data/assets/image/0007/490093/sidney_myer_asia_centre. spirit wall is a commanding marker to this busy Parkville campus entrance. while the annulus (ring) is the eastern symbol of heaven. http://asialink.unimelb. his final work (makigawa passed away in 1999 and completion was overseen by his wife.edu. the building area of 5. case stUDY architects: Nation Fender Katsalidis architects Location: victoria. asialink. and water symbolises life.09 PG No _ /16 ___ . there is more area for water damage to occur and so run-off will reduce the protective rust layer more so than that of a vertical surface. the area that has had the rust removed will eventually regenerate. 02_Damage from adhesives the use of blue-tak and other adhesives to support posters have left large amounts of weathered patches on the surface. 03 04 01 03_Weathering on angles Where the steel is placed at an angle. 01_Overall view of corten the difference in surface weathering is most obvious in this image. the erosion of rust from beneath the sculpted pieces and streaks also.10 PG No _ /16 ___ . and to avoid such occurences the surface will need to designed accordingly. It is the near horizontal surfaces which will pool water and create a streaking effect. although in this area poster placement is commonplace and degradation may continue. 02 . 04_Water damage the streaking of water may be a desired effect in some circumstances. such as above the window treatment shown above. 08_affect of water on certain forms the curves of this form have created a different form of water streaking. 05_graffiti engraving this was one of only three pieces of graffiti located on this corten steel structure. and it may even be that streaking cant be avoided and must be considered when creating the form of such structures.11 PG No _ /16 ___ . and it may be the program of the building which has discouraged graffiti from being marked on the surface of this building. (02) 05 07 06 08 06_Water Damage (streaking) streaking which occurs on this angle differs from that of image 04. 07_adhesive Damage close-up of adhesive damage to corten surface. . 10 . and the third is the intended state. 11 12 09 11_colour variations this panel has been altered by a chemical solvent as seen by the degradation of the panel. the weathering is light in colour as it is cleared of the protective coating. and it may be desirable to consider a thicker sheet of corten when designing.12 PG No _ /16 ___ . regarding only natural causes. 09_affect to form sharp corners of forms will erode quicker than other forms. 12_affect of water on certain forms the curves of this form have created a different form of water streaking. the second has recovered slightly and has produced rust which is crystalising. 10_Removal of protective layer three distinct layers are uncovered here. with the furtherest left being completely void of rust through erosion. 13 PG No _ /16 ___ . 15_circular Form the curves of this form have created a different form of water streaking. the properties of chalk will allow the graffiti to eventually weather away. and may have happened through a cleaning process. Wetting the panel will create such a problem. 13 15 14 16 14_cleaning Damage Damage to the panel appears to be uniform in its application. and with the use of smaller pieces of the material being used there is less noticable degradation of the material and there is less chance of the material being vandalised. 13_small scale this symbol of heaven (artist's impression) is a sculpted piece. and would be more desirable than engraving the material. 16_graffiti (chalk) Located under a covered area is this chalk graffiti piece. . Wetting the panel will create such a problem. 18_cleaning Damage Damage to the panel appears to be uniform in its application. 17_Water pooling damage (sill) Water will pool on a horizontal surface and when considering corten it is noticable that it will damage the protective coating and remove layers of rust. and may have happened through a cleaning process. 20_Overall view the wall facing swanston street. a fall to the form will help to resolve this issue. 18 . It appears to be of different colour to that of the vertical surface.14 PG No _ /16 ___ . 19 20 17 19_Protuding Form the curves of this form have created a different form of water streaking. eventually this material will need to be replaced. When a layer of protective rust is removed then the steel must lose part of its structure to form a new rust layer. there had not been a significant loss of steel thorugh excessive rusting. then these areas should be sealed or coated to provide protection. as it was a sculpture placed upon an external wall. It was this intricate design which produced findings of inappropriate design crevices or pockets which trap water. It was mostly engraving of the rust and only in two instances was it coloured paint. DIscUssION cORteN steeL ReseaRch PaPeR_ the two case studies had produced some similar findings in natural occurances of weathering. then a solution such as one of water mixed with a small percentage of hydrochloric acid should be used. this solution will not stain the material as such. acca is a building which is located in a less-densly populated area with visibly less security. if the rust were to be removed without a change in some factor in the environment the rust would eventually return to the original discolored appearance. the thickness of the steel sheet at its initial installation and at its time of restoration will affect the solution to restoring the steel to its intended finish. and this in turn will also need treatment at stages in its life cycle. design issues) were only small in one and not the other. In the case of discoloration of rust due to causes other than exessive corrosion. the sidney myer asia centre had a very intricate design. If the rust layer is considered to need a chemical solution applied to fasten the weathering process. or introduce a new finish which will affect the intended aesthetics of the material. although human alterations (graffiti. It is cost effective and easy to apply. the buildings purpose as an art gallery may have played a part in this vandalism. depending on the erosion level caused by any one of the mentioned factors it may vary from one building to another. . the program of the building will affect the connection which the public have with it and should be considered in design. this is a design intention in this case. whether intentional or unwanted.15 PG No _ /16 ___ . however if there was. and may need reinforcement if there has been significant steel loss. although in future buildings this should be considered. some may argue that using a sealer will distrupt the natural formation of rust upon the surface. the continual presence of water leads to excessive corrosion evidenced by rust flaking or observable metal loss. Noticed upon viewing this building was the amount of graffiti located around the perimeter of the building up to about 2 metres. Progress in Organic coatings.com. Retreived 15th December 2011 from < http://archive. 13. Jett. sullivan. volume 15. eight-Year atmospheric corrosion exposure of steels in china. Liang. eichhorn and W.edu. corrosion. January. Retreived 15th December 2011 from < http://www. Nace International. Number 01. L.html>. sidney myer asia centre . m. No. cramer and b.unimelb. 1999. Retreived 15th December 2011 from <http://www.archdaily. volume 55. the properties of oxide and water films formed during the atmospheric exposure of iron and low alloy steels. 8 17 . W.University of melbourne. Pages 125-148 . K. hou and c.31 may 2004. UniNews vol. Issue 2. sculpture trail invites people to enjoy public art treasures at the University of melbourne.com/178260/flashbackaustralian-centre-for-contemporary-art-acca-woodmarsh>. Flashback: australian centre for contemporary art (acca) / Wood/marsh.au/awards_search? option=showaward&entryno=20023072>.uninews. Forker. Nation Fender Katsilidis architects. 26 June 1987.au/ news/1440/index.-J. Nemec.architecture. bIbLIOgRaPhY cORteN steeL ReseaRch PaPeR_ L.16 PG No _ /16 ___ .