Ncma Tek Manual Parts 1-5

NCMA TEKNational Concrete Masonry Association an information series from the national authority on concrete masonry technology ASTM SPECIFICATIONS FOR CONCRETE MASONRY UNITS Keywords: absorption, ASTM specifications, calcium silicate brick, compressive strength, concrete brick, dimensions, face shell and web thickness, gross area, net area, specifications, testing, water absorption TEK 1-1E Codes & Specs (2007) 2003 and 2006 editions of the International Building Code (IBC) (refs. 1, 2), as well as the most current ASTM edition. Code officials will commonly accept more current editions of ASTM standards than that referenced in the code, as they represent more state-of-the-art requirements for a specific material or system. INTRODUCTION The most widely-used standards for specifying concrete masonry units in the United States are published by ASTM International. These ASTM standards contain minimum requirements that assure properties necessary for quality performance. These requirements include items such as conformance to specified component materials, compressive strength, permissible variations in dimensions, and finish and appearance criteria. Currently, seven ASTM standards apply to units intended primarily for construction of concrete masonry walls, beams, columns or specialty applications (see Table 1). The letter and first number of an ASTM designation is the fixed designation for that standard. For example, ASTM C 55 is the fixed designation for concrete building brick. The number immediately following indicates the year of last revision (i.e., ASTM C 55-06 is the version of C 55 published in 2006). ASTM standards are required to be updated or reapproved at least every five years. If the standard is reapproved, the reapproval date is placed in parentheses after the last revision date. Because significant changes can be introduced into subsequent editions, the edition referenced by the building code or by a project specification can be an important consideration when determining specific requirements. Also note that it may take several years between publication of a new ASTM standard and its subsequent reference by a building code. For this reason, Table 1 includes the editions referenced in the LOADBEARING CONCRETE MASONRY UNITS— ASTM C 90 As the most widely-referenced of the ASTM standards for concrete masonry units, ASTM C 90 is under continuous review and revision. The bulk of these revisions are essentially editorial, although two recent major changes are discussed here. In 2006, the minimum face shell thickness requirements were modified for units 10-in. (254-mm) and wider. Prior to ASTM C 90-06 (ref. 2), two minimum face shell thicknesses for these units were listed: • a standard thickness, 13/8 in. for 10-in. units, 11/2 in. for 12-in. and greater (35 mm for 254-mm units and 38 mm for 305-mm and greater), and • a reduced thickness that can be used when the allowable loads in empirical design are correspondingly reduced. Similarly, in the engineered design methods (allowable stress design and strength design), capacity is automatically reduced as the section properties are reduced. With the introduction of ASTM C 90-06, the two sets of face shell thicknesses were replaced with one minimum thickness requirement (see Table 2). In 2000, a prior change was made to ASTM C 90, removing the Type I (moisture-controlled) and Type II (non moisturecontrolled) unit designations which is reflected in the ASTM C 90 editions adopted by the 2003 and 2006 editions of the Table 1—ASTM Specifications for Concrete Masonry Units ASTM Edition referenced in Type of unit: Designation: the 2003 IBC: the 2006 IBC: Most current edition: Concrete Building Brick C 55 C 55-01a C 55-03 C 55-06 Calcium Silicate Brick C 73 C 73-99a C 73-99a C 73-05 Loadbearing Concrete Masonry Units C 90 C 90-01a C 90-03 C 90-06b Nonloadbearing Concrete Masonry Units C 129 C 129-99aA C 129-01A C 129-06 B Catch Basin and Manhole Units C 139 N/A N/AB C 139-05 Prefaced Concrete Units C 744 C 744-99 C 744-99 C 744-05 Concrete Facing Brick C 1634 N/AB N/AB C 1634-06 A Although not directly referenced in the IBC, C 129 is referenced in Specification for Masonry Structures (refs. 17, 18) B This standard is not referenced in the IBC. 1 TEK 1-1E © 2007 National Concrete Masonry Association (replaces TEK 1-1D) IBC. The designations were withdrawn because they were difficult to effectively use and enforce, and because of newly developed concrete masonry crack control provisions. The new crack control guidelines are based on anticipated total volume changes, rather than on the specified moisture contents that formed the basis for Type I requirements. Because the Type designations no longer influenced recommended control joint spacing or other crack control strategies, Type designations were removed. Control joint criteria can be found in References 5 and 6. Physical Requirements Physical requirements prescribed by ASTM C 90 include dimensional tolerances, minimum face shell and web thicknesses for hollow units, minimum strength and maximum absorption requirements, and maximum linear shrinkage. Overall unit dimensions (width, height and length) can vary by no more than ± 1/8 in. (3.2 mm) from the standard specified dimension. Exceptions are faces of split-face units and faces of slump units which are intended to provide a random surface texture. In these cases, consult local suppliers to determine achievable tolerances. Molded features such as ribs, scores, hex-shapes and patterns must be within ± 1/16 in. (1.6 mm) of the specified standard dimension and within ± 1/16 in. (1.6 mm) of the specified placement on the mold. For dry-stack masonry units, the physical tolerances are typically limited to ± 1/16 in. (1.6 mm), which precludes the need for mortaring, grinding of face shell surfaces or shimming to even out courses during construction (ref. 7). Minimum face shell and web thicknesses are those deemed necessary to obtain satisfactory structural and nonstructural performance. Note that although there are some unique face shell thickness requirements for split-faced units (see Table 2 Table 2—ASTM C 90 Minimum Thickness of Face Shells and Webs for Hollow Units (ref. 3) Web thickness Nominal Face shell Equivalent width thicknessB, C, web thickness, of units, minimum, WebsB, C, D in./linear ftE in. (mm) in. (mm) in. (mm) (mm/linear m) 3 3 3 (76.2) & 4 (102) /4 (19) /4 (19) 15/8 (136) 6 (152) 1 (25)D 1 (25) 21/4 (188) 1 D 8 (203) 1 /4 (32) 1 (25) 21/4 (188) 1 1 10 (254) and greater 1 /4 (32) 1 /8 (29) 21/2 (209) A Average of measurements on a minimum of 3 units when measured as described in Test Methods C 140. B When this standard is used for units having split surfaces, a maximum of 10% of the split surface is permitted to have thickness less than those shown, but not less than 3/4 in. (19.1 mm). When the units are to be solid grouted, the 10% limit does not apply and Footnote C establishes a thickness requirement for the entire face shell. C When the units are to be solid grouted, minimum face shell and web thickness shall be not less than 5/8 in. (16 mm). D The minimum web thickness for units with webs closer than 1 in. (25.4 mm) apart shall be 3/4 in. (19.1 mm). E Equivalent web thickness does not apply to the portion of the unit to be filled with grout. The length of that portion shall be deducted from the overall length of the unit for the calculation of the equivalent web thickness. footnote B), ground-face units (i.e., those ground after manufacture) must meet the face shell thickness requirements contained in the body of Table 2. In addition to minimum permissible web thicknesses for individual webs, the specification also requires a minimum total thickness of webs per foot of block length. When evaluating this equivalent web thickness, the portion of a unit to be filled with grout is exempted from the minimum requirement. This provision avoids excluding units intentionally manufactured with reduced webs, including bond beam units and open-end block, where grout fulfills the structural role of the web. For a unit to be considered a solid unit, the net cross-sectional area in every plane parallel to the bearing surface must be at least 75% of the gross cross-sectional area measured in the same plane. Minimum face shell and web thicknesses are not prescribed for solid units. The net area used to determine compressive strength is the “average” net area of the block, calculated from the unit net volume based on water displacement tests described in ASTM C 140 (ref. 8). For cored units having straight-tapered face shells and webs, average net area approximately equals the net cross-sectional area at the block mid-height. Gross and net areas of a concrete masonry unit are shown in Figure 1. Net area compressive strength is used for engineered masonry design, taking into account the mortar bedded and grouted areas. Compressive strength based on gross area is still used for masonry designed by the empirical provisions of IBC Section 2109. Maximum permissible water absorption is shown in Table 3. Absorption is a measure of the total water required to fill all voids within the net volume of concrete. It is determined from the weight-per-unit-volume difference between saturated and oven-dry concrete masonry units. Because absorption measures the water required to fill voids, aggregates with relatively large pores, such as some lightweight aggregate, would have a greater absorption than dense, nonporous aggregates, given the same compaction. As a result, lightweight units are permitted higher absorption values than medium or normal weight units. Because concrete masonry units tend to contract as they dry, ASTM C 90 limits their potential drying shrinkage to 0.065%, measured using ASTM C 426, Standard Test Method for Linear Drying Shrinkage of Concrete Masonry Units (ref. 9) 9). Finish and Appearance Finish and appearance provisions prohibit defects that would impair the strength or permanence of the construction, Gross area* (shaded) = width (actual) x length (actual) Net area* (shaded) = net volume (actual) height (actual) = (% solid) x (gross area) * For design calculations, a masonry element's section properties are based upon minimum specified dimensions instead of actual dimensions. Figure 1—Gross and Net Areas 2 but permit minor cracks incidental to usual manufacturing methods. For units to be used in exposed walls, the presence of objectionable imperfections is based on viewing the unit face or faces from a distance of at least 20 ft (6.1 m) under diffused lighting. Five percent of a shipment may contain chips not larger than 1 in. (25.4 mm) in any dimension, or cracks not wider than 0.02 in. (0.5 mm) and not longer than 25% of the nominal unit height. Similarly, the specification requires that color and texture be specified by the purchaser. An approved sample of at least four units, representing the range of color and texture permitted, is used to determine conformance. CONCRETE BUILDING BRICK—ASTM C 55 ASTM C 55-03 (ref. 10) included two grades of concrete brick: Grade N for veneer and facing applications and Grade S for general use. In 2006, however, the grades were removed from C 55 and requirements for concrete brick used in veneer and facing applications were moved into a new standard: C 1634 (see below). ASTM C 55-06 (ref. 11) now applies to concrete building brick only, defined as concrete masonry units with: a maximum width of 4 in. (102 mm); a weight that will typically permit it to be lifted and placed using one hand; and an intended use in nonfacing, utilitarian applications. Requirements for C 55-06 building brick include: • 2,500 psi (17.2 MPa) minimum compressive strength (average of three units), • 0.065% maximum linear drying shrinkage, • 75% minimum percent solid, and • maximum average absorption requirements of 13 pcf for normal weight brick, 15 pcf for medium weight brick and 18 pcf for lightweight brick (208, 240 and 288 kg/m3). The finish and appearance section of C 55-06 only addresses defects which might affect placement or permanence of the resulting construction. CONCRETE FACING BRICK—ASTM C 1634 The introduction of this new standard in 2006 reflects the rise in popularity of concrete brick used in architectural facing applications. A facing brick (C 1634) is distinguished from a building brick (C 55) primarily by its intended use. ASTM C 1634 (ref. 12) defines a concrete facing brick as a concrete masonry unit with: a maximum width of 4 in. (102 mm); a weight that will typically permit it to be lifted and placed using one hand; and an intended application where one or more faces of the unit will be exposed. Compression and absorption requirements are listed in Table 4. Linear drying shrinkage, dimensional tolerances and finish and appearance requirements are similar to those in C 90, with the exception that chip size is limited to + 1/2 in. (13 mm). The minimum permissible distance between any core holes in the brick and the edge of the brick is 3/4 in. (19 mm), as it is in C 55. Both C 1634 and C 55 refer to C 140 for compression testing, which requires compression test specimens to have a height that is 60% + 10% of its least lateral dimension, to minimize the potential impact of specimen aspect ratio on tested compressive strengths. NONLOADBEARING CONCRETE MASONRY UNITS—ASTM C 129 ASTM C 129 (ref. 13) covers hollow and solid nonloadbearing units, intended for use in nonloadbearing partitions. These units are not suitable for exterior walls subjected to freezing cycles unless effectively protected from the weather. ASTM C 129 requires that these units be clearly marked to preclude their use as loadbearing units. Minimum net area compressive strength requirements are 500 psi (3.45 MPa) for an individual unit and 600 psi (4.14 MPa) average for three units. CALCIUM SILICATE FACE BRICK—ASTM C 73 ASTM C 73 (ref. 14) covers brick made from sand and lime. Two grades are included: • Grade SW—Brick intended for use where exposed to temperatures below freezing in the presence of moisture. Minimum compressive strength requirements are 4,500 psi (31 MPa) for an individual unit and 5,500 psi (37.9 MPa) for an average of three units, based on average gross area. The maximum water absorption is 15 lb/ft3 (240 kg/m3). • Grade MW—Brick intended for exposure to temperatures Table 3—Strength and Absorption Requirements for Concrete Masonry Units, ASTM C 90 (ref. 3)A Oven-dry density Maximum water Minimum net area Weight of concrete, lb/ft3 (kg/m3) absorption, lb/ft3 (kg/m3) compressive strength, psi (MPa) classification Average of 3 units Average of 3 units Individual units Average of 3 units Individual units Lightweight Less than 105 (1,680) 18 (288) 20 (320) 1,900 (13.1) 1,700 (11.7) Medium weight 105 to less than 125 (1,680 - 2,000) 15 (240) 17 (272) 1,900 (13.1) 1,700 (11.7) Normal weight 125 (2,000) or more 13 (208) 15 (240) 1,900 (13.1) 1,700 (11.7) A Note that ASTM C 90-01a does not include requirements for maximum water absorption of individual units. Otherwise, the requirements are identical between C 90-03 and C 90-06b. Table 4—Strength and Absorption Requirements for Concrete Facing Brick, ASTM C 1634 (ref. 12) Oven-dry density of concrete, Density lb/ft³ (kg/m³) classification Average of 3 units Lightweight less than 105 (1,680) Medium weight 105 (1,680) to less than 125 (2,000) Normal weight 125 (2,000) or more Minimum net area compressive strength, psi (MPa) Average of Individual 3 units units 3,500 (24.1) 3,000 (20.7) 3,500 (24.1) 3,000 (20.7) 3,500 (24.1) 3,000 (20.7) Maximum water absorption, lb/ft³ (kg/m³) Average of Individual 3 units units 15 (240) 17 (272) 13 (208) 15 (240) 10 (160) 12 (192) 3 ASTM C 90-06b.. National Concrete Masonry Association.. Standard Specification for Concrete Facing Brick Brick. and dimensional tolerances.000 psi (20.. TEK 10-3. ASTM International. Standard Specification for Calcium Silicate Brick (Sand-Lime Brick) Brick). ASTM C 129-06. ASTM C 55-03.. 17.. ASTM C 744-99. 2006. 8.. 2006. with a minimum gross area compressive strength of 2. 2. cleansability. 2006. 1999. 2005. National Concrete Masonry Association. color permanence. 2002. ASTM C 140-03. 1999. 11. 2003.. Standard Test Method for Linear Drying Shrinkage of Concrete Masonry Units Units. Virginia 20171 www. Standard Specification for Concrete Building Brick Brick.7 MPa) for an individual unit and 3. ASTM International. 2006. 2006.1-05/ASCE 6-05/TMS 602-05. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. ASTM C 1634-06. ASTM International. ASTM C 73-99a. Specification for Masonry Structures Structures. ASTM International. International Building Code 2003. National Concrete Masonry Association. Standard Specification for Loadbearing Concrete Masonry Units Units. 2003..below freezing. 10.1-02/ASCE 6-02/TMS 602-02.. The maximum water absorption is 18 lb/ft3 (288 kg/m3).1 MPa) for an average of three units. 16. Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units Units. Facing requirements in C 744 include: resistance to crazing. REFERENCES 1. 4. Specification for Masonry Structures Structures.. For the concrete masonry units onto which the surface is molded. 15. International Code Council. Minimum compressive strength requirements are 3. 2003. 2006. 5. Units are required to be at least 5 in. 2003.org To order a complete TEK Manual or TEK Index. and a maximum water absorption of 10 pcf (16 kg/m³) (average of 3 units). TEK 10-2B. Control Joints for Concrete Masonry Walls Walls—Alternative Alternative Engineered Method. ASTM International. ASTM C 55-06.. as appropriate. Reported by the Masonry Standards Joint Committee. 12. 2005. Standard Specification for Nonloadbearing Concrete Masonry Units Units. Standard Specification for Loadbearing Concrete Masonry Units Units. 3. surface burning characteristics. CONCRETE MASONRY UNITS FOR CATCH BASINS AND MANHOLES—ASTM C 139 ASTM C 139 (ref. TEK 14-22. 16) covers solid precast segmental concrete masonry units intended for use in catch basins and manholes. but unlikely to be saturated with water... Control Joints for Concrete Masonry Walls Walls—Empirical Empirical Method Method.500 psi (24. 7. (127 mm) thick. International Code Council. PREFACED CONCRETE AND CALCIUM SILICATE MASONRY UNITS—ASTM C 744 ASTM C 744 (ref. Standard Specification for Concrete Brick Brick. 2003. International Building Code 2006.500 psi (17 MPa) (average of 3 units) or 2. abrasion.. 18. chemical resistance. 6. ASTM C 139-05. 14. ACI 530. ASTM C 426-06. C 90 or C 129. ACI 530. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 15) for prefaced units establishes requirements for the facing materials applied to masonry unit surfaces. C 744 requires compliance with the requirements contained in ASTM C 55. Standard Specification for Concrete Masonry Units for Construction of Catch Basins and Manholes Manholes. ASTM International.000 psi (13 MPa) for an individual unit.. 2003. adhesion. Standard Specification for Prefaced Concrete and Calcium Silicate Masonry Units Units. Herndon. ASTM International.ncma. 9. ASTM International. based on average gross area. 2005. ASTM International. Reported by the Masonry Standards Joint Committee. 13. Design and Construction of Dry-Stack Masonry Walls Walls. ASTM C 90-03. ASTM International.. The overall unit dimensions must be within ± 3% of the specified dimensions. ASTM International. contact NCMA Publications (703) 713-19004 . ." These articles do not become a part of the contract documents unless action is taken by the designer to include a requirement in the supplemental specifications. which accompanies the MSJC Specification. In addition to these three parts. Several articles of the MSJC Specification are prefaced with the phrase "when required.An information series from the national authority SPECIFICATION FOR MASONRY STRUCTURES on concrete masonry technology TEK 1-2C Codes & Specs (2010) INTRODUCTION Specification for Masonry Structures (MSJC Specification) (ref. the IBC typically amends or modifies some provisions. references other NCMA TEK which describe the various provisions in greater detail. 3) are based primarily on the MSJC Code and Specification. 1) is a national consensus standard intended to be incorporated by reference into the contract documents of masonry construction projects. Products and Execution) is described in the following sections. specifications 1 5 . They are not a mandatory part of the Specification. The document is formatted to allow the designer to modify those provisions which include a choice of alternatives. storage and handling of materials. When adopting the MSJC Code and Specification. and notes differences between the 2008 MSJC Specification and the 2009 IBC. The checklists identify the decisions that must be made when preparing any supplemental specifications. Because significant changes can be introduced into subsequent editions of both the MSJC and the IBC. testing and inspection. The advantages of a standard specification include consistency. the edition referenced by the local building code can be an important consideration when determining the specific requirements to be met. construction. Construction includes requirements for masonry placement. Compliance with this Specification is mandatory for structures designed in accordance with Building Code Requirements for Masonry Structures (MSJC Code) (ref. and clean- Related TEK: 1-3C NCMA TEK 1-2C ing.. quality assurance. outlines updates incorporated into the 2008 edition of the MSJC Specification. Note that building officials will often accept design and construction standards which are more current than those referenced in the applicable code. 2). A Commentary. Thus. bonding and anchorage. checklists are included at the end of the MSJC Specification to help the designer prepare the contract documents. as they represent more state-of-the art requirements for the specific material or system.. explains the mandatory requirements and further clarifies the Specification's intent. Modifications are considered to be a supplemental specification to the MSJC Specification. as well as provisions for quality assurance. and the placement of grout. THE MSJC SPECIFICATION The MSJC Specification covers material requirements. The document is written in the three-part section format of the Construction Specifications Institute. construction.. The masonry design and construction provisions in Chapter 21 of the International Building Code (IBC) (ref. This TEK provides a broad overview of the MSJC Specification's content. Each of the three parts (General. Other articles are prefaced with the phrase "unless otherwise required. the MSJC Specification may be tailored to meet the specific needs of a project. coordination and understanding among all parties involved." These articles are a part of the contract documents unless the designer takes Keywords: building codes. reinforcement and prestressing tendons. Compressive Strength Evaluation of Concrete Masonry (ref. These material properties are primarily references to applicable ASTM standards. Updates to 2008 MSJC Specification From the 2005 edition of the MSJC Specification to the 2008 edition. Columns were added to the tables to define the frequency of inspection for the various items. To avoid potential confusion. adhered veneer requirements (choice of two methods to determine adhesion). 2. which includes quality control measures as well as testing and inspection. The reinforcement used for stirrups and lateral ties that are terminated with a standard hook is now limited to a maximum reinforcing bar size of No. the unit strength table for concrete masonry implied 2 that the minimum compressive strength of units could be less than the 1. respectively. and • reinforcement fabrication requirements. PART 1—GENERAL Part 1 of the MSJC Specification covers: • definitions. Self-Consolidating Grout for Concrete Masonry (ref. additional submittals may be required. for more detailed information.1 MPa) required by ASTM C90. 5 (M# 16). metal accessories and other accessories such as movement joint materials. 12).6A (see TEK 3-8A. Table 2 was revised to reflect a minimum unit compressive strength of 1. and also within Article 2. Standard Specification for Mortar for Unit Masonry (ref. 6)). MSJC Level B corresponds to IBC Level 1 and MSJC Level C corresponds to IBC Level 2. storage and handling requirements. for more detailed information). mortar. Steel Reinforcement for Concrete Masonry (ref. These provisions are essentially the same as those in the MSJC Specification. • delivery. In prior editions of the MSJC Specification. Tables 3. Part 1 also includes new provisions addressing the addition of self-consolidating grout to the MSJC specification.5 of that code. prestressing tendons. • system description. f'm. The 2008 Specification includes minor modifications to the provisions for verifying compliance with the specified compressive strength of masonry. for more detailed information). • mortar and grout mixing requirements. 7) for further information. New inspection tasks in the tables are: • verification of the grade. • submittals. • referenced standards. All-Weather Concrete Masonry Construction (ref.specific action to modify the article in the supplemental specifications. 11).9). Concrete Masonry Construction (ref. If the designer wishes to specify a higher level of quality assurance. 5). • quality assurance. which includes a minimum list of required submittals. 3. reinforcement. Updates to 2008 MSJC Specification The Part 2 provisions were not greatly modified between the 2005 and 2008 editions of the MSJC Specification.1 A via ASTM C270. MSJC Level A requirements correspond to the basic inspection requirements performed by the building official as required in Section 110. compressive strength determination (choice of two methods). for further information. and • verification of the grade and size of prestressing tendons and anchorages for Level B quality assurance. Concrete Masonry Inspection (ref.3 of the IBC. and 12-4D.1 MPa). and • cold weather and hot weather construction requirements (see TEK 3-1C. IBC Inspection Requirements The International Building Code inspection requirements are almost identical to the MSJC requirements but are organized a little differently. because of the difficulty of bending. ASTM Specifications for Concrete Masonry Units (ref. 13). Standard Specification for Loadbearing Concrete Masonry Units (ref 8). type and size of anchor bolts prior to grouting for Levels B and C quality assurance. using the unit strength method.900 psi (13. 4 and 5 which define Level A Quality Assurance. ASTM C1314-07. PART 2—PRODUCTS Part 2 of the MSJC Specification covers: • required material properties for masonry units. NCMA TEK 1-2C 6 . which includes: 1. The services and duties of the testing agency. Level B Quality Assurance and Level C Quality Assurance. found within Article 2. grout. The special inspection requirements of IBC for masonry are found in Section 1704. 10). 4).900 psi (13. Standard Test Method for Compressive Strength of Masonry Prisms (ref. See TEKs 1-1E. IBC Section 2105 addresses quality assurance of masonry. inspection agency and contractor are included here (see TEK 18-3B. placing and developing larger diameter bars in typical masonry construction. via one of the referenced standards. Such prisms are addressed only to a minor extent within the MSJC Specification. with the exception that the IBC addresses testing prisms from constructed masonry. compressive strength requirements. were revised. See TEK 18-1A. See TEK 9-2B. Concrete Masonry Construction (ref. Levels of Quality (ref. including site tolerances (see TEK 3-8A. allowing foundation dowels that interfere with masonry unit webs to be bent up to 1 in. such as ASTM C90. Grouting Concrete Masonry Walls (ref. 15) for detailed guidance). MSJC Specification Article 3. (152 mm) of vertical height. as long as the grout meets the specified slump. 14)). Execution. • bracing. (25 mm) horizontally for each 6 in. Anchors and Ties for Masonry (ref. Grouting Concrete Masonry Walls (ref. several MSJC reference standards. several changes have been incorporated into the Part 3 provisions..8(d) is a new provision. terminating the grout at least 11/2-in. 13)).As in Part 1. To help ensure structural continuity between subsequent grout pours. • procedures for prestressing tendon installation and stressing (see TEK 3-14. Post-Tensioned Concrete Masonry Wall Construction (ref. (38mm) grout key (i. most of the text of these requirements was removed from the IBC and a simple reference was made to the 2008 MSJC. many of the provisions of the 2005 MSJC requirements were reiterated in the IBC. and • cleaning (see TEK 8-4A. Updates to 2008 MSJC Specification In addition to changes addressing self-consolidating grout. IBC Construction Requirements IBC Section 2104 addresses masonry construction procedures. which simply requires bracing to be designed and installed to assure stability (see TEK 3-4B. 18)). See TEK 9-2B. IBC Masonry Material Requirements IBC Section 2103 addresses masonry construction materials. ties and anchors (see TEK 12-1A. • masonry erection. Standard Specification for Loadbearing Concrete Masonry Units. • field quality control requirements. such as 1. dealing with foundation dowels and with grouting procedures. In the 2006 IBC. though several Articles. 17)). covers: • inspection prior to the start of masonry construction. • grout placement (see TEK 3-2A. Bracing Masonry Walls During Construction (ref. Cleaning Concrete Masonry (ref. which essentially references the MSJC Specification without modification. • preparation of reinforcement and masonry prior to grouting (see TEK 3-2A. 7) for further information. 16)). and the requirements are essentially the same as in the corresponding MSJC Specification.5A of the MSJC Specification requires that grout be placed within 11/2 hours from the introduction of water into the mix.e. 14)). PART 3—EXECUTION Part 3. which is not addressed in the MSJC Specification. specifically address this topic. • placement of reinforcement. In the 2009 IBC however. Additionally.6 D Sample Panels and 3. The 2008 edition exempts transitmixed grout from this requirement. Article 3. Grout keys may not be formed within masonry bond beams or lintels. as well as to NCMA TEK 1-1E ASTM Specifications for Concrete Masonry Units and TEK 8-4A Cleaning Concrete Masonry. NCMA TEK 1-2C 3 7 .5F now requires a 11/2-in. Part 2 also includes new provisions addressing the addition of self-consolidating grout to the MSJC Specification. 19). This provision is similar to that used in reinforced concrete construction.3 F Site Tolerances certainly may affect such. The IBC does include a provision for surface bonding mortar however. Further guidance may be found by including reference to state standards such as Arizona Masonry Guild Standard 107. Article 3. Self-Consolidating Grout for Concrete Masonry (ref. (38-mm) below a mortar joint) when the previous grout lift has set before the next lift is poured.4 B. FINISH AND APPEARANCE The MSJC Specification addresses structural requirements only and not finish or appearance. TEK 3-4B. ASTM C270-07a. 13. National Concrete Masonry Association. International Building Code. ASTM C1314-07. TEK 3-2A. Post-Tensioned Concrete Masonry Wall Construction. Reported by the Masonry Standards Joint Committee. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. Levels of Quality. TEK 18-3B. 2005. National Concrete Masonry Association. 2001. Specification for Masonry Structures. National Concrete Masonry Association. 2007. ASTM International. 9. National Concrete Masonry Association. 2002. 11. ASTM International. 2007. National Concrete Masonry Association. Arizona Masonry Guild. Reported by the Masonry Standards Joint Committee. 6. 2006 and 2009. 4. Virginia 20171 www. 2005. Concrete Masonry Inspection. TEK 18-1A. International Code Council. National Concrete Masonry Association. TEK 3-8A. NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. 19. 2005. Cleaning Concrete Masonry. 10. Standard Test Method for Compressive Strength of Masonry Prisms. 5.ncma. Bracing Masonry Walls During Construction. Building Code Requirements for Masonry Structures. contact NCMA Publications (703) 713-1900 Provided by: 4 NCMA TEK 1-2C 8 . Compressive Strength Evaluation of Concrete Masonry. Herndon. Standard Specification for Mortar for Unit Masonry. 2002. ASTM Specifications for Concrete Masonry Units. 2007. TEK 1-1E. 2009. 16. ASTM C90-09. Standard Specification for Loadbearing Concrete Masonry Units.1/ASCE 6. 2004. ASTM International. TEK 9-2B. 2007. 8. 2005 and 2008. TEK 12-1A. 2005 and 2008. TMS 602/ACI 530. Grouting Concrete Masonry Walls. 17. 12. Standard AMG 107-98. National Concrete Masonry Association. 2007.org To order a complete TEK Manual or TEK Index. National Concrete Masonry Association. National Concrete Masonry Association. National Concrete Masonry Association. Anchors and Ties for Masonry. 15.REFERENCES 1. 7. Concrete Masonry Construction. National Concrete Masonry Association. 14. TMS 402/ACI 530/ASCE 5. TEK 3-14. National Concrete Masonry Association. All-Weather Concrete Masonry Construction. 2001. 1998. 2. 3. Steel Reinforcement for Concrete Masonry. 12-4D. Self-Consolidating Grout for Concrete Masonry. 2006. TEK 8-4A. 18. TEK 3-1C. Because significant changes can be introduced into subsequent editions of both the MSJC and IBC. the IBC masonry design and construction provisions are based primarily on Building Code Requirements for Masonry Structures (MSJC code) (refs. sound insulation and energy efficiency are not addressed in the MSJC documents. To help determine which code provisions apply and highlight changes of note. N a t i o n a l p r o c e s s Consensus process MSJC Code and Specification adoption with modifications and additions International Building Code adoption. quality assurance. The MSJC code covers the design of concrete masonry. this TEK outlines the major modifications to the MSJC code and specification made in the 2003 and 2006 IBC. However. 7). Note that the scope of the MSJC code and specification covers structural design and construction. stone masonry. which governs masonry construction requirements and quality assurance provisions (see also TEK 1-2B. 2). modifications can be made to the IBC at the state or local level to better suit local building practices or design traditions. 4) and Specification for Masonry Structures (MSJC specification) (refs. The code adoption process is shown schematically in Figure 1. most state codes require that any modifications to the IBC be more stringent than the corresponding requirement in the IBC. requirements for items such as fire resistance. With this in mind. ref. as well as the principal changes made between the 2002 and 2005 editions of the MSJC code and specification. possibly with modifications State/ local process State or Local Building Code Figure 1—Masonry Structural Code Development Process 9 TEK 1-3C © 2007 National Concrete Masonry Association (replaces TEK 1-3B) . The 2003 International Building Code (ref. Hence. 3.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology BUILDING CODE REQUIREMENTS FOR CONCRETE MASONRY TEK 1-3C Codes & Specs (2007) Keywords: building codes. 3. 5. 5). construction. the IBC typically amends or modifies some provisions. 6). depending on state laws. as well as masonry veneer. 1) adopts by reference the 2002 editions of the MSJC code and MSJC specification (refs. specifications INTRODUCTION 2003 INTERNATIONAL BUILDING CODE The majority of jurisdictions in the United States adopt a national model code. as they represent more state-of-the-art requirements for a specific material or system. The intent of the IBC is to reference and coordinate other standardized documents. rather than to develop design and construction provisions from scratch. most commonly the International Building Code (IBC) (refs. masonry design. as the basis of their building code. 1. In adopting the MSJC code and specification. the edition referenced by the local building code can be an important consideration when determining the specific requirements to be met. Similarly. Note that code officials will often accept more current design and construction standards than those referenced in the code. clay masonry. glass unit masonry. The MSJC code requires compliance with the MSJC specification. 1. including prescriptive shear wall reinforcement (see TEK 14-18A. 9) and transition from Seismic Performance Categories to Seismic Design Categories (SDCs) (see TEK 14-18A. • new veneer anchor placement requirements (see TEK 3-6B. rather than the 1998 edition (ref. B or C. (203 mm). Strength Design For masonry designed using strength design procedures. ref. In addition.197 MPa) to a wind speed of 110 mph (145 km/h) three-second gust. ref. the IBC and MSJC empirical requirements are essentially the same. • revised cold weather construction requirements. or six times the thickness of the flange for in-plane bending of flange walls. except that the IBC also includes: • an exception allowing shear walls of one-story buildings to be a minimum of 6 in. • modifies welded and mechanical splice requirements (see ref. 18) referenced by the MSJC. and • revisions to the types of masonry veneer permitted to be supported by wood construction (see TEK 3-6B. and • adds maximum reinforcement percentage for special posttensioned masonry shear walls. • provisions for empirically-designed surface-bonded masonry walls. • for empirical design. See TEK 12-4D (ref.2. • modifies the minimum required lap splice length for reinforcing bars (Note that development length and corresponding lap splice length requirements have changed frequently in recent years. Differences Between the 2003 IBC and the 2002 MSJC The 2002 editions of the MSJC code and specification are included in their entirety (by reference) in the 2003 IBC. revised allowable flexural tension values for unreinforced grouted masonry elements when subjected to flexural tension perpendicular to the bed joints. Construction and Quality Assurance Specification revisions included: • new corrosion protection requirements for joint reinforcement. ref. • for empirical design. 15).1. Masonry Design Changes to masonry design provisions included: • for the design of masonry structures. ref. Allowable Stress Design For masonry designed using allowable stress design procedures. 9). anchors and ties depending on their intended use or exposure conditions (see TEK 12-4D. 8). (152 mm) thick. C. the IBC: • sets a maximum width for the equivalent stress block of six times the nominal thickness of the masonry wall or spacing between reinforcement (whichever is less).8 m2) and assigned to Seismic Design category A. • revised seismic design requirements. 13). 10). The most significant of these are summarized below. porches. rather than 8 in. but not identical between the IBC and MSJC. 14). D. • the addition of grout demonstration panels as a means of meeting grout pour requirements (see TEK 3-2A. • for allowable stress design. including new protection procedures for grouted masonry (see TEK 3-1C. The IBC modifies several areas of the MSJC code and specification applicable to concrete masonry. updates included in the 2002 edition are summarized below. 12). 12) for more detailed information. revised shear wall spacing requirements (see TEK 14-8A. the 2002 MSJC code included new strength design provisions (see TEK 14-4A. ref. 12).The 2002 MSJC Code and Specification Compared to earlier editions of the MSJC code and specification. • sets a maximum reinforcing bar size based on the size of the cell or collar joint where the reinforcement is placed (see ref. E and F. applicable to SDCs B. 11). sheds or similar structures with a maximum area of 450 ft2 (41. 17). However. • the IBC includes prescriptive seismic requirements for posttensioned masonry shear walls. • new prestressed masonry quality assurance provisions for Level 2 (moderate) and Level 3 (rigorous) programs (see TEK 18-3B. and • sets a limit on the amount of reinforcement permitted in the in-plane direction for special reinforced masonry shear walls. Seismic Design Requirements • The IBC bases loads on ASCE 7-02 (ref. NCMA recommends using the lap splice requirements published in the 2006 IBC. and 10 . Empirical Design The IBC includes empirical design procedures within the body of the code and references the MSJC code as an alternate means of compliance. and • updating of ASTM C 270 (ref. the IBC: • modifies load combinations to be based on IBC section 1605. • modifies minimum inspections required during construction. 11). ref. 12).). • new prohibition on the use of wall ties with drips (bends intended to inhibit moisture migration from one masonry wythe to the other). ref. ref. rather than those in MSJC code section 2. and • the IBC has some more stringent seismic requirements than the MSJC. • includes separate design requirements for columns used only to support light-frame roofs of carports. which are not included in the MSJC. ref. quality assurance provisions are close. offering a design method in addition to allowable stress design and empirical design. 16) mortar specification tables to include mortar cement. revised wind speed threshold from a design wind pressure of 25 psf (1. ref. 12) for more detailed information. the absence of reinforced bond beams between the top and bottom of the grout pour. NCMA recommends using the lap splice requirements published in the 2006 IBC. • the modulus of rupture for in-plane bending is now the same as that for out-of-plane bending. The first section below highlights the major changes between the 2002 and 2005 MSJC code and specification. • new provisions for noncontact splices have been added. 11 . For masonry veneers. respectively in the 2005 edition. 2 and 3. In addition to the modifications listed under the 2003 IBC (which are also included in the 2006 IBC unless noted below). using the same requirements historically employed for allowable stress design.). This change in nomenclature is wholly editorial and does not affect the requirements specified for each level.e. rather than on allowable stress design with strength checks.). the maximum grout lift height has been increased from 5 ft to 12 ft-8 in (1. a horizontal construction joint formed by stopping the grout pour 11/2 in. design and construction provisions for autoclaved aerated concrete (AAC) appear in the MSJC for the first time. In the 2002 MSJC documents. the IBC prescribes a maximum reinforcement percentage. rather than ASCE 7-02. and • provisions for computing effective compression width have been added. • For grouted masonry. (38 mm) below a mortar joint. Strength Design For masonry designed using strength design procedures: • the 2005 MSJC code includes explicit bearing strength provisions. The most significant of these are summarized below. The following section summarizes important changes between the 2005 MSJC and the 2006 IBC. Differences Between the 2006 IBC and the 2005 MSJC The 2005 editions of the MSJC code and specification are included in their entirety (by reference) in the 2006 IBC. • Design loads and load combinations are based on ASCE 7-05 (ref. the 2006 IBC modifies several areas of the MSJC code and specification applicable to concrete masonry. (254 and 279 mm). 4. the three levels of quality assurance were designated Levels 1.5 to 3. the 2005 edition includes the following changes and additions. 12) for more detailed information. • the maximum reinforcement limits have been modified. and new prescriptive requirements have been introduced for areas with high winds (wind speeds between 110 and 130 mph (177 and 209 km/hr)).9 m) under controlled conditions. making the design procedures easier to use for those accustomed to strength design of prestressed concrete. In addition. NCMA recommends using the lap splice requirements published in the 2006 IBC. i. Allowable Stress Design For masonry designed using allowable stress design procedures: • the use of the one-third increase in allowable stresses has been tied to specific load combinations. For grouted masonry. such as a consistent grout slump between 10 and 11 in. applicable in the in-plane direction. 6). Empirical design includes several revisions to the limitations that define where empirical design can be used. which were replaced by Levels A. making the corbel requirements independent of the design procedure used. prescriptive seismic requirements have been modified (several requirements that previously applied in SDC D and higher now apply in SDC E and higher). • Development length and minimum lap splice length for reinforcing bars has been updated to 48 bar diameters for Grade 60 steel. 19). Other Revisions The post-tensioned masonry design provisions have been updated. The most significant change is that design is now based on strength design with serviceability checks.• additional parapet wall requirements. • the minimum required lap splice and development lengths for reinforcing bars are the same for allowable stress design and strength design (Note that development length and corresponding lap splice length requirements have changed frequently in recent years. 2006 INTERNATIONAL BUILDING CODE The 2006 International Building Code (ref. See TEK 12-4D (ref. 14) for further information. See TEK 12-4D (ref. See TEK 12-4D (ref. See TEK 3-2A (ref. with some exceptions. covering flashing and copings. 12) for more detailed information. The 2005 MSJC Code and Specification Compared to the 2002 edition of the MSJC code and specification. 2) adopts by reference the 2005 editions of the MSJC code and MSJC specification (refs. the IBC requires a "grout key" between grout pours. and a minimum masonry curing time of 4 hours prior to grouting. • For certain special reinforced masonry shear walls. • the minimum required lap splice and development lengths for reinforcing bars are the same for allowable stress design and strength design (Note that development length and corresponding lap splice length requirements have changed frequently in recent years. based on less restrictive assumptions that are related directly to the expected seismic ductility demand. Prescriptive requirements for corbelled masonry have been moved from the empirical design chapter to Chapter 1. B and C. and • in-plane allowable flexural tension has been changed from zero to be the same value as for out-of-plane flexural tension. 11. Specification for Masonry Structures. National Concrete Masonry Association. 3. ASCE 7-05. ASTM International. 2005. 15. All-Weather Concrete Masonry Construction. 13. Minimum Design Loads for Buildings and Other Structures. 2006. 12 contact NCMA Publications (703) 713-1900 . International Building Code 2006. International Code Council. TEK 1-2B. Building Code Requirements for Masonry Structures. Specification for Masonry Structures. 2006. Concrete Masonry Inspection. National Concrete Masonry Association. 9. 4. National Concrete Masonry Association. 2. Minimum Design Loads for Buildings and Other Structures. National Concrete Masonry Association. 16. 2001. 2002. TEK 3-1C.1-05/ASCE 6-05/TMS 602-05. 17. National Concrete Masonry Association. 10. National Concrete Masonry Association. TEK 3-2A. TEK 3-6B. 2003.REFERENCES 1. 2002.ncma. ASCE 7-98. Reported by the Masonry Standards Joint Committee. 2002. International Building Code 2003. Reported by the Masonry Standards Joint Committee. 6. ACI 530-02/ASCE 5-02/TMS 402-02. ASTM C 270-99b. Grouting Concrete Masonry Walls. TEK 18-3B. National Concrete Masonry Association. 19. 2003. Strength Design of Concrete Masonry. 2006. Reported by the Masonry Standards Joint Committee. Standard Specification for Mortar for Unit Masonry. National Concrete Masonry Association. 14. ACI 530. 2005. 2005. Specification for Masonry Structures. 1999. 2002. TEK 14-18A.1-02/ASCE 6-02/TMS 602-02. 2005. Inc. Prescriptive Seismic Reinforcement Requirements for Masonry Structures. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. 5. Empirical Design of Concrete Masonry Walls. 2005. American Society of Civil Engineers. 7. 8. TEK 14-4A. Minimum Design Loads for Buildings and Other Structures. Steel Reinforcement for Concrete Masonry. National Concrete Masonry Association. 18. 1998. American Society of Civil Engineers. ASCE 7-02. Building Code Requirements for Masonry Structures. ACI 530-05/ASCE 5-05/TMS 402-05. Virginia 20171 www. International Code Council.. Concrete Masonry Veneers. ACI 530. Herndon. TEK 12-4D. 2004. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 12. Reported by the Masonry Standards Joint Committee. American Society of Civil Engineers. 2002. TEK 14-8A.org To order a complete TEK Manual or TEK Index. tie. Adhesive anchor : An anchoring device that is placed in a predrilled hole and secured using a chemical compound. [3] Aggregate: An inert granular or powdered material such as natural sand. mortar. grout and reinforcement. Blended cement: Portland cement or air-entrained portland cement combined through blending with such materials as blast furnace slag or pozzolan. crushed stone. terminology “A” block: Hollow masonry unit with one end closed by a cross web and the opposite end open or lacking an end cross web. This includes the total area of a section perpendicular to the TEK 1-4 Codes & Specs (2004) direction of the load. aggregate and cementitious materials added to concrete. Area. grout or mortar. designed to primarily resist flexure. expressed as weight of water per cubic foot of concrete.”) Absorption: The difference in the amount of water contained within a concrete masonry unit between saturated and ovendry conditions. Bond beam block: A hollow unit with depressed webs or with "knock-out" webs (which are removed prior to placement) to accommodate horizontal reinforcement and grout. based on out-to-out dimensions and neglecting the area of all voids such as ungrouted cores. May be used as an alternative to portland cement in mortar. Burnished block: (See “Ground face block.”) Bedded area: The surface area of a masonry unit that is in contact with mortar in the plane of the mortar joint. steel framing or wood framing. See reference 6 for illustrations and descriptions of common masonry bond patterns. glossary. open spaces. masonry. Sometimes referred to as a relieving angle. [1] Beam: A structural member. Backing: The wall or surface to which veneer is secured. adhered. May be cast. Bond beam: (1) The grouted course or courses of masonry units reinforced with longitudinal bars and designed to take the longitudinal flexural and tensile forces that may be induced in a masonry wall. (3) To connect wythes or masonry units. concrete masonry unit. mortar or grout to improve one or more chemical or physical properties. slag. Also used as a shelf to vertically support masonry veneer. which is usually fly ash. [1] Area.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology GLOSSARY OF CONCRETE MASONRY TERMS Keywords: definitions. The backing material may be concrete. stability or a unique visual effect created by laying units in a prescribed pattern. Bond: (1) The arrangement of units to provide strength. (2) A horizontal grouted element within masonry in which reinforcement is embedded. [1] Axial load: The load exerted on a wall or other structural element and acting parallel to the element’s axis. An example of an accelerator material is calcium nitrite. expanded or fastened into masonry. Arch: A vertically curved compressive structural member spanning openings or recesses. net cross-sectional: The area of masonry units. Blast furnace slag cement: A blended cement which incorporates blast furnace slag. Used as a lintel to support masonry over openings such as doors or windows in lieu of a masonry arch or reinforced masonry lintel. which. but may be otherwise depending on the type and orientation of the element. manufactured sand. Axial loads typically act in a vertical direction. [1] Angle: A structural steel section that has two legs joined at 90 degrees to one another. Admixture: Substance other than prescribed materials of water. (2) The physical adhesive or mechanical binding between masonry units. fines and lightweight aggregate. (See “Open end block. Anchor: Metal rod. [4] Accelerator: A liquid or powder admixture added to a cementitious paste to speed hydration and promote early strength development. grout and mortar crossed by the plane under consideration. or any other area devoid of masonry. Bond breaker: A material used to prevent adhesion between two surfaces. consolidate and compact shapes when manufacturing concrete masonry units. May also be built flat by using special masonry shapes or specially placed units. [3] Air entraining: The capability of a material or process to develop a system of uniformly distributed microscopic air bubbles in a cementitious paste to increase the workability or durability of the resulting product. typically horizontal. bolt or strap used to secure masonry to other elements. gravel. when bound together by a cementitious matrix forms concrete. Some admixtures act as air entraining agents. gross cross-sectional: The area delineated by the out-toout dimensions of masonry in the plane under consideration. (See also “Concrete block. masonry unit”) Block machine: Equipment used to mold. including areas within cells and voids. Block: A solid or hollow unit larger than brick-sized units. 13 TEK 1-4 © 2004 National Concrete Masonry Association . [1] (See also “Cavity. pozzolans and ground granulated blast furnace slag. mortar and grout in accordance with ref. stack: For structural design purposes. Damp-proofing: The treatment of masonry to retard the passage or absorption of water or water vapor. [3] Cleanout/cleanout hole: An opening of sufficient size and spacing so as to allow removal of debris from the bottom of the grout space. [2] (See also “Specified compressive strength of masonry. pozzolanic or other finely divided mineral admixtures or other reactive admixtures. sawed or tooled in a masonry structure to regulate the location and amount of cracking and separation resulting from dimensional changes of different parts of the structure. (2) For the purposes of design. water and may contain admixtures. Curing: (1) The maintenance of proper conditions of moisture and temperature during initial set to develop a required strength and reduce shrinkage in products containing portland cement. the binder is a mixture of portland cement. sometimes filled with mortar or grout. It is generally placed near grade to prevent upward 14 migration of moisture by capillary action. Cull: A masonry unit that does not meet the standards or specifications and therefore has been rejected. thereby avoiding the development of high stresses. (2) The initial time period during which cementitious materials gain strength. jack-on-jack and checkerboard bond. [1] Compressive strength: The maximum compressive load that a specimen will support divided by the net cross-sectional area of the specimen. (See also “Coping block. a relatively long.Bond. Larger in size than a concrete brick. or strut. Concrete block: A hollow or solid concrete masonry unit. determined by testing masonry prisms or as a function of individual masonry units. jack bond. includes anchors. either by application of a suitable coating or membrane to exposed surfaces or by use of a suitable admixture or treated cement. [1] Composite action: Transfer of stress between components of a member designed so that in resisting loads. bevels or slopes to facilitate drainage. An example is steel that is galvanized after fabrication. Concrete masonry unit: Hollow or solid masonry unit. Brick: A solid or hollow manufactured masonry unit of either concrete. Bond. Typically located in the first course of masonry. curved over an arch. an isolated vertical member whose horizontal dimension measured at right angles to the thickness does not exceed 3 times its thickness and whose height is greater than 4 times it thickness. chimney or pilaster to protect the masonry below from water penetration. In general. Connector: A mechanical device for securing two or more pieces. Column: (1) In structures. tie: A metal device used to join wythes of masonry in a multiwythe wall or to attach a masonry veneer to its backing. slender structural compression member such as a post. called center or half bond. Course: A horizontal layer of masonry units in a wall or. the following are considered cementitious materials: portland cement. hydraulic cements. Usually vertical. or a mixture of such materials that sets and develops strength by chemical reaction with water. pillar.”) Cavity: A continuous air space between wythes of masonry or between masonry and its backup system. May be either structural or nonstructural. water and aggregate (usually a combination of fine aggregate and coarse aggregate) with or without admixtures. Also called plumb joint bond. May contain ridges. chemically stable admixture that gives a cementitious matrix its coloring. (51 mm) in thickness. (51 mm) in thickness. pier. Damp check: An impervious horizontal layer to prevent vertical penetration of water in a wall or other masonry element. 2. In portland cement concrete. Cementitious material: A generic term for any inorganic material including cement. [2] Cold weather construction: Procedures used to construct masonry when ambient air temperature or masonry unit temperature is below 40°F (4. Cantilever: A member structurally supported at only one end through a fixed connection.”) Cell: The hollow space within a concrete masonry unit formed by the face shells and webs. Coping: The materials or masonry units used to form the finished top of a wall. the combined components act together as a single member. Cap block: A solid slab used as a coping unit. manufactured using low frequency. Typically greater than 2 in. The opposite end has no structural support. high amplitude vibration to consolidate concrete of stiff or extremely dry consistency. clay or stone. a column supports loads that act primarily in the direction of its longitudinal axis. running: The placement of masonry units such that head joints in successive courses are horizontally offset at least onequarter the unit length. Coping block: A solid concrete masonry unit intended for use as the top finished course in wall construction. Corbel: A projection of successive courses from the face of masonry. color fast. [1] (See also “Anchor.”) Concrete: A composite material that consists of a water reactive binding medium.4°C). A horizontal offset between head joints in successive courses of one-third and one-quarter the unit length is called third bond and quarter bond. hydrated lime. Concrete brick: A concrete hollow or solid unit smaller in size than a concrete block. much less commonly. wall ties and fasteners.”) Color (pigment): A compatible. Bond strength: The resistance to separation of mortar from masonry units and of mortar and grout from reinforcing steel and other materials with which it is in contact. A damp check consists of either a course of solid masonry. straight stack. size and location of cracking in masonry including reinforcing steel. Typically less than 2 in. is the most common form of running bond. metal or a thin layer of asphaltic or bituminous material. . stack bond typically refers to masonry laid so head joints in successive courses are vertically aligned. parts or members together. [1] Connector. Collar joint: A vertical longitudinal space between wythes of masonry or between masonry wythe and backup construction.”) Corrosion resistant: A material that is treated or coated to retard corrosive action. Also called core. [1] In common use. [1] Core: (See “Cell.”) Control joint: A continuous unbonded masonry joint that is formed. respectively. (See “Collar joint. Building Code Requirements for Masonry Structures considers all masonry not laid in running bond as stack bond. [1] Centering head joints over the unit below. Crack control: Methods used to control the extent. Compressive strength of masonry: Maximum compressive force resisted per unit of net cross-sectional area of masonry. control joints and dimensional stability of masonry materials. lime putty. Eccentricity: The distance between the resultant of an applied load and the centroidal axis of the masonry element under load. fire resistance is most often determined based on the masonry’s equivalent thickness and aggregate type. low lift: The technique of grouting as the wall is constructed. to cause rainwater to drip off and prevent it from penetrating the wall. followed by height and then length. high lift: The technique of grouting masonry in lifts for the full height of the wall. specified: The dimensions specified for the manufacture or construction of a unit.5 mm). [1] Glazed block: A concrete masonry unit with a permanent smooth resinous tile facing applied during manufacture. (2) The surface of a unit designed to be exposed in the finished masonry. brick. A grout pour consists of one or more grout lifts. Grouting. that may form on the surface of stone. [5] Face shell mortar bedding: Hollow masonry unit construction where mortar is applied only to the horizontal surface of the unit face shells and the head joints to a depth equal to the thickness of the face shell. A grout pour consists of one or more grout lifts. [2] Grout. hot gases and heat when subjected to a standardized fire and hose stream test. actual: The measured size of a concrete masonry unit or assemblage. In new construction. joint or element. Grout lift: An increment of grout height within a total grout pour. Ground face block: A concrete masonry unit in which the surface is ground to a smooth finish exposing the internal matrix and aggregate of the unit. Nominal dimensions are usually stated in whole numbers.”) Header: A masonry unit that connects two or more adjacent wythes of masonry. Dry stack: Masonry work laid without mortar. Footing: A structural element that transmits loads directly to the soil. Fire resistance: A rating assigned to walls indicating the length of time a wall performs as a barrier to the passage of flame. Effective height: Clear height of a braced member between lateral supports and used for calculating the slenderness ratio of the member. typically 3/8 in. or multiwythe construction in which the space between wythes is solidly filled with grout. concrete or mortar when moisture moves through the masonry materials and evaporates on the surface. Face: (1) The surface of a wall or masonry unit. (9. but not greater than 4 to 6 ft (1. [1] Effective thickness: The assumed thickness of a member used to calculate the slenderness ratio. Grout: (1) A plastic mixture of cementitious materials.219 to 1. depending on code limitations. prestressing: A cementitious mixture used to encapsulate bonded prestressing tendons. Grout. . Equivalent thickness: The solid thickness to which a hollow unit would be reduced if the material in the unit were recast into a unit with the same face dimensions (height and length) but without voids. [1] Dowel: A metal reinforcing bar used to connect masonry to masonry or to concrete. Full mortar bedding: Masonry construction where mortar is applied to the entire horizontal surface of the masonry unit and the head joints to a depth equal to the thickness of the face shell. causing a wedge action.829 mm). Grouting. (See also “Full mortar bedding. [2] Grouted masonry: (1) Masonry construction of hollow units where hollow cells are filled with grout. (See also “Open end block. [1] Height of wall: (1) The vertical distance from the foundation wall or other similar intermediate support to the top of the 15 wall. water. (2) Masonry construction using solid masonry units where the interior joints and voids are filled with grout. “H” block: Hollow masonry unit lacking cross webs at both ends forming an “H” in cross section.”) Glass unit masonry: Masonry composed of glass units bonded by mortar. Also called prefaced block. Expansion anchor: An anchoring device (based on a friction grip) in which an expandable socket expands. with or without admixtures initially produced to pouring consistency without segregation of the constituents during placement. Flashing: A thin impervious material placed in mortar joints and through air spaces in masonry to prevent water penetration and to facilitate water drainage. Drying shrinkage: The change in linear dimension of a concrete masonry wall or unit due to drying. usually to scaffold or bond beam height. as a bolt is tightened into it. [1] Dimension. For masonry.”) Facing: Any material forming a part of a wall and used as a finished surface. Used primarily to determine masonry fire resistance ratings. typically nonstructural in nature. Freeze-thaw durability: The ability to resist damage from the cyclic freezing and thawing of moisture in materials and the resultant expansion and contraction. all calculations are based on specified dimensions. Drip: A groove or slot cut beneath and slightly behind the forward edge of a projecting unit or element. [2] Grout pour: The total height of masonry to be grouted prior to erection of additional masonry. Used with reinforced masonry construction. the bloom normally disappears or is removed with water. Unless otherwise stated. (2) The vertical distance between intermediate supports. Face shell: The outer wall of a hollow concrete masonry unit. Fastener: A device used to attach components to masonry. No mortar is applied to the unit cross webs. Dimension. [3] (2) The hardened equivalent of such mixtures. The equivalent thickness of a 100% solid unit is equal to the actual thickness. (See also “Face shell mortar bedding. Fly ash: The finely divided residue resulting from the combustion of ground or powdered coal. such as a sill. nominal: The specified dimension plus an allowance for mortar joints. [1] Dimension. Once the structure dries. Also called burnished or honed block. Also called a bonder. Width (thickness) is given first.Diaphragm: A roof or floor system designed to transmit lateral forces to shear walls or other lateral load resisting elements. self-consolidating: Highly fluid and stable grout used in high lift and low lift grouting that does not require consolidation or reconsolidation. Efflorescence: A deposit or encrustation of soluble salts (generally white). lintel or coping. sometimes referred to as new building bloom. Actual dimensions may vary from specified dimensions by permissible variations. aggregates. The thickness of cavity walls is taken as the overall thickness minus the width of the cavity.8°C) or temperature exceeds 90°F (32.”) Mortar joint. Pier: An isolated column of masonry or a bearing wall not bonded at the sides to associated masonry.4 to 13 mm) is removed from the outside of the joint. a vertical member whose horizontal dimension measured at right angles to its thickness is not less than three times its thickness nor greater than six times its thickness and whose height is less than five times its length.000 kg/m3). Mortar bond: (See “Bond. [3] (2) The hardened equivalent of such mixtures. or roofs. Mix design: The proportions of materials used to produce mortar. Pilaster block: Concrete masonry units designed for use in the construction of plain or reinforced concrete masonry pilasters and columns. hydrated lime and hydraulic hydrated lime. Inspection: The observations to verify that the masonry construction meets the requirements of the applicable design standards and contract documents. loadbearing.”) Normal weight concrete masonry unit: A unit whose ovendry density is 125 lb/ft3 (2000 kg/m3) or greater. with or without admixtures. It has a uniform cross section throughout its height and serves as a vertical beam. Common profiles include: Concave: Produced with a rounded jointer.”) Pilaster: A bonded or keyed column of masonry built as part of a wall.” Net section: The minimum cross section of the member under consideration. Lightweight concrete masonry unit: A unit whose oven-dry density is less than 105 lb/ft3 (1. or in the vertical span by beams. [1] Mortar joint. Loadbearing: (See “Wall. Modular coordination: The designation of masonry units.”) Manufactured masonry unit: A man-made noncombustible building product intended to be laid by hand and joined by mortar. [4] Open end block: A hollow unit. natural pumice. grout or other methods. 16 Plain masonry: (See “Unreinforced masonry.”) . [4] Mortar: (1) A mixture of cementitious materials. (6. [5] Masonry cement: (1) A mill-mixed cementitious material to which sand and water is added to make mortar. Multi-wire joint reinforcement assemblies have cross wires welded between the longitudinal wires at regular intervals. joined with mortar. this is the standard mortar joint unless otherwise specified.) Parging: (1) A coating of mortar. floors. Modular design: Construction with standardized units or dimensions for flexibility and variety in use. Lintel block: A U-shaped masonry unit. a general term for the various chemical and physical forms of quicklime. Lap splice: The connection between reinforcing steel generated by overlapping the ends of the reinforcement. Moisture content: The amount of water contained within a unit at the time of sampling expressed as a percentage of the total amount of water in the unit when saturated. sintered fly ash or industrial cinders. It may be flush or project from either or both wall surfaces.Height-to-thickness ratio: The height of a masonry wall divided by its nominal thickness. [4] Metric: The Systeme Internationale (SI). Also called channel block. Lap: (1) The distance two bars overlap when forming a splice. (2) The process of applying such a coating. high lift. perlite. then converted into metric dimensions. Struck: An approximately flush joint. Jamb block: A block specially formed for the jamb of windows or doors. Hard metric refers to products or materials manufactured to metric specified dimensions. See also “Strike. bed: The horizontal layer of mortar between masonry units.”) Hollow masonry unit: A unit whose net cross-sectional area in any plane parallel to the bearing surface is less than 75 % of its gross cross-sectional area measured in the same plane. (2) Hydraulic cement produced for use in mortars for masonry construction. generally with a vertical slot to receive window frames. door and window frames. [4] Honed block: (See “Ground face block. nonloadbearing.”) Hot weather construction: Procedures used to construct masonry when ambient air temperature exceeds 100°F (37. Recommended for exterior walls because it easily sheds water. etc.”) Low lift grouting: (See “Grouting. (See “A” block and “H” block. If they are held together by mortar. Joint reinforcement: Steel wires placed in mortar bed joints (over the face shells in hollow masonry). slate. Used primarily with reinforced masonry construction. grout or other accepted methods. fine aggregate water. Raked: A joint where 1/4 to 1/2 in. [1] Pigment: (See “Color. Soft metric refers to products or materials manufactured to English specified dimensions. which may contain dampproofing ingredients. placed with the open side up to accommodate horizontal reinforcement and grout to form a continuous beam. head: The vertical mortar joint placed between masonry units within the wythe. Nonloadbearing: (See “Wall. over a surface. vermiculite. foundations. diatomite. pilasters or cross walls.680 kg/m3). a column or both. Lintel: A beam placed or constructed over a wall opening to carry the superimposed load. and other construction components that fit together during construction without customization. low lift. [4] Lime: Calcium oxide (CaO). such as expanded or sintered clay. buttresses. shale. diatomaceous shale. the mortar-filled volume is the joint. [1] Mortar joint profile: The finished shape of the exposed portion of the mortar joint. Also called sash block. slag. Mortar bed: A horizontal layer of mortar used to seat a masonry unit. High lift grouting: (See “Grouting.2°C) with a wind speed greater than 8 mph (13 km/h). Lateral support: The means of bracing structural members in the horizontal span by columns. with one or both ends open. Medium weight concrete masonry unit: A unit whose ovendry density is at least 105 lb/ft3 (1. volcanic cinders. Joint: The surface at which two members join or abut. grout or concrete.680 kg/m3) but less than 125 lb/ft3 (2. Lightweight aggregate: Natural or manufactured aggregate of low density. (2) The distance one masonry unit extends over another. used to construct unit masonry assemblages. For design. [5] Masonry: An assemblage of masonry units. the standard international system of measurement. For example. Prism strength: Maximum compressive force resisted per unit of net cross-sectional area of masonry. [2] Veneer. [1] Wall.”) . (2) The ratio of a member's height to thickness. upon which the project design is based (expressed in terms of force per unit of net cross-sectional area). bonded: A masonry wall in which two or more wythes are bonded to act as a composite structural unit. location. Quality assurance: The administrative and procedural requirements established by the contract documents and by code to assure that constructed masonry is in compliance with the contract documents. Sill: A flat or slightly beveled unit set horizontally at the base of an opening in a wall. adhered: Masonry veneer secured to and supported by the backing through adhesion. used to impart prestress to masonry. Reinforced masonry: (1) Masonry containing reinforcement in the mortar joints or grouted cores used to resist stresses. Also called fluted. vibration. (2) A standardized measurement of a plastic cementitious material to determine its flow and workability. product and service is in accordance with the specifications. or placement. and review of usage to determine any necessary revisions to the specifications. Also called plain masonry.Plaster: (See "Stucco. Also called a split-faced or rock-faced block. Ribbed block: A block with projecting ribs (with either a rectangular or circular profile) on the face for aesthetic purposes. Stirrup: Shear reinforcement in a flexural member. Veneer. flexibility or extensibility. or some combination. Thermal movement: Dimension change due to temperature change. Slump: (1) The drop in the height of a cementitious material from its original shape when in a plastic state. prestressed. The overall program involves integrating factors including: the proper specification. dimensional changes after installation. Wall. masonry: A masonry wythe that provides the finish of a wall system and transfers out-of-plane loads directly to a backing. Unreinforced masonry: Masonry in which the tensile resistance of the masonry is taken into consideration and the resistance of reinforcement. Simply supported: A member structurally supported at top and bottom or both sides through a pin-type connection.”) Shoring and bracing: The props or posts used to temporarily support members during construction. [1] Veneer. Post-tensioning: A method of prestressing in which prestressing tendons are tensioned after the masonry has been placed. decrease in temperature or carbonation of a cementitious material. Tie: (See “Connector. is neglected. Stucco: A combination of cement and aggregate mixed with a suitable amount of water to form a plastic mixture that will adhere to a surface and preserve the texture imposed on it. adequate. [1] Wall. Screen block: An open-faced masonry unit used for decorative purposes or to partially screen areas from the sun or from view. Retarding agent: An ingredient or admixture in mortar that slows setting or hardening. The objective of quality control is to provide a system that is safe. Spall: To flake or split away due to internal or external forces such as frost action. Reinforcing steel: Steel embedded in masonry in such a manner that the two materials act together to resist forces. most commonly in the form of finely ground gypsum. Slushed joint: A mortar joint filled after units are laid by “throwing” mortar in with the edge of a trowel. Slump block: A concrete masonry unit produced so that it slumps or sags in irregular fashion before it hardens. Primarily used for quality control purposes to assess the strength of full-scale masonry members. cavity: A multiwythe noncomposite masonry wall with a continuous air space within the wall (with or without insulation).”) Tolerance: The specified allowance in variation from a specified size. (2) Unit masonry in which reinforcement is embedded in such a manner that the component materials act together to resist applied forces. [1] Prism: A small assemblage made with masonry units and mortar and sometimes grout. if present. [1] Quality control: The planned system of activities used to provide a level of quality that meets the needs of the users and the use of such a system. [1] Strike: To finish a mortar joint with a stroke of the trowel or special tool. See "Mortar joint profile" for definitions of common joints. which is tied together with metal ties. Solid masonry unit: A unit whose net cross-sectional area in every plane parallel to the bearing surface is 75 percent or more of its gross cross-sectional area measured in the same plane.") Plasticizer: An ingredient such as an admixture incorporated into a cementitious material to increase its workability. Tooling: Compressing and shaping the face of a mortar joint with a tool other than a trowel. Shell: (See “Face shell. Slenderness ratio: (1) The ratio of a member’s effective height to radius of gyration. Temper: To moisten and mix mortar to a proper consistency. Project specifications: The written documents that specify project requirements in accordance with the service parameters and other specific criteria established by the owner or owner’s agent. inspection to determine whether the resulting material. tie.” Prestressing tendon: Steel element such as wire. Shrinkage: The decrease in volume due to moisture loss. composite: A multiwythe wall where the individual masonry wythes act together to resist applied loads. bar or strand. Sash block: (See “Jamb block. which assumes no moment transfer. impact. determined by testing masonry prisms. specified. Specified dimensions: (See “Dimension. production to meet the full intent of the specification. [1] Split block: A concrete masonry unit with one or more faces purposely fractured to produce a rough texture for aesthetic purposes. [4] Note that Canadian standards define a solid unit as 100% solid.”) Scored block: A block with grooves on the face for aesthetic purposes. (See 17 also “Composite action. the grooves may simulate raked joints. simultaneously removing extruded mortar and smoothing the surface of the mortar remaining in the joint. pressure. dependable and economic. anchored: Masonry veneer secured to and supported laterally by the backing through anchors and supported vertically by the foundation or other structural elements. [1] See also “Wall. f'm: Minimum masonry compressive strength required by contract documents. but is not considered to add load resisting capacity to the wall system.”) Specified compressive strength of masonry. [1] Wall. 1999. ASTM International. Workability: The ability of mortar or grout to be easily placed and spread. Standard Terminology of Masonry. shear: A wall. but not Wall. 2. 2002. designed to resist lateral forces acting in the plane of the wall. 2002. (3) An exterior nonloadbearing wall in skeleton frame construction. partition: An interior wall without structural function. (2) A nonloadbearing exterior wall vertically supported only at its base. By code. Standard Terminology of Concrete Masonry Units and Related Units. multiwythe: Wall composed of 2 or more masonry wythes. Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible.org To order a complete TEK Manual or TEK Index. single wythe: A wall of one masonry unit thickness. 2001. foundation: A wall below the floor nearest grade serving as a support for a wall. [1] REFERENCES 1. Wall.1-02/ASCE 6-02/ TMS 602-02. Wythe: Each continuous vertical section of a wall. 6. ASTM C 1180-03. Wall. (2) A nonloadbearing exterior masonry wall having bearing support at each story. 18 contact NCMA Publications (703) 713-1900 . NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. 5. Web: The portion of a hollow concrete masonry unit connecting the face shells. screen: A masonry wall constructed with more than 25% open area intended for decorative purposes. nonloadbearing: A wall that supports no vertical load other than its own weight.9 kN/m) in addition to its own weight. Can be a surface treatment or integral water repellent admixture. wholly supported at each story. Wall. a wall carrying vertical loads greater than 200 lb/ft (2. 2003. Reported by the Masonry Standards Joint Committee. ASTM International. retaining: A wall designed to prevent the movement of soils and structures placed behind the wall. pier. Specification for Masonry Structures. ACI 530. column or other structural part of a building and in turn supported by a footing. Wall tie: A metal connector that connects wythes of masonry. curtain: (1) A nonloadbearing wall between columns or piers. Wall. Concrete Masonry Bond Patterns. Wall tie. typically to partially screen an area from the sun or from view. Wall. Water repellency: The reduction of absorption. veneer: A wall tie used to connect a facing veneer to the backing. Wall. [1] Wall. Waterproofing: (1) The methods used to prevent moisture flow through masonry. Virginia 20171 www. Herndon. ASTM International. (2) A wall containing reinforcement used to resist shear and tensile stresses. [1] Wall. ASTM C 1232-02. Water permeance: The ability of water to penetrate through a substance such as mortar or brick. Reported by the Masonry Standards Joint Committee. reinforced: (1) A masonry wall reinforced with steel embedded so that the two materials act together in resisting forces. Usually located immediately above flashing. [1] Wall. 3. (2) The materials used to prevent moisture flow through masonry.9 kN/m) in addition to its own weight. By code. [2] Wall. solid masonry: A wall either built of solid masonry units or built of hollow units and grouted solid. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. prestressed: A masonry wall in which internal compressive stresses have been introduced to counteract stresses resulting from applied loads. one masonry unit in thickness. Standard Terminology of Mortar and Grout for Unit Masonry. TEK 14-6. a wall carrying vertical loads less than 200 lb/ft (2. loadbearing: Wall that supports vertical load in addition to its own weight. Wall.Wall. Building Code Requirements for Masonry Structures.ncma. Such walls may be anchored to columns. or having bearing support at prescribed vertical intervals. National Concrete Masonry Association. 2002. Water repellent: Material added to the masonry to increase resistance to water penetration. bearing or nonbearing. spandrel beams or floors. ASTM C 1209-01a. Weep hole: An opening left (or cut) in mortar joints or masonry face shells to allow moisture to exit the wall. panel: (1) An exterior nonloadbearing wall in skeleton frame construction. ACI 53002/ASCE 5-02/TMS 402-02. 4. concrete masonry units have nominal face dimensions of 8 in. 6. (9. different concrete masonry units can be combined within the same wall to achieve variations in texture. ASTM C 90 includes minimum face shell and web thicknesses for 8" (203 mm) 8" (2 03 m m) ) mm 6 0 4 ( 16" Nominal Unit Dimensions Stretcher unit Single corner unit Concrete brick 75/8" (194 mm) 7 5/8" (194 mm) m) 97 m 3 ( " 55 /8 1 Actual Unit Dimensions Figure 1—Nominal and Actual Unit Dimensions TEK 2-1A © 2002 National Concrete Masonry Association Corner return unit Double corner or plain end unit Figure 2—Typical Concrete Masonry Units 19 (2002) . 8.5 mm) mortar joints. equivalent thickness. colors. Local manufacturers can provide detailed information on specific products. lintels. 203. lengths. screen block. A more complete guide to concrete masonry units is the Shapes and Sizes Directory (ref. 5) is the most frequently referenced standard for concrete masonry units. Concrete masonry units are manufactured in different sizes. (203 mm) by 16 in. (102 or 203 mm) module is maintained with 3/ 8 in. dimensions. (9. 10. 2). 152. pattern. Actual dimensions of concrete masonry units are typically 3/ 8 in. Standard Specification for Load-Bearing Concrete Masonry Units. so that the 4 or 8 in. bond beams.5 mm) less than nominal dimensions. concrete brick. (102. Nominal dimensions refer to the module size for planning bond patterns and modular layout with respect to door and window openings. In addition to these standard sizes. and 12 in. (203 x 203 x 406 mm) concrete masonry unit. because of its modular nature. In addition. ASTM C 90 (ref. Figure 1 illustrates nominal and actual dimensions for a nominal 8 x 8 x 16 in. while others are popular only in certain regions. and textures to achieve a number of finishes and functions. TEK 2-1A Unit Properties UNIT SIZES Typically. and 305 mm). other unit heights. and color. or the feasibility of producing custom units.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology TYPICAL SIZES AND SHAPES OF CONCRETE MASONRY UNITS Keywords: architectural units. available in nominal thicknesses of 4 . and thicknesses may be available from local concrete masonry producers. 254. shapes. sizes and shapes INTRODUCTION Concrete masonry is one of the most versatile building products available because of the wide variety of appearances that can be achieved using concrete masonry units. (406 mm). Certain concrete masonry sizes and shapes are considered standard. and a wide range of heights. (3. Bond beam units are either manufactured with reduced webs or with “knock-out” webs. The taper provides a wider surface for mortar and easier handling for the mason.2 mm) from the dimensions specified by the manufacturer.1 mm). (203 and 406 mm). (102 mm) width. (mm) in. When the units are solid grouted. (19. In addition to the “standard” sizes listed above.c of unit. multiplied by 12 and divided by the length of the unit.2 to 6. Like ASTM C 90. (3. units may be manufactured to closer tolerances than those permitted in ASTM C 90. in. Bond beam units Pilaster units Figure 3—Shapes to Accommodate Reinforcement after the wall is constructed. Lintel units are available in various depths to carry appropriate lintel loads over door and window openings. the 10% limit does not apply. or length) are permitted to vary by ±1/8 in. Where required.the different sizes of concrete masonry units as listed in Table 1.2 mm) from the dimensions specified by the manufacturer. concrete brick is available in typical lengths of 8 and 16 in.e 11/4 (32) Open end. (mm) (mm/m) 3/4 (19) 3 (76) and 4 (102) 3/4 (19) 15/8 (136) d 6 (152) 1 (25) 1 (25) 21/4 (188) d 1 8 (203) 1 /4 (32) 1 (25) 21/4 (188) d 10 (254) 13/8 (35) 11/8 (29) 21/2 (209) 11/4 (32)d. nominal dimensions of nonmodular sized concrete brick usually exceed the standard dimensions by 1/8 to 1/4 in. b Average of measurements on 3 units taken at the thinnest point when measured as described in ASTM C 140. Websa. (25. When this standard is used for split face units. or may have two or three cores. The shapes illustrated in Figure 3 have been developed specifically to accommodate reinforcement. UNIT SHAPES Concrete masonry unit shapes have been developed for a wide variety of applications. width. ASTM C 55 (ref. d For solid grouted masonry construction. ASTM C 90 also defines the difference between hollow and solid concrete masonry units. a maximum of 10% of a split face shell area is permitted to have thicknesses less than those shown. The minimum web thickness for units with webs closer than 1 in. Bond beams in concrete masonry walls can be accommodated either by saw-cutting out of a standard unit. Standard Specification for Concrete Building Brick. (mm) in. Equivalent web thickness does not apply to the portion of the unit to be filled with grout. (16 mm). Lintel units are similar to the U shaped bond beam units. nominal 4 in. The solid bottom confines grout to the lintel. but not less than ¾ in./linear footb. except that allowable design loads on solid grouted units shall not be reduced. They may be 100% solid. Nominal dimensions of modular concrete brick equal the actual dimensions plus 3/8 in. or may have a straight taper from top to bottom. However.4 mm) apart shall be ¾ in. in. Pilaster and column units are used to easily accommodate a wall-column or wallpilaster interface. This eliminates the need to lift units over the top of the reinforcing bar. minimum face shell thickness not less than 5/8 in. the thickness of one standard mortar joint. The most common shapes are shown in Figure 2. The length of that portion shall be deducted from the overall length of the unit for the calculation. Nominal width thicknessa. Horizontal bond beam reinforcement is easily accommodated in these units. 5) Web thickness Equivalent Face shell web thickness. the face shells and webs are tapered on concrete masonry units. Typically. permits overall unit dimensions to vary ±1/8 in. 3). (19. Depending on the core molds used in the manufacture of the units. (3.5 mm). c Sum of the measured thickness of all webs in the unit.1 mm). allowing space for vertical reinforcement in 20 . e This face shell thickness is applicable where allowable design load is reduced in proportion to the reduction in thickness from basic face shell thicknesses shown. Open-ended units allow the units to be threaded around reinforcing bars. The net cross-sectional area of a solid unit is at least 75% of the gross cross-sectional area. face shells and webs may be tapered with a flare at one end.4 mm). or by using bond beam units.e 12 (305) 11/2 (38) 11/8 (29) 21/2 (209) d. (9. or to thread the reinforcement through the masonry cores Table 1—Minimum Thickness of Face Shells and Webs (ref. 4). or "A" shaped unit Double open end unit Lintel unit a Average of measurements on 3 units taken at the thinnest point when measured as described in ASTM C 140 (ref. which are removed prior to placement in the wall. Overall unit dimensions (height. Sash unit All purpose or kerf unit Control joint unit Bevelled unit Bull-nosed unit Screen units Figure 4—Special Shapes Figure 5—Examples of Concrete Masonry Units Designed For Energy Efficiency Figure 6—Examples of Acoustical Concrete Masonry Units the hollow center. Figure 4 shows units developed for specific wall applications. Sash block have a vertical groove molded into one end to accommodate a window sash. Sash block can be laid with the grooves adjacent to one another to accommodate a preformed control joint gasket. Control joint units are manufactured with one male and one female end to provide lateral load transfer across control joints. An all-purpose or kerf unit contains two closely spaced webs in the center, rather than the typical single web. This allows the unit to be easily split on the jobsite, producing two 8 in. (203 mm) long units, which are typically used adjacent to openings or at the ends or corner of a wall. Bullnosed units are available with either a single or double bull nose, to soften corners. Screen units are available in many sizes and patterns. Typical applications include exterior fences, interior partitions, and openings within interior concrete masonry walls. Bevelled-end units, forming a 45o angle with the face of the unit, are used to form walls intersecting at 135o angles. Units in adjacent courses overlap to form a running bond pattern at the corner. A variety of concrete masonry units are designed to increase energy efficiency. These units, examples of which are shown in Figure 5, may have reduced web areas to reduce heat loss through the webs. Web areas can be reduced by reducing the web height or thickness, reducing the number of webs, or both. In addition, the interior face shell of the unit can be made thicker than a typical face shell for increased thermal storage, and hence further increase energy efficiency. Insulating inserts can also be incorporated into standard concrete masonry units to increase energy efficiency. Acoustical units (Figure 6) dampen sound, thus improving the noise reduction attributes of an interior space. Acoustical units are often used in schools, industrial plants, and churches, and to improve internal acoustics. SURFACE FINISHES The finished appearance of a concrete masonry wall can be varied with the size of units, shape of units, color of units and mortar, bond pattern, and surface finish of the units. The various shapes and sizes of concrete masonry units described above are often available in a choice of surface finishes. Some of the surfaces are molded into the units during the manufacturing process, while others are applied separately. Figure 7 shows some of the more common surface textures available. Ribs, flutes, striations, offsets, and scores are accomplished by using a unit mold with the desired characteristics. Split-faced units are molded with two units face-to-face and then the units are mechanically split apart. Glazed units are manufactured by bonding a permanent colored facing to a concrete masonry unit, providing a smooth impervious surface. Glazed units are often used for brightlycolored accent bands, and in gymnasiums, rest rooms, and indoor swimming pools where the stain and moisture resistant finish reduces maintenance. Glazed units comply to Standard Specification for Prefaced Concrete and Calcium Silicate Masonry Units, ASTM C 744 (ref. 6). Ground-face units are ground to achieve a smooth finish which reveals the natural colors of the aggregates. Often, specific aggregates will be used to enhance the appearance. For more information on surface finishes, see TEK 2-3A 21 Architectural Concrete Masonry Units (ref. 1). Figure 7—Examples of Surface Finishes Available For Concrete Masonry Units (clockwise from bottom left: split face with three scores; single score ground face; glazed corner unit; ground face; ground face; single score glazed ; split face; ground face; split face; center: eight-ribbed split face) REFERENCES 1. Architectural Concrete Masonry Units, TEK 2-3A, National Concrete Masonry Association, 2001. 2. Shapes and Sizes Directory, National Concrete Masonry Association, 1995. 3. Standard Methods of Sampling and Testing Concrete Masonry Units and Related Units, ASTM C 140-01ae1. American Society for Testing and Materials, 2001. 4. Standard Specification for Concrete Building Brick, ASTM C 55-01a. American Society for Testing and Materials, 2001. 5. Standard Specification for LoadBearing Concrete Masonry Units, ASTM C 90-01a. American Society for Testing and Materials, 2001. 6. Standard Specification for Prefaced Concrete and Calcium Silicate Masonry Units, ASTM C 744-99. American Society for Testing and Materials, 1999. Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible, NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive, Herndon, Virginia 20171 www.ncma.org To order a complete TEK Manual or TEK Index, contact NCMA Publications (703) 713-1900 22 An information series from the national authority on CONSIDERATIONS FOR USING SPECIALTY CONCRETE MASONRY UNITS INTRODUCTION Concrete masonry is an extremely versatile building product in part because of the wide variety of aesthetic effects that can be achieved using concrete masonry units. Concrete masonry units are manufactured in different sizes, shapes, colors, and textures to achieve a number of finishes and functions. In addition, because of its modular nature, different concrete masonry units can be combined within the same wall to produce variations in texture, pattern, and color. For the purposes of this TEK, “standard” concrete masonry units are considered to be two-core units (i.e., those with three cross webs), 8 in. (203 mm) high, 16 in. (406 mm) long and 4, 6, 8, 10 or 12 in. (102, 154, 203, 254 or 305 mm) wide. In addition, concrete brick is available in typical lengths of 8, 9, 12 and 16 in. (203, 229, 305 and 406 mm), nominal 4 in. (102 mm) width, and a wide range of heights. In addition to these "standard" units, many additional units have been developed for a variety of specific purposes, such as aesthetics, ease of construction and improved thermal or acoustic performance. For the purposes of this TEK, units other than those described above as standard will be referred to as specialty units. Specialty units can include units of different sizes or different unit configurations. Units of specialty configuration which are used at discreet wall locations rather than to construct an entire wall, such as sash units, pilaster units, etc. are not discussed here, nor are proprietary units discussed in detail. See TEK 2-1A, Concrete Masonry Unit Shapes and Sizes (ref. 1), for information on these units. By definition, specialty units are not available from all concrete masonry manufacturers. In some cases, such as the A- and H-shaped units used for reinforced construction, Related TEK: 1-1E, 2-1A, 5-12, 5-15, 14-1B, 14-13B NCMA TEK 2-2B concrete masonry technology TEK 2-2B Unit Properties (2010) the “specialty” is commonly available in certain geographic areas. In California, for example, A- and H-shaped units are considered to be standard units. Other unit configurations discussed below may be available across the country, but from a relatively small number of producers. For this reason, it is imperative that the designer communicate with local concrete masonry manufacturers to establish the availability of the units discussed in this TEK, as well as other specialty units that may be available. Local manufacturers can provide detailed information on specific products, or the feasibility of producing custom units. Regardless of unit size or configuration, concrete masonry units are required to comply with Standard Specification for Loadbearing Concrete Masonry Units, ASTM C90 (ref. 2). See TEK 1-1E, ASTM Specifications for Concrete Masonry Units (ref. 3), for more detailed information. This TEK discusses the advantages of using specialty units, and some of the design and construction issues that may impact the use of these units SPECIALTY UNIT SIZES Concrete masonry units may be produced with widths, heights, and/or lengths other than the standard sizes listed above. Use of these units produces walls with a scale and aesthetic properties different from those built with standard-sized units. Construction productivity may be impacted by the size, weight and configuration of the units selected. Also, some of the special shapes and sizes may not be available, and may require modification on site by the contractor. One of the most important construction consideration when using specialty-sized units is modular coordination. Modular coordination is the practice of laying out Keywords: unit shapes, unit sizes, modular coordination, section properties 23 1 Modular coordination helps maximize construction efficiency and economy by minimizing the number of units that must be cut to accommodate window and door openings. MW18) joint reinforcement. (2. long (406 x 610 mm). For units with a height greater than 8 in. (102and 305-mm) high units.. so this veneer anchor spacing meets the code requirements.134 mm) 48 in. (203-mm) high unit. horizontal reinforcement in low seismic categories. these specialty height units can be considered to be structurally equivalent to their corresponding 8-in.235 mm) 120 in.25 m2). anchors need to be installed in every course to meet the requirement for a maximum vertical anchor spacing of 18 in. (305-mm) high veneer units installed over a concrete masonry backup wythe. Half-high units are gaining in popularity. Another consideration for units with a height exceeding 8 in. (813 mm) (ref. (457 mm). ("half-high") or 12-in. 7) for more detailed information. up to 16 in. See TEK 5-12. and bond for multiple wythes. For example. They provide an aspect ratio similar to brick. as the wall is built on a 4-in. Using 4-in. (3. A better alternative is to use 2-wire W2. In this case. Note that special door frames may need to be ordered to fit the masonry opening. 11). door opening height and window opening height should ideally be a multiple of 12-in. See TEK 5-15.and dimensioning structures and elements to standard lengths and heights to accommodate proportioning and incorporating modular-sized building materials. Details for Half-High Concrete Masonry Units (ref. high units. (102-mm) high units provides some additional flexibility in placing wall openings.219 mm) 36 in. With 12-in. empirical concrete masonry crack control criteria calls for horizontal reinforcement of at least 0. the joint reinforcement of that size needs to be placed in every horizontal bed joint to meet this requirement. but are hollow loadbearing units. (203-mm) high unit. Modular Layout of Concrete Masonry (ref. concrete masonry units may be available in 4-in. for example. veneer units (typically 4 in. (203-mm) Unit Height 2 24 NCMA TEK 2-2B . When using 12-in. (305-mm) high units.8 (3/16 in. with a Specialty Unit Heights Although the most commonly available concrete masonry unit height is 8 in. Vertical modular coordination must be adjusted in some cases with these units.. (203 mm). (102-mm) vertical module rather than an 8-in.7 (9 gage. Joint reinforcement in concrete masonry can be used to provide crack control. Veneer anchor spacing requirements remain the same regardless of unit height. further information. This corresponds to a maximum vertical spacing of 16 in.048 mm) 32 in. (1. (203 mm). As long as the unit cross-section (i.2/ft of wall height (52. 8).25 m2). 4) for information on modular coordination with standard-sized units. consider 12-in. (305-mm) Unit vs. (914 mm) 120 in. The anchor spacing requirements are: maximum wall surface area supported of 2. (2.219 mm) 88 in. If the anchors are spaced horizontally at the maximum 32 in. (203-mm) vertical module.e.048 mm) 84 in. (305-mm) to minimize cutting units on site (see Figure 1).9 mm2/m) between control joints. In addition to the specialty height units and specialty length units discussed below. (102 mm) thick) may be available in various specialty sizes. (813 mm) Figure 1—Vertical Modular Coordination: 12-in. these spacing requirements should be verified and the anchor spacing planned out prior to construction. Most requirements and rules of thumb for joint reinforcement are based on a specific area of reinforcement per foot of wall height and assume an 8-in. (1.025 in. face shell and web thicknesses) is the same as the corresponding 8-in. corners and intersections. (203 mm). (203 mm) is the use of joint reinforcement.67 ft2 (0.67 ft2 (0. As an example. (813 mm). MW11) joint reinforcement is used. (406 mm) when 2-wire W1. (203-mm) modular unit height. high by 24 in. and maximum horizontal anchor spacing or 32 in. Height 8-in. (457 mm). the wall area supported is 2. These should be considered prior to construction for units with heights exceeding 8 in. Concrete Masonry Veneers (ref. See TEK 5-12 for 48 in. the wall height. maximum vertical anchor spacing of 18 in. Veneer anchor spacing requirements are presented in detail in TEK 3-6B. (3. corner details for these units are similar to those for 8-in. 152. Properties of wire for masonry (including steel cross-sectional area) can be found in Table 3 of TEK 12-4D. 5. as shown in Figure 2. SPECIALTY UNIT CONFIGURATIONS Specialty unit configuration refers to units whose crosssection varies significantly from that of a standard two-core concrete masonry unit. (813 mm) 16 in. (406-mm) long units. specialty widths may include 14 and 16 in. Horizontal modular coordination should be considered when using these units. and require more grout to fill reinforced cells. the larger cores of 14. 40 in. Joint Reinforcement for Concrete Masonry (ref. and TEK 12-2B. TEK 5-9A. 203. (305-mm) high units. (102. and 24-in. 10. 152. (356-mm) wide units are similar to those for 12-in. Concrete Masonry Corner Details (ref. In this case. (203-mm) wide unit is used in each course at the corner to maintain the running bond. For example. One construction issue that arises with different unit widths is corner details. Structural considerations may differ. when used. (102. 203. Specialty Unit Widths In addition to the standard unit widths of 4. 24 in. 10. A standard 8-in. using 8-in. (406-mm) Unit Length NCMA TEK 2-2B 25 3 . (356 and 406 mm) wide walls. From a construction standpoint. (305mm) long unit of the same width.e. (914 mm) 36 in. TEKs 14-1B. per ASTM C90.. and 12 in. (203-mm) wide units with 2 x 6 in. Veneer anchor spacing and joint reinforcement considerations are the same as for standard-length units. Corner details for 14-in.and 16-in. Section Properties of Concrete Masonry Walls. (1. 254. these units can be considered to be structurally equivalent to a 16-in. (406 mm) is a modular size. 6. 36 in. Concrete Masonry Wall Weights (refs. (457-mm) Unit Length vs. (610 mm). list these properties for 14 and 16 in. 6). Because 16 in. 8. Concrete masonry units longer than 16 in. Modular coordination is the same as for standard units. 305 mm) wide units. 254. 13).maximum vertical spacing of 24 in. Control Joints for Concrete Masonry Walls—Empirical Method (ref. (203-mm) wide units. 8. however.and 610-mm) long units. the average web thickness per length of wall) as 16-in. and 14-13B. presents details to minimize cutting of units while maintaining modularity for 4. unless the specialty configuration 32 in. (305 mm) wide units. 40 in. (356 and 406 mm). As such. (356 and 406 mm) wide units accommodate more reinforcement or insulation. layout 36 in. 10). (457. Because unit width does not affect modular coordination.016 mm) (610 mm) (1.016 mm)(406 mm) Figure 2—Horizontal Modular Coordination: 18-in. for an overview of code requirements for the use of joint reinforcement. as both the section properties and wall weight varies with wall width. 16-in. 12) Specialty Unit Lengths Specialty concrete masonry unit lengths include 18in. See TEK 10-2C. Steel Reinforcement for Concrete Masonry (ref. allowing the joint reinforcement to be placed every other course when using 12-in. (914 mm) (457 mm) (914 mm) (457 mm) considerations are generally the same as for walls constructed using standard concrete masonry units. and 12 in. 6. 18 in. (51 x 152 mm) pieces of masonry to fill the gaps in the inside corners. structural properties may be different from standard units. 18 in. (406 mm) are produced with the same equivalent web thickness (i. 9) for a discussion of joint reinforcement for crack control. 305 mm). wall length and placement of wall openings should ideally be a multiple of the unit length. National Concrete Masonry Association. ASTM International. Building Code Requirements for Masonry Structures. NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. National Concrete Masonry Association. TEK 2-1A. contact NCMA Publications (703) 713-1900 4 26 NCMA TEK 2-2B . TEK 12-4D. 2008. ASTM C90-09. For example. The concrete masonry producer should be contacted for more detailed information on the specific unit under consideration. Reported by the Masonry Standards Joint Committee. 2006. 2005. 2002. Concrete Masonry Corner Details. walls constructed with these units can use the same structural design parameters as for grouted standard units. 2008. Open-ended or Open end. TEK 14-13B. Open-ended units allow concrete masonry units to be inserted around vertical reinforcing bars. Virginia 20171 www. and/or additional cavities within the unit to accommodate insulation. 2. Modular Layout of Concrete Masonry. TEK 5-9A. Herndon. 4.org Provided by: To order a complete TEK Manual or TEK Index. Concrete Masonry Unit Shapes and Sizes. 2005. National Concrete Masonry Association. a thickened interior face shell for increased thermal storage. or unit A-shaped "A" shaped unit Double-open-ended Double open end unit or H-shaped unit Figure 3—Examples of Unit Shapes that Accommodate Reinforcement REFERENCES 1. Concrete Masonry Wall Weights. TEK 1-1E. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 2009. 2004. TEK 12-2B. TMS 402-08/ACI 530-08/ASCE 5-08. 9. Section Properties of Concrete Masonry Walls. 13. National Concrete Masonry Association. TEK 5-12. TEK 5-15. 2007. National Concrete Masonry Association. 2008. National Concrete Masonry Association. Acoustical concrete masonry units provide increased sound absorption and/ or diffusion. 11. TEK 3-6B. TEK 10-2C. 8. These units may have unique construction and/or structural considerations. units developed for improved energy efficiency may have reduced web areas to reduce heat loss through the webs. Details for Half-High Concrete Masonry Units.and H-shaped units are grouted and bond beam and lintel units are fully grouted. Bond beam and lintel units have also been developed to accommodate horizontal reinforcement. 3. 6. 7. National Concrete Masonry Association. Concrete Masonry Veneers. Units to Facilitate Reinforced Construction Concrete masonry unit shapes have been developed for a wide variety of applications. This eliminates the need to lift units over the top of embedded vertical reinforcement. National Concrete Masonry Association. 2008. Control Joints for Concrete Masonry Walls—Empirical Method. 12. Steel Reinforcement for Concrete Masonry. Standard Specification for Loadbearing Concrete Masonry Units. TEK 14-1B. Because all open cells of A. Joint Reinforcement for Concrete Masonry. or to thread the reinforcement through the masonry cores after the wall is constructed. 5. A variety of concrete masonry units have been developed to address specific performance or construction criteria. National Concrete Masonry Association.ncma. National Concrete Masonry Association.is also produced in a specialty size. The shapes illustrated in Figure 3 have been developed specifically to accommodate vertical reinforcement. 10. 2007. depending on their configuration. National Concrete Masonry Association. 2010. ASTM Specifications for Concrete Masonry Units. ground face. as the texture tends to discourage graffiti vandals. split-face. The term “architectural concrete masonry units” typically is used to describe units displaying any one of several surface finishes that affects the texture of the unit. However. bond pattern. Architectural concrete masonry units are used for interior and exterior walls. Architectural units comply with the same quality standards as conventional concrete masonry. not all products listed will be available in all locations. The units described herein are some of the more common architectural concrete masonry units. partitions. offset face. striated INTRODUCTION One of the most significant architectural benefits of designing with concrete masonry is its versatility – the finished appearance of a concrete masonry wall can be varied with the unit size and shape. prefaced. In some cases. and conversely. sandblasted. fluted. increasing both the economic and aesthetic advantages. split-rib. Consult a local manufacturer for final unit selection. Some units are available with the same treatment or pattern on both faces. Architectural Unit TYPEs Split Faced Units Split faced units have a natural stone-like texture produced by molding two units face-to-face. terrace walls. noted below where applicable. and other enclosures. ribbed. ASTM C 90 (ref. raked. then mechanically splitting them apart after curing. Because coarse aggregate is also fractured and exposed in this process. color of units and mortar.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology ARCHITECTURAL CONCRETE MASONRY UNITS TEK 2-3A Unit Properties (2001) Keywords: architectural units. to serve as both exterior and interior finish wall material. scored. are often used in areas prone to graffiti. creating a fractured surface. Standard (a) Split Face and Glazed Specification for Loadbearing Concrete Masonry Units. additional provisions govern which are more applicable to the specific unit. slump. like those available with split face units. allowing the structural wall and finished surface to be installed in a single step. aggregate selection can alter the final appearance. and surface finish of the units. (b) Fluted Split Face (c) Split and Ground Face Figure 1—Examples of Architectural Concrete Masonry Units TEK 2-3A © 2001 National Concrete Masonry Association (replaces TEK 2-3) 27 . Rough textures. manufacturers may carry additional products not listed here. glazed. burnished. 3). Split-faced units can also be manufactured with ribs or scores to provide strong vertical lines in the finished wall. The units have the appearance of polished natural stone. (203 x 406 mm). This 10% limit does not apply. Scored units reduce the perceived scale of the masonry while still allowing construction using full sized units. mortar is typically placed to all outside edges of the masonry unit. specific aggregates will be used to enhance the appearance of the polished surface (Figure 1c and 2a). will be larger than those published for non-ribbed units.e. The appearance from a distance is very similar to that of a split face. In the second case. with ribbed units. and may be either smooth or split for added texture. In addition. Honed) Ground face concrete masonry units are polished after manufacture to achieve a smooth finish which reveals the natural aggregate colors. 3. the net area. units with two and five scores can be placed in either stack bond or in a one-third running bond to align scores in adjacent courses. while a closer inspection shows a surface that is not as well defined as that achieved with a conventional split face. and corresponding section properties. Walls utilizing a variety of split face units are shown in Figure 1. Figure 2a shows units with 3 vertical scores in a standard sized ground face block. or 8 vertical ribs which align to form continuous vertical elements in the finished wall. (203 x 203 mm) units laid in stack bond. Other appropriate bond patterns are included in Table 1. and give the appearance of 8 in. The ribs can be manufactured to project beyond the overall unit thickness (i. although the effect of this increase is typically neglected in structural calculations. aggregate is not fractured in a soft split as it is in a conventional split face unit. while coatings are sometimes used to deepen the color. however. but not less than 3/4 in. depending on the configuration of the scores or ribs. ASTM C 90 prescribes minimum faceshell thickness requirements for all loadbearing concrete masonry units. Ground Face Units (Burnished. or 7 vertical scores. Ground face units are often scored to achieve a scale other than the conventional 8 x 16 in. 5. when the units are solidly grouted. where the rib projection is included in the overall unit thickness. and moment of inertia are less than those published for non-ribbed units. it is difficult to properly tool the mortar due to the projections. 6. Scored Units Scored concrete masonry units are manufactured with one or more vertical scores on the face to simulate additional mortar joints in the wall. section modulus. x 8 in. In the first case. the final appearance is not significantly affected by aggregate choice. This may require different bond patterns. as shown in Figure 2a. The scores are molded into the face of the unit during manufacture. The ribs are molded into the unit using a special mold. 1). or with the rib projection included in the overall unit thickness. The ribs may have either a rectangular or circular profile. Split face units are governed by ASTM C 90. Soft Split A soft split unit is produced using a special mold which textures the face of the unit as it is removed from the mold. Sandblasted Units Sand (or abrasive) blasting is used to expose the aggregate in a concrete masonry unit and results in a "weathered" look. The finished look of the ground surface can be altered by changing aggregate type and proportions. the unit thickness including ribs is thicker than a typical CMU). (a) Scored and Ground Face (b) Glazed (c) Slump Block Figure 2—Additional Examples of Architectural Concrete Masonry Units 28 . Often. When building concrete masonry walls. However. the designer should be aware that the actual bearing area. which includes an allowance to account for the rough face. Units may also be available with 2. but also contains a variance for split face units where up to 10% of a split faceshell can be less than the minimum specified thickness. Note that varying bond patterns can impact how the wall responds to structural loads (see ref.Ribbed Units Ribbed concrete masonry units (often called fluted units) typically have 4. Units with one vertical score are most common. For example. Figure 1b shows an example of a wall using ribbed (fluted) split face units.. As a result. (19 mm). It is usually desirable to lay units so that scores or ribs align vertically when the units are placed. The use of white cement results in more vibrant colors. The aggregates used in the concrete mix also impact the final appearance. and even faux granite and marble patterns. applicable for one-half running bond 07 7 scores. Striation can be applied to scored and ribbed units as well (see Figure 3c). there are typically some subtle variations in color among units. providing a smooth impervious surface. producing a marbled effect. resistant to staining and graffiti. COLOR Architectural concrete masonry units are often integrally colored to enhance the appearance or achieve a particular effect. 1/16 in. Mortars can also be integrally colored to blend or contrast with the masonry units. Slump Block Units Slump block concrete masonry units have a rounded face that resembles handmade adobe. applicable for one-half running bond 06 6 ribs. the unit to which the facing is applied must comply with ASTM C 90 when used in loadbearing applications. 1 in. (51 mm) radius bullnose SCV vertically scored unit GRF ground face unit MDC circular ribs. the structural design should assume the actual width of slump units is 1 in. there are often regional differences in terminology for the same type of architectural concrete masonry units: ribbed and fluted. This effect is accomplished by using a unit mold with the desired offsets. rib projects beyond the overall unit thickness MNC circular ribs. Glazed (Prefaced) Units Glazed concrete masonry units are manufactured by bonding a permanent colored facing (typically compsed of polyester resins. In addition. where “XX” describes the number of scores or ribs. ground and burnished.6 mm) uniform striation pattern SPF split face unit NPF split face ribbed unit. The glazed facings must comply with ASTM C 744 (ref. bacteria. Variegated units provide color variations within each unit. “YYY” describes the architectural finish. applicable for any running bond 01 one score. These units are manufactured by mixing two different concrete colors into the same unit mold. (25 mm) radius bullnose BN2 bullnose unit with 2 in. etc. uncolored units should be used. Slump unit widths may vary as much as 1 in. The offsets make it appear as if adjacent units are staggered. which contains minimum requirements for facing quality and dimensional tolerances. rest rooms. height. then painted or stained the desired color. pastels. 4). which holds its shape when removed from the manufacturing mold. highly impact resistant. as well as being resistant to many chemicals and bacteria. but are sometimes available in uniform striation patterns. rib projection included in unit thickness STR striated unit STS striated unit. When units must be exactly the same color to achieve a particular architectural effect. Slump units. and in gymnasiums. but also increases cost. Concrete masonry units are colored by adding mineral oxide pigments to the concrete mix. Scores or Ribs: 00 no scores or ribs. (25 mm) uniform striation pattern STT striated unit. They are more commonly available in the Southwest United States where adobe is part of the architectural heritage. The various codes are described below. (25 mm). are manufactured using a concrete mix that slumps within desired limits when removed from its mold (see Figure 2c). Both white and gray cements are available. 2) Each unit is described using a three-part code in the following format: XX YYY WWHHLL. and water penetration resistance. Offset Face Units Units with an offset face produce a very highly textured wall. Kitchens and laboratories also benefit from the chemical and bacteria-resistant surface. cement color. and length. Conventional concrete masonry units are manufactured using a “no-slump” concrete mix. and WWHHLL describes the overall nominal unit dimensions for width. on the other hand. with strong patterns of light and shadow. Because of these varying factors. Special admixtures and mortars are available for use with glazed units that provide better stain. and indoor swimming pools where the stain and moisture resistant finish reduces maintenance. For this reason. The striations are most often random. applicable for one-third running bond 03 3 scores. (25 mm) less than the nominal dimension. They are often used for brightly-colored accent bands.Striated (Raked) Units Striated units achieve an overall texture by means of small vertical grooves molded into the unit face. rib projects beyond the overall unit thickness MNR rectangular ribs. applicable for one-half or one-quarter running bond Architectural Finish: BN1 bullnose unit with 1 in. aggregate color. applicable for one-half or one-quarter running bond 04 4 ribs. The final unit color varies with the amount and type of pigment used. The glazed surface is waterproof. applicable for one-half or one-quarter running bond 08 8 ribs. Standard Specification for Prefaced Concrete and Calcium Silicate Masonry Units. silica sand and various other chemicals) to a concrete masonry unit. (1. rib projection included in overall unit thickness MDR rectangular ribs. Table 1 – Standard Unit Nomenclature (ref. applicable for one-half running bond (units overlap the unit above and below by one-half the unit length) 02 2 scores. to achieve a naturally rough look. The National Concrete Masonry Association has developed a standardized nomenclature (see Table 1) which can be used to avoid confusion when specifying and supplying masonry units. (See Figure 3 for examples). applicable for one-half or one-quarter running bond 05 5 scores. and the amount of water used in the mix (a wetter mix will generally produce lighter and brighter colors). Glazed units are available in a variety of vibrant colors. Standard Unit Nomenclature As with many construction products and systems. earth tones. rib projections included in unit thickness SLP slump block **Q locally provided product 29 . 1997. National Concrete Masonry Association. Standard Specification for Prefaced Concrete and Calcium Silicate Masonry Units. Virginia 20171-3499 www.ncma. with 8 ribs Figure 3a—Rectangular Ribbed Unit 06 MNC 080816 8 x 8 x 16 rounded ribbed unit (rib projection included in overall unit thickness). contact NCMA Publications (703) 713-1900 30 . American Society for Testing and Materials. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. with 6 ribs Figure 3b—Rounded Rib Unit 01 STR 080816 8 x 8 x 16 striated corner unit striated patterns are often applied to scored or ribbed units Figure 3c—Striated Scored Unit 00 BN1 120816 12 x 8 x 16 Bullnose Unit with 1 in. 4. Herndon. Concrete Masonry Bond Patterns. 3. 1999. American Society for Testing and Materials. ASTM C 90-00. 1996. NATIONAL CONCRETE MASONRY ASSOCIATION 2302 Horse Pen Road. Standard Specification for Loadbearing Concrete Masonry Units.org To order a complete TEK Manual or TEK Index. National Concrete Masonry Association. ASTM C 744-99. CM 260A. 2.08 MNR 080816 8 x 8 x 16 Rectangular ribbed unit (rib projection included in overall unit thickness). 2000. Figure 3d—Bullnose Unit Figure 3—Examples of Standard Unit Nomenclature References 1. TEK 14-6. (25 mm) radius bullnose. Concrete Masonry Shapes & Sizes Manual. 1 m) or more in height. and blend naturally with the surrounding environment. and other retaining wall systems because they are durable. overturning forces due to soil pressure are resisted by the weight of the units. coupon testing. A variety of surface textures and features are available. ribbed. architectural units. and molded face units. any one of which may be scored. (204 mm) high terraces for erosion control to retaining walls 20 ft (6. retaining wall. cast-in-place concrete. including split faced. or colored to fit any project application. specifications. erosion control. durability. Successive courses are stacked dry on the course below in the architectural pattern desired. nor does the system require special construction skills to erect. and numerous other applications. Manufactured concrete retaining wall units weigh approximately 30 to 100 lb (14 to 45 kg) each and are placed by hand on a level or sloped gravel bed. driveways. dimensions. steel. Concrete units resist deterioration when exposed to the elements without addition of toxic additives which can threaten the environment. In low-height walls. The individual concrete units can be installed to virtually any straight or curved plan imaginable. Construction of segmental retaining walls does not require heavy equipment access. patios and parking lots. testing INTRODUCTION Mortarless segmental retaining walls are a natural enhancement to a variety of landscape projects. buildings. Mechanical interlocking and/or frictional shear strength between courses resists lateral soil pressure. Segmental retaining walls are used to stabilize cuts and fills adjacent to highways. easier and quicker to install. sometimes aided by an incline toward the retained soil. Segmental retaining walls replace treated wood. segmental retaining wall. compressive strength. stone faced.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology SEGMENTAL RETAINING WALL UNITS TEK 2-4B Unit Properties Keywords: absorption. Applications range from 8 in. Higher walls resist lateral soil pressures by inclining the wall toward the retained Shoreline erosion control Terracing Figure 1—Examples of Segmental Retaining Wall Installations TEK 2-4B © 2008 National Concrete Masonry Association (replaces TEK 2-4A) 31 (2008) . The reason for the difference is size and aspect ratio.5 in. Therefore. The coupon height is measured in the same direction as the unit height dimension. and continued aesthetic value. and the tensile stresses imposed as a result of typical wall settlement. surface texture. and other constituents used in the manufacture of concrete segmental retaining wall units. The preferred size is 2 x 4 x 8 in. Segmental retaining wall units currently being supplied to the market should be produced in accordance with this standard so that both the purchaser and the supplier have the assurance and understanding of the expected level of performance of the product. it is important that all retaining wall units be tested using a similar size and shape. but not less than 1. Segmental retaining wall units will not fail in service due to compressive forces since axial loads are only a result of selfweight. compressive strength of these units is determined from testing coupons cut from the units. 1) and Segmental Retaining Wall Drainage Manual (ref. However. Compressive strength testing of full size units is impractical due to the large size and/or unusual shape of some segmental retaining wall units. Because tested strengths are affected by size and shape of the specimen tested. If these procedures are followed. Water-cooled. nonuniform distribution of loads between units. it is important to keep in mind that the compression test is not intended to determine the load carrying capacity of the unit.000 (20. or other special features. (38 mm). (51 x 102 x 203 mm) (width x height x length). Units are designed to interlock between courses or to use mechanical devices to resist sliding due to lateral soil pressure. since segmental retaining walls are not designed to carry vertical structural loads. Compressive Strength Minimum compressive strength requirements for segmental retaining wall units are included in Table 1. Alignment of the specimen in the compression machine is critical. Segmental retaining wall units are factory manufactured to quality standards in accordance with ASTM C 1372. aggregates. local suppliers should be consulted as to the availability of units with such features before specifying them.24) Maximum water absorption requirements lb/ft3 (kg/m3) Weight classification—oven dry density of concrete lb/ft3 (kg/m3) Lightweight Medium weight Normal weight less than 105 (1680) to 125 (2000) 105 (1680) less than 125 (2000) or more 18 (288) 15 (240) 13 (208) 32 . color. These requirements are similar to those included in ASTM C 90. However. 3) Minimum required net area compressive strength psi (MPa) Average of three units Individual unit 3. Materials ASTM C 1372 includes requirements that define acceptable cementitious materials.500 (17. 3). Segmental retaining wall units complying with the requirements of ASTM C 1372 have been successfully used and have demonstrated good field performance. Compressive strength is used solely to determine the quality of the concrete. ASTM C 140. 4). (51 mm) as possible based on the configuration of the unit and the capacity of the testing machine. little or no maintenance. Units meeting or exceeding these strengths have demonstrated the integrity needed to resist the structural demands placed on them in normal usage. If particular features are desired. 2). Standard Method of Sampling and Testing Concrete Masonry Units (ref. the compressive strength of the coupon is considered to be the strength of the whole unit. this minimum requirement is used to ensure overall performance. the weight of the units above them in the wall. Care should be taken in capping the test specimen to assure that capping surfaces are perpendicular to the vertical axis of the specimen. The results of tests on these smaller coupons will typically yield lower strengths than if the larger. Standard Specification for Segmental Retaining Wall Units (ref. The coupon width is to be as close to 2 in. Further information on the design of segmental retaining walls can be found in Design Manual for Segmental Retaining Walls (ref. 5) requires that specimens cut from full-size units for compression testing shall be a coupon with a height to thickness ratio of 2 to 1 before capping and a length to thickness ratio of 4 to 1. These demands include impact and vibration during transportation. or by other methods such as anchoring to geosynthetic reinforcement embedded in the soil.68) 2. finish. such as a specific weight classification. higher compressive strength. Standard Specification for Loadbearing Concrete Masonry Units (ref. they should be specified separately by the purchaser. Proper equipment and procedures are essential to prevent damaging the test specimen as a result of saw-cutting. ASTM C 1372 covers both solid and hollow units which are to be installed without mortar (dry-stacked). Due to the direct relationship between compressive strength and tensile strength. full-size specimen were tested. structural integrity. These requirements are intended to assure lasting performance. Saw-cutting is the required method of extracting a test specimen from a full size unit. diamond-tipped blades Table 1—Strength and Absorption Requirements (ref.earth. The three classifications. deicing material exposure. Units used in exposed wall construction are not to show chips or cracks or other imperfections in the exposed face when viewed from a distance of not less that 20 ft (6. ASTM C 1372 includes three different methods of satisfying freeze-thaw durability requirements: 1. tests in water are considered sufficient. Similar to compression testing. 33 . While reduced voids indicate a desired tightly compacted unit. ASTM C 140 requires that specimens be dried for a period of not less than 24 hours at a temperature of at least 212 °F (100 °C). “Height” refers to the vertical dimension of the unit as placed in the wall. are a function of the oven dry density of the concrete. Many variations can exist in exposure conditions. This value is used to represent the volume of voids in a concrete masonry unit. (25. sunlight exposure. it generally is not practical to test full-size retaining wall units in absorption tests due to their size and weight. Lightweight aggregates used in the production of lightweight and medium weight units contain voids within the aggregate itself that also fill with water during the immersion test. “width” refers to the horizontal dimension of the unit measured perpendicular to the face of the wall. When placing larger specimens in an oven. Testing larger specimens requires particular attention to drying times. Dimensional tolerance requirements for width are waived for split faced and other architectural surfaces. Permissible Variations in Dimensions Mortarless systems require consistent unit heights to maintain vertical alignment and level of the wall. and normal weight. including voids inside the aggregate itself. Absorption Absorption requirements are also included in Table 1.02 inches (0. Sampling location typically has little effect on tested results. Freezing and thawing cycles and a constant source of moisture must both be present for potential damage to occur. Regarding dimensions. four of five specimens shall have less than 1. The blade should have a diameter sufficient enough to make all cuts in a single pass. 2. Therefore. Most segmental retaining wall units fall into the normal weight category. However. and others. Manufacturers of the unit (or licensors of proprietary shapes) should be consulted about recommended locations for obtaining the compression specimen. Freeze-Thaw Durability Segmental retaining wall units may be used in aggressive freezing and thawing environments. In addition.4 mm) in any dimension. Therefore. 6).2% of the previous specimen weight). are not grounds for rejection. If not dried adequately. (3. the requirements above apply only to “areas where repeated freezing and thawing under saturated conditions occur. chemical exposure. because it takes a greater length of time to remove all moisture from larger masses. five specimens shall each have less than 1% weight loss after 100 cycles in water using ASTM C 1262 (ref. tightly compacted lightweight and medium weight units will still have higher absorption due to the voids in the aggregates. Minor cracks incidental to the usual method of manufacture or minor chipping resulting from customary methods of handling in shipment and delivery. Absorption limits are typically expressed as mass (weight) of water absorbed per concrete unit volume. The surface is intended to be rough to satisfy the architectural features desired and can not be held to a specific tolerance. For this reason the maximum allowable absorption requirements vary according to weight classification. directional facing. this relationship is opposite of the absorption characteristics of the material. source and amount of moisture. For most applications. proven field performance. The 24-hour time period does not start until the oven reaches the specified temperature. For this reason permissible variation in dimensions is limited to not more than + 1/8 in. As previously discussed. freeze-thaw damage can occur when units are saturated with water and then undergo temperature cycles that range from above to below the freezing point of water. or cracks not wider than 0. reported absorptions will be lower than the actual value. lightweight. any of which may affect the freeze-thaw durability performance of the units.2 mm) from the specified standard dimensions.5 mm) and not longer than 25% of the nominal height of the unit. Finish and Appearance Finish and appearance requirements are virtually the same as those in ASTM C 90 for loadbearing concrete masonry units. This will require 48 hours or more for some specimens.” Freeze-thaw durability tests can be conducted in accordance with ASTM C 1262 using water or saline as the media. medium weight. up to five percent of a shipment are permitted to contain chips not larger than 1 in. ASTM C 140 permits the testing of segments saw-cut from full-size units to determine absorption and density.5% weight loss after 150 cycles in water using ASTM C 1262. it may take several hours for the oven to reach the prescribed temperature. Such variations include: maximum and minimum temperatures. ASTM C 140 then requires that specimen weights be determined every two hours to make sure that the unit is not still losing water weight (maximum weight loss in two hours must be less than 0. Weight Classification Weight classifications for segmental retaining wall units are defined in Table 1. Segmental retaining wall units in many areas of the country are not exposed to severe exposures. This is preferred to expressing by percentage which permits a denser unit to absorb more water than a lighter weight unit. “Length” refers to the horizontal dimension of the unit measured parallel to the running length of the wall. The void space is measured by determining the volume of water that can be forced into the unit under the nominal head pressure that results from immersion in a tank of water. rate of temperature change.1 m) under diffused lighting. or 3.on a masonry table saw are recommended. duration of temperatures. Standard Specification for Dry-Cast Segmental Retaining Wall Units. ASTM C 140-03. if the units fail the test. 2005. ASTM International. National Concrete Masonry Association. National Concrete Masonry Association. Standard Methods of Sampling and Testing Concrete Masonry Units and Related Units. However. 7. 2003. a new sample is selected by the purchaser from the remaining units of the shipment and tested. 2004. See TEK 18-10 Sampling and Testing Segmental Retaining Wall Units (ref. ASTM C 1372-04e2. ASTM International. 2. Design Manual for Segmental Retaining Walls. consideration should be given to performing the tests in saline. Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. 2002. Standard Specification for Loadbearing Concrete Masonry Units. If a sample fails. 2003.org To order a complete TEK Manual or TEK Index. Herndon. Segmental Retaining Wall Drainage Manual. 2nd edition. 2007. National Concrete Masonry Association. Compliance Guidance regarding compliance is also provided in ASTM C 1372. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. TEK 18-10. and acceptance. 6. However. The specification also provides guidance on responsibility for payment of the tests. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. ASTM C 1262-07. the seller bears the cost of the testing. Standard Test Method for Evaluating the Freeze-Thaw Durability of Manufactured Concrete Masonry Units and Related Concrete Units. 4.If the units are to be exposed to deicing salts on a regular basis. 7) for more detailed information on SRW unit sampling. ASTM International. ASTM International. Sampling and Testing Segmental Retaining Wall Units. 2002. Then. the manufacturer can then remove or cull units from the shipment. If the second sample passes then the remaining units of the lot being sampled are accepted for use in the project.ncma. testing. Virginia 20171 www. 3. the purchaser typically pays for the testing if the units pass the test. If the second sample fails. REFERENCES 1. which is paid for by the manufacturer. Unless otherwise provided for in the contract. ASTM C 90-03. no pass/fail criteria has been adopted by ASTM for saline testing. the entire lot represented by the sample is rejected. however. 5. 34 contact NCMA Publications (703) 713-1900 . towards roof drains. testing INTRODUCTION Concrete roof pavers provide resistance to wind uplift and surface protection for roofing membranes. and other equipment without damaging the roofing membrane and insulation. Also presented are methods of sampling and testing pavers to demonstrate compliance with these requirements. TEK 2-5A © 1999 National Concrete Masonry Association (replaces TEK 2-5) TEK 2-5A Unit Properties 8" MAX. PERIMETER SPACE DECK MEMBRANE ROOFING INSULATION TREATED NAILER AS REQUIRED Figure 1—Typical Concrete Paver Roof Installation 35 (1999) . See Figure 1 for a typical concrete paver roof installation. or rain water to drain from below the roof paver surface. ballasted roofs. min. interlocking roof pavers. 1/4" per foot (20 mm/m). roof pavers can be routinely subjected to freezing and thawing in a saturated condition. Noninterlocking systems resist uplift by the ballast weight of individual paver units. Where roof pavers are installed over existing roofs. durability. flexural strength. Design and Execution In addition to the physical characteristics of the roof paver units themselves. Ballast weight of the concrete roof paver system is designed to resist uplift forces from the entire range of design wind speeds. In cold weather regions. COUNTERFLASHING IN REGLET Concrete Roof Paver Units Roof pavers are exposed to severe weather conditions due to their horizontal installation over flat or low slope roofs. roof ballast.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology SPECIFICATIONS FOR CONCRETE MASONRY ROOF PAVERS Keywords: ASTM Standards. Typically these units will also be required to support foot traffic. Since modern roof paver systems usually contain integral drainage grooves. Specifications for concrete roof pavers included herein specify the physical requirements to ensure field performance. loaded wheelbarrows. it is important to evaluate the structural adequacy of the existing roof to support the roof pavers. Interlocking systems distribute uplift forces to adjacent pavers by a tongue and groove edge connection or by a mechanical interlock between units. roof pavers. Concrete Roof Paver Systems Concrete roof paver systems are categorized as interlocking or non-interlocking. CLEAT & ANGLE SECURED TO WALL RETAINER ANGLE BASE FLASHING CONCRETE ROOF PAVER MASTIC OR SEALANT 3 / 8 " MIN. Concrete roof paver systems are installed over flat roofs and allow melting snow and ice. The following specification is recommended to ensure a product of consistent quality. Concrete roof pavers also provide a durable wearing surface for roof maintenance and repair operations. absorption. These conditions require that concrete roof pavers be manufactured to specific criteria. consideration should be given to their orientation parallel to the roof slope. compressive strength. parameters for design of concrete roof paver systems include the following: • Basic wind speed at building site • Building height • Parapet height • Wind gust factors • Adjacent structures and terrain features to account for obstructions in the area • Load capacity of the roof structure • Roof discontinuities • Roof slope • Weight of the units Roof structures must be designed to support the dead weight of roof paver systems. 5 Blast Furnace Slag . Building codes and other standards should be consulted in designing for wind uplift resistance. (3) Limitation on Loss on Ignition . finely ground silica. with or without the inclusion of other materials.1. and mineral aggregates. except that grading requirements shall not necessarily apply: 3. 2.2 Concrete roof pavers covered by this specification are made from lightweight or normal weight aggregates.2.1 Portland Cement . Note 1 – The design of roof ballast systems for resisting wind uplift is beyond the scope of this standard. coloring pigments. shall be shown by test or experience satisfactory to the purchaser to be not detrimental to the durability of the units. integral water repellents.1 C 33. Lightweight Aggregates . Normal Weight Aggregates .Air-entraining agents. Referenced documents 2.Materials shall conform to the following applicable specifications: 3. 4.Specification C 595/C 595M or C 1157/C 1157M.Aggregates shall conform to the following specifications. Physical Requirements 4.2 331.Specification C 989 3. water.1 Cementitious Materials .1. for use as roof ballast and protection of roof membranes. with a minimum 85% calcium carbonate (CaCO3) content.7%.1 ASTM Standards: C33 Specification for Concrete Aggregates C140 Methods of Sampling and Testing Concrete Masonry Units C150 Specification for Portland Cement C331 Specification for Lightweight Aggregates for Concrete Masonry Units C595/C595M Specification for Blended Hydraulic Cements C618 Specification for Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Portland Cement Concrete C989 Specification for Ground Granulated BlastFurnace Slag for Use in Concrete and Mortars C1157/C1157M Performance Specification for Blended Hydraulic Cement C1262 Standard Test Method for Evaluating the Freeze-Thaw Durability of Manufactured Concrete Masonry Units and Related Concrete Units 3.2 Aggregates . Materials 3. 1.Portland Cement conforming to specification C 150 modified as follows: 3. 3. 1.5% (2) Limitation on Air Content of Mortar .3 Other Constituents .specification C 150. or both.1. provided the requirements of Specification C 150 as modified are met: (1) Limitation on Insoluble Residue . The values given in parentheses are for information only.3 The values stated in inch-pound units are to be regarded as the standard.2.1. 3. and other constituents shall be previously established as suitable for use and shall conform to applicable ASTM Standards or.2.1 This specification covers concrete roof pavers made from portland cement.1 Limestone .3 Blended Cements .Specification for CONCRETE ROOF PAVERS 3. 1.4 Pozzolans .Specification C 3.1.Specification C 618 3. 22% max.Specification 3.2 Modified Portland Cement .Limestone.1 At the time of delivery to the purchaser.Volume percent.1. all units shall conform to the requirements prescribed in Table 1 and shall have a minimum net area average compression strength (average of 3 units) of 3000 psi (20.1. shall be permitted to be added to the cement.68 MPa) Table 1—Absorption Requirements for Concrete Roof Pavers Concrete Density lb/ft3/(kg/m3) 95 (1522) or less over 95 to 115 (1522 to 1842) 115 (1842) or more Maximum Water Absorption lb/ft3/(kg/m3) (average of 3 units) 15 (240) 13 (208) 10 (160) 36 . Scope 1. Permissible Variations in Dimension and Weight 5. are not grounds for rejection.2 4. these criteria should be specified by the purchaser. (3. 4. the units shall be tested in accordance with the requirement of Section 7. and length shall not differ by more than ± 1/8 in. Where required. Finish and Appearance 6.2 mm) from the specified standard dimensions. height.2 Resistance to Flexural Load .7 kg/m2) from the specified weight. (25.1 Overall dimensions for width.2. (0.4.1 All units shall be sound and free of cracks or other defects that would interfere with the proper placement of the unit or would significantly impair the strength or permanence of the construction. 6. or cracks not wider than 0. 4. freeze-thaw durability shall be demonstrated by test or by proven field performance that the concrete roof paver units have adequate durability for the intended use.5% of its initial weight. 5. When testing is required by the specifier to demonstrate freezethaw durability.3.90 LENGTH UNIT NEOPRENE PAD CAP THIS SURFACE Figure 2—Compressive Strength Test Set-up Figure 3—Flexural Strength Test Set-up 37 . Minor cracks incidental to the usual method of manufacture or minor chipping resulting from customary methods of handling in shipment and delivery. 6. or (2) the weight loss of each of four or five test specimens at the conclusion of 150 cycles shall not exceed 1. Note 3 . The finished surfaces that will be TEST FORCE DIRECTION LOAD CUT STRIP FROM FULL PAVER 1.75" SPECIMEN HEIGHT (EQUAL TO SPECIMEN WIDTH) SP EC IM EN CAP THIS SURFACE LE NG TH SPECIMEN WIDTH NEOPRENE PAD 2 X 4 WOOD BLOCK CUT TO WIDTH OF ROOF PAVER UNIT ROOF PAVER 1" DIA.0 lb/ft2 (9.4 mm) in any dimension. Note 2 – This standard does not include criteria for large hail stone impact.75" 1.3 Ballast Weight—Requirements for ballast weight per unit area shall be specified separately.5 mm) and not longer than 25% of the nominal height of the unit is permitted. 6. 5.93 MPa) when tested in accordance with Section 7.Standard dimensions of units are the manufacturer’s designated dimensions.The average resistance to flexural load for three paver units shall exceed 350 lb (1557 N) and resistance to flexural load of each individual unit shall exceed 280 lb (1246 N) when tested in accordance with Section 7.2 Five percent of a shipment containing chips not larger than 1 in. STEEL ROD .02 in.3 The color and texture of units shall be specified by the purchaser.2 Ballast weight shall not differ by more than ± 2.4 Freeze-Thaw Durability—In areas where repeated freezing and thawing under saturated conditions occur. 4.with no individual unit compressive strength less than 2600 psi (17.1 Specimens shall comply with either of the following: (1) the weight loss of each of five test specimens at the conclusion of 100 cycles shall not exceed 1% of its initial weight. and dimensional tolerance in accordance with Test Methods C 140. 8. 8. 7.1 If a sample fails to conform to the specified requirements.1 The purchaser or authorized representative shall be accorded proper facilities to inspect and sample the units at the place of manufacture from the lots ready for delivery.ncma. Compliance 7.3 When required. Virginia 22071-3499 www. manufacturing process. 7.exposed in place shall conform to an approved sample consisting of not less than four units. the cost is typically borne by the seller. the remaining portion of the shipment re[resented by the sample fails to meet the specified requirements. contact NCMA Publications (703) 713-1900 38 . If the second sample fails to meet the specified requirements. flexural load. the manufacturer shall be permitted to remove units from the shipment.org To order a complete TEK Manual or TEK Index. Herndon. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. represetning the range of texture and color permitted. concrete mix design. sample and test five specimens for freeze-thaw durability in water in accordance with C 1262. NATIONAL CONCRETE MASONRY ASSOCIATION 2302 Horse Pen Road. (2) if the results of the tests show that the units conform to the specification requirements. and curing method. Note 4 .Unless otherwise spcified in the purchase order. A new sample shall be selected by the purchaser from the remaining units from the shipment with a similar configuration and dimension and tested at the expense of the manufacturer. absorption. the cost of the test is typically borne as follows: (1) if the results of the tests show that the units do not conform to the requirements of this specification. conducted not more than 24 months prior to delivery. Sampling and Testing 7. the remaining portion of the shipment represented by the sample meets the specified requirements. the cost is typically borne by the purchaser. If the second sample meets the specified requirements.2 Sample and test units for compressive strength. Freeze-thaw durability shall be based on tests of units made with the same materials. Although not all aggregate types are produced in all areas of the country. size. In production. compressive strength. Whether through direct measurement or by cal39 TEK 2-6 © 2008 National Concrete Masonry Association . the resulting density of concrete masonry units can be varied by the producer to achieve one or more desired physical properties. through a listing service. aggregates used to manufacture concrete masonry units must conform to either ASTM C 33. strength. may be directly referenced in building codes such as the International Building Code (ref. configurations and densities. Although most of the following discussions use lightweight and normal weight concrete masonry as examples. Standard Specification for Concrete Aggregates (ref. As with all physical properties of concrete masonry. minor variation in density from unit to unit and from batch to batch should be expected. Fire Resistance Rating of Concrete Masonry Assemblies (ref. This TEK illustrates the various physical and design properties influenced by the density of concrete masonry units. mined or quarried from a natural source.680 kg/m3) or more. lightweight aggregates may be manufactured. 5). Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units (ref. If a concrete masonry unit of a specific aggregate type is desired. ASTM C 90. but less than 125 lb/ft3 (2. 6). FIRE RESISTANCE Fire resistance ratings of one to four hours can be achieved with concrete masonry of various widths (or thicknesses). 3) defines three density classes for concrete masonry units: • Lightweight – units having an average density less than 105 lb/ft3 (1. or by a standardized calculation procedure. color. 1). normal weight aggregates. Before specifying a specific density range. and provides references to guide the user towards a fuller discussion and more detailed information. but largely by the type of aggregate used in production. or a by-product of another process. water penetration resistance INTRODUCTION The versatility of concrete masonry as a construction assembly is well established through the variety of applications and structures it is used to create. movement control. productivity. shape. it should be specified in the project documents along with the other physical properties of the concrete masonry units such as size.000 kg/m3) or more. the properties of medium weight masonry can typically be expected to fall between the two. Concrete masonry offers almost limitless combinations of color. In accordance with ASTM C 90. • Medium Weight – units having an average density of 105 lb/ft3 (1. 2). aesthetics.680 kg/m3). other properties or characteristics. such as aesthetics and construction productivity fall outside the scope of the building code. texture. strength. Through the use of lightweight aggregates. • Normal Weight – units having an average density of 125 lb/ft3 (2. When a specific density classification or density range is desired for a project. and texture.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology DENSITY-RELATED PROPERTIES OF CONCRETE MASONRY ASSEMBLIES Keywords: acoustics. fire resistance rating. energy efficiency.000 kg/m3). 4). such as sound transmission loss. concrete density. BASICS OF CONCRETE MASONRY UNIT DENSITY The density of a concrete masonry unit is expressed as the oven-dry density of concrete in pounds per cubic foot (lb/ft3 [kg/m3]) as determined in accordance with ASTM C 140. Whereas normal weight aggregates are typically mined or quarried. non-local aggregates may be available. and density. potential suppliers should be consulted for availability prior to specifying them. designers are encouraged to first consult with manufacturers local to the project for availability. As outlined in TEK 7-1A. Standard Specification for Lightweight Aggregates for Concrete Masonry Units (ref. the fire resistance rating of a concrete masonry assembly can be determined by physical testing. the density of a given concrete masonry unit is controlled in part by the methods used to manufacture the unit. or blends of lightweight and normal weight aggregates. or ASTM C 331. Standard Specification for Loadbearing TEK 2-6 Unit Properties (2008) Concrete Masonry Units (ref. Note that while some of these density-related properties. culation, the fire resistance rating of a given concrete masonry assembly varies directly with the aggregate type and with the volume of concrete in the unit, expressed as the equivalent thickness. Through extensive testing and analysis, empirical relationships have been established between the fire resistance rating of a concrete masonry assembly and the corresponding type of aggregate and equivalent thickness of the unit used to construct the assembly. These relationships are summarized in Figure 1. These relationships between aggregate type/equivalent thickness and the corresponding fire resistance rating are shown graphically in Figure 2. Note that equivalent thicknesses used in Figure 2 are for illustration only, and represent typical equivalent thicknesses for standard hollow concrete masonry units. Actual units may have higher or lower equivalent thicknesses than those shown, with corresponding higher or lower fire resistance ratings. In general, 8-in. (203-mm) and wider concrete masonry units can be supplied with fire resistance ratings up to four hours. For example, a typical hollow 8 in. (203 mm) concrete masonry unit with an equivalent (solid) thickness of 4.0 in. (102 mm), can have a calculated fire resistance rating from 1.8 hours to 3 hours, depending on the type of aggregate used to produce the unit. SOUND CONTROL The control of sound between adjacent dwelling units or between dwelling units and public areas is an important design consideration for user comfort. Sound Transmission Class (STC), expressed in decibels (dB), is a single number rating that provides a measure of the sound insulating properties of walls. The higher the STC rating, the better the assembly can block or reduce the transmission of sound across it. For concrete masonry construction, STC can be calculated using the installed weight of the assembly, which is a function of the unit density, unit size and configuration, presence of surface finishes, and presence of grout or other cell-fill materials such as sand. See Sound Transmission Class Ratings for Concrete Masonry Walls, TEK 13-1B (ref. 7) for a full discussion. In accordance with Standard Method for Determining the Sound Transmission Class Rating for Masonry Walls (ref. 8), the STC rating for single wythe concrete masonry assemblies without additional surface treatments is determined by the following equation: STC = 19.6W0.230 Eqn. 1. SI STC = 13.6W0.230 Where W = the average wall weight based on the weight of: the masonry units; the weight of mortar, grout and loose fill material in the voids within the wall; and the weight of surface treatments (excluding drywall) and other wall components, lb/ft2 (kg/m2). All other design variables being equal, the STC value of masonry construction increases with increasing unit density. Note that STC values determined by the calculation tend to be conservative. Generally, higher STC values are obtained by referring to actual tests than by the calculation. In addition to the STC rating, the value of the Noise Reduction Coefficient (NRC) can also be influenced to some extent by concrete unit density. NRC measures the ability of a surface to absorb sound (based on a scale of 0 to 1), which can be an important characteristic in some applications, such as concert halls and assembly areas. A higher NRC value indicates that more sound is absorbed by an assembly. NRC values for concrete masonry walls are tabulated according to: the application of any coatings to the wall, the surface texture (coarse, medium or fine) and the density classification (lightweight or normal weight). Aggregate type in the concrete masonry unit2 Calcareous or siliceous gravel the equi . 4 ) .0 5 in thicknes Limestone, cin7 8 mm (103 4 in. 4 mm particula ders or slag (19 ) solid un Expanded clay, The equivalent thickness of this particular unit (a shale or slate solid unit with the same amount of material) is Expanded slag or 4.04 in. (103 mm). pumice Minimum required equivalent thickness for fire resistance rating, in. (mm)1 4 hr 3 hr 2 hr 1.5 hr 1 hr 0.75 hr 0.5 hr 6.2 (157) 5.9 (150) 5.0 (130) 4.7 (119) 5.3 (135) 5.0 (127) 4.4 (112) 4.0 (102) 4.2 (107) 4.0 (102) 3.6 (91) 3.2 (81) 3.6 (91) 3.4 (86) 3.3 (84) 2.7 (69) 2.8 (71) 2.7 (69) 2.6 (66) 2.1 (53) 2.4 (61) 2.3 (58) 2.2 (56) 1.9 (48) 2.0 (51) 1.9 (48) 1.8 (46) 1.5 (38) 1 Fire resistance ratings between the hourly fire resistance rating periods listed may be determined by linear interpolation based on the equivalent thickness value of the concrete masonry assembly. 2 Minimum required equivalent thickness corresponding to the hourly fire resistance rating for units made with a combination of aggregates shall be determined by linear interpolation based on the percent by volume of each aggregate used in the manufacture. Figure 1— Calculated Fire Resistance Rating for Single Wythe Concrete Masonry Walls 40 7 6 180 160 Typical equivalent thickness of a hollow 16 in. (406 mm) Typical equivalent thickness of a hollow 14 in. (356 mm) unit 140 Typical equivalent thickness of a hollow 12 in. (305 mm) unit 120 Typical equivalent thickness of a hollow 10 in. (254 mm) unit 4 Typical equivalent thickness of a hollow 8 in. (203 mm) unit 100 Typical equivalent thickness of a hollow 6 in. (152 mm) unit 80 3 Typical equivalent thickness of a hollow 4 in. (102 mm) unit 60 Equivalent thickness, mm Equivalent thickness, in. 5 2 40 1 20 0 0 0.5 0.75 Calcareous or siliceous gravel 1 1.5 Fire resistance, hr Limestone, cinders, or slag 2 3 Expanded clay, shale, or slate 4 Expanded slag or pumice Figure 2—Calculated Fire Resistance Ratings Assuming a similar surface texture and coating, a concrete masonry wall constructed with lightweight units will have a higher NRC than a companion wall constructed with normal weight units, due to the larger pore structure often associated with lower density units. Painting or coating the surface of the concrete masonry assembly reduces the NRC for both lightweight and normal weight concrete masonry. See Noise Control with Concrete Masonry, TEK 13-2A (ref. 9) for a full discussion. Table 1—Absorption Requirements for Concrete Masonry Units Density Maximum water absorption, lb/ft3 (kg/m3) classification Average of 3 units Individual unit Lightweight 18 (288) 20 (320) Medium weight 15 (240) 17 (272) Normal weight 13 (208) 15 (240) WATER PENETRATION AND ABSORPTION COMPRESSIVE STRENGTH Regardless of unit density, all loadbearing concrete masonry units meeting the physical properties of ASTM C 90 (ref. 3) must have a minimum average compressive strength of 1,900 psi (13.1 MPa). It is possible to produce concrete masonry units that meet or exceed the ASTM C 90 minimum strength in any density classification, although not all combinations of physical properties may be commonly available in all regions. Therefore, local producers should always be consulted for product availability before specifying. In general, for a given concrete masonry unit mix design, higher compressive strengths can be achieved by increasing the unit density through adjustments to the manufacturing methods. (ref. 16). Concrete masonry unit specifications typically establish upper limits on the amount of water permitted to be absorbed. Expressed in pounds of water per cubic foot of concrete (kilograms of water per cubic meter of concrete), these limits vary with the density classification of the unit, as shown in Table 1. While the absorption values are not directly related to unit physical properties such as compressive strength and resistance to mechanisms of deterioration such as freezethaw, they do provide a measurement of the void structure within the concrete matrix of the unit. Several production variables can affect the void structure, including degree of compaction, water content of the plastic mix, and aggregate gradation. Due to the vesicular structure of lower density units, there is a potential for higher measured absorption than is typical for most higher density units. Consequently, 41 ASTM C 90 permits lower density units to have a higher maximum absorption value. The higher absorption limits permitted by ASTM C 90 for lower density units do not necessarily correlate to reduced water penetration resistance. One reason is that water penetration resistance is known to be highly affected by workmanship and dependent on detailing for water management. It is generally recognized that these two factors more heavily influence the wall’s water penetration resistance than do other factors, such as unit density. AESTHETIC CONSIDERATIONS One of the most significant architectural benefits of designing with concrete masonry is the versatility afforded by the layout and appearance of the finished assembly, which can be varied with the unit size and shape, color of the units and mortar, bond pattern, and surface finish of the units. The term “architectural concrete masonry unit” (ref. 10) is often used to generically describe units exhibiting any number of surface finishes or colors. Loadbearing single wythe masonry walls constructed with these units uniquely offer the designer structural function, envelope enclosure and the aesthetics of a finished wall surface without the need for additional materials, components or assemblies. In general, the many options available for architectural concrete masonry units can be offered in any of the three unit density classifications. However, with respect to unit appearance, any change in aggregates (whether a change in source or a change in aggregate type) used to manufacture a concrete masonry unit may change its color or texture, particularly for units with mechanically altered features such as split or ground-face surfaces. As a result, when aesthetics are an important consideration, sample units submitted for conceptual design should incorporate the specific aggregate intended to be used in the actual production of the units. Note that various degrees of surface “smoothness” (tight, fine, medium, coarse) can be obtained using the same aggregate by varying the mix design (proportions and moisture), aggregate gradation, aggregate shape, and degree of compaction during manufacture. In addition to production variables, the appearance of the finished masonry is also affected by workmanship, and the mortar color and jointing. Where color, texture and finish are of particular concern, the designer should specify a special sample panel for review and approval during the submittal process (ref. 1, 17). ENERGY EFFICIENCY When selecting masonry for its energy efficiency, two material thermal properties should be considered: • R-value—a material’s ability to resist the transfer of heat under steady-state conditions; and • Thermal mass (heat capacity)—a material’s ability to store and release heat (ref. 11). These physical properties, in combination with a building’s design, layout, location, climate, exposure, use, or occupancy as required by building codes, influence the energy efficiency and thermal characteristics of the building envelope and of the building. Increasing the unit density, unit thickness, unit solid content, and amount/extent of grout, increases the installed weight of the masonry assembly, which is directly related to its heat capacity. (ref. 11). Conversely, increasing the density or amount of grout used in a concrete masonry assembly decreases its R-value (ref. 12). Because of the multitude of variables that determine the overall energy efficiency of a structure, some projects benefit more by increasing the thermal mass of an assembly while others see more energy efficiency by increasing the R-value. As such, the unique requirements of each project should be considered individually for maximum benefit. STRUCTURAL DESIGN INFLUENCES The structural design of masonry is based on the specified compressive strength of masonry, f'm, which is a function of the compressive strength of the unit and the type of mortar used in construction. It is possible to produce a wide range of compressive strengths within each of the density classes. Therefore, for a given unit compressive strength and mortar type, the strength of the masonry assembly is unaffected by the unit density. As such, the design flexural, shear, and bearing strengths of masonry, some deformational properties such as elastic modulus, and the structural behavior of the masonry assembly determined by contemporary codes and standards are independent of the density of the concrete masonry unit. Unit density, however, can influence other structural design considerations, aside from compressive strength. Reducing the density of a concrete masonry unit can reduce the overall weight of a structure, and potentially reduce the required size of the supporting foundation, slab, or beam. Reducing the weight of a structure or element also reduces the seismic load a structure or element must be designed to resist, because the magnitude of seismic loading is a direct function of dead load. As with thermal mass and sound control, there may be circumstances where increasing the unit density is structurally beneficial. For example, the structural stability against overturning and uplift is increased with increasing structural weight. Hence, while increased structural dead load increases seismic design forces, it also concurrently helps to resist wind loads. Therefore, there may be some structural advantage to using lightweight units in areas of high seismic risk; and normal weight units in areas prone to high winds, hurricanes and/or tornadoes. Structural design considerations, however, are often relatively minor compared to other factors that may influence the choice of unit density. PRODUCTIVITY For a given unit configuration, and with all other factors affecting production being equal, lower unit weights 42 unit size and shape. ASTM International. Holm. Concrete Facts. 2007. National Concrete Masonry Association. ASTM C 140-06. Sound Transmission Class Ratings for Concrete Masonry Walls. 2002 and 2005. 2006. 5. International Code Council. ACI 530. National Concrete Masonry Association. 2. Virginia 20171 www. Crack Control in Concrete Masonry Walls. No. established movement control recommendations (refs. A. Productivity and Modular Coordination in Concrete Masonry Construction. 2006. 1972. TEK 7-1A.org To order a complete TEK Manual or TEK Index. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. 2005. 2002. but generally the resulting effects of varying unit density on masonry behavior and performance are quite limited. the designer can be assured that concrete masonry constructed of any unit density offers sufficient flexibility and alternatives in the choice of materials. SUMMARY Issues of masonry design and construction can be influenced and addressed to varying extents through the choice of concrete masonry unit density. and reinforcement and other detailing (ref. Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units. The Masonry Society. REFERENCES 1. R-Values for Single Wythe Concrete Masonry Walls. 2007. Control Joints for Concrete Masonry Walls – Empirical Method. and construction detailing to satisfy the structural and architectural requirements of the project. Standard Specification for Concrete Aggregates.typically enable a mason to lay more units within a given timeframe (ref. 3. National Concrete Masonry Association. TEK 13-2A. 43 contact NCMA Publications (703) 713-1900 . 2001. TEK 10-2B. Specification for Masonry Structures. 2006. Noise Control with Concrete Masonry. Standard Specification for Loadbearing Concrete Masonry Units. ASTM C 90-06a. Architectural Concrete Masonry Units. 2005. despite the fact that not all concrete masonry units exhibit the same linear drying shrinkage within this limit. 17. TEK 10-2B (refs. 12. ASTM C 90 requires that linear drying shrinkage of all concrete masonry units. 2006. National Concrete Masonry Association. 16. regardless of unit density.1/ASCE 6/TMS 602. 6. ASTM C 331-05. TEK 10-1A.ncma. ASTM International. and Control Joints for Concrete Masonry Walls – Empirical Method. 2006. Notwithstanding these effects. TEK 10-1A. National Concrete Masonry Association. National Concrete Masonry Association. 9. Herndon. building size and configuration. the established movement control recommendations for concrete masonry construction are applicable. TEK 6-16. 14. Standard Specification for Lightweight Aggregates for Concrete Masonry Units. ASTM International. ASTM C 33-03. Other factors influencing the daily productivity of a mason may include environmental conditions. However. Engineered Masonry With High Strength Lightweight Concrete Masonry Units. 2003 and 2006. National Concrete Masonry Association. 13). TEK 4-1A. 13. masonry bond pattern. 2. 10. Fire Resistance Rating of Concrete Masonry Assemblies. 2007. TEK 6-2A. 14. International Building Code. See Crack Control in Concrete Masonry Walls. not exceed 0. TEK 2-3A. 15) for more detailed guidance. Vol. TMS 0302-07. 17. TEK 13-1B. 13). 14. ASTM International. National Concrete Masonry Association. Reported by the Masonry Standards Joint Committee. National Concrete Masonry Association.065% at the time of delivery to the jobsite. T. 7. 1989. MOVEMENT CONTROL Regardless of the density of a concrete masonry unit. design. 8. Standard Method for Determining the Sound Transmission Class Rating for Masonry Walls. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 11. 4. Heat Capacity (HC) Values for Concrete Masonry Walls. 2005. 15) are independent of the concrete masonry unit density. 15. S. rain. Grout is a close relative of mortar in composition and performance characteristics. 3) requires consideration of special construction procedures to help ensure the final construction is not adversely affected. wet weather construction. The best source for this type of information is the U. 44 TEK 3-1C © 2002 National Concrete Masonry Association (replaces TEK 3-1B) .ncdc.gov. However. Type III.4oC) during the first 48 or 24 hours after construction respectively. cold. however. Similarly the mean daily temperature is the average of the hourly temperatures forecast by the local weather bureau over a 24 hour period following the onset of construction. Weather Bureau. Minimum daily temperature is the lowest temperature expected during the period. mortar. windy weather construction INTRODUCTION Masonry construction can continue during hot. COLD WEATHER CONSTRUCTION When ambient temperatures fall below 40oF (4. grout. affecting workability.4oC) and only when sufficient water is available.S. This disruptive effect increases as the water content increases. compressive strength. highearly strength portland cement should be considered in lieu of Type I portland cement in mortar or grout to accelerate setting. grouted masonry needs to be protected for longer periods to allow the water content to be dissipated. mortar should not be allowed to freeze until the mortar water content is reduced from the initial 11% to 16% range to a value below 6%. Therefore. Department of Commerce which can be accessed at their web site http://www.4oC) provided cold weather construction and protection requirements of reference 3 are followed. Dry concrete masonry units have a demonstrated capacity to achieve this moisture reduction in a relatively short time. 3). Environmental Science Services Administration (ESSA) of the U. The acceleration not only reduces the curing time but generates more heat which is beneficial in cold weather. construction techniques. storage of materials. and susceptibility to freezing. Therefore. Temperatures between 40 and 90oF (4.4 and 32.2oC) are considered “normal” temperatures for masonry construction and therefore do not require special procedures or protection protocols.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology ALL-WEATHER CONCRETE MASONRY CONSTRUCTION Keywords: cold weather construction. TEK 3-1C Construction (2002) Mortar and Grout Performance Hydration and strength development in mortar and grout generally occurs at temperatures above 40oF (4.noaa. During cold weather. environmental conditions may warrant the use of special construction procedures to ensure that the masonry work is not adversely affected. bond.4oC). It is for this reason that the specification requires protection from freezing of mortar for only the first 24 hours (ref. Cement During cold weather masonry construction. Mortars and grouts mixed at low temperatures have longer setting and hardening times. and lower early strength than those mixed at normal temperatures. Effects of Freezing The initial water content of mortar can be a significant contributing factor to the resulting properties and performance of mortar. Research has shown a resulting disruptive expansion effect on the cement-aggregate matrix when fresh mortars with water contents in excess of 8 %mortar are frozen (ref. special protection considerations are required. masonry construction may proceed when temperatures are below 40oF (4. snow. In some cases. However. 2). mortars and grouts produced with heated materials exhibit performance characteristics identical to those produced during warm weather. hot weather construction. Work stoppage may be justified if a short period of very cold or very hot weather is anticipated. the Specification for Masonry Structures (ref. and wet weather conditions. In the following discussion. Similarly when the minimum daily temperature for grouted masonry or the mean temperature for ungrouted masonry falls below 40oF (4. The ability to continue masonry construction in adverse weather conditions requires consideration of how environmental conditions may affect the quality of the finished masonry. ambient temperature refers to the surrounding jobsite temperature when the preparation activities and construction are in progress. more attention must be directed toward the protection of grout because of the higher water content and resulting disruptive expansion that can occur from freezing of that water. One of the prerequisites of successful all-weather construction is advance knowledge of local conditions. 20 to 25oF (-6.9oC) Same as above. or mean daily temperature is predicted to fall below 40°F (4. polyethylene.9 to 0oC) Same as above for mortar. As indicated in Table 1a—Cold Weather Masonry Construction Requirements (ref. 3) due to corrosion of embedded metals and contribution to efflorescence. Material Storage Construction materials should be protected from water by covering.4 and 48.1oC) at time of grout placement.7 to -3. Heat masonry to a minimum of 40oF (4. Coverings for materials include tarpaulins. Maintain grout temperature above 70oF (21.9oC).9 to 4. plus use heat masonry surfaces under construction to 40oF (4. However. Remove visible snow and ice on masonry units before the unit is laid in the masonry.7oC) and below Maintain masonry temperature above 32oF (0oC) for 24 hours after construction by enclosure with supplementary heat. Do not heat water or aggregates above 140oF (60oC).4oC) Protect completed masonry from rain or snow by covering with a weather-resistive membrane for 24 hours after construction.7oC) and below Same as above.4°C) during the first 24 hours following construction of ungrouted masonry.4oC) prior to grouting. by infrared heat lamps. 20 to 25oF (-6. Antifreezes are not recommended for use in mortars and are prohibited for use in grouts. Maintain mortar temperature above freezing until used in masonry.4oC) Construction requirements Do not lay masonry units having a temperature below 20oF (-6. Heat grout aggregates and mixing water to produce grout temperatures between 70 and 120oF (21. 20oF (-6. or other water repellent sheet materials.7oC). While specifically not addressed by the Specification. If the weather and size of the project warrant.4°C) during construction. Extend time to 48 hours for grouted masonry unless the only cement in the grout is Type III portland cement. a shelter may be provided for the material storage and mortar mixing areas.9oC) Completely cover the completed masonry with a weather-resistive insulating blanket or equal for 24 hours after construction (48 hr for grouted masonry unless only Type III portland cement used in grout).4oC) and install wind breaks or enclosures when wind velocity exceeds 15 mph (24 km/hr). Table 1b—Cold Weather Masonry Protection Requirements (ref.1 and 48.7 to -3. Noncloride accelerators are available but they must be used in addition to cold weather procedures and not as a replacement for them. Remove snow and ice from foundation. 3) Mean daily temperature for ungrouted masonry Minimum daily temperature for grouted masonry Protection requirements 25 to 40oF (-3. Bagged materials and masonry units should be protected from precipitation and ground water by storage on pallets or other acceptable means. reinforced paper. Material Heating When the ambient temperature falls below 40°F (4. Grout materials to be 32oF (0oC) minimum.9oC). by electric heating blankets. or the minimum daily temperature is predicted to fall below 40°F (4. 3) requires specific construction and protection procedures to be implemented as summarized in Tables 1a and 1b.Admixtures The purpose of an accelerating type of admixture is to hasten the hydration of the portland cement in mortar or grout. or by other acceptable methods. Heat existing foundation and masonry surfaces to receive new masonry above freezing. plus provide an enclosure for the masonry under construction and use heat sources to maintain temperatures above 32oF (0oC) within the enclosure.2% chloride ions are not permitted to be used in mortar (ref. Heat mixing water or sand to produce mortar temperatures between 40 and 120oF (4.4°C) during the first 48 hours for grouted masonry. 3) Ambient temperature o 32 to 40 F (0 to 4. Specification for Masonry Structures (ref. 20oF (-6. the use of chloride admixtures in grout is generally discouraged. 45 . 25 to 32oF (-3. admixtures containing chlorides in excess of 0. 9oC). Also. 3).9 km/hr) Maintain sand piles in a damp. 3) are shown in Tables 2a and 2b. Above 115oF (46.4 and 32. mortar washout is no Table 2a—Hot Weather Masonry Preparation and Construction Requirements (ref. and mortar boards with cool water before they come into contact with mortar ingredients or mortar. the presence of rain. Use a water barrel as water hoses exposed to direct sunlight can result in water with highly elevated temperatures. Additional Recommendations Store masonry materials in a shaded area. Use cool mixing water for mortar and grout. even when the temperature of dry units approaches the 20oF (-6. loose condition.7oC) at the time of placement. or the likelihood of rain. HOT WEATHER CONSTRUCTION WET WEATHER CONSTRUCTION High temperatures. Masonry should never be placed on a snow or ice-covered surface. solar radiation. Ice is permitted in the mixing water as long as it is melted when added to the other mortar or grout materials.4oC) and maintained above that temperature for the first 48 hours (ref. should receive special consideration during masonry construction. Use mortar within 2 hours of initial mixing.8oC) or above 90oF (32. Glass Unit Masonry For glass unit masonry.2 m) ahead of masonry and to set masonry units within one minute of spreading mortar. at least three times a day until the masonry is three days old.Table 1a. Table 2b—Hot Weather Masonry Protection Requirements (ref. Hot weather construction procedures involve keeping masonry materials as cool as possible and preventing excessive water loss from the mortar.6oC) with a wind speed greater than 8 mph (12. as partially set or plastic mortar is susceptible to washout. Additionally. Even when ambient temperatures are between 40 and 90°F (4. masonry construction should not continue during heavy rains. it may lose water so rapidly that the cement does not fully hydrate. but the hot water resulting from hose inactivity should be flushed and discarded first. past requirements contained within Specification for Masonry Structures (ref.9 km/hr) Protection requirements Fog spray all newly constructed masonry until damp. 3) Ambient temperature Preparation and construction requirements Above 100oF (37. the bond between the mortar and the supporting surface will be compromised. both the ambient temperature and the unit temperature must be above 40oF (4.2oC) with a wind speed greater than 8 mph (12. wet frozen masonry units should be thawed before placement in the masonry.9 km/hr) Same as above.8oC) or above 90oF (32. Maintain mortar consistency by retempering with cool water. Furthermore. However. Movement occurring when the base thaws will cause cracks in the masonry. 46 . However. Flush mixer. the temperature of dry masonry units may be as low as 20oF (-6. This is no longer a requirement in the current document but the concept still merits consideration. The barrel may be filled with water from a hose. Maintain temperature of mortar and grout below 120oF (48.2oC) with a wind speed greater than 8 mph (12. Specific hot weather requirements of the Specification for Masonry Structures (ref. mortar mixing times should be no longer than 3 to 5 minutes and smaller batches will help minimize drying time on the mortar boards. If surface drying does occur. and ambient relative humidity influence the absorption characteristics of the masonry units and the setting time and drying rate for mortar. it may be advantageous to heat the units for greater mason productivity. 3) were to not spread mortar bed joints more than 4 feet (1.7oC) threshold. the mortar can often be revitalized by wetting the wall but care should be taken to avoid washout of fresh mortar joints.2°C). 3) Mean daily temperature Above 100oF (37.1oC) or above 105oF (40. which could result in reduced strength or staining of the wall. To minimize mortar surface drying. mortar transport container. after approximately 8 to 24 hours of curing (depending upon environmental conditions). Unless protected. When mortar gets too hot. plus materials and mixing equipment are to be shaded from direct sunlight. Early surface drying of the mortar results in decreased bond strength and less durable mortar. 1) provides guidance in this regard. Damp surfaces are not considered wet surfaces. 2).org To order a complete TEK Manual or TEK Index. A concrete masonry unit for which 50% or more of the surface area is observed to be wet is considered to have unacceptable moisture content for placement. This simple field procedure can quickly ascertain whether a concrete masonry unit has acceptable moisture content at the time of installation. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. TEK 3-4B Bracing Concrete Masonry Walls During Construction (ref. When rain is likely. Newly constructed masonry should be protected from rain by draping a weather-resistant covering over the assemblage. a surface would be considered wet if moisture is observed and the surface does not darken when free water is applied. Reported by the Masonry Standards Joint Committee. As a means of determining if a unit has acceptable moisture content at the time of installation. Recommended Maximum Unit Moisture Content When the moisture content of a concrete masonry unit is elevated to excessive levels due to wetting by rain or other sources. decreased mason productivity. Bracing Concrete Masonry Walls During Construction. Conversely. 1999. Specification for Masonry Structures. the unit is acceptable for placement. the danger of excessive wind resulting in structural failure of newly constructed masonry prior to the development of strength or before the installation of supports must be considered. WINDY WEATHER CONSTRUCTION In addition to the effects of wind on hot and cold weather construction. this is a design consideration with unreinforced masonry. the wetting of masonry by rainwater provides beneficial curing conditions for the mortar (ref. several deleterious consequences can result including increased shrinkage potential and possible cracking. Further. Virginia 20171-3499 www. For this application. all construction materials should be covered. the concerns associated with structural bond in reinforced masonry construction are diminished. ACI 530. The cover should extend over all mortar that is susceptible to washout. the following industry recommended guidance should be used. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive.ncma.longer of concern. National Concrete Masonry Association. a surface would be considered damp if some moisture is observed. If less than 50% of the surface area is wet. It should be noted that these limitations on maximum permissible moisture content are not intended to apply to intermittent masonry units that are wet cut as needed for special fit. 3.1-02/ASCE 6-02/TMS 602-02. 2002. and decreased mortar/unit bond strength. but the surface darkens when additional free water is applied. Herndon. While reinforced masonry construction does not rely on mortar/unit bond for structural capacity. As such. REFERENCES 1. 2000 2. Hot & Cold Weather Masonry Construction. TEK 3-4B. contact NCMA Publications (703) 713-1900 47 . Masonry Industry Council. Place mesh or other grout stop device under bond beam to confine grout or use solid bottom unit Vertical reinforcement lap and secure as required Reinforcement in bond beams is set in place as wall is laid up Flashing Leave this block out to serve as a cleanout until wall is laid up Drip edge Cells containing reinforcement are filled solidly with grout. concrete masonry units. If vertical reinforcement is spaced close together and/or there are a significant number of bond beams within the wall. continuous series of vertical spaces within the wall. heat capacity or anchor- age capabilities. demonstration panel. In partially grouted walls. When walls will be grouted. pour height. Grout is a mixture of: cementitious material (usually portland cement). reinforced concrete masonry. WALL CONSTRUCTION Figure 1 shows the basic components of a typical reinforced concrete masonry wall. blast resistance. it may be faster and more economical to solidly grout the wall. Grout may also be added to increase the wall's fire rating. grout. whether plain or reinforced. The industry is experiencing fast-paced advances in grouting procedures and materials as building codes allow new opportunities to explore means and methods for constructing grouted masonry walls. with or without reinforcement. grout is placed only in wall spaces containing steel reinforcement. and information on admixtures are covered in Grout for Concrete Masonry (ref. grout bonds the masonry units and reinforcing steel so that they act together to resist imposed loads. When all cores. and sometimes admixtures. Specifications for grout. 1). substantially free of mortar droppings Place mortar on cross webs adjacent to cells which will be grouted Figure 1—Typical Reinforced Concrete Masonry Wall Section 48 TEK 3-2A © 2005 National Concrete Masonry Association (replaces TEKs 3-2 and 3-3A) (2005) . aggregate. sampling and testing procedures. acoustic effectiveness termite resistance. grouting. reinforcement INTRODUCTION Grouted concrete masonry construction offers design flexibility through the use of partially or fully grouted walls. puddling. In reinforced masonry. It is also used to fill bond beams and occasionally to fill the collar joint of a multi-wythe wall. lift height. placing steel reinforcement and grouting.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology GROUTING CONCRETE MASONRY WALLS TEK 3-2A Construction Keywords: cleanouts. the wall is considered solidly grouted. construction techniques. are grouted. consolidation. This TEK covers methods for laying the units. concrete masonry units must be laid up so that vertical cores are aligned to form an unobstructed. enough water to cause the mixture to flow readily and without segregation into cores or cavities in the masonry. vertical cells should provide a continuous cavity. Grout may also be used to stabilize screen walls and other landscape elements. Grout is used to give added strength to both reinforced and unreinforced concrete masonry walls by grouting either some or all of the cores. (203 to 279 mm) (refs. Noncontact lap splices may be spaced as far apart as one-fifth the required length of the lap but not more than 8 in. If a dowel interferes with the placement of the units. 2. This slump may be adjusted under certain conditions such as hot or cold weather installation. open end or open core units (see Figure 3) should be considered as there is no space between end webs with these types of units. filling all spaces. full head joint mortaring should also be considered when solid grouting since it is unlikely that grout will fill the space between head joints that are only mortared the width of the face shell. At the footing. saw cutting or chipping away a portion of the web to better accommodate the dowel may also be acceptable. 4). If the wall will be partially grouted. (152 mm) vertically (see Figure 2). 3) at the time of placement.. To prevent bridging. the cross webs need not be mortared since the grout flows laterally. (203 mm) per Building Code Requirements for Masonry Structures (ref. Open end. when penetration resistance is a concern such as torm shelters and prison walls. as required Concrete masonry wall Dowels may be bent up to 1 in. Using the grout demonstration panel option in Specification for Masonry Structures (ref. reinforcing steel positioners or other adequate devices to hold the reinforcement in place are commonly used. Vertical reinforcing steel may be placed before the blocks are laid. When walls will be solidly grouted. the use of open-end A or Hshaped units will allow the units to be easily placed around the reinforcing steel (see Figure 3). (25 mm) horizontally for every 6 in. When reinforcement is placed after wall erection. If the wall will be solidly grouted. In cases such as those. they should align with the cores of the masonry units. If foundation Vertical reinforcement. If there is a substantial dowel alignment problem. but not required.Head and bed joints must be filled with mortar for the full thickness of the face shell. which will tend to bridge at these locations potentially causing incomplete filling of the grout space. This provision accommodates construction interference during installation as well as misplaced dowels. See the Grout Demonstration Panel section of this TEK for further information. This is because large protrusions can restrict the flow of grout. Approval should be obtained before adjusting the slump outside the requirements. or after laying is completed. On occasion there may be locations in the structure where splices are prohibited. as required dowels are present. the project engineer must be notified. If reinforcement is placed prior to laying block. Reinforcement can be spliced by either contact or noncontact splices.e. Those locations are to be clearly marked on the drawing. In certain instances. it may be bent a maximum of 1 in. Mortar that projects more than 1 /2 in. or "A" shaped unit Double open end or "H" shaped unit Grout. 3). grout slump is required to be between 8 and 11 in. mortar bedding under the first course of block to be grouted should permit grout to come into direct contact with the foundation or bearing surface. i. it is required that both horizontal and vertical reinforcement be located within tolerances and secured to prevent displacement during grouting (ref. 3) is an excellent way to demonstrate the acceptability of an alternate grout slump. (25 mm) laterally per 6 in. 3). (13 mm) into the grout space must be removed (ref. Laps are made at the end of grout pours and any time the bar has to be spliced. However. those webs adjacent to the cores to be grouted are mortared to confine the grout flow. (152 mm) vertically Concrete foundation Figure 2—Foundation Dowel Clearance Bond beam units Lintel unit Pilaster units Open core unit Figure 3—Concrete Masonry Units for Reinforced Construction 49 . The length of lap splices should be shown on the project drawings. low absorption units or other project specific conditions. Care should be taken to prevent excess mortar from extruding into the grout space. the grout may be confined within the desired grout area either by using solid bottom masonry bond beam units or by placing plastic or metal screening. which are removed prior to placement in the wall. Horizontal reinforcement in concrete masonry walls can be accommodated either by saw-cutting webs out of a standard unit or by using bond beam units. (3.5 m) lift Lap Cleanout 12 ft 8 in. Light rust. Shop drawings may be required before installation can begin. Mud. in the hollow center. Pilaster and column units are used to accommodate a wallcolumn or wall-pilaster interface. The primary structural reinforcement used in concrete masonry is deformed steel bars. TEK 12-4C for more information (ref.5 m) lift Lap Grouting without cleanouts: (Low-lift) No cleanouts required Wall built in 3 stages Bars spliced at pour height Three grout lifts 5 ft (1.5 m) pour and 5 ft (1.9 m) lift Lap Cleanout Grouting with cleanouts: Grouting with cleanouts per (High-lift) MSJC (2005) or grout demonstration panel: Cleanouts required Cleanouts required Wall built full height Wall built full height Bars installed full length (no splicing) Bars installed full length (no splicing) Three grout lifts One grout lift Figure 4—Comparison of Grouting Methods for a 12 ft-8 in. Open-ended units allow the units to be placed 2 ft 8 in. Concrete masonry units should meet applicable ASTM standards and should typically be stored on pallets to prevent excessive dirt and water from contaminating the units. expanded metal lath or other approved material in the horizontal bed joint before laying the mortar and units being used to construct the bond beam.Splices are not required to be tied. heavy rust and 2 ft 8 in. This eliminates the need to thread units over the top of the reinforcing bar. mill scale or a combination of both need not be removed from the reinforcement. Reinforcing bars must be of the specified diameter.5 m) lift around reinforcing bars. (3. oil. The concrete masonry units illustrated in Figure 3 are examples of shapes that have been developed specifically to accommodate reinforcement. type and grade to assure compliance with the contract documents. (813 mm) lift 5 ft (1.860 mm) High Concrete Masonry Wall 50 . if necessary. allowing space for vertical reinforcement and ties. The units may also need to be covered to protect them from rain and snow.5 m) lift 12 ft 8 in. See Steel Reinforcement for Concrete Masonry.5 m) pour and 5 ft (1. Roofing felt or materials that break the bond between the masonry units and mortar should not be used for grout stops. As the wall is constructed.9 m) pour and 12 ft 8 in (3. CONCRETE MASONRY UNITS AND REINFORCING BARS Standard two-core concrete masonry units can be effectively reinforced when lap splices are not long. however tying is often used as a means to hold bars in place.9 m) pour Lap 5 ft (1. If the wall will not be solidly grouted. horizontal reinforcement can be placed in bond beam or lintel units. (3. since the mason must lift the units over any vertical reinforcing bars that extend above the previously installed masonry. (813 mm) pour and 2 ft 8 in. (813 mm) lift 5 ft (1. 6). Bond beam units are manufactured with either reduced webs or with “knock-out” webs. lift heights in excess of the 12 ft-8 in. and 3. the maximum area of vertical reinforcement does not include the area at lap splices.8) 2 x 3 (50. Written approval is also required. One advantage is that a larger volume of grout can be placed at one time. ft (m) Fine Fine Fine Fine Coarse Coarse Coarse Coarse 1 2 3 4 1 (0. the difference between a grout lift and a grout pour needs to be understood. mechanical vibration is required and reconsolidation is also required. this is needed only when a cold joint is formed between the lifts and only in areas that will be receiving additional grout. (3. These advances permit more efficient installation and construction options for grouted concrete masonry walls (see Figure 4).5 x 76.1) 2 (50.2) 3 x 3 (76. in. A pour is the entire height of masonry to be grouted prior to the construction of additional masonry.66) 24 (7.52) 12 (3.2) 1½ (38.520 mm) without cleanouts—generally termed “low lift grouting. a third option became available – grout demonstration panels. 3) offers an additional option: to increase the grout lift height to 12 ft-8 in.5) 3 (76. (3. x in. especially on larger projects. except at the top of the finished wall. on finished masonry unit faces or into cores not immediately being grouted. Care should be taken to minimize grout splatter on reinforcement.2) 3 x 3 (76. Typically called high-lift grouting within the industry. For higher pour heights. 2).52) 12 (3.32) Min.2) Min.” With the advent of the 2002 Specification for Masonry Structures (ref. Grouting With Cleanouts—"High-Lift Grouting” Many times it is advantageous to build the masonry wall to full height before grouting rather than building it in 5 ft (1.860 mm) under the following conditions: 1. grout space dimensions for grouting cells of hollow units 3. Grouting Without Cleanouts—"Low-Lift Grouting” Grout installation without cleanouts is sometimes called low-lift grouting. (25 mm) below the top bed joint to help provide some mechanical keying action and water penetration resistance. Steel reinforcement should project above the top of the pour for sufficient height to provide for the minimum required lap splice. without the requirements for cleanout openings.2 x 102) Fine and coarse grouts are defined in ASTM C 476 (ref.2 x 76. the masonry has cured for at least 4 hours. Through the use of a grout demonstration panel.8) 2½ (63. as illustrated in Figure 4. it is considered good practice (for all lifts except the final) to stop the level of the grout being placed approximately 1 in. no intermediate reinforced bond beams are placed between the top and the bottom of the pour height. See the section titled Consolidation and Reconsolidation in this TEK.2) 2½ x 3 (63. width of grout space 2. A pour may be composed of one lift or a number of successively placed grout lifts. A Table 1—Grout Space Requirements (ref. 5).2 x 76. The 2005 Specification for Masonry Structures (ref. GROUT PLACEMENT To understand grout placement. The dimensions and weights (including heights of deformations) of a cleaned bar cannot be less than those required by the ASTM specification. to a maximum of 5 ft (1. Further.8 x 76. it is common industry language to describe the process of constructing walls in shorter segments.66) 24 (7. For grouting between masonry wythes. Grout is to be placed within 11/2 hours from the initial introduction of water and prior to initial set (ref. special concrete block shapes or equipment.1) 2 (50. The wall is built to scaffold height or to a bond beam course.4 in.30) 5 (1.32) 1 (0.2) 1½ x 3 (38. With the installation of cleanouts this can be done. only two grout placement procedures have been in general use: (l) where the wall is constructed to pour heights up to 5 ft (1. 3) Grout Max. 2. thereby increasing the overall speed of construction. (mm x mm) 1½ x 2 (38.3. grout buckets equipped with chutes or other mechanical means designed to move large volumes of grout without segregation.8) 2½ (63. Grout must be consolidated either by vibration or puddling immediately after placement to help ensure complete filling of the grout space.) High lift grouting offers certain advantages.2) 2½ x 3 (63. Grout space dimension is the clear dimension between any masonry protrusion and shall be increased by the diameters of the horizontal bars within the cross section of the grout space. Puddling is allowed for grout pours of 12 in. grouting with cleanouts permits the wall to be laid up to story height or to the maximum pour height shown in Table 1 prior to the installation of reinforcement and grout. (245 and 279 mm). Historically.” and (2) where the wall is constructed to a maximum pour height of 24 ft (7.520 mm) increments as described above.2) 3 x 4 (76. (Note that in Table 1. 3). Steel reinforcing bars and other embedded items are then placed in the designated locations and the cells are grouted. 51 . grout type1 pour height. While the term is not found in codes or standards.30) 5 (1. grout slump is maintained between 10 and 11 in. A lift is the amount of grout placed in a single continuous operation.5 x 76.520 mm). (mm) ¾ (19. (305 mm) or less.5) 3 (76.320 mm) with required cleanouts and lifts are placed in increments of 5 ft (1. Although not a code requirement. Larger quantities should be placed by grout pumps.1 x 50.860 mm) limitation may be permitted if the results of the demonstration show that the completed grout installation is not adversely affected.520 mm)—generally termed “high lift grouting.1 x 76. Small amounts of grout can be placed by hand with buckets.other materials which adversely affect bond must be removed however. Area of vertical reinforcement shall not exceed 6 percent of the area of the grout space. At flashing where reduced thickness units are used as shown in Figure 1. This “pencil head” vibrator is activated for a few seconds in each grouted cell. absorptive properties of the masonry units and the presence of water repellent admixtures in the units. the exterior unit can be left out until after the masonry wall is laid up. Although not addressed by the code. minimization of reconsolidation. (13 mm) must be removed from the masonry walls. so that it may be replaced in whole to better conceal the opening. to 1 in. Specification for Masonry Structures (ref. which varies with such factors as temperature. (813 mm) on center (horizontal measurement) for solidly grouted walls. TEK 3-4B (ref. Debris may be removed using an air hose or by sweeping out through the cleanouts. When using the increased grout lift height provided for in Article 3. Face shells are removed either by cutting or use of special scored units which permit easy removal of part of the face shell for cleanout openings (see Figure 5). 52 . After laying masonry units. Bracing may be required during construction. Face shell plugs should be adequately braced to resist fluid grout pressure. consolidation of a lift and reconsolidation of the lift below may be done at the same time by extending the vibrator through the top lift and into the one below. reinforcement and foundation or bearing surface. Excess vibration may blow out the face shells or may separate wythes when grouting between wythes and can also cause grout segregation. Cleanouts must be located at the bottom of all cores containing dowels or vertical reinforcement and at a maximum of 32 in. Consolidation and Reconsolidation An important factor mentioned in both grouting procedures is consolidation. (305 to 406 mm) apart. Grout demonstration panels have been used to allow placement of a significant amount of a relatively new product called self-consolidating grout to be used in many parts of the country with outstanding results.440 mm) of a grout lift. Less reinforcement is used for splices and the location of the reinforcement can be easily checked by the inspector prior to grouting. See Bracing Concrete Masonry Walls During Construction. relying on head pressure to consolidate the grout below. 7) for further information. (76 mm). If conditions permit and grout pours are so timed. puddling and innovative consolidation techniques. The most common of these include increases in lift height. one cell is considered to be formed by the two open ends placed together. Consolidation eliminates voids. As the water from the grout mixture is absorbed into the masonry. it may be desirable to remove the entire face shell of the unit. The top lift is reconsolidated after the required waiting period and then filled with grout to replace any void left by settlement. the masonry is required to cure for a minimum of 4 hours prior to grouting for this reason. in order to prevent horizontal movement (blowout) of the wall during grouting. The timing depends on the water absorption rate. Cleanout openings must be made in the face shells of the bottom course of units at the location of the grout pour. Proper preparation of the grout space before grouting is very important. or by blocking the openings to allow grouting to the finish plane of the wall. (19 to 25 mm) head. When double openend units are used. Then after cleaning the cell. The openings must be large enough to allow debris to be removed from the space to be grouted. The grout spaces should be checked by the inspector for cleanliness and reinforcement position before the cleanouts are closed. 3) requires a minimum opening dimension of 3 in. recent research (ref. GROUT DEMONSTRATION PANEL Figure 5—Unit Scored to Permit Removal of Part of Face Shell for Cleanout Specification for Masonry Structures (ref. It is important to reconsolidate after the initial absorption has taken place and before the grout loses its plasticity. The vibrator should be withdrawn slowly enough while on to allow the grout to close up the space that was occupied by the vibrator. For example.second advantage is that high-lift grouting can permit constructing masonry to the full story height before placing vertical reinforcement and grout. Reconsolidation acts to remove these small voids and should generally be done between 3 and 10 minutes after grout placement. mortar droppings and projections larger than 1/2 in. It may be advisable to delay grouting until the mortar has been allowed to cure. the vibrator is placed at points spaced 12 to 16 in. A mechanical vibrator is normally used for consolidation and reconsolidation—generally low velocity with a 3/4 in. 3) contains a provision for “alternate grout placement” procedures when means and methods other than those prescribed in the document are proposed. small voids may form and the grout column may settle. Cleanout openings may be sealed by mortaring the original face shell or section of face shell. 8) has demonstrated adequate consolidation by vibrating the top 8 ft (2. helping to ensure complete grout fill and good bond in the masonry system.5 D of Specification for Masonry Structures (ref 3). the unit is mortared in which allowed enough time to gain enough strength to prevent blowout prior to placing the grout. When grouting between wythes. reduced or increased grout slumps. When the cleanout opening is to be exposed in the finished wall. TEK 3-1C (ref. 2004. Specification for Masonry Structures. COLD WEATHER PROTECTION Protection is required when the minimum daily temperature during construction of grouted masonry is expected to fall below 40oF (4. construction techniques and grout space geometry is required. ASTM C 476-02. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 2005. Steel Reinforcement for Concrete Masonry. National Concrete Masonry Association. ACI 530. 2. 53 contact NCMA Publications (703) 713-1900 . National Concrete Masonry Association. Construction and approval of a grout demonstration panel using the proposed grouting procedures. Therefore. 2002. TEK 12-4C. 2002. Grouted masonry requires special consideration because of the higher water content and potential disruptive expansion that can occur if that water freezes. TEK 9-4. Reported by the Masonry Standards Joint Committee. 5.ncma. MR 25. With the advent of self-consolidating grouts and other innovative consolidation techniques. ACI 530.Research has demonstrated comparable or superior performance when compared with consolidated and reconsolidated conventional grout in regard to reduction of voids. Bracing Concrete Masonry Walls During Construction. 6. compressive strength and bond to masonry face shells. 4. National Concrete Masonry Association. see All-Weather Concrete Masonry Construction.1-05/ ASCE 6-05/TMS 602-05. 9. and wet weather protection. National Concrete Masonry Association. 2005. 8. All-Weather Concrete Masonry Construction. 2005.1-02/ ASCE 6-02/TMS 602-02. ACI 530-05/ASCE 5-05/TMS 402-05. 2002. Standard Specification for Grout for Masonry. 9). Herndon. Specification for Masonry Structures. grouted masonry requires protection for longer periods than ungrouted masonry to allow the water to dissipate. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. TEK 3-4B. Reported by the Masonry Standards Joint Committee. hot. 2002. 2002. Building Code Requirements for Masonry Structures. this provision of the Specification has been very useful in demonstrating the effectiveness of alternate grouting procedures to the architect/engineer and building official. 3. Reported by the Masonry Standards Joint Committee. TEK 3-1C. Virginia 20171 www. For more detailed information on cold.org To order a complete TEK Manual or TEK Index. Investigation of Alternative Grouting Procedures in Concrete Masonry Construction Through Physical Evaluation and Quality Assessment. National Concrete Masonry Association.4oC). Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. ASTM International. Grout for Concrete Masonry. 7. REFERENCES 1. Hybrid masonry/frame structures were first proposed in 2006 (ref. which offers multiple alternative means of transferring loads into the masonry—or isolating the masonry infill from the frame. the masonry walls share the support of the vertical loads. hybrid. Type I. The masonry walls are constructed within the plane of the framing. Type I walls have soft joints (gaps that allow lateral drift at the columns or vertical deflection at the top) at the columns and the top of the wall. U. users are strongly urged to become familiar with the hybrid masonry concept. It can be used in single wythe or cavity wall construction provided the connections and joints are protected against water penetration and corrosion. including the wall weight. and its limitations particularly in the way in which inelastic loads are distributed during earthquakes throughout the masonry and frame system. or design methods. with the framing. Type III walls are built tight at the columns and the top of the wall. and additional design guidance is outlined in adopted codes and standards. While the frame can be constructed of reinforced concrete or structural steel. While many designers prefer masonry infill walls as the backup for veneers in framed buildings. For Type II and III walls. The reinforced masonry infill participates structurally with the frame and provides strength and stiffness to the system.S. tie-down. Keywords: frame structures. Type II and Type III. The classification is dependent upon the degree of confinement of the masonry within the frame. Prior to implementing the design procedures outlined in this TEK. The concept of using masonry infill to resist lateral forces is not new. The hybrid walls are constructed within the plane of the framing. 1). having been used successfully throughout the world in different forms. the framing supports some or all of the masonry wall weight. reinforced masonry 1 54 .An information series from the national authority on concrete masonry technology Prepared in cooperation with the International Masonry Institute HYBRID CONCRETE MASONRY TEK 3-3B CONSTRUCTION DETAILS Construction (2009) INTRODUCTION Hybrid masonry is a structural system that utilizes reinforced masonry walls with a framed structure. This leads to detailing and construction interferences trying to fit masonry around braces. Type II walls have soft joints at the columns and are built tight at the top of the wall. One solution is to eliminate the steel bracing and use reinforced masonry infill as the shear wall bracing to create a hybrid structural system. infill. its modeling assumptions. based codes and standards have lagged behind in the establishment of standardized means of designing masonry infill. there is often a conflict created when structural engineers design steel bracing for the frame which interferes with the masonry infill. The hybrid masonry system outlined in this TEK is a unique method of utilizing masonry infill to resist Related TEK: 14-9A NCMA TEK 3-3B lateral forces. The framing supports the full weight of the masonry walls and other gravity loads. While common worldwide. This system. should not be used in Seismic Design Category D and above until further studies and tests have been performed. Depending on the type of hybrid wall used. There are several reasons for its development but one primary reason is to simplify the construction of framed buildings with masonry infill. The novelty of the hybrid masonry design approach relative to other more established infill design procedures is in the connection detailing between the masonry and steel frame. the discussion here includes steel frames with reinforced concrete masonry walls. CLASSIFICATION OF WALLS There are three hybrid wall types. shear walls. the concept of Type I walls is that the masonry wall is a nonloadbearing shear wall built within the frame which also supports out-ofplane loads (see Figure 1). The engineer’s design should reflect whether anchors are required but only for out-of-plane loads. each wall is built independently. and David Biggs. The masonry does have to be isolated from the columns so the columns do not transmit loads to the walls when the frame drifts. These anchors only need to transmit out-of-plane loads. In multi-story buildings. including: the wall base. at columns. In multi-story buildings. There are two options: Type IIa and Type IIb. Type I Hybrid Wall Type II Hybrid Wall Figure 1—Hybrid Wall Types I and II 2 NCMA TEK 3-3B 55 . there are no standards in the United States that govern Type III design. For Type IIa walls. Because the steel framing is supporting the entire wall weight. It is possible with Type 1 walls to position the walls outside the framing so they are foundation supported as in caged construction (ref. Type II Hybrid Walls With Type ll walls.CONSTRUCTION Type I Hybrid Walls Practically speaking. Currently. The top connectors must extend down from the framing to overlap with the vertical wall reinforcement. Options include grouting the top course. 1). The design must take into account the construction phasing. The details closely match those for current cavity wall construction where the infill masonry is within the plane of the frame. using solid units.org and the IMI web site at www. Type III Hybrid Walls This wall type is fully confined within the framing—at beams and columns. Alternate details for hybrid construction are continually under development and will be posted on the web sites. The engineer must indicate which will be used. Since the walls are generally designed to span vertically.org. DETAILS Sample construction details were developed in conjunction with the National Concrete Masonry Association. the walls may not have to be anchored to the columns. For Type IIb walls. There are several key details that must be considered.ncma. the engineer must decide whether column anchors are needed similar to Type I walls. imiweb. 1). providing a more economical design for the framing. vertical reinforcement only needs to be doweled to the concrete slab to transfer shear forces because tie-down is not required. Walls can be constructed on multiple floors simultaneously. the top of the wall. The vertical dowels also transfer shear. This simplifies the construction of multi-story buildings. the vertical reinforcement (dowels) must be welded to the perimeter framing to transfer tension tiedown forces into the frame. except that the vertical reinforcement must be welded to the perimeter framing at supported floors. They are hosted on the NCMA web site at www. and parapets. Type 1 walls are more economical for lower rise buildings. no details are provided at this time. or casting the top of the wall. Therefore. Since the walls generally span vertically. The top of the masonry wall must bear tight to the framing. Standards are under development and research is underway to help determine structural and construction requirements. the masonry wall is essentially a loadbearing shear wall built within the frame: it supports both gravity and out-of-plane loads (see Fig. each wall may be structurally dependent on a wall from the floor below which is very similar to a loadbearing masonry building. International Masonry Institute (IMI). Base of Wall As previously noted for Type I and Type IIa walls. For Type IIb walls. Figure 2 shows the reinforcement anchored to the foundation with a tension lap splice. Top of wall construction raises the most concern by designers. If the design does not work. 3. For Type II walls. the gap at the top of the wall must allow for the framing to deflect without bearing on the wall or loading the bolts. 2. Top of Wall For all wall types. and also shows the reinforcement anchored at a floor level and tension lap spliced. vertical reinforcement must be anchored to either foundation or frame to provide tension-tie downs for the structure. The design concept for the connectors is: 1. connectors at the top of the wall. Figures 5 and 5A show an example with bent plates and slotted holes. Determine the out-of-plane loads to the wall top. the gap is filled tight so the framing bears on the wall. Constructability testing by masons has been successfully performed. The designer must determine if the dowel can be effectively anchored to the slab for shear or if it must be welded to the framing as shown for Type I and Type IIa walls. Design the top bond beam to span horizontally between connectors.22 m) o. 4. Figure 4 shows the reinforcement anchored at a floor level. It also accommodates out-of-plane forces. Since the top course could be a solid unit. analyze the connector and design the bolts.09 and 1. c. Using the in-plane loading. Connector spacing is a designer's choice but is generally between 2 and 4 ft (6. the vertical reinforcement does not have to be anchored for tension forces because it only transfers shear forces. For Type I walls. repeat using a smaller connector spacing. The vertical reinforcement must overlap with the Figure 3—Type IIb Foundation Detail Figure 2—Type I and IIa Foundation and Floor Detail NCMA TEK 3-3B Figure 4—Type IIb Floor Detail 3 56 . Figure 3 shows the reinforcement anchored to the foundation. the connector should extend down to a solid grouted bond beam. This is accomplished by a connector. the top of the wall must be anchored to transfer in-plane shear loads from the framing to the wall. For Type II walls. Figure 5—Top of Wall Details 4 NCMA TEK 3-3B 57 . fill gap tight.Note: For Type I walls. provide soft joint (gap to allow for movement. Figure 5—Top of Wall Details (continued) Figure 5A—Connector Plate Detail NCMA TEK 3-3B 5 58 . Figure 6—Column Details Option 1 Figure 7—Parapet Details 6 NCMA TEK 3-3B 59 . Option 2 Option 3 Figure 7—Parapet Details (continued) NCMA TEK 3-3B 7 60 . ncma. 2. wide flange framing. Beam analysis and flange bracing concerns for the steel are identical to those for any infill wall. Type I and Type II hybrid systems can be designed and constructed in the United States using existing codes and standards. Biggs.org To order a complete TEK Manual or TEK Index.13. IMI Technology Brief 02. Besides verifying the vertical reinforcement is properly installed as required by Building Code Requirements for Masonry Structures (ref. redundancy is improved. Column For Type I and IIa walls. 2008. the wall must be kept separated from the columns so that when the frame drifts it does not bear on the wall. 4. D. Proceedings of the Tenth North American Masonry Conference. Figure 6 shows a possible anchor. By using the masonry as a structural shear wall. contact NCMA Publications (703) 713-1900 Provided by: 8 NCMA TEK 3-3B 61 . The Masonry Society.13. Herndon. Hybrid Concrete Masonry Design. Design issues for hybrid walls are discussed in TEK 14-9A and IMI Tech Brief 02. Virginia 20171 www. If Type I walls are used. lateral stiffness is increased.01 (refs. Hybrid Masonry Structures. June 2007. 4). 3.01. Lightweight anchors can be used to support out-of-plane loads if desired. Hybrid Masonry Design. Details vary depending on the framing used but are similar to Figure 2. NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. 2009. Criteria for Type III hybrid systems are under development. QUALITY ASSURANCE of the quality assurance plan.. 2009. CONCLUSIONS Hybrid masonry offers many benefits and complements framed construction. and bar joist framing. and opportunities for improved construction cost are created. the constructability of the masonry with the frames is improved.The steel framing is affected by out-of-plane load transfer to the beam's bottom flange. National Concrete Masonry Association. There is a plate on the beam's top flange for the bar joist and wide flange framing options. International Masonry Institute. the bolts from the connector to the wall must allow for vertical deflection of the framing without loading the wall. Parapet Parapets can be constructed by cantilevering off the roof framing. 3. ACI 530-08/ASCE 5-08/TMS 402-08. 2). For now. TEK 14-9A.T. Building Code Requirements for Masonry Structures. The Masonry Society. Figure 7 shows three variations for: concrete slab. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. the connector must be checked as well. Special inspections should be an essential aspect REFERENCES 1. Wind speeds as defined in the Standard are five-second gusts measured at the job site. Based on this assumption and a wind speed limit of 20 mph (32. as shown in Restricted zone h ngt Le Height He igh t+ 4f t (1 . there were no uniform guidelines for masonry wall stability. construction loads. there is a chance that the masonry wall could fail and the Restricted Zone must be evacuated in order to ensure life safety. 3) by the Council for Masonry Wall Bracing.22 m).2 km/hr).2 km/hr) during the Initial Period. During this period.” Restricted Zone The Restricted Zone is the area on each side of a wall equal to the length of the wall and extending a distance perpendicular to the wall equal to the height of the constructed wall plus 4 ft. restricted zone. the mortar is assumed to have no strength and wall stability is accomplished from its self weight only. A section is provided at the end of this TEK regarding bracing and support of basement walls during backfilling operations. seismic. basement walls. The Standard only addresses strategies to resist the lateral loading effects of wind during construction. (1. lateral loads. work on the wall must cease WALLS SUBJECT TO WIND FORCES Recognizing that it may be impracticable to prevent the collapse of a masonry wall during construction when subjected to extreme loading conditions and that life safety is the primary concern. Until the recent development of the Standard Practice for Bracing Masonry Walls During Construction (ref. the Standard includes a procedure whereby the wall and the area around it is evacuated at prescribed wind speeds.” “Initial Period. Initial Period The Initial Period is the time frame during which the masonry is being laid above its base or highest line of bracing. If wind speeds exceed 20 mph (32.22 Restricted zone m) He igh t+ 4f t (1 . INTRODUCTION Various codes and regulations relating to buildings and structures place responsibility on the erecting contractor for providing a reasonable level of life safety for workers during construction. bracing walls. and lateral earth pressure are present.” and “Intermediate Period. When the wind speeds exceed those allowed during the Initial and Intermediate Periods. When other lateral loads such as impact. they need to be considered and evaluated separately. limited to a maximum of one working day. scaffolding. They are “Restricted Zone. walls can be built to the height shown in Table 1 without bracing during the Initial Period. The critical wind speed resulting in evacuation is dependent on the age of the wall being constructed and involves three new terms. wind loads Figure 1. plain concrete masonry.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology BRACING CONCRETE MASONRY WALLS DURING CONSTRUCTION TEK 3-4B Construction (2005) Keywords: backfilling. unreinforced concrete masonry.22 m) Le h ngt Figure 1—Restricted Zone for Masonry Walls 62 TEK 3-4B © 2005 National Concrete Masonry Association (replaces TEK 3-4A) . 0(6. (These the provisions of the Code.84) 28. bonded = 13'-4" (4. ment of No.6(9. unbraced heights in Table 2 are 5 mph greater than the The maximum unbonded height during the Intermediate evacuation speed to allow time for the masons to get off the Table 1—Maximum Unbraced Height1 of Ungrouted Hollow Concrete Masonry Walls During the Initial Period2.10) 22.1 kph) speed exceeds 35 mph (56. use 105 < γ < 115 (1682 < γ < 1842) category unless it is known that units are 115 < γ < 125 (1842 < γ < 2002). (No. (16M at 1. γ . bonded or unbonded = 26'-0" warning with an evacuation program is implemented.c. control joints are spaced at 24'-8" (7.37 m) maximum. 16M at 813 kph). unbonded = 12'-8" (3. The Standard also provides mm) o.44) 8.3 Connections to masonry can be designed using the prekm/hr) in keeping with a long-standing OSHA requirement. (No.0(2. the table values for No. 8(203) 10.Unbraced Option evacuation program. The design wind speed is 40 Design Example mph (64. 3).0(5.32 m) tall wind speed exceeds 35 mph (56. Units Units3 Units etary pipe bracing systems and cable systems in (mm) 95 < γ < 105 105 < γ < 115 115 < γ < 125 125 < γ are also available for all heights shown in Table (1522<γ<1682) (1682<γ<1842) (1842<γ<2002) (2002< γ) 3 and are detailed in the Standard. (762 mm) splice lengths. can conservatively be used. Mortar is masonry cement to have one half of its design compressive strength and plain Type S. For medium weight units. Proprithickness. restricted working loads for post-drilled anchors as reported in the Intermediate Period manufacturer's literature may be used.0(2.1 kph).1(8. 5 at 32 in.44) 8. and masonry allowable flexural stresses are taken as two-thirds flashing is at the base of the wall only. 5 (No. 1). and 35 mph (56.44) 8. 25 mph (40.3 kph).8(5.44 m) above mm) for No.3 kph).c. been in place 24 hours..1(3.0(3. Height of walls above grade or highest line of lateral support 24 hours (ref.4 kph). As an alternate.66) 13.33) achieve up to 75% of the specified yield stress Footnotes: of the reinforcing steel at 12 hours and 100% at 1. and 3) Unreinforced wall: alternative bracing designs and methods approved by a regisMaximum height. Alternatively.0(2. The Intermediate Period is the time following the Initial Period but before the wall is connected to the elements that provide its final lateral stability. Provisions 4 (102) 8. the Restricted wall constructed with 8 in.0(2.0(2.0(6. lows the full capacity of splices after grout has 3.0 km/hr) having a density of 110 lb/ft3 (1762 kg/m3) and reinforceis to allow workers time to evacuate the area.44) 8. (203 mm) concrete masonry Zone must be evacuated. 5 at 48 in.2 and 48. of the design value given in the Masonry Standards Joint Committee’s Building Code Requirements for Masonry Initial Period Structures (ref.0(2. They are: 1) an early warning and Intermediate Period .33) Research has shown that properly designed 10(254) 17.44) 8.44) also are included in the Standard for strength 6(152) 8.scaffolding and evacuate the restricted zone. the full splice capacity can be used after only 12 hours and the Restricted Zone on both sides of the wall must be if the design lap length is increased by 1/3 (to 40 in.44) 8. acceptable level of life safety for masons and others working on the construction site. 2) bracing to a design wind speed of 40 From Table 2: mph (64.73) 20.1(2. grade is not necessary until wind speeds reach 35 mph (56. When the Determine the bracing requirements for a 24 ft (7.2(7. Adapted from ref.06 m) field conditions. The masonry structural capacity then can From Table 1: be designed using these reduced values in accordance with Maximum unsupported height = 12'-0" (3. Build the wall to a are not presented in this TEK. The difference of 5 mph (8. Evacuation for walls up to 8 ft (2.52 m). Reinforced wall: Table 2 lists maximum unbraced wall heights when early Maximum height. Therefore. lb/ft3 (kg/m3) Nominal wall Lightweight Medium Weight Normal Weight heights up to 14'-4" (4. 3.66 m). (1016 evacuated. 16M at 813 mm) on center using During the Intermediate Period. Table 3 lists bracing points determined by the bracing method previously described and Figure 2 shows a wood brace detail for support Density of Masonry Units.3 km/hr).99) 14. initial period provisions apply to all of the options that The Standard allows for several methods of providing an follow). Design wind speeds for the height of 12'-0" (3. ft (m) 63 .92 m) mum allowable heights are provided for evacuation for 5 second gust wind speeds of 15 mph (24.2 Strategy: Since reinforcement is No.18) 18.29) 12.0(2. the masonry is assumed 30 in. 5 second gust.22 additional tables for 20 and 30 mph (32.4 km/hr) 5 second gust for brace design.8(3.3 kph) which m) o.86 m) tered professional engineer if supported by data representing Maximum height.66 m) the first day (Initial Period). Maxi(7. 5 at 32 in.47) design methods.56) 30. 16M) bars).07) 25. viously quantified reduced masonry strengths and design formulas included in the Standard. 5 second gust and evacuating if the wind Alternate 1: Evacuation wind speed of 15 mph (24.2(4.71) and constructed reinforcement splices can 12(305) 23.7(7. the Standard al2. Table 2—Intermediate Period Maximum Unbraced Heights, ft (m)1,2 (adapted from ref. 3) Evacuation Wind Speed3 15 mph (24.1 kph) Bracing Condition PCL & MRC4 M/S N 25 mph (40.2 kph) MC 5 M/S N PCL & MRC4 M/S N 35 mph (56.3 kph) MC 5 M/S PCL & MRC4 N M/S N MC 5 M/S N Unreinforced 8 in. (203 mm) wall Unbonded6 Bonded8 6'-0" (1.83)7 12'-8" (3.66) 8'-0" 3'-4" (1.02)7 16'-0" 14'-8" 13'-4" 12'-0" 10'-0" 8'-8" 6'-8" 6'-8" 6'-0" 5'-4" 4'-8" (4.88) (4.47) (4.06) (3.66) (3.05) (2.64) (2.44) (2.03) (2.03) (1.83) (1.63) (1.42) Unreinforced12 in. (305 mm) wall Unbonded6 Bonded8 28'-0" (8.53) 7'-4" (2.24)7 12'-8" (3.86) 27'-4" 25'-4" 23'-8" 22'-0" 15'-4" 14'-0" 12'-8" 11'-4" 10'-8" 10'-0" 8'-8" 8'-0" (8.33) (7.72) (7.21) (6.71) (4.67) (4.27) (3.86) (3.45) (3.25) (3.05) (2.64) (2.44) Reinforced 8 in.(203 mm) wall9,10 Unbonded or bonded No. 5 at 10 ft (16M at 3.05 m) o.c.11 20'-8" (6.30) 16'-8" (5.08) 26'-0" (7.92) 25'-4" (7.72) 12'-0" (3.66) Unbonded or bonded No. 5 at 4 ft (16M at 1.22 m) o.c.11 19'-4" (5.89) 9,10 Reinforced 12 in. (305 mm) wall Unbonded or bonded No. 5 at 10 ft (16M at 3.05 m) o.c.11 28'-8" (8.74) 23'-4" (7.11) 20'-0" (6.10) 33'-4" (10.2) 33'-4" (10.2) 24'-0" (7.32) Unbonded or bonded No. 5 at 6 ft (16M at 1.22 m) o.c.11 Footnotes: 1. Maximum height above highest line of lateral support permitted without bracing at windspeed indicated. 2. These values can be applied to all hollow concrete masonry of 95 lb/ft3 (1522 kg/m3) and greater density and all solid concrete masonry. 3. Wall design wind speed is 5 mph (8.05 kph) greater than evacuation wind speed. 4. PCL indicates portland cement/lime. MRC indicates mortar cement. 5. MC indicates masonry cement mortar. 6. Assumes an unbonded condition between the wall and foundation such as at flashing. 7. Exception: Walls may extend up to a height of 8 ft (2.44 m) above the ground without bracing. 8. Assumes continuity of masonry at the base (i.e. no flashing). 9. Reinforced walls shall be considered unreinforced until grout is in place 12 hrs. 10. Reinforcement indicated is minimum vertical required and shall be continuous into the foundation. Minimum lap splice for grout between 12 and 24 hrs. old is 40 in. (1016 mm) or 30 in. (762 mm) splice length for grout 24 hrs. old and over. 11. For reinforced walls not requiring bracing, check adequacy of foundation to prevent overturning. Period is 12'-8" (3.86 m) for this wind speed, therefore neither bracing nor grouting needs be done for the 12 ft (3.86 m) height for the intermediate period. If the wall is reinforced and grouted, it can support a total height of 26 ft (7.92 m), the top 13'-4" (4.06 m) of which can be unreinforced, bonded masonry. Therefore if the first 12 ft (3.86 m) is reinforced and grouted, the remaining 12 ft (3.86 m) could be built after 24 hours of placing the grout if the standard 30 in. (1016 mm) reinforcement splice is used (or 12 hours with a 40 in. (762 mm) splice). The total height of 24'-0" (7.32 m) is less than the maximum of 26'-0" (7.92 m) that the reinforced section can support and the top 12'-0" (3.66 m) is less than 13'-4" maximum that unreinforced bonded masonry can support. Therefore the wall can be built in this manner without bracing. Note: This option requires early warning and evacuation when wind speeds reach 15 mph (24.1 kph) 5 second gust. This may not be practical in all areas. 64 Alternate 2: Design for an evacuation wind speed of 25 mph (40.2 kph). Unreinforced wall: Maximum height, unbonded = 8'0" (2.44 m) at ground level, 6'-0" (1.83 m) otherwise Maximum height, bonded = 8'0" (2.44 m) Reinforced wall: Maximum height, bonded or unbonded = 25'-4" (7.92 m) Strategy: Again, build the wall to a height of 12'-0" (3.66 m) the first day (Initial Period). Since the maximum unbonded height above grade during the Intermediate Period is 8'-0" (2.44 m) for this wind speed, grouting must be done the first day. The restricted zone must then be vacated for the first 24 hours after placing the grout when using the standard 30 in. (762 mm) reinforcement splice (or 12 hours for 40 in. (1016 mm) splices). After that continue building the wall up to the height of 24'-0" (7.32 m) which is less than the maximum of 25'-4" (7.72 m). The top 12'-0" (3.66 m) of this is bonded unreinforced masonry which is more than 6'-0" (1.83 m) maximum. Therefore, it must also be grouted the same day and the restricted zone vacated for the next 12 or 24 hours depending on the splice length used. Intermediate Period - Braced Option From Table 3 ( for 35 mph, 56.3 kph): Unreinforced wall: Maximum unsupported height = 3'-4" (1.02 m) Maximum height above top brace = 5'-4" (1.63 m) Maximum vertical spacing of braces = 11'-4" (3.45 m) Reinforced wall: Maximum height above top brace =10'-8" (3.25 m) Maximum vertical spacing of braces = 21'-4" (6.50 m) Strategy: Build the wall to a height of 12'-0" (3.66 m) the first day (Initial Period) and brace at a height of 11'-4" (3.45 m) by the end of Table 3—Intermediate Period Brace Locations, ft-in. (m)1,2 35 mph (56.3 kph) Evacuation Wind Speed, 40 mph (64.4 kph) Design Wind Speed Hollow Concrete Masonry, 95 lb/ft3 (1522 kg/m3) Density, (adapted from ref. 3) PCL & MRC3 MC4 Bracing Condition M/S N M/S N Unreinforced 8" (203 mm) wall Maximum unbraced height, unbonded condition5 (i.e. at flashing)5 3'-4"6(1.02) 7 Maximum height above top brace 6'-8"(2.03) 6'-0"(1.83) 5'-4"(1.62) 4'-8"(1.42) Maximum vertical spacing between braces7 14'-0"(4.26) 12'-8"(3.85) 11'-4"(3.45) 10'-0"(3.04) Unreinforced 12" (305 mm) wall 5 Maximum unbraced height, unbonded condition (i.e. at flashing)5 7'-4"6 (2.24) 7 Maximum height above top brace 10'-8"(3.25) 10'-0"(3.04) 8'-8"(2.64) 8'-0"(2.44) Maximum vertical spacing between braces7 21'-4"(6.50) 19'-4"(5.89) 17'-4"(5.28) 16'-0"(4.88) Reinforced 8" (203 mm) wall8,9 Maximum unbraced height, unbonded condition5 and height above top brace7,11 10'-8"(3.25) Maximum vertical spacing between braces 21'-4"(6.50) 8,10 Reinforced 12" (305 mm) wall Maximum unbraced height, unbonded condition5 and height above top brace7,11 19'-4"(5.89) Maximum vertical spacing between braces 30'-0"(9.14) Footnotes: 1. Applies to panels up to 25' (7.62 m) wide with a brace located at 0.2 times the panel width from each end. 2. These values can be applied to all concrete masonry units of 95 lb/ft3 (1522 kg/m3)density and greater and all solid concrete masonry. 3. PCL indicates portland cement/lime. MRC indicates mortar cement mortar. 4. MC indicates masonry cement mortar. 5. Assumes an unbonded condition between the wall and foundation such as at flashing - affects only unreinforced walls. 6. Exception: Walls 8' (2.44 m) tall and less above the ground do not need to be braced. 7. Assumes continuity of masonry other than at the base (i.e. no flashing other than at base). 8. Reinforced walls shall be considered unreinforced until grout is in place 12 hours. 9. Minimum reinforcement for 8" (203 mm) reinforced walls is No. 5 (No. 16M) vertical bars at 48" (1219 mm) on center and 40" (1016 mm) minimum lap splice for grout between 12 and 24 hours old or 30 inch (762 mm) splice length for grout 24 hours and over. 10. Minimum reinforcement for 12" (305 mm) reinforced walls is No. 5 (No. 16M) vertical bars at 72" (1829 mm) on center and 40" (1016 mm) minimum lap splice for grout between 12 and 24 hours old or 30 inch (762 mm) splice length for grout 24 hours and over. 11. For reinforced walls not requiring bracing, check adequacy of foundation to prevent overturning. 12. Cantilevered retaining walls must meet the bonded condition. 65 Wall height 6 in. (152 mm) 5 in. (127 mm) 5 in. (127 mm) Wall See top connection detail Vertical member Wall plate typical each side at each brace height 16 in. x 16 in. x 1 2 in. (407 mm x 406 mm x 12.7 mm) plywood plate 16 in. (406 mm) Brace height 1 2 max 4 in. x 4 in. x 16 ft (102 mm x 102 mm x 4.88 m) timber brace, No. 2 or better, any species 1 2 in. (12.7 mm) thick plywood plate typ. both sides-sandwich vertical member Continuous 2 in. x 4 in. (51 mm x102 mm) bridging at midheight with (4) #8 screws, typ. at each timber space 2 in. x 4 in. (51 mm x 102 mm) vertical member typ. (2) 3 8 in. (9.5 mm) diameter A307 through bolts, typ. 3 4 in. (19.0 mm) thick plywood gusset plate with (12) no. 8 screws each at vertical and timber brace member both sides (1) 2 in. x 4 in. (51 mm x 102 mm) knee brace with (4) # 8 screws typ. at each brace end Gusset plate-adjust geometry to accomate multiple braces-typ. See footing anchor detail Timber brace member Vertical member Footing plate 2 in. x 4 in. (51 mm x 102 mm) horizontal member typ. Top Connection Detail Concrete floor, augered anchor or concrete dead man of the following min. dimensions: Timber brace 3 ft (0.91 m) diameter x 3 ft 6 in. (1.07 m) deep for 32 ft (9.75 m) wall height 2 ft (0.61 m) diameter x 3 ft 6 in. (1.07 m) deep for 24 ft (7.32 m) wall height 3 in. (19.0 mm) thick plywood 4 gusset with (12) No. 8 wood screws each at vertical and timber brace member, typ. both sides (2) 3 4 in. (19.0 mm) diameter wedge or epoxy set anchors spaced 6 in. (152 mm) apart minimum at standard embedment 1 ft 6 in. (0.46 m) diameter x 3 ft 6 in. (1.07 m) deep for 16 ft (4.88 m) wall height Horizontal member 1 2 in. (127 mm) thick plywood plate-sandwich horizontal member Note: This brace as detailed is adequate only for support heights of 14 ft 4 in. (4.37 m) or less. For greater support heights, the brace must be redesigned or a pipe or cable brace used. Concrete footing per main drawing Footing Anchor Detail Figure 2—Wood Brace Detail the first working day. This leaves an extension of 8 in. (203 mm) above the top brace which is less than the 5'-4" (1.63 m) allowed (OK). The next level of masonry could be built to a height of 11'-4" + 12'-0" = 23'-4" (3.45 m + 3.66 m = 7.11 m). At the end of that working day, place the second brace at 24'0" - 5'-4" = 18'-8" (7.32 m - 1.63 m = 5.69 m). Check the vertical spacing between the braces: 18'-8" - 11'-4" = 7'-4" < 21'-4" (5.69 m - 3.45 m = 2.24 m < 6.50 m) (OK). Then after installing the brace, place the remaining final course for the total height of 24'-0" (7.32 m). Note: The bottom brace could be removed after the 12 or 24 hour curing period (depending on the splice length) as the reinforced wall section can span 21'-4" (6.50 m) vertically and the height of the top brace is only at 18'-8" (5.69 m). WALLS SUBJECT TO BACKFILLING Unless concrete masonry basement walls are designed and built to resist lateral earth pressure as cantilever walls, they should not be backfilled until the first floor construction is in place and anchored to the wall or until the walls are adequately braced. Figure 3 illustrates one type of temporary lateral bracing being used in the construction of concrete masonry basement walls. Heavy equipment, such as bulldozers or cranes, should not be operated over the backfill during construction unless the basement walls are appropriately designed for the higher resulting loads. Ordinarily, earth pressures assumed in the design of 66 Virginia 20171 www.4 m t (2 ) ) 2 x 10 plank 2 x 4 cleat 2 x 4 brace 2 x 4 struct brace Two 2 x 6 stakes driven into firm soil at least 12 in. TR-134. and bracing are properly in place prior to backfilling 8f . (305 mm) Figure 3—Typical Temporary Bracing for Concrete Masonry Basement Walls (ref. Also if needed. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. Care should be taken to avoid subjecting the walls to impact loads. Standard Practice for Bracing Masonry Walls Under Construction. 2) REFERENCES 1. a unit can be left out at the bottom of a wall to prevent an unbalanced accumulation of water and replace before backfilling.org To order a complete TEK Manual or TEK Index. dampproofing. Building Code Requirements for Masonry Structures. Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. July 2001. 2. Since lateral earth pressures will increase as the moisture content of the earth is increased. or insulation applied to the walls.ncma. water jetting or soaking should never be used to expedite consolidation of the backfill. Reported by the Masonry Standards Joint Committee. 2002. ACI 530-02/ASCE 5-02/TMS 402-02. drainage systems. National Concrete Masonry Association. basement walls should not be backfilled with saturated materials nor should backfill be placed when any appreciable amount of water is standing in the excavation. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. 67 contact NCMA Publications (703) 713-1900 . 8f Ensure waterproofing. NCMA Guide for Home Builders on Residential Concrete Masonry Walls.4 m t (2 . Herndon. 3. as would be imparted by earth sliding down a steep slope and hitting the wall. Council for Masonry Wall Bracing.basement walls are selected on the assumption that the backfill material will be in a reasonably dry condition when placed. This could also damage waterproofing. Similarly. 1994. The synthetic fibers which reinforce the surface bonding mortar impart a tensile strength of about 1500 psi Many structural and nonstructural tests have been per(10. In surface bonded construction. mortar. tages: There are a few differences between the structural prop• Less time and skill are required for wall construction. to form walls. such as sound transmission together in a strong composite construction. producing a strong wall despite the relatively formed on surface bonded walls to establish design parameters thin thickness of material on each side. The surface coating for the system. bonded concrete masonry can be considered equivalent to a Surface bonded concrete masonry has a number of advanconventional mortared concrete masonry wall. concrete masonry units are laid dry and stacked. These differences are In a 1972 study of mason productivity sponsored by the discussed in the following paragraphs. Department of Agriculture for use in low cost housing. Walls are constructed with units that have been precision ground or honed to achieve a uniform bearing surface. and serves as a class. Surface bonded concrete masonry construction offers all of the benefits and advantages of conventional concrete masonry construction. without mortar. Colored pigment can be incorporated into the surface bonding mortar to produce a finished surface without the need to paint. Both sides of the wall are then coated with a thin layer of reinforced surface bondDESIGN STRENGTH ing mortar. S. erties of the two types of construction. such as: • fire safety • acoustic insulation • energy efficiency • lasting durability and beauty • INTRODUCTION TEK 3-5A © 1998 National Concrete Masonry Association (replaces TEK 3-5) SURFACE BONDED GROUNDED CONCRETE MASONRY SURFACE BONDED UNGROUND CM UNITS CONVENTIONAL CONCRETE MASONRY SURFACE BONDED CONCRETE MASONRY CONVENTIONAL CONCRETE MASONRY SURFACE BONDED CONCRETE MASONRY CONVENTIONAL CONCRETE MASONRY SURFACE BONDED CONCRETE MASONRY CONVENTIONAL CONCRETE MASONRY RELATIVE WALL STRENGTH. Tests of surface bonded walls have repeatedly shown their resistance to wind driven SHEAR LOADS FLEXURAL LOADS COMPRESSIVE LOADS rain to be “excellent” even with VERTICAL HORIZONTAL SPANS SPANS wind velocities as great as 100 mph (161 km/h). and energy efficiency. and are illustrated in U. or with shims placed periodically to maintain a level and plumb condition. COMPANION WALLS OF CONVENTIONAL CONSTRUCTION. S. surface bonding TEK 3-5A Structural (1998) periods of 8 hours. fire resistance period. of surface protective water resistant shield. PERCENTAGE Surface bonding is an economical construction technique which was first introduced in the late sixties by the U.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology SURFACE BONDED CONCRETE MASONRY CONSTRUCTION Keywords: construction techniques. THE STRENGTH OF SURFACE BONDED and Urban Development and WALLS IN VERTICAL SPAN HAS BEEN TWO TO THREE TIMES THAT OF other interested organizations. and over test 68 . • The surface bonding mortar 50 50 provides excellent resistance to water penetration in addition to its function of holding the units together. it was found that surface bonded 100 100 concrete masonry construction resulted in 70 percent greater productivity than that achievable with conventional construction. Department of Housing NOTE: IN SOME COMPARISONS. on each side of the wall bonds the concrete masonry units The nonstructural properties.3 MPa). 8 MPa) to ensure their long term durability after the wall is loaded. In Table 1. Care should be taken to ensure uncoated walls are adequately braced.28 MPa). hence minimizing cracks. Nine surface bonded walls. Dry. (102 mm) design module. such as wind. CONSTRUCTION The construction procedure for surface bonded walls is similar to that of conventional. and three 6 in. governs the construction methods. Because the walls are constructed without mortar joints. failure occurs at a horizontal joint with bond failure between the mortar and the masonry units. In comparison. (203 mm) in thickness. and testing. This reduced wall strength is depicted in Figure 1 for walls constructed with unground concrete masonry units. and tested in the horizontal span.31 MPa) Shear: 10 psi (0. note that surface bonded walls built with precision ground concrete masonry units are equally as strong in compression as the conventional construction. surface bonded wall dimensions do not conform to the standard 4 in. As for mortared masonry construction. 8 in. a wall supported at each end is subjected to a horizontal wind force) the strength in bending depends primarily on the strength of the units.12 MPa) based on the gross area. Stronger units make stronger walls. With mortared construction. based on gross area. 5) governs these requirements. the wall strength of the surface bonded wall is exactly the same as the conventional construction. which are typically 75/8 in. long (194 by 397 mm). With mortared construction. results similar to those for a mortared wall can be expected. surface bonded walls built with unground concrete masonry units develop approximately thirty percent of the strength of the individual block. failure occurs in the surface bonded coating due to tensile stress at or near one of the horizontal joints. Materials Surface bonding mortar should comply with Standard Specification for Packaged. conventional concrete masonry walls averaged 42 Table 1—Allowable Stress. is applied to a wall that is supported at the top and bottom) surfaced bonded walls and mortared walls have about the same average strength. 4). 3) do not specifically address reinforced or grouted surface bonded walls. materials should be properly stored on site to prevent contamination by rain.12 MPa) a References 1 & 3 psi (0. moisture-controlled. If the masonry unit bearing surfaces are ground flat and smooth before the wall is erected. When walls are laid in a running bond pattern. had an average shear resistance of 39 psi (0. This is due to the interlocking of the masonry units laid when in a running bond configuration.. 1. unreinforced walls. Although national building codes. 69 . Shear Strength The shear resistance of surface bonded construction is the same as that of conventional walls. (i.21 MPa) Vertical span: 18 psi (0. Type I units must be in a dry condition when delivered to the job site. such as the BOCA National Building Code and the Standard Building Code (refs. Walls laid using dry units will undergo less drying shrinkage after construction. due to the natural roughness of the concrete units. 6). metal or plastic shims or mortar may occasionally be required between units to maintain the wall level and plumb. Flexural Resistance The flexural strength of a surface bonded wall is about the same as that of a conventional mortared wall.07 MPa) Flexural Tension: Horizontal span: 30 psi (0. mud. When walls are tested in the vertical span (i. Standard Specification for Loadbearing Concrete Masonry Units. which governs flexural and compressive strength.07 MPa) on the gross area (see Table 1). Shims must have a minimum compressive strength of 2000 psi (13. The mortar bed used in conventional construction compensates for this roughness and provides a uniform bearing between units. a rule of thumb is that the wall strength will generally be about seventy percent of the unit strength. either with mortar joints or with surface bonding. Metal shims. The data from numerous tests on surface bonded constructions led to an allowable stress of 18 psi (0. sampling. The lower value obtained with the unground units is due to a lack of solid bearing contact between units. With face shell mortar bedding. ASTM C 90 (ref. concrete masonry units be used for surface bonded construction. an allowable flexural stress of 30 psi (0. if used. (152 mm) thick surface bonded walls averaged 40 psi (0. and led to a recommended allowable shear stress of 10 psi (0. except that mortar is not placed between the masonry units. Surface-Bonded Concrete Masonry Wallsa Compression: 45 psi (0. high by 155/8 in. In such tests in the horizontal span. and other materials likely to cause staining or to have other deleterious effects.29 MPa) shear resistance. manufacturers of surface bonding mortars may have code-approved criteria for their products. Standard Practice for Construction of Dry-Stacked. Surface-Bonded Walls. If the bearing surfaces of the concrete masonry units are unground. ASTM C 946 (ref.Figure 1 for ungrouted.27 MPa).e. Combined Materials for Surface Bonding Mortar.21 MPa) is recommended for horizontal span when the units have been laid in running bond. ASTM C 946 requires Type I. In Figure 1. as shown in Figure 1.e. a horizontal force. Gross Cross-Sectional Area. Wall and opening dimensions should be based on actual unit dimensions. These data are compared in Figure 1. ASTM C 887 (ref. ground water.. Compressive Loads Resistance to vertical compressive loads depends primarily on the compressive strength of the concrete block used in the wall construction. Dry-Stacked. should be corrosion resistant to reduce the possibility that they will corrode and bleed through the finished masonry at a later time. as overmixing can damage the reinforcing fibers. until the mixture is creamy.3 m) when bond beams are in- Figure 2—Change in Wall Thickness corporated every 4 ft (1. Leveling courses should be placed when: • the wall is out of level by more than 1/2 in. additional leveling courses are constructed in the wall. and followed by stacking. It is very important that the surface bonding mortar be applied to both sides of the dry stacked wall since the wall strength and stability depend entirely on this coating. The stacked concrete masonry units should be clean and free of any foreign matter which would inhibit bonding of the plaster. (13 mm) glass fibers which reinforce the mixture. so control joints or bond beams are used for crack control. chases. rather than a structural. while deeper notches are cut with a masonry saw. the “sprayed-on” surface bonding mortar usually has a rougher surface texture than a troweled finish. dry stacking proceeds with the remaining courses beginning with the corners. Electrical lines and plumbing are often located in the cores of concrete masonry units. the surface bonding mortar should be raked out and the joint caulked. use of a power sprayer greatly increases the coverage rate of the mortar and further reduces wall costs. As with mortared masonry construction.1 m) when there are no bond beams in the construction. at wall intersections. the dry stacked concrete masonry units should be damp when the surface bonding plaster is applied to prevent water loss from the mortar due to suction of the units. (13 mm) in 10 ft. A coarse rasp is typically used to make small notches. Batches should be mixed in full bag multiples only. Hand or mechanical troweling of the sprayed coating also assures that all gaps and crevices are filled. These lines should be placed before the surface bonding mortar is applied.2 m) vertically.Leveling Because the footing is not typically level enough to lay up the dry units without additional leveling. The mortar should be troweled on smoothly with a minimum thickness of 1/8 in. or bond beams are used to control cracking. the wall should be checked for plumb and level. Control joints for surface bonded walls are similar to those for mortared concrete masonry. After every fourth course. After the first course of masonry units is laid level in a mortar bed. even when the first course is mortar bedded. so that the masonry units are visible. and recesses 3. At the control joint location. The workability is due to the short 1/2 in. at pilasters. All materials should be mixed for 1 to 3 minutes. On large projects. This can be overcome by troweling. Crack Control Temperature and moisture movements have the potential to cause small vertical cracks in a masonry wall. clean water and mixing equipment should be used to prevent foreign materials from being introduced into the mortar. smooth. Applying Surface Bonding Mortar Manufacturer’s recommendations should be followed for job site mixing of the premixed surface bonding mortar and application to the dry stacked concrete masonry wall. As they are dry stacked. or other adequate anchorage should be provided. and possesses slightly less tensile strength due to the lack of fiber orientation in the plane of the mortar coating. Vertical head joints should not be mortared. horizontal joint reinforcement. and at intervals of 60 ft (18. in walls without openings. Note that mixing time should be kept to a minimum. As applied. following spray application of the mortar. Small burrs should be removed prior to placement. at intervals of 20 ft (6. Placing Accessories & Utilities The absence of a mortar bed joint in the construction also requires that the face shell and/or the cross web of the concrete masonry units be notched or depressed whenever wall ties or anchors must be embedded in the wall. and • at a horizontal change in wall thickness (see Figure 2). in running bond. where shrinkage cracks may be objectionable. Surface bonding mortar can also be sprayed on. In exposed concrete masonry. • at each floor level. Premixed surface bonding mortars are smooth textured and easily applied by hand with a trowel. The absence of a mortar bed joint in surface bonded walls means that there is no space in the wall for joint reinforcement. These cracks are an aesthetic. the first course of masonry units is laid in a mortar bed or set in the fresh footing concrete to obtain a level base for the remainder of the wall. Care should be taken to avoid saturating the units. (3 mm). hand or mechanical. concern. Control joints should be placed: 1. Cores containing anchors or wall ties should be grouted. control joints. at wall openings and at changes in wall height and thickness 2. Contrary to recommended practice with conventional mortared walls. the ends of the concrete masonry units should be butted together tightly. since mortar in the head joints will misalign the coursing along the wall length. and easy to apply. When required. When a second coat of surface bonding mortar is ap70 . to compensate for any segregation of materials within a bag. between the corners. for a slab on grade. 1997. Building Code Requirements for Masonry Structures. American Society for Testing and Materials. Typically. 5. the wall must be properly cured by providing sufficient water for full hydration of the mortar. REFERENCES 1. 71 contact NCMA Publications (703) 713-1900 . Virginia 20171-3499 www. ACI 530-95/ASCE 5-95/TMS 402-95. and weighted down with lumber or masonry units. 2. although with pigmented mortar. to ensure full strength development. (BOCA). but before it is completely hardened or dried out.plied. Curing After surface bonding application. Birmingham. For example. BOCA National Building Code. If application of the surface bonding mortar is discontinued for more than one hour. At the foundation. the first application should be stopped at least 11/4 in. dry. Standard Specification for Loadbearing Concrete Masonry Units. should extend below the masonry onto the slab edge. 1997. Standard Practice for Construction for Dry-Stacked. The second coat may be textured to achieve a variety of finishes. SurfaceBonded Walls. Inc. the wall should be fog sprayed twice within the first 24 hours. (32 mm) from the horizontal edge of the concrete masonry unit. ASTM C 946-91 (1996)e1. either by trowel or spray. ASTM C 90-97. tops of walls should be covered to prevent moisture from entering the wall until the top is permanently protected. Reported by the Masonry Standards Joint Committee. this may be extended to 48 hours. 3. At the end of the day. for this reason. American Society for Testing and Materials. Herndon. In addition. The recommendations above may need to be modified for either cold or hot weather conditions. Joints in surface bonding mortar are weaker than a continuous mortar surface. Country Club Hills. (SBCCI). IL: Building Officials and Code Administrators International. as shown in Figure 3. extending at least 2 ft (0. the surface bonding mortar should either form a cove between the wall and the footer or. warm. AL: Southern Building Code Congress International. 1996. Standard Building Code. 1995. The wall should be dampened with a water mist between 8 and 24 hours after surface bonding mortar application. and.ncma. a tarp is placed over the wall. wall-footing wall-slab on grade Figure 3—Wall/Footing Interface Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. These details help prevent water penetration at the wall/footer interface.6 m) down both sides of the wall.org To order a complete TEK Manual or TEK Index. Inc. should not align with joints between masonry units. 1996. windy weather accelerates the water evaporation from the mortarrequiring more frequent fog spraying. 4. it should be applied after the first coat is set. NATIONAL CONCRETE MASONRY ASSOCIATION 2302 Horse Pen Road. differential movement between the veneer and its supports must be accommodated. or as the exterior wythe of composite and noncomposite walls. See TEK 5-1B (ref. Architectural units such as split-face. 3) for full construction details 72 TEK 3-6B © 2005 National Concrete Masonry Association (replaces TEK 3-6A) . prescriptive code requirements have been developed based on judgement and successful performance. wall ties INTRODUCTION In addition to its structural use as through-the-wall units. (25 mm) min. For the purposes of design. scored. Veneers provide the exterior wall finish and transfer out-of-plane loads directly to the backing. not all construction elements are shown. wood studs or steel studs. veneer. but they are not considered to add to the loadresisting capacity of the wall system. (813 mm) o. joint reinforcement. Backing material may be masonry.5 to 38 mm) 8 Adhered Veneer Figure 1—Types of Veneer Note: For clarity. concrete. veneer is assumed to support no load other than its own weight. The variety of surface textures. (9. concrete masonry or other masonry material securely attached to a wall or backing. and patterns available makes concrete masonry a versatile and popular exterior facing material.c. air space Foundation Anchored Veneer Concrete masonry backing Type S mortar Neat portland cement paste Veneer unit with neat portland cement paste Type S mortar applied to veneer unit 3 to 1 1 2 in. concrete brick and architectural facing units are also used as veneer over various backing surfaces. multiwythe walls. Masonry veneers may be designed using engineered design methods to proportion the stiffness properties of the veneer and the backing to limit stresses in the veneer and achieve compatibility (ref.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY VENEERS TEK 3-6B Construction (2005) Keywords: anchors. The backing must be designed to support the vertical and lateral loads imposed by the veneer in addition to the design loads on the wall since it is assumed the veneer does not add to the strength of the wall. 1 in.. cavity walls. The prescriptive requirements relate to size and spacing of anchors and methods of attachment. In addition to structural requirements. As an alternative. fluted. (25 mm) weeps at 32 in. Movement may be caused by tempera- Concrete masonry backing 1 in. ground face. partially open head joints Flashing VENEER—GENERAL Veneer is a nonstructural facing of brick. and slump are available in a variety of colors and sizes to complement virtually any architectural style. 4). and are described in the following sections. stone. colors. moisture-volume changes. 2) 73 . except for corrugated anchors used with wood ANCHORED VENEER Anchored veneer is veneer which is supported laterally by the backing and supported vertically by the foundation or other structural elements. They should be at least 1 in. A 1 in.3 .13 mm) 0. 5). (32 mm) Joint reinforcement as required Vertical Section W2. insects can be thwarted by inserting stainless steel wool into the opening or by using proprietary screens. (813 mm) on center. or as required to prevent excessive cracking. Unless otherwise noted.6 . For exterior veneer.0. anchored veneer and its attachments must meet additional requirements to assure adequate performance in the event of an earthquake.5 in.8 (MW 18) wire. This support does not necessarily have to occur at the floor height. They differ by the method used to attach the veneer to the backing. (25 mm) high and spaced not more than 32 in. (1. As an alternative. the veneer must be supported by noncombustible lintels or supports attached to noncombustible framing. The exception is when anchored veneer is applied over frame construction.76 mm) 0.5 . open weep holes can also serve as vents. (7. (114 mm). solid units = Minimum cover from exterior = / in. veneer height is limited to 30 ft (9. (0. Therefore. In areas where seismic activity is a factor. Two types of veneer are discussed—anchored veneer and adhered veneer. (25 mm) air space is considered appropriate if special precautions are taken to keep the air space clean (such as beveling the mortar bed away from the cavity). (16 mm) 7 8 Figure 3—Corrugated Sheet Metal Anchor Requirements (ref. clearance 16 in.2. Where anchored veneers are not self-supporting. Otherwise. allowing air circulation in the cavity to speed the rate of drying. as illustrated in Figure 1. A 1 in. In areas where the basic wind speed exceeds 110 mph (145 km/hr). See Crack Control for Concrete Brick and Other Concrete Masonry Veneers (ref. 3.10 in. Additional vents may be installed at the tops of walls to further increase air circulation. control joints and horizontal joint reinforcement effectively relieve stresses and accommodate small movements.14 m) (height at plate) or 38 ft (11. In concrete masonry. (22 mm) 0. minimum Max. 1 1 4 in. water penetration through the veneer is anticipated. Flashing and weep holes in the veneer collect any water that penetrates the veneers and redirect it to the exterior.06 .03 in. and the following prescriptive requirements may not be used. veneer requirements are those contained in Building Code Requirements for Masonry Structures (ref. Similarly. proprietary insulating drainage products can be used. such as over openings. a 2 in. For anchored veneer. (1. (51 mm) air space is preferred. The height and length of the veneered area is typically not limited by building code requirements. Masonry units used for anchored veneer must be at least 2 5/8 in. If necessary. (67 mm) thick. Floors that support anchored veneers are subject to the same deflection limit.6 mm). For wood stud backup. 2). 2).58 m) (height at gable) (ref.5 mm) 1 1/2 in. but instead can be provided at a window head or other convenient location.58 m) (height at gable).6 mm) 1 Pintle unit Plan View Eye unit Figure 2—Adjustable Anchors W g len av e th ude plit Am Wid th Minimum width Minimum thickness Wavelength = = = Amplitude = Thickness Minimum embedment. (25 mm) minimum air space must be maintained between the anchored veneer and backing to facilitate drainage. More detailed information is contained in Concrete Masonry Veneer Details and Flashing Details for Concrete Masonry Walls (refs. (7. whichever is smaller. masonry veneer over steel stud backing must be supported by steel shelf angles or other noncombustible construction for each story above the first 30 ft (9. Anchors and supports must be noncombustible and corrosion-resistant.ture changes.0. (38 mm) 5/8 in. Anchors are used to secure the veneer and to transfer loads to the backing. 6) for further information. Partially open head joints are one preferred type of weep hole.14 m) (height at plate) or 38 ft (11. Max. Deflection of these horizontal supports is limited to 1/600 of the span or 0. Control joints should be placed in the veneer at the same locations as those in the backing. the veneer must be designed using engineering philosophies. the backing system must be designed and detailed to resist water penetration and prevent water from entering the building.3 in. The maximum distance between the inside face of the veneer and the outside face of the backing is limited to 4 1/2 in. or deflection. 25) 18 (457) 18 (457) 18 (457) 32 (813) 32 (813) 32 (813) Additional requirements: . When anchored veneer is laid in other than running bond. the veneer shall have joint reinforcement of at least one W1. (406 mm) maximum Figure 4—Requirements for Joint Reinforcement Used to Anchor Veneer (ref. (1. For proper fastening of corrugated sheet metal anchors.25) 3. the International Building Code (ref. anchors of wire size W 1. each anchor is attached to the backing with a corrosion-resistant 8d W 1. a For Seismic Design Categories D. such as building paper ship lapped a minimum of 6 in. space anchors around perimeter of opening at a maximum of 3 ft (0.8 mm) corrugated sheet metal all other anchors Steel stud adjustable Anchor spacing Max. When masonry veneer is anchored to steel backing. E and F. When the interior Table 1—Anchor Spacing Requirements (ref. . in. (152 mm) at seams. (914 mm) in any face dimension.67 (0. 2) Adhered veneer is veneer secured and supported through adhesion to a bonding material applied over the backing. or a fastener with equivalent or greater pullout strength. where the maximum distance is 1 in.043 in. Sheathing requirements are the same as those for wood stud backing. 36 in.backing. adjustable anchors or joint reinforcement. joint reinforcement or adjustable anchors. Masonry units used in this application are limited to 25/8 in.1 mm).7 (MW 11).7 (MW 11) wire.25) 2. the code stipulates a maximum weight of 20 lb/ft2 (97 kg/m2). Requirements for the most common anchor types are summarized in Figures 2 through 4.19 in.67 (0. (MW 11) minimum common nail. Around openings larger than 16 in.25) 18 (457) 18 (457) 32 (813) 32 (813) 2. (mm) 2.67 (0. (mm) spacing. 74 . to protect the backing from any water which may penetrate the veneer.67 (0. reduce maximum wall area supported by each anchor to 75% of values shown . vertical Max. (25 mm). Anchors Veneers may generally be anchored to the backing using corrugated sheet metal anchors.91 m) on center. Attachment to Backing When masonry veneer is anchored to wood backing. 2) Maximum vertical spacing Maximum wall surface area per anchor Anchor location Maximum horizontal spacing Backing Masonry Max.46 m2) in total face area and 15 lb/ft2 (73 kg/m2) weight (ref. Masonry veneer anchored to masonry backing may be attached using wire anchors. sheet metal anchors. (305 mm) of opening. The exterior sheathing must be either water repellent with taped joints or be protected with a water repellent membrane. wire anchors. ft2 (m2)a Type of anchor wire. Veneer anchored to a concrete backing must be attached with adjustable anchors. 5 ft2 (0. (406 mm) in either dimension.5 (0. adjustable. ADHERED VENEER 5 in.7. or joint reinforcement Concrete adjustable Wood stud adjustable two-piece. In this application. Each anchor is attached with corrosion-resistant screws that have a minimum nominal shank diameter of 0. 2). In addition. or 22 gauge (0. spaced at a maximum of 18 in. When anchored veneer is used as an interior finish supported on wood framing. Coldformed steel framing must be corrosion resistant and should have a minimum base metal thickness of 0. (457 mm) on center vertically to increase the flexural strength of the veneer in the horizontal span. the nail or fastener must be located within 1/2 in. and place anchors within 12 in. horizontal spacing. (67 mm) thickness. the veneer weight is limited to 40 lb/ ft2 (195 kg/m2). 1) includes requirements for adhered masonry veneers used on interior walls. (4. adjustable anchors must be used to attach the veneer. although building codes may restrict the use of some anchors.8 mm).33) 2. in. wall surface area. (13 mm) of the 90° bend in the anchor. (16 mm) minumum 8 16 in. 1995.ncma. National Concrete Masonry Association. 2005. The units are then tapped into place to eliminate voids between the units and the backing which could reduce bond. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. REFERENCES: 1. Materials that may affect bond. Flashing Details for Concrete Masonry Walls. 6. which can cause veneer cracking or loss of adhesion. Backing materials for adhered veneer must be continuous and moisture-resistant (wood or steel frame backing with adhered veneer must be backed with a solid water repellent sheathing). National Concrete Masonry Association. ACI 530-05/ASCE 5-05/TMS 402-05. The surface of the backing material must be capable of securing and supporting the imposed loads of the veneer. 2003. Structural Backup Systems for Masonry Veneer. Reported by the Masonry Standards Joint Committee. 2001. 2003. metal lath and portland cement plaster applied to masonry. 4. TEK 16-3A. Type S mortar is then applied to the backing and to each veneer unit in a layer slightly thicker than 3/8 in. concrete. 2003 International Building Code.org To order a complete TEK Manual or TEK Index. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. National Concrete Masonry Association. (9. National Concrete Masonry Association. Mortar joints are tooled with a round jointer when the mortar is thumbprint hard. 3. TEK 5-1B. Backing may be masonry.veneer is supported by wood construction. such as dirt. (9.5 mm). This cement coating provides a good bonding surface for the mortar. TEK 195A. grease. Concrete Masonry Veneer Details. the wood backup must be designed for a maximum deflection of 1/600 of the span of the supporting wood member. Herndon. 2004. 5. Building Code Requirements for Masonry Structures. concrete. Crack Control for Concrete Brick and Other Concrete Masonry Veneers. A paste of neat portland cement is brushed on the backing and on the back of the veneer unit immediately prior to applying the mortar coat. International Code Council. Note that care must be taken when adhered masonry veneer is used on steel frame or wood frame backing to limit deflection of the backing. Adhered veneer and its backing must also be designed to either have sufficient bond to withstand a shearing stress of 50 psi (345 kPa) based on the gross unit surface area after curing 28 days (refs. or be installed according to the following. or paint (except portland cement paint) should be cleaned off the backing surface prior to adhering the veneer. Sufficient mortar should be used so that a slight excess is forced out the edges of the units. 1. oil. The resulting thickness of mortar between the backing and veneer must be between 3/8 and 11/4 in. 2). 75 contact NCMA Publications (703) 713-1900 . steel framing or wood framing.5 and 32 mm). TEK 10-4. 2. Virginia 20171 www. (152 mm) if firebrick Base assembly Ash dump Cleanout door 6 in. BASE The fireplace base consists of the foundation and hearth extension support. All fireplaces contain essentially the same elements: a base. thickness Temporary forming Flue liner support 8 in. Forming the concrete Keywords: chimneys. smoke dome thickness if parged. Local building codes should be reviewed for design soil pressures for foundations. (203 mm). (102 mm). External air damper Hearth extension Ash drop Air passageway Double joists Smoke chamber. Concrete masonry. (203 mm). support for the combustion chamber and the hearth extension are necessary. heat is not only radiated to the room from the fire. 6 in. combustion chamber. (102 mm) concrete masonry Combustion chamber 10 in. but also from the concrete masonry hours after the fire dies. fire protection. firebox thickness or 8 in. (305 mm). (254 mm) min. heat is stored in the concrete masonry itself. Lintel Fireplace opening height 4 in. Slope 30° from vertical. Immediately above the foundation walls. max. due to its inherent fire resistance and beauty. corbels. is a popular and versatile building material for constructing part or all of a fireplace. Noncombustible concrete masonry effectively isolates the fireplace fire from nearby combustible materials such as wood. min. 1). Concrete footing 12 in. but is usually provided by a poured concrete slab that also supports the combustion chamber. The hearth extension may be supported by corbelling the masonry foundation wall. an ash pit or both. min. plastic and insulation. Nonessential void areas should be solidly Air space not to exceed thickness of flue liner Flue Chimney block or concrete brick Chimney Fire clay flue liner Mantle Smoke dome Parging Throat damper Smoke shelf Lintel angle 8 in. (102 mm) min. Thus. (152 mm). (203 mm) where fire brick lining is used External air supply register Non-combustible forming 8 in. In addition. Requirements herein are based on the 2003 International Residential Code (IRC) (ref. combustion chamber. Reinforced concrete slab. (203 mm) min. height ≤ inside width of fireplace opening Parging 4 in. as shown in Figure 1 for a single opening fireplace. 4 in. (508 mm) min. footings INTRODUCTION The fireplace is an American tradition and remains today a central feature of the home. min. because of concrete masonry's thermal mass. Figure 1—Single Opening Fireplace 76 TEK 3-7A © 2003 National Concrete Masonry Association (replaces TEK 3-7) (2003) . smoke chamber and chimney. construction details. Concrete masonry fireplaces are a safe and efficient source of auxiliary heat when properly designed and constructed. min.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY FIREPLACES TEK 3-7A Construction filled with masonry. fireplaces. Void areas are often provided in the base to form an air passage for external combustion air. 20 in. min. The foundation consists of a concrete footing and concrete masonry foundation walls or a thickened slab for slab-on-grade construction (see Figure 1). Width of fireplace opening. 16 x 30 (4. lintel expansion due to high temperatures will not crack the masonry. the dimensions of the masonry combustion chamber may be determined using Table 2. When no lining is used. The metal damper.4. Inches (ref. The use of noncombustible fibrous insulation at the ends of the lintel angle will usually compensate for this expansion and eliminate cracking problems. The fireplace throat should be as wide as the firebox and should be not less than 8 in. the firebox and surrounding masonry and the throat. C 1261 (refs.slab requires “block outs” for external combustion air dampers and ash drops if there are air passageways or ash pits incorporated into the base of the fireplace. (508 mm) in front of the fireplace face and at least 12 in.66 x 4.524) this minimum thickness is 10 in. smoke shelf.97) 40 to 48 (1.14) 36 to 40 (914-1.27 x 8. (203 mm) of solid 14 x 28 (4. the damper should be wide open.66 x 7. 2.016-1. (51 mm). the hearth extension must be 20 in. (203 mm) beyond each side of the fireplace opening for fireplaces with openings that are less than 6 ft2 (0. The hearth extension must extend at least 16 in. The forming should be placed so that the projected slab will meet a doubled wood floor joist. COMBUSTION CHAMBER The fireplace opening should be based on the room size for aesthetics and to prevent overheating the room. When the fireplace is not in use. Fire brick ft x ft (m x m) in short wall in long wall is laid using medium-duty refractory mortar conform10 x 14 (3.10) 32 to 36 (813-914) 36 to 40 (914-1.016) 40 to 48 (1.53) 32 to 40 (813-1. must conform to Standard Classification of Table 1—Suggested Width of Fireplace Openings Appropriate Fireclay and High-Alumina Refractory Brick.219) 48 to 72 (1.56 m2). 77 . which is critical for proper performance.219-1. Temporary wood forming is typically used to pour the hearth extension support.10 x 10. Once the The combustion chamber consists of the hearth extension. Suggested fireplace opening widths are provided in Table 1. with /4 in. Because the hearth extension must be constructed of noncombustible materials. (305 mm) beyond each side of the opening. The total minimum thickness of 12 x 24 (3. like the lintel over the fireplace opening. The size and position of the throat is critical for proper burning and draft. If permanent forming is required at the top of the foundation walls. The concrete slab must be at least 4 in.27) 24 (610) 24 to 32 (610-813) ing to Standard Test Method for Pier Test for Refrac12 x 16 (3. (203 mm) above the fireplace opening. multiply inches by 25. (406 mm) in front of the fireplace face and at least 8 in. 3). concrete brick or decorative concrete masonry units are often used to construct the hearth extension. smoke dome and surrounding concrete masonry. it must be a noncombustible material. Fire brick. (6. reinforced and capable of resisting thermal stresses resulting from high temperatures. (254 mm).829) Table 2—Single-Opening Fireplace Dimensions. laid to form Size of room. 5)a Opening Width Height 24 26 28 30 32 36 40 42 48 54 60 60 72 a 24 24 24 29 29 29 29 32 32 37 37 40 40 Firebox Throat Rear wall depth Depth Width Vertical Splayed height height 16 11 14 18 83 / 4 16 13 14 18 83 / 4 16 15 14 18 83 / 4 16 17 14 23 83 / 4 16 19 14 23 83 / 4 16 23 14 23 83 / 4 16 27 14 23 83 / 4 16 29 16 24 83 / 4 18 33 16 24 83 / 4 20 37 16 29 13 22 42 16 29 13 22 42 18 30 13 22 54 18 30 13 Smoke chamber Steel angles Width Height Shelf Length depth 32 19 12 36 34 21 12 36 36 21 12 36 38 24 12 42 40 24 12 42 44 27 12 48 48 29 12 48 50 32 12 54 56 37 14 60 68 45 12 66 72 45 14 72 72 45 14 72 84 56 14 84 Size 3 x 3 x 1/4 3 x 3 x 1/4 3 x 3 x 1/4 3 x 3 x 1/4 3 x 3 x 1/4 3 x 3 x 1/4 3 x 3 x 1/4 31/2 x 3 x 1/4 31/2 x 3 x 1/4 31/2 x 3 x 1/4 31/2 x 3 x 1/4 31/2 x 3 x 1/4 5 x 31/2 x 5/16 For millimeters.016-1.219-1.35 mm) 12 x 20 (3. Once the opening width is selected. should not be solidly embedded in mortar. is placed directly over the throat.016) mortar joints maximum. SMOKE CHAMBER The smoke chamber consists of the damper.219) masonry including the lining.88 x 9.05 x 4. The steel angle lintel used above the fireplace opening should not be solidly embedded in mortar.016) 48 to 60 (1. 4). the damper should be closed to prevent heat loss. The damper. With the ends free to move. (mm) a firebox wall thickness of at least 2 in. in. When a fire is started. If the area of the fireplace opening is 6 ft2 (0. (102 mm) thick.32) 32 to 36 (813-914) 36 to 48 (914-1.88) 28 to 36 (711-914) 32 to 36 (813-914) 1 tory Mortars.56 m2) or larger. ASTM C 199 (ref.66 x 6. 20 x 36 (6. 5) C 27 or Standard Specification for Firebox Brick for Residential Fireplaces. ASTM to Size of Room (ref. if used.219) the back and side walls must be 8 in. and be such that it can be easily removed. additional reinforcement and anchorage requirements apply to masonry chimneys in accor- dance with applicable building codes. this parging is required). the damper should be adjusted to produce more efficient combustion. Care should be taken to use only enough mortar to make the joint. The chimney is constructed directly over the smoke shelf and consists of a flue liner and a chimney wall. when hot. this minimum thickness is reduced to 6 in. Maintaining efficient fuel consumption by properly adjusting the damper is critical. For residential fireplaces. The walls of the smoke dome should be solid masonry or hollow unit masonry grouted solid and should provide a minimum of 8 in. including soffits or cornices. High form dampers are constructed such that the damper. which checks down drafts. a high form damper may be used. the clearance between the chimney wall and combustibles may be reduced to 1 in. and increases the amount of usable radiant heat from the concrete masonry. The chimney wall should be separated from the flue lining by an airspace or insulation not thicker than the thickness of the flue lining to permit the flue lining. 1) contains minimum clearances between masonry fireplaces or chimneys and exposed combustible trim and the edges of sheathing materials such as wood siding. as shown in Figure 2. 8). with flush mortar joints on the inside. These air spaces should be firestopped using noncombustible materials as precribed by the building code. Additionally. excluding trim and the edges of sheathing materials. Metal pan flashing over the top of the chimney will also perform adequately. This clear space should be firestopped in the same manner as described for fireplaces. (51 mm) clearance is required around the perimeter of the chimney wall. The International Residential Code ( ref.048 mm) of the chimney (see Figure 2). The inside of the smoke dome should be parged to reduce friction and help prevent gas and smoke leakage (when the inside is formed by corbelling the masonry. and be at least 4 in. When the smoke dome is lined using fire brick at least 2 in. Higher chimneys may be required for adequate draft. or 4 in.fire is burning readily. flooring and drywall as well as mantles. The cap should be either cast-in-place or precast concrete. positioning the fireplace on interior rather than exterior walls reduces heat loss when the fireplace is not in operation. Fireplace efficiency can also be improved by introducing external air into the firebox for draft and combustion (not within Table 3—Minimum Flue Net Cross-Sectional Area for Masonry Fireplaces Flue shape Net cross-sectional area of flue.572 mm) high chimneys (measured from the top of the fireplace opening to the top of the chimney). (51 mm) airspace must be maintained between combustible framing and masonry fireplaces. The chimney wall must be constructed of solid masonry units or hollow units grouted solid. (102 mm) from the back face. Inserts include the elements of the high form damper as well as the firebox. smoke shelf and smoke dome are contained in one metal unit. (25 mm). The IRC (ref. Any down drafts strike the smoke shelf and are diverted upward by the damper assembly. FLUE AND CHIMNEY The chimney should be positioned so that it is centered on the width of the fireplace and the back of the flue liner aligns with the vertical rear surface of the smoke dome. a listed chimney lining system complying with Standard for Safety for Chimney Liners. (16 mm) thick. The smoke shelf may be curved to assist in checking down drafts. (152 mm). Good draft is normally achieved with 15 ft (4. (51 mm) thick or vitrified clay at least 5 /8 in. 4). This lintel must be allowed to expand independently and thus should not be solidly embedded in the masonry. Flue lining installation should conform to Standard Practice for Installing Clay Flue Lining. 6). If the entire perimeter of the chimney wall is outside the building. but flat smoke shelves perform adequately. The masonry above the damper should be supported on a second lintel angle (if required) and not on the damper. since adjusting a poker controlled damper usually requires reaching into the firebox. For ease of construction. (102 mm) in nominal thickness. fireplace inserts may be used. The inserts are placed directly on the firebrick hearth. 1) has an Option 2 where the flue size is based on chimney height as well as the fireplace opening area. a rotary controlled damper that is adjusted with a control on the face of the fireplace is preferred. A mortar wash that is feathered to the edge of the chimney wall is not an adequate cap. UL 1777 (ref. Immediately behind the damper is the smoke shelf. and any combustibles. to expand freely without cracking the chimney wall. Fireclay flue liners are laid in medium-duty refractory mortar conforming to Standard Test Method for Pier Test for Refractory Mortars. For convenience and safety. fraction of fireplace opening size 1 /12 1 /10 Round Square Rectangular: aspect ratio < 2 to 1 aspect ratio > 2 to 1 1 /10 /8 1 78 . The chimney must be capped to resist water penetration. The chimney must extend at least 3 ft (914 mm) above the point where the chimney passes through the roof and at least 2 ft (610 mm) above any part of the building within 10 ft (3. flue size is determined by the shape of the flue and the size of the fireplace opening (see Table 3). The smoke dome should be constructed so that the side walls and front wall taper inward to form the chimney support. ENERGY EFFICIENCY Proper fireplace design and operation helps maximize the efficiency. To ensure the fireplace draws adequately. theflueliningmaybeaclayflueliningcomplyingwithStandard Specification for Clay Flue Linings. For example. ASTM C 1283 (ref. Note that in Seismic Design Categories D and E. There are several other ways to significantly improve the performance of the concrete masonry fireplace. A 2 in. This configuration funnels the smoke and gases from the fire into the chimney. (203 mm) of solid masonry between the smoke dome and exterior surfaces when no lining is used. ASTM C 199 (ref. ASTM C 315 (ref. 7) or other approved system or material. Keeping the damper wide open reduces the fireplace efficiency. CLEARANCES AND FIREBLOCKING A minimum 2 in. Standard Test Method for Pier Test for Refractory Mortars. ASTM International. Base flashing (fire stop) Fire clay flue liner Air space not to exceed thickness of flue liner Concrete brick or block 4 in. 2002. Decorate and Use Them. Standard Classification of Fireclay and HighAlumina Refractory Brick. Farmington. Precast cap 1 2 in. Underwriters Laboratory. Precast Cap: Noncombustible resilient sealant Temporary forming 10 ft (3. 2 in. Cast-in-Place Cap: Concrete cap 4 in. 79 contact NCMA Publications (703) 713-1900 . (13 mm) min. 1 2 in. ASTM C 1261-98. (102 mm) thick. Counter flashing Roof rafter 2 in. (610 mm) min. 5. Standard Practice for Installing Clay Flue Lining. REFERENCES 1. 8. 2. Structures Publishing Company. 20th Edition. 1998. galvanized hardware cloth reinforcement 24 in. Book of Successful Fireplaces. Virginia 20171 www. (102 mm) min. Herndon. International Code Council. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. and M. 1996. Standard Specification for Clay Flue Linings. 3. ASTM International. by R. 2002. ASTM C 1283-02. An external combustion air system requires a damper in the firebox. How to Build. The damper should be capable of directing air flow towards the back of the firebox so that when down drafts or negative pressures occur. (102 mm) max. 7. hot ashes or embers are not forced into the room. The external air damper should permit the control of both the direction and volume of the airflow for temperature control. 2003. (51 mm) clearance to framing. adequate ducting or air passageways and a grill or louver at the exterior opening. 6. UL 1777. ASTM C 199-84 (2000). J. min. ASTM C 27-98. Lytle. ASTM C 315-02. (51 mm) min. Michigan. 4. 1998. ASTM International. (914 mm) min. min. ASTM International.048 mm) 4 in. 36 in.org To order a complete TEK Manual or TEK Index. ASTM International. Standard Specification for Firebox Brick for Residential Fireplaces.J. 2000.ncma.the garage or basement. 1977. (13 mm) non-combustible wall board (fire stop) Ceiling joist Figure 2—Chimney Roof Penetration Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. Standard for Safety for Chimney Liners. typ. 2003 International Residential Code. i. shapes. MATERIALS CONSTRUCTION METHODS Keywords: ASTM specifications. allowing them to act as a composite structural assembly. In admanufactured in a wide variety of sizes. and ties to help enPlacement of Concrete Masonry Units sure all elements perform as TEK 3-8A © 2001 National Concrete Masonry Association (replaces TEK 3-8) 80 . a unit. and its resistance to fire. and sound attenubond or joint pattern of a concrete masonry wall can create a ation to a wall system.NCMA TEK Provided by: BetcoSupreme National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY CONSTRUCTION TEK 3-8A Construction (2001) INTRODUCTION Concrete masonry is a popular building material because of its strength. fire resistance. cleaning. Reinforcement incorporated into concrete masonry structures increases strength and ductility. and architectural finishes to achieve any number of appearances and functions. in the case of horizontal reinforcement. anchors. grout. units are bonded together with mortar. to shrinkage cracking. economy. Mortar bonds the individual masonry units together.. In addition. durability. Grout is most commonly used in reinforced construction. Specifications governing material requirements are listed in Table 1. In addition. its influence on the performance of a wall is significant. In addition. To function as designed however. each contribute to the performance of a Most concrete masonry construction is mortared construcmasonry structure.e. grout. 4) illustrates a broad sampling of available units. and steel. tion. This TEK provides a brief overview of the variety of materials and construction methods currently applicable to concrete masonry. to structurally bond the steel reinforcing bars to the masonry. a typical construction sequence is described in detail. colors. construction tolerances. Grout is used to fill masonry cores or wall cavities to improve the structural performance and/or fire resistance of masonry. While mortar constitutes approximately 7% of a typical masonry wall area. concrete masonry units are wide variety of interesting and attractive appearances. morMortared Construction tar. bond patterns. mortar seals joints against moisture and air leakage and bonds to joint reinforcement. providing increased resistance to applied loads and. allowing the two elements to act as one unit in resisting loads. Concrete masonry units provide strength. construction techniques. noise. and insects. energy efficiency. The Concrete Masonry Shapes and Sizes Manual (ref. concrete masonry buildings must be constructed properly. Varying the durability. The constituent masonry materials: concrete block. ASTM C 129 Prefaced Concrete and Calcium Silicate Masonry Units. it should be retempered. Dry-Stacked Construction The alternative to mortared construction is dry-stacked (also called surface bonded) construction. where vertical head joints are offset by half the unit length. the rest of the water is added. ASTM A 767 Masonry Joint Reinforcement. calm conditions will increase the board life of the mortar. 2). To retemper. Mortar should be discarded if it shows signs of hardening or if 21/2 hours have passed since the original mixing. Although it is important to provide sufficient mortar to properly bed concrete masonry units. the same quantities of materials should be added to the mixer. Excluding running bond construction. water retention. the mortar is mixed with a small amount of additional water to improve the workability. Approximately half the sand is then added. For this reason. Typically. In concrete masonry construction. site-mixing of mortar should ideally be performed in a mechanical mixer to ensure proper uniformity throughout the batch. then both surfaces of the wall are coated with surface bonding material. it is defined as masonry laid such that the head joints in successive courses are horizontally offset less than one quarter the unit length (ref. 7). ASTM A 615 Epoxy-Coated Reinforcing Steel Bars. ASTM A 775 Low-Alloy Steel Deformed Bars for Concrete Reinforcement. and slide off the trowel easily as it is spread. ASTM A 951 Ties & Anchors dition. the mortarboard should be moistened when a fresh batch is loaded. dry. A longer mixing time can increase workability. the strength of the masonry can be influenced by the bond pattern. ASTM C 90 Concrete Building Brick. where units are placed without any mortar. ASTM C 270 Grout Grout for Masonry. 81 . Shims or ground units are used to maintain elevations. the mortar mixture may not attain the uniformity necessary for the desired performance. excessive mortar should not extend into drainage cavities or into cores to be grouted. cool. Concrete Masonry Bond Patterns (ref. For grouted masonry. After a significant amount of the cement has hydrated. retempering will no longer be effective. and tooling must also be consistent to achieve uniform mortar for the entire job. ASTM C 744 Mortar Mortar for Unit Masonry. ASTM A 617 Deformed and Plain Billet-Steel Bars for Concrete Reinforcement. ASTM C 476 Reinforcement Axle-Steel Deformed and Plain Bars for Concrete Reinforcement. about half the mixing water is added first into a mixer. CONSTRUCTION SEQUENCE Mixing Mortar To achieve consistent mortar from batch to batch. mortar can be retempered for only 11/2 to 21/2 hours after initial mixing. Mortar should extend fully across bedding surfaces of hollow units for the thickness of the face shell. When mortar on the board does start to dry out due to evaporation. 9) con- tains further information on this method of construction. As the mortar is mixed and begins to stiffen. and they should be added in the same order. If the mortar is not mixed long enough. depending on the site conditions. followed by any lime. In addition. ASTM A 616 Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement. To help keep mortar moist. Solid units are required to be fully bedded in mortar. Mortar should also hold enough water so that the mortar on the board will not lose workability too quickly. mortar protrusions extending more than 1 /2 in. This construction method results in faster construction. and windy conditions will shorten the board life. placement methods. Although stack bond typically refers to masonry constructed so that the head joints are vertically aligned. the surface bonding coating provides excellent rain penetration resistance. 7) requires that these materials be mixed for 3 to 5 minutes. Mortar mixing times. and damp. The mortar must also be stiff enough to initially support the weight of the concrete masonry units. ASTM C 73 Nonloadbearing Concrete Masonry Units. and is less dependent on the skill of the laborer than mortared construction. except at foundations. (13 mm) into cells or cavities to be grouted should be removed (ref. The cement and the remainder of the sand are then added. For example.Table 1—Masonry Material Specifications Units Loadbearing Concrete Masonry Units. hot. Surface Bonded Concrete Masonry Construction (ref. so that joints will be completely filled. the most popular bond pattern with concrete masonry units is stack bond. and to allow the mason to spread mortar bed joints ahead of the masonry construction. The mortar should stick to the trowel when it is picked up. (10 mm) thick. and board life. Mortar materials should be placed in the mixer in a similar manner from batch to batch to maintain consistent mortar properties. ASTM C 55 Calcium Silicate Face Brick (Sand-Lime Brick). ASTM A 706 Rail-Steel Deformed and Plain Bars for Concrete Reinforcement. Placing Mortar Head and bed joints are typically 3/8 in. 3) shows a variety of bond patterns and describes their characteristics. The most traditional bond pattern for concrete masonry is running bond. Specification for Masonry Structures (ref. The Importance of Laying to the Line Experienced masons state that they can lay about five times as many masonry units when working to a mason line than when using just their straightedge. The mason line gives the mason a guide to lay the block straight, plumb, at the right height, and level. The line is attached so that it gives a guide in aligning the top of the course. If a long course is to be laid, a trig may be placed at one or more points along the line to keep the line from sagging. Before work begins, the mason should check to see that the line is level, tight, and will not pull out. Each mason working to the same line needs to be careful not to lay a unit so it touches the line. This will throw the line off slightly and cause the rest of the course to be laid out of alignment. The line should be checked from time to time to be certain it has remained in position. PLACING UNITS The Foundation Before building the block wall, the foundation must be level, and clean so that mortar will properly adhere. It must also be reasonably level. The foundation should be free of ice, dirt, oil, mud, and other substances that would reduce bond. Laying Out the Wall Taking measurements from the foundation or floor plan and transferring those measurements to the foundation, footing, or floor slab is the first step in laying out the wall. Once two points of a measurement are established, corner to corner, a chalk line is marked on the surface of the foundation to establish the line to which the face of the block will be laid. Since a chalk line can be washed away by rain, a grease crayon, line paint, nail or screwdriver can mark the surface for key points along the chalk line, and a chalk line re-snapped along these key points. After the entire surface is marked for locations of walls, openings, and control joints, a final check of all measurements should be made. The Dry Run—Stringing Out The First Course Starting with the corners, the mason lays the first course without any mortar so a visual check can be made between the dimensions on the floor or foundation plan and how the first course actually fits the plan. During this dry layout, concrete blocks will be strung along the entire width and length of the foundation, floor slab, and even across openings. This will show the mason how bond will be maintained above the opening. It is helpful to have 3/8 in. (10 mm) wide pieces of wood to place between block as they are laid dry, to simulate the mortar joints. At this dry run the mason can check how the block will space for openings which are above the first course—windows, etc., by taking away block from the first course and checking the spacing for the block at the higher level. These checks will show whether or not units will need to be cut. Window and door openings should be double checked with the window shop drawings prior to construction. When this is done, the mason marks the exact location and angle of the corners. It is essential that the corner be built as shown on the foundation or floor plan, to maintain modular dimensions. Laying the Corner Units Building the corners is the most precise job facing the mason as corners will guide the construction of the rest of the wall. A corner pole can make this job easier. A corner pole is any type of post which can be braced into a true vertical position and which will hold a taut mason’s line without bending. Corner poles for concrete block walls should be marked every 4 or 8 in. (102 to 203 mm), depending on the course height, and the marks on both poles must be aligned such that the mason’s line is level between them. Once the corner poles are properly aligned, the first course of masonry is laid in mortar. Typically, a mortar joint between 1 /4 and 3/4 in. (6.4 to 19 mm) is needed to make up for irregularities of the footing surface. The initial bed joint should be a full bed joint on the foundation, footing, or slab. In some areas, it is common practice to wet set the initial course of masonry directly in the still damp concrete foundation. Where reinforcing bars are projecting from the foundation footing or slab, the first course is not laid in a full mortar bed. In this case, the mason leaves a space around the reinforcing bars so that the block will be seated in mortar but the mortar will not cover the area adjacent to the dowels. This permits the grout to bond directly to the foundation in these locations. After spreading the mortar on the marked foundation, the first block of the corner is carefully positioned. It is essential that this first course be plumb and level. Once the corner block is in place, the lead blocks are set—three or four blocks leading out from each side of the corner. The head joints are buttered in advance and each block is lightly shoved against the block in place. This shove will help make a tighter fit of the head joint, but should not be so strong as to move the block already in place. Care should be taken to spread mortar for the full height of the head joint so voids and gaps do not occur. If the mason is not working with a corner pole, the first course leads are checked for level, plumb, and alignment with a level. Corners and leads are usually built to scaffold height, with each course being stepped back one half block from the course below. The second course will be laid in either a full mortar bed or with face shell bedding, as specified. Laying the Wall Each course between the corners can now be laid easily by stretching a line between. It should be noted that a block has thicker webs and face shells on top than it has on the bottom. The thicker part of the webs should be laid facing up. This provides a hand hold for the mason and more surface area for mortar to be spread. The first course of block is thereafter laid from corner to corner, allowing for openings, with a closure block to complete the course. It is important that the mortar for the closure block be spread so all edges of the opening between blocks and all edges of the closure block are buttered 82 before the closure block is carefully set in place. Also, the location of the closure block should be varied from course to course so as not to build a weak spot into the wall. The units are leveled and plumbed while the mortar is still soft and pliable, to prevent a loss of mortar bond if the units need to be adjusted. As each block is put in place, the mortar which is squeezed out should be cut off with the edge of the trowel and care should be taken that the mortar doesn’t fall off the trowel onto the wall or smear the block as it is being taken off. Should some mortar get on the wall, it is best to let it dry before taking it off. All squeezed out mortar which is cut from the mortar joints can either be thrown back onto the mortar board or used to butter the head joints of block in place. Mortar which has fallen onto the ground or scaffold should never be reused. At this point, the mason should: • Use a straightedge to assure the wall is level, plumb and aligned. • Be sure all mortar joints are cut flush with the wall, awaiting tooling, if necessary. • Check the bond pattern to ensure it is correct and that the spacing of the head joints is right. For running bond, this is done by placing the straightedge diagonally across the wall. If the spacing of head joints is correct, all the edges of the block will be touched by the straightedge. • Check to see that there are no pinholes or gaps in the mortar joints. If there are, and if the mortar has not yet taken its first set, these mortar joint defects should be repaired with fresh mortar. If the mortar has set, the only way they can be repaired is to dig out the mortar joint where it needs repairing, and tuckpoint fresh mortar in its place. Tooling Joints When the mortar is thumbprint hard, the head joints are tooled, then the horizontal joints are finished with a sled runner and any burrs which develop are flicked off with the blade of the trowel. When finishing joints, it is important to press firmly, without digging into the joints. This compresses the surface of the joint, increasing water resistance, and also promotes bond between the mortar and the block. Unless otherwise required, joints should be tooled with a rounded jointer, producing a concave joint. Once the joints are tooled, the wall is ready for cleaning. Cleanup Masonry surfaces should be cleaned of imperfections that may detract from the final appearance of the masonry structure including stains, efflorescence, mortar droppings, grout droppings, and general debris. Cleaning is most effective when performed during the wall construction. Procedures such as skillfully cutting off excess mortar and brushing the wall clean before scaffolding is raised, help reduce the amount of cleaning required. When mortar does fall on the block surface, it can often be removed more effectively by letting it dry and then knocking it off the surface. If there is some staining on the face of the block, it can be rubbed off with a piece of broken block, or brushed off with a stiff brush. Masons will sometimes purposefully not spend extra time to keep the surface of the masonry clean during construction because more aggressive cleaning methods may have been specified once the wall is completed. This is often the case for grouted masonry construction where grout smears can be common and overall cleaning may be necessary. The method of cleaning should be chosen carefully as aggressive cleaning methods may alter the appearance of the masonry. The method of cleaning can be tested on the sample panel or in an inconspicuous location to verify that it is acceptable. Specification for Masonry Structures (ref. 7) states that all uncompleted masonry work should be covered at the top for protection from the weather. DIMENSIONAL TOLERANCES While maintaining tight construction tolerances is desirable to the appearance, and potentially to the structural integrity of a building, it must be recognized that factors such as the condition of previous construction and non-modularity of the project may require the mason to vary the masonry construction slightly from the intended plans or specifications. An example of this is when a mason must vary head or bed joint thicknesses to fit within a frame or other preexisting construction. The ease and flexibility with which masonry construction accommodates such change is one advantage to using masonry. However, masonry should still be constructed within certain tolerances to ensure the strength and appearance of the masonry is not compromised. Specification for Masonry Structures (ref. 7) contains site tolerances for masonry construction which allow for deviations in the construction that do not significantly alter the structural integrity of the structure. Tighter tolerances may be required by the project documents to ensure the final overall appearance of the masonry is acceptable. If site tolerances are not being met or cannot be met due to previous construction, the Architect/Engineer should be notified. Mortar Joint Tolerances Mortar joint tolerances are illustrated in Figure 1. Although bed joints should be constructed level, they are permitted to vary by ± 1/2 in. (13 mm) maximum from level provided the joint does not slope more than ± 1/4 in. (6.4 mm) in 10 ft (3.1 m). Collar joints, grout spaces, and cavity widths are permitted to vary by -1/4 in. to + 3/8 in. (6.4 to 9.5 mm). Provisions for cavity width are for the space between wythes of non-composite masonry. The provisions do not apply to situations where the masonry extends past floor slabs or spandrel beams. Dimensions of Masonry Elements Figure 2 shows tolerances that apply to walls, columns, and other masonry building elements. It is important to note that the specified dimensions of concrete masonry units are 83 /8 in. (9.5 mm) less than the nominal dimensions. Thus a wall specified to be constructed of 8 in. (203 mm) concrete masonry units should not be rejected because it is 7 5/8 in. (194 mm) thick, less than the apparent minimum of 7 3/4 in. (197 mm) (8 in. (203 mm) minus the 1/4 in. (6.4 mm) tolerance). Instead the tolerance should be applied to the 7 5/8 in. (194 mm) specified dimension. 3 Location of Elements Requirements for location of elements are shown in Figures 4 and 5. Plumb, Alignment, and Levelness of Masonry Elements Tolerances for plumbness of masonry walls, columns, and other building elements are shown in Figure 3. Masonry building elements should also maintain true to a line within the same tolerances as variations from plumb. Columns and walls continuing from one story to another may vary in alignment by ± 3/4 in. (19 mm) for nonloadbearing walls or columns and by ± 1/2 in. (13 mm) for bearing walls or columns. The top surface of bearing walls should remain level within a slope of ± 1/4 in. (6.4 mm) in 10 ft (3.1 m), but no more than ± 1/2 in. (13 mm). HEAD JOINT THICKNESS - 1/4 IN., + 3/8 IN. = 3/8 IN. Figure 3—Permissible Variations From Plumb BED JOINT THICKNESS= 3/8 IN. +_ 1/8 IN. FOOTING INITIAL BED JOINT THICKNESS= 1/ IN. MIN. 4 3/4 IN. MAX. Figure 1—Mortar Joint Tolerances Figure 4—Location Tolerances in Plan Figure 2—Element Cross Section and Elevation Tolerances Figure 5—Location Tolerances in Story Height 84 9. National Concrete Masonry Association. Provided by: BetcoSupreme Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. CM 260A. 2. 2000. Masonry & Concrete Construction. 5. ASTM C 90-00. American Society for Testing and Materials. TEK 3-5A.1-99/ASCE 6-99/TMS 602-99. Nolan. Virginia 20171-3499 www. Concrete Masonry Shapes and Sizes Manual.org To order a complete TEK Manual or TEK Index. Reported by the Masonry Standards Joint Committee. Surface Bonded Concrete Masonry Construction. Inspection of Concrete Masonry Construction. 1996. Craftsman Book Company. National Concrete Masonry Association. ACI 530. Specification for Masonry Structures. National Concrete Masonry Association. 6.REFERENCES 1. 1999. 1997. Reported by the Masonry Standards Joint Committee. 1999. VO 6. J. Standard Specification for Loadbearing Concrete Masonry Units. National Concrete Masonry Association. TR 156. 1982. 85 contact NCMA Publications (703) 713-1900 .ncma. ACI 530-99/ASCE 5-99/TMS 402-99. TEK 14-6. 7. 3. 4. 1988. 8. National Concrete Masonry Association. Herndon. Building Code Requirements for Masonry Structures. Building Block Walls. Concrete Masonry Bond Patterns. K. 1998. 1999. NATIONAL CONCRETE MASONRY ASSOCIATION 2302 Horse Pen Road. termites. causing substantial damage to unprotected wood buildused as a construction material.Light to Region IV .Moderate to Region III . Buildings that do not use wood or cellulose products as a construcNote: Local conditions may be more or less severe than indicated by the region classification. This TEK focuses on measures to reduce the possibility of subterranean termite entry into a building. most notably wood. If a sheltered path cally increasing in numbers and spreading toward the northern to the food source is not available. sizes textures and colors available. much attention and concern has been directed to require a moist. the lower the likelihood of termite infestation United States alone (over 2. the very aggressive Formosan termite. termite entry. 2). Although there are over forty species of termites in the from the soil. grouting procedures. Such known local conditions should take tion material are not prone to terprecedence in determining the applicability of protective measures. crack control. Region II . Severe Hazard.500 species around the world). Formosan termite. such as the traditional wood roof framing. it is possible for termites states.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology STRATEGIES FOR TERMITE RESISTANCE TEK 3-9A Construction (2000) Keywords: bond beams. In Southern Louisiana the population is estimated to have increased more than 3. a building must be gained through a sheltered path. do feed on any products containing cellulose. This includes a composite block/steel bar joist floor system that is immune to termite attack (ref.No Hazard damage to masonry materials. Concrete masonry is TEK 3-9A © 2000 National Concrete Masonry Association (replaces TEK 3-9) 86 . humid environment to survive.No Hazard. most termite damage is attributed to subterranean termites. the further the food source is ings.000% in the past ten years alone. termite resistance INTRODUCTION very versatile with an almost endless array of architectural Termites are distributed widely throughout the United shapes. Entire structures can be constructed of concrete and masonry materials. While termites do not cause any Region I . Moderate Hazard. mite infestation making concrete masonry the perfect application for both above and below grade Figure 1—Termite Infestation Potential construction. but is dramatias a crack in a foundation wall or slab. capping concrete masonry walls. Entry into the relative newcomer. they to Light Hazard. such found mainly in the southern states and Hawaii. virtually eliminating the possibility of damage from termites. When wood is States. Concrete masonry is one of the best products available for termite resistance since it does not provide a source of nutrition. Subterranean termites nest in the ground because they Recently. Where such information is not available. Strategies for termite control include: • building out of all concrete masonry. This level of severity for a particular location can be determined from local experience or from the state entomological authorities. These same methods may already be employed for protection from water penetration or soil gas entry. Many of these measures focus on proper design and quality construction to reduce possible entry routes and to provide a hostile (that is. These general clearances do not apply 87 . these access tunnels can be the only direct sign of a termite infestation. In extreme circumstances. It is important to consider the potential for termite infestation during the construction phase since the building construction practices themselves can help protect against future infestation. Key Notes 1 – Ensure that the soil directly adjacent to the foundation is dry and free of scrap lumber or decaying wood.79 mm) wide. Figure 2—Concerns Regarding Termite Protection Reducing Entry Routes Once the termites have established a path. • along the outside of pipes penetrating slabs or foundation walls. all roots. Leaving them in place attracts termites and provides a direct path for them through the concrete. Where conditions exist such that wood remains continuously wet. which protect them from sunlight and open air. Refer to Figure 2 for a summary of critical termite access areas. Nonstructural wood elements. • maintaining a minimum clearance between wood members and soil. • providing access to inspect for termite tunnels. or as otherwise required by local building codes. Site Conditions While preparing the site prior to construction. Termites are capable of moving through a crack only 1/32 inch (0. such as wood in direct contact with the soil. • treating soil with chemicals to repel termites.to build their own access tunnels. and installing proper abovegrade water drainage will help keep the foundation and adjacent soil dry. Otherwise untreated or not naturally termite resistant wood provides a direct path for termite passage. Therefore. sill plates. and • access tunnels on the interior or exterior of walls. providing a less hospitable environment for termites. Similarly. However. 3 – Remove any dead or decaying wood from the area. Structural wood framing. • minimizing cracks in walls and slabs. Similarly. and • utilizing termite resistant construction materials. All trees and plants should be healthy. attracting them and increasing the likelihood of infestation. • sealing around all wall and floor penetrations. if the nonstructural wood is in contact with the structural wood (which is generally the case). Figure 1 may serve as a guide. 2 – All utility penetrations through foundation walls should be sealed for both termite and water penetration resistance. keeping termites out of the structure should always be the paramount objective. the 6 inch (152 mm) minimum clearance should be increased to 8 inches (203 mm). stumps. incorporating a subgrade drainage system. Minimum Clearance to Soil It is desirable to keep wood elements as far as possible from the soil to minimize termite access. The level of termite control employed on a particular job should be consistent with the expected severity of the termite hazard. they have unimpeded access to the entire structure. • installing barriers to prevent termite entry. and sheathing should be kept at least 8 inches (203 mm) above the soil. should be kept a minimum of 6 inches (152 mm) from the soil surface. • adequate drainage around the foundation and adjacent soil. Leaving this material on site or in the backfill provides additional food sources for termites. 5 – Inspect the foundation at regular intervals for signs of termite activity or the development of cracks. subterranean termites may not require constant access to and from the adjacent soil. • direct access from soil under porches or patio slabs. other obscure (but critical) termite entry routes include: • through cracks in exposed wall faces or slabs. such as wood siding and trim. termites do not need to return to the soil to obtain water. Often. However. dry) environment to ward off termites. 4 – Any wood in direct contact with the ground should be rated for such use. wood scraps from construction should be properly disposed. such conditions are rare if proper design and construction for water penetration resistance are adhered to. Backfilling with a free draining soil. In addition to the obvious points of entry. and other wood debris should be removed from the site. wood grade stakes or bracing stakes should be removed before or during a concrete placement and not be cast into the concrete. dead timber. 5 mm) should be repaired before applying a waterproof or damp-proof barrier. the primary concern focuses on shrinkage resulting in the development of tensile stresses. This includes storing block on pallets (or otherwise isolating block from direct contact with the ground) and covering the units with plastic or other water-repellent materials. Some surface moisture is acceptable. and slabs will help prevent structural cracking that may allow termite entry. the barrier is typically carried above the finished grade level to prevent water entry between the barrier and the foundation wall. the recommendations of the American Concrete Institute (ref. Due to fluctuations in the temperature and moisture content.to pressure-treated wood or other termite and decay resistant woods. In these instances. crack control measures become more important. providing a continuous barrier to water entry. however. random cracking. sheet membranes. At the end of each workday. efflorescence. and penetrations must be properly sealed. The lack of a need for control joints is attributed to the relatively low range of thermal and moisture fluctuations occurring in below grade walls afforded by the soil adjacent to the walls and to the water resistant systems applied to basement walls. Concrete masonry units should never be wetted before or during placement in the wall. termites can enter the block through small cracks and move unseen up ungrouted cores. and fireplaces and to wall penetrations. a weatherproof membrane should be placed over uncompleted walls to protect the units from rain or snow. which typically are not treated on the exterior to prevent water entry as basement walls are. To limit concrete slab cracking. All seams. but it will hold the cracks so tightly together that the termites cannot get through. Capping Concrete Masonry Walls Various methods are used to seal the tops of masonry foundation walls. Similarly. The bond beam also provides a cap. the repair of hairline cracks is typically not required. Many of the membrane systems are better able to remain intact in the event of settlement or other movement of the foundation wall. Care must also be exercised during the backfilling process to ensure that the barrier is not damaged. as may be customary with other types of masonry units. Minimizing Cracks Proper structural design of foundation walls. therefore shrinkage may result in small cracks within the masonry. as most barriers will either fill or span these small openings. It is normally not necessary to provide control joints in below grade residential concrete masonry basement walls. Coatings should be applied to clean. structurally sound walls. waterproofing and dampproofing systems should be applied to clean dry walls. usually at 16 inches on center. Because stress concentrations develop at these intersections. Because drying shrinkage is a primary cause of cracking in concrete masonry walls. However. trowelled. 5) for quality concrete placement should be followed. In basement walls. footings. terminations. A control joint is a planned joint in a concrete masonry wall at regular intervals that accommodates shrinkage movement without unsightly. the cap prevents them from direct access to the wood superstructure. Bond beam units are specifically designed to accommo88 .02 inches (0. preventing termites from coming up through the empty cores of ungrouted block and gaining entry into the building. With concrete masonry foundations. also provides additional tensile strength for the masonry and aids in crack control. it is important to minimize the potential for wetting concrete masonry during the construction process. In these cases. Joint reinforcement embedded in the horizontal bed joints. In reinforced construction. In addition to preventing cracks due to structural overload. or other materials that may reduce the bond between the coating and the wall. solid grouting or capping of the walls is recommended. Particular attention should be paid to reentrant corners at garages. Cracks exceeding 0. pliable membranes and/or additional reinforcement are often recommended at these locations to span any potential cracks or hold them tightly together. or brushed onto below-grade walls. Coatings are sprayed. as shown in Figure 3. Typical water penetration measures include coatings. This is because the tensile strength of concrete is relatively small compared to the compressive strength. In crawl space and stem walls. Concrete masonry units should be dry when laid. manufacturer’s directions should be carefully followed for proper installation. Placing a board on top of the membrane will help hold it in place and will prevent the membrane from sagging into the masonry cores and allowing water to collect. Waterproofing and dampproofing systems require that the barrier be continuous to prevent water penetration into voids or open seams. At the jobsite. In all cases. Walls should be brushed or washed to remove dirt. porches. In addition. the dampproofing and waterproofing measures employed to reduce water penetration aid in the prevention of termite entry. and drainage boards. cracking due to concrete shrinkage also needs to be addressed. It should be pointed out that horizontal reinforcement will not completely eliminate cracking. oil. saturated units should be allowed to dry out before placement in the wall. the masonry bond beam at the top of the wall serves as an effective cap. Sheet membranes and panels (drainage boards) are less dependent on workmanship and on surface preparation than coatings. Additional measures to reduce the shrinkage cracking potential of concrete masonry include keeping the walls dry during construction. concrete block should be stored so as to protect the units from absorbing ground water or precipitation. it is possible to provide a reinforced bond beam at or near the top of the wall in lieu of control joints to minimize crack development. all materials have a tendency to expand and contract over time. Should termites penetrate the face shell of a concrete masonry wall below. In most below grade basement wall construction. and 6). 9). If infestation occurs. 4. All seams must be soldered and all openings around anchor bolts and service lead-ins must be sealed.8 barrier directly below the sill plate. ACI 530. 7). Additionally. A lift is the layer of grout date horizontal reinforcement and grout as shown in Figure 4. 3. 6). helping to ensure complete grout fill and good bond is preferred to solid units or solid bottom units with solid with the masonry units. reconsolidation must be cells to be filled. Because termites require only a 1/32 inch (0. Grout should conform to the Specification completed before the grout loses its plasticity.The Specification also requires enough water in the grout mixture to achieve a slump of 8 to 11 inches (203 to 279 mm) (ref. each lift should be consolidated with either a 3/4 in. HowMINIMUM FINISH BONd BEAM COURSE ever. CLOSEd BOTTOM Closed bottom OPEN BOTTOM Open bottom Figure 4—Bond Beam Units for Reinforced Construction Exterior Insulation The rigid plastic foams that are often used to insulate crawl space and the exterior side of basement walls can allow termites to create undetectable tunnels and is prohibited for such use by some codes (ref. In any case. 7) or be specified Metal termite shields may be installed as a continuous to have a minimum compressive strength of 2.1/ASCE 6/TMS 402 (ref. Figure 3—Masonry Bond Beam Cap Grout should also be placed in lifts not exceeding 5 ft. of the unit and weather conditions). for Grout for Masonry. WOOd SILL Many engineers mistakenly try to apply this same CONTINUOUS REINFORCEMENT analogy to masonry – lowering the water content AS REQUIREd 8 in. 3). (ref. the high slump GRADE is critical as it allows the grout to be fluid enough GROUT STOP to flow around reinforcement and completely fill MATERIAL all the voids (ref. the grout should be re Proper grouting procedures are important to ensure bond consolidated to close the space left by the excess water that with the masonry units and void free areas in bond beams and was absorbed (ref. making detection easy. depending on the absorption characteristics through the cracks. (203 mm) in an effort to reduce shrinkage potential. in masonry construction. they generally are not to be relied on for termite protection. termite shields must be installed with great care to be effective. (19 The latter requires a screen grout stop or expanded metal mm) diameter low velocity vibrator. After the water is absorbed from the head joints since the reinforcement in bond beams will hold grout mixture into the masonry (normally 3 to 10 minutes any cracks that form tightly together to prevent termite entry after placement. some of the cement is drawn into the unit with the water creating excellent bond and reducing the formation of voids. 6. An advantage of concrete masonry foundation walls is their ability to accommodate 89 . as the excess water is absorbed into the masonry units. terMPa) at 28 days in accordance with the Specification for mites are forced to build conspicuous access tunnels around Masonry Structures. ally. Consolidation eliminates to contain the grout within the unit. See Figure 5. A reinforced bond beam voids.000 psi (13. resulting in higher strengths and low shrinkage properties despite the high initial water-to-cement ratio. Because of the extreme care required to provide an impenetrable metal termite shield. ASTM C 476 (ref. 6). AdditionBond beam units can be either solid bottom or open bottom.79 mm) gap for penetration. 4) when tested in accordance with ASTM C 143 Standard Test FLOOR SHEATHING Method for Slump of Hydraulic Cement Concrete (ref. placed in a single continuous operation. EXPOSEd WOOd FLOOR JOIST This high slump is contrary to the principles SHEATHING of cast-in-place concrete where high slump levels lead to reduced strengths and higher shrinkage. The initial high water-to-cement ratio is reduced significantly as the masonry units absorb the excess water. the shield. (203 mm) MINIMUM FLOOR JOIST WOOD GIRDER 18 in. Where this is not possible. Unless specified otherwise by local codes. (ref. (457 mm) MINIMUM 24 in. Crawl space floors should be kept at or above the exterior finished grade to facilitate drainage in the crawl space. Limited access to some areas may not allow for an effective chemical barrier to be established. area drains should be installed. the soil under the slab can also be pretreated. Slump to be between 8 and 11 in. (305 mm) CONE Chemical Treatments 8 in. (203 TO 279 mm) SLUMP 12 in. (203 mm) Figure 5—Masonry Requires a Fluid Grout. If a slab-on-grade is also going to be used. it is also more difficult. FLOOR SHEATHING EXPOSEd WOOd SHEATHING FINISH GRADE 8 in. granular fill insulation. (305 mm) MININUM DESIRED GRADE LEVEL OPTIONAL FOOTING DRAIN WHERE CRAWL SPACE GRADE IS BELOW EXTERIOR GROUND LEVEL REINFORCING STEEL AS REQUIREd OPTIONAL AREA dRAIN AT LOW POINT Figure 6—Termite Control Measures for Crawl Space Foundations 90 . and wood joists should be no closer than 18 inches (457 mm) to the soil. While post-construction treatment is far more common. In all cases. Soil treatment before or during construction is often most effective as there is better access to the subgrade soil. 6) insulation within the cores of the masonry units where it is protected from direct contact with the soil. or foamed-in-place insulation can be used for this purpose. or on sites where water flows toward the building due to the site slope. (102 mm) Additional Considerations for Crawl Spaces Figure 6 illustrates termite control measures for crawl space foundations. Either rigid foam insulation inserts. (610 mm) dESIRABLE 12 in. Numerous methods are available to create a pesticide barrier within the soil adjacent to a structure to prevent termite entry. enough clearance should be maintained to allow access to the crawl space for inspection.4 in. 8 TO 11 in. wood girders should be at least 12 inches (305 mm) above the crawl space floor. 5. 1999. Standard Test Method for Slump of Hydraulic Concrete. American Concrete Institute. National Concrete Masonry Association. Basement Manual. It is also very versatile with an almost endless amount of architectural shapes. 91 contact NCMA Publications (703) 713-1900 . 1999. Grouting Concrete Masonry Walls. ASTM C 143/C 143M.ncma. National Concrete Masonry Association. Reported by the Masonry Standards Joint Committee. ACI 530. 1997. An innovative. ASTM C 476-99. 7. Virginia 20171-3499 www. American Society for Testing and Materials. NCMA TEK 9-4. and provides a barrier to prevent termite entry. National Concrete Masonry Association. Standard Building Code. Office of Policy Development and Research. 1984. 1998 Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication.S. and colors available. 4. 8. 9. Standard Specification for Grout for Masonry.1. Specification for Masonry Structures. totally termite proof concrete masonry floor system utilizing a hidden steel bar joist supporting system is also available. American Society for Testing and Materials. Guide to Residential Cast-In-Place Concrete Construction. NATIONAL CONCRETE MASONRY ASSOCIATION 2302 Horse Pen Road. 1998. Concrete Masonry Homes: Recommended Practices. 2000 2. Southern Building Code Congress International. Herndon. NCMA TEK 3-2.4.org To order a complete TEK Manual or TEK Index. 3. References 1. TR-68B. ACI 332-84. Department of Housing and Urban Development. Grout for Concrete Masonry.1-99/ASCE 6-99/TMS 602-99. 6. textures. 1999. sizes. It does not provide food to attract them. 1999: 2304. U.Conclusion Concrete masonry is an ideal construction material to resist termites. Table 2 lists common inch-pound units used in building design and construction. dimensions. For example. the use of symbols to represent feet (') and inches (") is second nature. Symbols When using inch-pound units. No such symbols are used in the metric system. lengths are given in millimeters.. As with any form of communication. a similar practice is not used in the metric system. not in yards). 3).NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology METRIC CONCRETE MASONRY CONSTRUCTION TEK 3-10A Construction Keywords: construction. Stating Metric Units While mixing feet and inches is common practice. metric.e. not in centimeters or hectometers. modular coordination. 1000 one million.1 ten. 0. For example. 5) places strong limitations for Federal agencies requiring hard metric concrete masonry units and allows conventional concrete masonry units to be used in metric construction projects. Note the use of capital and lower case letters. Complying with these government mandates requires a knowledge of the metric system of measurement and its conventions as well as an understanding of how construction materials. Table 1 lists the metric decimal prefixes and their magnitudes. the metric equivalent of 8' 92 TEK 3-10A © 2008 National Concrete Masonry Association (replaces TEK 3-10) (2008) . 10 one hundred. building dimensions are measured in feet. If mPa were written instead. When combined with the prefix kilo—meaning one thousand—the unit of measurement is kilometer (km). Just as the inch-pound system has preferred units of measurement (i. meaning one thousand meters. there are some basic rules that apply to the use of the metric system so that the meaning is consistent and clear. Table 1—Metric Decimal Prefixes Prefix milli centi deci deca hecto kilo mega Symbol m c d da h k M Order of magnitude 10-3 10-2 10-1 10 102 103 106 Expression one thousandth. 0. For example.01 one tenth. or kilometers. The following sections summarize common metric conventions. Abbreviations The third column of Table 2 indicates the proper abbreviations for metric units. Economical adjustments that have virtually no impact on the configuration of the final project can be made to accommodate inch-pound units on a job where the plans and specifications are in metric. megapascal is abbreviated MPa.000 The metric system uses several base units of measurement with various prefixes that indicate magnitude. 100 one thousand. meters. typically only the prefixes milli and kilo are used. 0. 1. hard metric. For design and construction in the United States. are best incorporated into a metric building design. For example. only the abbreviations listed in Table 2.001 one hundredth. soft metric METRIC UNITS INTRODUCTION The metric system (Systeme Internationale or SI system) is the standard international system of measurement.000. and the system that has been mandated by the Metric Conversion Act (ref. metric conversion. and conversion factors. thereby minimizing the potential for errors during construction. 1) for use in the construction of all United States Federal buildings. Essentially. The subsequent Savings in Construction Act of 1996 (ref. the Metric Conversion Act requires building designs and construction drawings to be submitted in metric units and constructed according to metric specifications. if dual units are shown on a set of plans. it would indicate millipascals rather than megapascals. such as concrete masonry. as described here and in Metric Design Guidelines for Concrete Masonry Construction (ref. their standard metric unit equivalents. The metric units listed in Table 2 are the preferred units. the metric system also conforms to a preferred set of units. the base unit for length is the meter. 2 or ksi) pound/square foot (lb/ft2 or psf) foot-pound (ft-lb) foot-kip (ft-k) inch-pound per foot (in.453592 16.176 5.89476 47. with no physical change to the product dimensions.0185 4.. Similarly.5 mm. K) degrees Celsius (oC) degrees Kelvin (K) multiply the inch-pound units by: 1.44822 14. (3 mm) because it is impractical to build to a tighter tolerance.00689476 6.609344 0. Specified dimensions are 10 mm smaller than nominal to provide space for vertical and horizontal mortar joints.44822 4. degree Kelvin/ Watt (m2 . .3) pound (lb) kip (k) pounds/cubic foot (lb/ft3 or pcf) pound (lb) kip (k) pound/foot (lb/ft or plf) kip/foot (k/ft) pound/square inch (lb/in. .8 Example: The specified length of a concrete masonry unit is typically 155/8 in.2) cubic yard (yd3) cubic foot (ft3) cubic inch (in. Table 3 lists the inch-pound and metric equivalent dimensions for typical concrete masonry units of various sizes. use the conversion factor 25. fractions are never used in the metric system. In addition.2 or psi) kip/square inch (k/in. meter (kN.064 0.5939 14. To convert this length to millimeters. Table 2—Inch-Pound To Metric Conversions Quantity Length Area Volume Mass Mass density Force Force per unit length Force per unit area Bending moment Thermal resistance (R-Value) Thermal conductance (U-Factor) Temperature to convert from these inch-pound units.5939 0. The converted actual length = 15. 250. and nominal lengths of 200 and 400 mm. decimals are used instead.16 0.32)/1.-lb/ft) square foot-hourdegree Fahrenheit/British thermal unit (ft2-h-oF/Btu) British thermal unit/square foothour-degree Fahrenheit (Btu/h-ft2-oF) degrees Fahrenheit (oF) degrees Fahrenheit (oF) to these metric units.67)/1.83612736 0. a length of nine and one-half meters is written as 9. 93 . it is meaningless to state dimensions in decimals of millimeters.203 mm.4 = 397 mm. degree Kelvin (W/m2 . Hard metric conversion is principally applied to modular products where dimensional tolerances are critical.453592 0. meter per meter (N.0283168 16.4. The difference between soft and hard metric concrete masonry units is shown in Figure 1. and 300 mm.8 K = (oF + 459.4 m . . m) kilonewton . m) newton . mile (mi) foot (ft) foot (ft) inch (in. rather than + 9.64 m.4 0. Hard metric concrete masonry units are manufactured to nominal widths of 100. 150.678 o C = (oF .5 m.35582 0.3048 304. the metric equivalents of concrete masonry unit dimensions are simply the exact metric conversions of the inch-pound unit dimensions. .764555 0.625 x 25. nominal heights of 100 and 200 mm.09290304 645. 200. Hard metric conversion means the product is resized to metric modular dimensioning.) square yard (yd2) square foot (ft2) square inch (in.8" would be 2. SOFT VERSUS HARD METRIC CONVERSION The most common consequence of the metric conversion effort has been a simple relabeling of products with equivalent metric dimensions. K/W) Watt/square meter . From a practical standpoint.35582 1. not as 9 1/2 m. not 2. soft metric conversion is easily accomplished. For soft metric conversion of concrete masonry.370686 0.m/m) square meter .8 25. a required tolerance of +3/8 in. Rounding Dimensions on building plans are rarely shown to less than 1/8 in. For example. For example. kilometer (km) meter (m) millimeter (mm) millimeter (mm) square meter (m2) square meter (m2) square millimeter (mm2) cubic meter (m3) cubic meter (m3) cubic millimeter (mm3) kilogram (kg) metric ton (t) kilogram/cubic meter (kg/m3) newton (N) kilonewton (kN) newton/meter (N/m) kilonewton/meter (kN/m) megapascal (MPa) megapascal (MPa) pascal (Pa) newton . thick becomes +10 mm. This is commonly called soft metric conversion.367. meter (N.8803 1. Because soft metric units are longer. which are then converted to their metric equivalents. Modular components are massproduced to exacting physical properties and dimensions. From the beginning of the project. the inchpound module is 1. in 4 ft (6 mm in 406 mm and 19 mm in 1. and 3 /4 in. heights and thicknesses that are multiples of the given module. which corresponds to the nominal dimensions of the hard metric masonry units.) (mm) (in. complications arise when they are incorporated into a structure designed according to the 100 mm module. Cutting can also be minimized by moving one side of the opening to the nearest inch-pound modular dimension. Vertical coursing can be adjusted by either of the two 94 . (194 mm) 7 5/8 in. two options are available: lay out the building using inch-pound modules. When hard metric concrete masonry units are available for a metric project. or 1. cutting around openings will be required. they produce wall lengths. (203 mm) minus the width of one mortar joint ( 3/8 in. Structures designed based on soft metric conversions should incorporate windows and doors sized to the inch-pound module as well.9-in. (194 mm) 15 5/8 in. in 16 in. Since 4 inches equals 101. These are described in more detail below. the width of piers should be a multiple of 8 in.) 190 mm (7. (397 mm) "Soft Metric" CMU 190 mm (7. significant coordination and adjustment is needed. (203 mm).) (mm) (in. or use soft metric concrete masonry units in a building laid out using a 100-mm module. modular coordination is straightforward. (203 mm) plus the width of one mortar joint ( 3/8 in. When hard metric concrete masonry units are not available for a metric job. This seemingly small difference (about 1/16 in. The height of the opening should be a multiple of 8 in.219 x 1. soft metric concrete masonry units can be used without further adjustment.5 in. Soft Metric Units Used With Hard Metric Building Modules This option uses soft metric concrete masonry units in a project laid out using 100-mm modules. The width of an opening in a concrete masonry wall should be a multiple of 8 in. which helps increase the efficiency and cost-effectiveness of construction. rather than 100 mm.2 m). a nominal 4 ft x 4 ft (1.4 in. are not readily available. when units of different modular dimensions are incorporated into the same wall.6 mm. This allows building dimensions and wall openings to be placed and sized to minimize cutting on site. 4). (203-mm) concrete masonry unit in a wall laid out on a 100-mm module.) module in the metric system.6 percent larger than the 100 mm metric module.219 mm).5 mm). Modular products are based on a 4-in.Table 3—Typical Concrete Masonry Unit Dimensions Nominal unit size Inch-pound Soft metric (in. or when other modular metric components.229 x 1. making the two modules incompatible. becoming 1/4 in. 7 5/8 in. In this case. (102-mm) module in the inch-pound system and a 100-mm (3.) "Hard Metric" CMU Figure 1—Specified Dimensions of Soft and Hard Metric Concrete Masonry Units MODULAR COORDINATION Modular design is based on the use of standardized components. however is cumulative. or 10 mm).) 390 mm (15. eliminating the need to cut units on both sides of the opening. For example. Cutting around door and window openings can be avoided by substituting soft metric door and window units in the masonry.3/8 in. Because soft metric units are approximately 2% larger in height and length than hard metric units. is used.5 in. Similarly. Metric Design Based on Soft Metric Building Modules This option essentially applies a soft metric conversion to the project plans and specifications. However. or 10 mm).6 mm.) (mm) 4 x 8 x 16 102 x 203 x 406 6 x 8 x 16 152 x 203 x 406 8 x 8 x 16 203 x 203 x 406 10 x 8 x 16 254 x 203 x 406 12 x 8 x 16 305 x 203 x 406 (a) Specified unit size Faceshell thickness(a) Web thickness(a) Inch-pound Soft metric Inch-pound Soft metric Inch-pound Soft metric (in. such as windows and doors.) (mm) 3 3 3 5/8 x 7 5/8 x 15 5/8 92 x 194 x 397 /4 19 /4 19 5 5/8 x 7 5/8 x 15 5/8 143 x 194 x 397 1 25 1 25 7 5/8 x 7 5/8 x 15 5/8 194 x 194 x 397 1 1/4 32 1 25 9 5/8 x 7 5/8 x 15 5/8 244 x 194 x 397 1 3/8 35 1 1/8 29 11 5/8 x 7 5/8 x 15 5/8 295 x 194 x 397 1 1/2 38 1 1/8 29 Dimensions are minimums required by Standard Specification for Loadbearing Concrete Masonry Units (ref.219 mm) opening should have actual dimensions of 4 ft . When modular units are placed. a module of 101. x 4 ft (1. such as an 8-in. as the building is laid out on a 100-mm module. 5 190.5 mm) 190.641 mm = 8 ft . Executive Order 12770.7 193.7 193. 190.). the story height would increase to 2641 mm (8 ft . The first method (Case A) is to use soft metric concrete masonry units with a 3/8 in. (10 mm) mortar joint and allow each story to be slightly taller than specified. contact NCMA Publications (703) 713-1900 95 . The second method (Case B) uses custom soft metric concrete masonry units manufactured to an actual height of 7 1/2 in. Metric Design Guidelines for Concrete Masonry Construction. TR 172.5 190. 3. (9. 1991.7 193. 8 ft . 1991. (41 mm) per story height. Public Law 104-298.8 in.7 193.600 mm = 8 ft .7 Case A Story Height = 2. (191 mm) rather than 7 5/8 in.7 193. see Metric Design Guidelines for Concrete Masonry Construction (ref.7 193. (191 mm) high units are used with standard 3/8 in.ncma. First Edition. (194 mm) (unit height is more easily adjusted during manufacture than is unit length). Herndon. ASTM C 90-03. DC: National Institute of Building Sciences.org To order a complete TEK Manual or TEK Index. 2003. Washington.5 190.8 in.5 190.5 190.6 3/8 in. high soft metric units 3 Joints = /8 in.5 3 Joints = / 8 in. For more information on using soft metric units in 100-mm module construction. Custom 7 1/ 2 in. For example. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. an increase of 1 5/8 in. 3). (10 mm) horizontal mortar joints. Savings in Construction Act of 1996.5 190.). 2.5 mm) Case B Figure 2—Vertical Coursing With Inch-Pound Concrete Masonry Units (ref.7 193. Standard Specification for Loadbearing Concrete Masonry Units.6 3 /8 in. (9. ASTM International. 4.5 190. Metric Usage in Federal Government Programs.7 193. Metric Guide for Federal Construction. 1996.5 Standard 190. the metric module is maintained for the entire wall height when 7 1/2 in. 2000. Virginia 20171 www. National Concrete Masonry Association.7 193. 3) REFERENCES 1. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 5. Using soft metric units.5 190.7 193.5 190.5 soft metric units 190. 193. consider a specified story height of 13 courses (2600 mm.7 193.5 Story Height = 2. In the example given above.methods illustrated in Figure 2.7 193. 12) Proportions by volume (cementitious materials) Portland cement or Masonry cement Mortar cement Mortar Type blended cementa M S N M S N Cement.5 mm) mortar joints. This estimate assumes the use of 3/8 in. Regardless of whether the wall is plain or reinforced. (9. When plastic cement is used in lieu of portland cement.3 m2) of wall area. or storage space at a relatively low cost. Specific colors and textures may be specified to provide a finished interior to the basement. foundation walls. Historically. insulation. and anchors so that all components perform as a structural element. A rule of thumb for estimating the number of concrete masonry units to order is 113 units for every 100 ft2 (9. bracing. successful performance of a basement wall relies on quality construction in accordance with the structural design and the project specifications. construction details. hydrated lime or putty may be added. 8). 96 TEK 3-11 © 2001 National Concrete Masonry Association . surface bonding. working.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY BASEMENT WALL CONSTRUCTION Keywords: basements. and safe haven during storms. 9). grout. and bonds to joint reinforcement. however. reinforced concrete masonry. improved drainage systems. ties. corners. Currently. ASTM C 270 (ref. basement wall. and natural lighting features such as window wells. increased resale value. In addi- Table 1—Mortar Proportions by Volume (Ref. seals joints against air and moisture penetration.M 1 — — — — — — lime S 1 — — — — — — N 1 — — — — — — O 1 — — — — — —Mortar M 1 — — — — — 1 cement M — --. Drywall can also be installed on furring strips. reinforced walls are becoming more popular as a way to use thinner walls to resist large backfill pressures. if desired. details. plain concrete masonry. it bonds the units together. unreinforced concrete masonry. ASTM C 90 (ref. mortar. Mortar Mortar serves several important functions in a concrete masonry wall. Other potential benefits of basements include room for expansion of usable space. but not in excess of one tenth of the volume of cement. plain (unreinforced) concrete masonry walls have been used to effectively resist soil loads. Old perceptions of basements have proven outdated by stateof-the-art waterproofing. loose condition Not less than 21/4 and not more than 3 times the sum of the separate volumes of cementitious materials.— — 1 — — 1/2 S — — — — — 1 S — — — — — 1 — N — — — — — — 1 Masonry M 1 — — 1 — — — cement M — 1 — — — — — 1/2 S — — 1 — — — S — — 1 — — — — N — — — 1 — — — O — — — 1 — — — 1 Hydrated lime or lime puttya 1/4 over 1/4 to 1/2 over 1/2 to 11/4 over 11/4 to 21/2 — — — — — — — — — — — Aggregate measured in a damp. construction techniques. TEK 3-11 Construction (2001) MATERIALS Concrete Masonry Units Concrete masonry units should comply with Standard Specification for Loadbearing Concrete Masonry Units. Mortar should comply with Standard Specification for Mortar for Unit Masonry. waterproofing INTRODUCTION Basements allow a building owner to significantly increase usable living. This also allows the mason to plan where cuts are necessary for window openings or to fit the building’s plan. Water Penetration Resistance Protecting below grade walls from water entry involves installation of a barrier to water and water vapor. A space of at least 1/2 in. Tooled concave joints provide the greatest resistance to water penetration. In partially grouted construction. A mortar cover of at least 5/8 in. All other mortar joints should be approximately 3/8 in. See Figures 1-4 for construction details. ice or other materials which reduce the bond between the mortar and the footing. Table 2—Grout Proportions by Volume (Ref. (15. Level coursing is maintained by using a rubbing stone to smooth small protrusions on the block surfaces and by inserting shims every two to four courses.3 m2) of masonry wall area. hot dipped galvanized joint reinforcement is recommended. Enough water should be added to the grout so that it will have a slump of 8 to 11 in. (9. these fibers.9 mm) should be provided between the exterior face of the wall and the joint reinforcement. 4. This initially high water-to-cement ratio is reduced significantly as the masonry units absorb excess mix water.8 MPa) at 28 days. Surface Bonding Another method of constructing concrete masonry walls is to dry stack units (without mortar) and then apply surface bonding mortar to both faces of the wall. Dry-stacked walls should be laid in an initial full mortar bed to level the first course. although excessive oil or dirt may require sand blasting. grout is used to bond the reinforcement and the masonry together. dirt. 2. Masons typically lay the corners of a basement first so that alignment is easily maintained. it should be placed directly on the block with mortar placed over the reinforcement in the usual method. loose condition Fine Coarse 2¼ to 3 times the sum of the volumes of the cementitious materials 2¼ to 3 times the sum of the volumes of cementitious materials 1 to 2 times the sum of the volumes of cementitious materials CONSTRUCTION Prior to laying the first course of masonry. along with the strength of the mortar itself. (12. As mix water is absorbed by the units.5 ft3 (0. Grout should conform to Standard Specification for Grout for Masonry. face shell mortar bedding. Head joints must be filled solidly for a thickness equal to a face shell thickness of the units. 5.7 mm) for coarse grout and 1/4 in. In most cases. As an alternative to complying with the proportion requirements in Table 2. Bar positioners at the top and bottom of the wall prevent the bars from moving out of position during grouting.5 mm) thick and. because Type M and S mortars provide higher compressive strengths. most building codes require the use of Type M or S mortar for construction of basement walls (refs. webs adjacent to the grouted cells are mortared to restrict grout from flowing into ungrouted cores. although mortar should not excessively protrude into cells that will be grouted. need only provide face shell bedding for the masonry units. To make up for surface irregularities in the footing.7 mm) is needed on the interior face of the wall. Reinforced Masonry For reinforced masonry construction. When joint reinforcement is used. the top of the footing must be cleaned of mud. On the exterior face of the wall. 10). Table 1 lists mortar proportions. grout must be puddled or consolidated after placement to eliminate these voids and to increase the bond between the grout and the masonry units.24 m3) of mortar for every 100 ft2 (9. A mortar cover of 1/2 in. voids can form in the grout. For added safety against corrosion. the reinforcing bars must be properly located to be fully functional. This can usually be accomplished using brushes or brooms. vertical bars are positioned towards the interior face of basement walls to provide the greatest resistance to soil pressures. The surface bonding mortar contains thousands of small glass fibers. (6. (305 mm). Surface bonded walls offer the benefits of excellent dampproof coatings on each face of the wall and ease of construction. grout gains high strengths despite the initially high water-to-cement ratio. (9. Most codes permit puddling of grout when it is placed in lifts less than about 12 in. with the proportions listed in Table 2.tion. The high slump allows the grout to be fluid enough to flow around reinforcing bars and into small voids. Lifts over 12 inches (305 mm) should be mechanically consolidated and then reconsolidated after about 3 to 10 minutes. the first course of masonry is set on a mortar bed joint which can range from 1/4 to 3/4 in.4 mm) for fine grout should be maintained between the bar and the face shell of the block so that grout can flow completely around the reinforcing bars. (6. and a 10% allowance for waste. 10) Type Fine Grout Coarse Grout Proportions by volume (cementitious materials) portland hydrated cement or lime or blended cement lime putty 1 0 to 1/10 1 0 to 1/10 Aggregate measured in a damp. (203 to 279 mm). Grout In reinforced concrete masonry construction. (12. This initial bed joint should fully bed the first course of masonry units. This figure assumes 3/8 in. Thus. grout can be specified to have a minimum compressive strength of 2000 psi (13. ASTM C 476 (ref. except for partially grouted masonry.4 to 19 mm) in thickness. mortar joints may be cut flush if parging coats are to be applied. Accordingly. help produce walls of comparable strength to conventionally laid plain masonry walls. Typical concrete masonry construction uses about 8. 13). An imper97 . When the mortar is applied properly to the required thickness.5 mm) thick mortar joints. 9. although many designers prefer footings to be as thick as the wall thickness and twice as wide as the wall thickness. Reinforcement should be placed adjacent to openings. typically 8-in. Continuous or lapped sheets of 6 mil (152 mm) polyethylene. (305 mm) of washed gravel or other free draining backfill material should be placed around drains to facilitate drainage. Floor diaphragm.000 psi (13. butyl rubber and/or drainage boards should be considered. A 4 to 6 in. typically minimum 2500 psi (17. 1) 98 . Foundation drain. Solid grouted and reinforced top course to distribute loads from the walls above and increase soil gas and insect resistance. Vertical reinforcing bars. Anchor bolts significantly increase earthquake and high wind resistance. Mortar.7 mm) diameter anchor bolts are spaced no more than 4 ft (1. D. Figure 1— Basement/Foundation Wall (Ref. Larger sizes may be required in for some soil and backfill height conditions.19 18 17 12 7 5 6 1 4 3 9 15 11 14 2 10 13 8 16 1. 3. 15. See TEK 14-18 (ref. 9. 4. Backfill should be placed after wall has gained sufficient strength and is properly braced or supported. or a sump.2 MPa) and be at least 6 in. 4 in. (102 to 203 mm) of soil should be of low permeability so that water is absorbed slowly into the soil.2 m) on center. if required. (12. consideration of waterproof membranes such as rubberized asphalt. Concrete slab. Typically 7 in. 5. (152 mm) thick. 16. 12. Joints should be tooled for improved impermeability unless the exterior side is parged. Waterproof or dampproof membrane. generally Type S. The top 4 to 8 in. At least 12 in. Surrounding soil should slope away from building to drain water away from walls. (178 mm) long. soil drainage is slow. Flashing should be installed at the top of basement walls to prevent water from entering the wall. A floor diaphragm supports the tops of masonry walls and distributes loads from the superstructure to them. 11. a storm water sewer. provides a level. Backfill. Vapor retarders can be placed on top of the aggregate base to increase the effectiveness of the soil gas barrier system. or under the aggregate to reduce concrete placement and curing difficulties. 6. 10. Positioners hold the vertical bars in proper position.8 MPa) minimum compressive strength in cores containing reinforcement. Joint reinforcement or horizontal reinforcing bars to aid in control of shrinkage cracking and in Seismic Design Categories C.2 MPa). Vapor retarder. (102 to 152 mm) base of washed aggregate (3/4 to 11/2 in. 8. Aggregate base. 17. Undisturbed soil. Free draining backfill. Concrete footing. Top of grade. Dampproof where hydrostatic pressure will not occur. Flashing. Where ground water levels are high. units. Concrete masonry units. 13. and F. clean surface for slab placement. polymer-modified asphalt. 2. Soil beneath footings and slabs should be undisturbed or compacted. 19. 7) for more information on seismic reinforcement requirements. Concrete should have a minimum strength of 2500 psi (17. 7. PVC or equivalent reduce rising dampness and block soil gas infiltration through the slab. Footings distribute loads to the supporting soil. Cover the top of the gravel with a filtering geotextile to prevent clogging. Contraction joint spacing should not exceed about 15 ft (4. 18. Grout of 2. Incorporating two #4 bars (or larger) increases the ability to span weak spots. in corners and at a maximum spacing determined from a structural analysis. Consolidate grout by puddling or vibration to reduce voids. 14. 1/2 in. (101 mm) thick. E. Anchor bolts. or where radon gas levels are high. and allows for inclusion of a soil gas depressurization system.6 m). Drains should be located below the top of the slab and should be sloped away from the building to natural drainage. Welded wire fabric located near the center of the slab increases strength and holds unplanned shrinkage cracks tightly together. (19 to 38 mm) diameter) distributes slab loads evenly to the underlying soil. Welded wire fabric should be cut at contraction joints. Perforated pipe collects and transports ground water away from the basement. 2. dampproofing. (254 to 254 mm) Wall Corner Detail 4 15 3 Figure 3—Typical Floor Connection (Ref. impact or puncture resistance. Building codes (refs. filter fabrics are often placed 99 . resistance to mildew and algae. When choosing a waterproof or dampproof system. gutters. to 8-in. Dampproofing is appropriate where groundwater drainage is good. for example where granular backfill and a subsoil drainage system are present. such as heavy clay soils. absorption characteristics. When placed on the exterior side of basement walls. and waterproofed where hydrostatic pressures may exist. 6). to 10-in. 1) vious barrier on the exterior wall surface can prevent moisture entry.1 3 4 5 12 15 9 10 Alternate Courses 14 13 2 8 11 16 Figure 2—Typical Footing Detail (Ref. allowing them to span small cracks and accommodate minor movements. 4 . which includes proper wall construction and the installation of drains. 9. Materials used for waterproofing are generally elastic. (102 x 102 x 203 mm) (C) 12-in. (203 to 203 mm) Wall Corner Detail Alternate Courses 18 19 Solid 2 x 6 x 8 in. To prevent migration of fine soil into the drains. and drainage systems is included in TEK 19-3A (ref. (305 to 305 mm) Wall Corner Detail Figure 4—Standard Corner Layout Details and other materials which may reduce bond between the coating and the concrete masonry wall. and proper grading. elasticity. (51 x 153 x 203 mm) 7 17 6 1 2 5 (B) 10-in. 13) typically require that basement walls be dampproofed for conditions where hydrostatic pressure will not occur. A complete discussion of waterproofing. All dampproofing and waterproofing systems should be applied to walls that are clean and free from dirt. 1) (A) 8-in. stability in moist soil. 5. Draining water away from basement walls significantly reduces the pressure the walls must resist and reduces the possibility of water infiltration into the basement if the waterproofing (or dampproofing) system fails. consideration should be given to the degree of resistance to hydrostatic head of water. perforated pipes are usually laid in crushed stone to facilitate drainage. Perforated pipe has historically proven satisfactory when properly installed. and abrasion resistance. or due to poorly draining backfill. The barrier is part of a comprehensive system to prevent water penetration. to 12 in. mud Alternate Courses Solid 4 x 4 x 8 in. Hydrostatic pressure may exist due to a high water table. .... Otherwise..... The R-value is rials should be low permeability soil so rain water is determined by the size and type of masonry unit.(12. Care should be taken when placing the back.. (6. Elements 100 .1 m) should generally not be used as backfill materials since .7 mm) in 20 ft (6...5 mm) in 20 ft (6.1 m) and frozen earth. (19..over the gravel.. 10 feet (3. +1/2 in.. The drainage and waterproofing systems should always be inspected prior to backfilling to ensure they are adequately placed. Walls should be properly braced Figure 5—Typical Bracing for Concrete Masonry Basement or have the first floor in place prior to backfilling...7 mm) max large soil pressures. (12......+1/2 in (12...... and finish materials... value describes the ability to resist heat flow..... Masonry walls remain warm or Construction Tolerances cool long after the heat or air-conditioning has shut off.+1/2 in..+3/4 in.5 mm) in 20 ft (6.. The insula2..... (3................. integrity...5 mm) grade to maintain durability.. +1/2 in... Location of elements and each layer should be compacted with small mechania.... keepSpecifications for Masonry Structures (ref....... Indicated in plan.4 mm) in 10 ft (3.....+1/4 in...1 m).+1/2 in..4 mm)................. and effectiveness....... (12.. (19..........1 m) The backfill material should be free-draining soil with... 1...... +1/2 in.... waterb. +3/8 in.... organic materials.-1/4 in (6.. Variation from level: bed joints. Ensure water/dampproofing or drainage systems and bracing are properly in place prior to backfilling 2x10 in.. type and absorbed into the backfill slowly.. These when insulation is placed on the exterior or in the cores of tolerances were developed to avoid structurally impairthe block....+1/8 in... (9......... heavy equipment should not be operThe thermal performance of a masonry wall depends ated within about 3 feet (0........ (6. Thermal mass describes the ability of materials like concrete masonry to store heat.....9 m) of any basement wall on its R-value as well as the thermal mass of the wall..........(9... (9. Rsystem. Thermal mass is most effective fies tolerances for concrete masonry construction.....4 mm) in story height ders and soil down steep slopes should thus be avoided .. (51x254 mm) plank vertical brace 2x4 in. (6.. Two 2x6 in....... (9.....-1/4 in. Depending on away from the basement at least 6 in.1 mm) maximum fill materials to avoid damaging the drainage........ especially saturated clays.... c... which has been widely used for residential basement walls..... Sliding boul..4 mm) in 10 ft (3.. 8) speciing the interior comfortable....+1/4 in...... a shallow swale can be inthe cores of hollow units.. True to a line.1 m) cal tampers... where the masonry is in direct contact with the ing a wall because of improper placement.....1 mm) maximum since the high impact loads generated can damage not only the drainage and waterproofing systems but the wall Insulation as well... (51x152 mm) stakes driven into firm soil at least Backfilling (51x102 mm) brace strut One of the most crucial aspects of basement construction is how and when to properly backfill.. or on the interior of the walls... If the ground naturally insulation may be placed on the outside of block walls...... Indicated in elevation proofing or exterior insulation systems...+1/4 in.. (6................. (6.. Saturated soils. +3/8 in............. Alignment of columns and bearing walls (bottom versure on the walls. higher R-values The top 4 to 8 in..5 mm)..7mm) max More substantial bracing may be required for high walls b.... Likewise........... Figure 5 shows one bracing scheme top surface of bearing walls.7 mm) maximum wet materials significantly increase the hydrostatic presd............ (152 mm) within the particular site conditions and owner’s preference..1 m) or large backfill pressures.. ... Dimension of elements in cross section or elevation Exterior insulated masonry walls typically use rigid board .... Drainage pipes can also be placed beneath the slab and connected into a sump.+3/8 in... stalled to redirect runoff...............2 mm) tion requires a protective finish where it is exposed above head.. interior conditioned air....... (102 to 203 mm) of backfill mategive better insulating performance.1 m) of the building... (12. a wall which is designed to a..... Any questionable workmanship or materials should be repaired at this stage since repairs are difficult and expensive after backfilling.... Pipes through the footing or the wall drain water from the exterior side of the basement wall.. sus top)... 3... Grade should be sloped amount of insulation...........4 mm). (51x102 mm) cleat 2x4 in.. construction debris.... (12...............+3/8 in.......7 mm) Backfill materials should be placed in several lifts 4......7 mm) maximum out large stones..4 mm) 10 ft (3....+3/4 in. Mortar joint thickness: bed.7 mm) insulation adhered to the soil side of the wall. be supported at the top may crack or even fail from the +1/4 in.....4 mm)..(6......... ......... in slopes toward the building..+1/2 in (12.. Variation from plumb......... +1/4 in..... Concrete masonry cores may be insulated with molded polystyrene inserts. Whittier. Natural Lighting Because of the modular nature of concrete masonry. BOCA National Building Code. Birmingham. AL: Southern Building Code Congress International. Reported by the Masonry Standards Joint Committee. ASTM C 476-01. 10. 13. Standard Building Code. 2002. Falls Church. 1999. Country Club Hills. ASTM C 90-01. Specifications for Masonry Structures. ACI 530. For additional protection and privacy. TEK 19-3A. rigid board. 2000. American Society for Testing and Materials. 7. giving basements warm. 12.Uniform Building Code. 2001. 2000. 1997. Inserts may be placed in the cores of conventional masonry units. 2000. VA: International Code Council. contact NCMA Publications (703) 713-1900 101 . expanded perlite or vermiculite granular fills. 2001.org To order a complete TEK Manual or TEK Index. Although construction with staggered vertical mortar joints (running bond) is standard for basement construction. Building Code Requirements for Masonry Structures. ASTM C 270-00. or fibrous blown-in insulation. 2001. the appearance of continuous vertical mortar joints (stacked bond pattern) can be achieved by using of scored units or reinforced masonry construction. scored. (BOCA).Standard Specification for Grout for Masonry. American Society for Testing and Materials. DESIGN FEATURES Interior Finishes Split faced. TR-68A. TEK 14-18. (SBCCI). windows and window wells of a variety of shapes and sizes can be easily accommodated. Preventing Water Penetration in Below-Grade Concrete Masonry Walls. Seismic Design Provisions for Masonry Structures. IL: Building Officials and Code Administrators International. 3. 4. Interior insulation typically consists of insulation installed between furring strips. 1999. Inc. 2002. Reported by the Masonry Standards Joint Committee. National Concrete Masonry Association. American Society for Testing and Materials. natural lighting. 9. Inc. International Building Code. Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. Basement Manual-Design and Construction Using Concrete Masonry. International Residential Code. and fluted block give owners and designers added options to standard block surfaces. Virginia 22071-3499 www.1-02/ASCE 6-99/TMS 602-02. Herndon.ncma. 2. or they may be used in block specifically designed to provide higher R-values. Falls Church. NATIONAL CONCRETE MASONRY ASSOCIATION 2302 Horse Pen Road.Standard Specification for Mortar for Unit Masonry. 11. Colored units can be used in the entire wall or in sections to achieve specific patterns. National Concrete Masonry Association.Standard Specification for Load-Bearing Concrete Masonry Units. or foamed-in-place insulation. 5. 6. 1996. National Concrete Masonry Association. finished with gypsum wall board or panelling. VA: International Code Council. burnished. CA: International Conference of Building Officials (ICBO). 2001. 8. ACI 530-02/ASCE 5-02/TMS 402-02. REFERENCES 1. The insulation may be fibrous batt. glass blocks can be incorporated in lieu of traditional glass windows. economy. Tennessee which was built in 1969 utilizing partially reinforced concrete masonry walls. LLC National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONSTRUCTION OF HIGH-RISE CONCRETE MASONRY BUILDINGS TEK 3-12 Construction (1998) Keywords: construction techniques. economical construction. 2) and Specification for Masonry Structures (ref. permit the place- ment of units around vertical reinforcing bars. load-bearing masonry. Open end units. scaffolding. This served as the building code for engineered concrete masonry structures and was adopted by the Southern Building Code Congress and other model codes. and versatility of the masonry system. resulting in consistent quality of materials.NCMA TEK Provided by: Nitterhouse Masonry Products. Today there are many examples of loadbearing masonry buildings up to 15 to 28 stories high. Slots manufactured into the webs of units (termed bond beam units) are used to position horizontal reinforcement within the wall. Concrete masonry units. One of the earliest wall bearing concrete masonry structures using this new technology was a nine story senior citizens building in Cleveland. one of the first examples of engineered multistory construction was used by Professor Paul Haller in Switzerland. are a relatively recent innovation. and curing methods. 3). Excalibur Hotel and Casino (photo) Figure 1–The four towers of the 28-story Excalibur Hotel in Las Vegas are load-bearing masonry. block production had developed to incorporate automated mixing. these units were made with hand-operated equipment. The modular nature of concrete masonry units makes construction straightforward and the small unit size makes changes in plan or elevation easy. Special unit shapes are manufactured to accommodate reinforcement. molding. These new manufacturing processes allowed concrete masonry to be used in engineered structural systems such as multistory load-bearing structures. architectural appeal. with one or both end webs removed. 1). 102 TEK 3-12 © 1998 National Concrete Masonry Association . It has evolved into our present-day Building Code Requirements for Masonry Structures (ref. inspection. although by the 1940’s. A major milestone in the advancement of engineered concrete masonry was the establishment of the Specifications for Design and Construction of Load Bearing Concrete Masonry by NCMA in the late 1960's (ref. high-rise. specified compressive strength of masonry (f'm) INTRODUCTION Masonry structures have been used for centuries throughout the world. Concrete masonry is widely used because of the strength. Initially. however. durability. In the late 1940’s. Concrete masonry walls are often used in this application because of the cost effectiveness and ease of construction. Ohio. although precast hollow core slabs are the most common. is 1500 psi (10. However. Contractors prefer repetitive floor plans for high-rise construction. is essential to assure that the building was constructed as designed. Because of the large size of most multistory buildings. Designs which facilitate scheduling repetitive. 28-story towers of the $300 million. should accommodate building movements from expansion and/or contraction of building materials. the bottom line is still a deciding factor in determining a building's construction type. a predefined quality control/quality assurance plan is recommended. vibrant colors and graffiti resistance are also available.000 room Excalibur hotel in Las Vegas. These high strength units are often specified on high-rise loadbearing projects to minimize wall thickness. aesthetic and functional constraints must also be considered. using high strength concrete masonry units. since high strength units may cost more than standard units. These gaps act as isolation joints. and other contractors can begin working on one floor while masonry wall and plank construction continues on floors above them. Obviously. painted block. Inspection. where necessary. Gapped infilled walls are constructed with a predetermined space between the masonry and the building frame. until the top floors where standard block with an f'm of 1500 psi (10. However. “assembly-line” construction procedures improve productivity and reduce construction costs. Material testing may be required by the Specifications for Masonry Structures or the contract documents to verify that supplied materials meet the project specifications. however. most of these walls have been constructed using standard concrete masonry units which were painted or plastered. f'm. Regarding finish.e. Construction of infilled masonry walls is usually straightforward since the main building system is in place prior to the masonry construction. tolerances should be carefully monitored. stucco or a variety of proprietary finishing systems also can be applied. The same holds true for architectural details. In one case. Connections should be simple and easy to construct and. As with all construction. The most important consideration is whether “gapped” or “ungapped” infilled walls will be provided.6 MPa) for the loadbearing walls on the first thirteen floors (ref. and also provides enough lateral stiffness to transfer wind and seismic loads from the brick to the floor diaphragms. loadbearing shear wall-type buildings and infilled walls. This important design feature allows similar construction and provides structural continuity from floor to floor both of which lend to economy in construction. fluted.3 MPa). while clay tends to expand. This accommodates the differential movement. a wide variety of architectural units are available (i. The Uniform Building Code (ref. and slump block). so that mechanical. these movements were accommodated by designing the exterior brick as a reinforced curtain wall supported on the foundation (ref. Additionally. The concrete diaphragms can be poured in place. DESIGN CONSIDERATIONS The typical specified compressive strength of concrete masonry. f'm values up to 4000 psi (27. economical construction method that has allowed some builders to construct one story each week. Steel or concrete frames con103 . these opposing movements can be significant. allowing the building frame to drift and sway under lateral loads. Ungapped infilled walls. where the higher compressive strength is not needed. 6). the seventeen story Crittenden Court in Cleveland.6 MPa) are achievable. Loadbearing/Shear Wall Buildings Loadbearing concrete masonry shear wall buildings make the most effective use of concrete masonry by relying on both the economy and the structural capacity—compressive strength and shear resistance—of the concrete masonry. Connections between building elements is key to the performance of the structures and should therefore be considered carefully during the design process. split-face. used an f'm of 4000 psi (27. for building dimensions and openings. by contrast.In our world of economics. fast-track. Over the height of many stories. For further economy. For example. 5). The specified compressive strength decreased in successive stories. the most economical one of course is normally plain. Prefaced units with a glazed finish. Differential movement deserves particular attention on high-rises where concrete masonry is clad with clay brick. if the owner's budget permits enhancements. The brick was tied to the precast concrete floor planks using slotted anchors that allow vertical but not horizontal movement. so that buildings are useful and attractive as well as economical. electrical. colored. Historically. Floors are enclosed quickly. Concrete Masonry Infill Infilled concrete masonry walls utilize the concrete masonry as cladding and interior partitions between concrete or steel frames. The real economy of concrete masonry lies in utilizing the strength of the masonry units (making them load-bearing) and minimizing the cutting of the modular building unit by utilizing multiples of 8 in. Concrete materials tend to shrink. which form the structural load-resisting system. Concrete masonry/precast slab buildings provide a fast. plumbing. architectural units are being used to eliminate the need for finishing the walls. 4. are constructed tightly against the building frame so that the infilled walls serve as shear walls. The most common application uses concrete masonry walls with concrete floor and roof diaphragms. scored. Nevada. the four. Architectural units not only provide pleasing aesthetics but also greatly reduce maintenance and upkeep costs. burnished. BUILDING TYPES Most concrete masonry multistory buildings fall into two main types. some designers specify lower f'm values in the upper stories.3 MPa) was used. 4) has also recently approved a design method for moment-resisting masonry wall frames. More recently. to ensure that key building elements have been installed properly. An adequate supply of concrete masonry units for the entire story should be supplied at one time. only one level of scaffold is required. Block for the next story are normally stacked on the concrete floor as soon as it has hardened enough to prevent damaging the surface. attachment requirements. mortar containment. speed. the building design and construction must accommodate the construction technique. To ensure structural adequacy and maximum economy. depending on the type chosen. but often must rent supplemental scaffolds for high-rise construction. and produce consistent mortar from batch to batch. Grout is typically supplied via ready-mix trucks and is pumped to the top of the wall or is lifted using cubic yard buckets. one-way. 8) are work platforms that are suspended from either the roof of the building or from an intermediate floor and therefore would mainly be limited to use on infill projects where the structural frame precedes the wall. Powered mast-climbing work platforms are erected on the ground and use electric or hydraulic power to move the platform up and down the supporting mast or masts (ref. which can be substantial. The masts are attached to the building using adjustable ties or anchors. CONSTRUCTION Construction Materials For construction to proceed smoothly and quickly. although silo mix mortar systems have become increasingly popular. Most mason contractors own a supply of scaffolding. Although some scaffolding is needed to lay the top portion of each wall. and other building materials. For masonry veneers laid from the interior. as with all grouted masonry. Mortar materials can be mixed using traditional techniques. Also. Materials can either be stocked from the building floors. Laying Units from Inside the Building For load-bearing and infilled exterior walls. it is necessary to carefully schedule construction procedures and supply of materials. One advantage of these systems is that the platform can be easily moved in small increments. it is preferable to stockpile materials on site so that they are readily available when needed.structed out of tolerance make the mason's job difficult and slow. Silo mixed grout is also supplied on some jobs. Materials are delivered to the masons on upper stories via crane or hoist. This reduces the amount of lifting of individual units and improves productivity. For small sites. Like the mast-climbing platforms. If. both masonry wythes can easily be laid at the same time. dismantling. and easy cleanup. and moving scaffolds on the job. and optional equipment such as overhead protection. if the platform is large enough and can support the weight. unexposed. Reinforcement cut to proper length and provided in bundles for each story level also facilitates construction. two practices must be observed: 1) no shoring can be removed until the next story of walls has been laid up. Powered mastclimbing platforms have maximum heights ranging from 300 to almost 700 ft (91 to 213 m). Similarly. if the walls are masonry veneer with concrete masonry backup. This normally is the most efficient and cost effective method as this allows the masons to work on the building's floor area providing ample room for units.4 m3) of mortar ingredients. concrete masonry can often be laid from the inside of the building. it is vitally important that the grout has a slump between 8 and 11 in. on the other hand. Laying from the interior may also be an advantage in windy conditions. For example. Laying Units from Work Platforms Scaffolds and other temporary work platforms allow the masons to work facing the exposed side of the masonry. the veneer would have to be placed from the exterior. usually a couple of hours after the steel troweling is completed. Two alternatives to traditional scaffolding for high-rise construction are powered mast-climbing platforms and suspended scaffolds. An example of this is a hotel structure where the wall between each room is a bearing wall and the floor system is a concrete. mortar. making it easier to ensure the exposed side is laid plumb and level. This means the platform can be adjusted as the wall is laid to keep it at the mason's optimum working height. Since the mason's work is confined to the perimeter of the floor. Coordination with crane and elevator schedules should also be considered so that they are available when materials arrive on site. Time should be allotted for placing. when work on exterior platforms may be limited. One drawback to laying units from the inside of the building is that more time is typically required to place the units to assure they align on the exterior since the masons are facing the interior. and 2) sand must be spread over the new slab to facilitate cleanup of any dropped mortar. side of the wall. However. per the Specification for Masonry Structures for proper placement and final performance of the building. type of construction. or can be placed on the work platform. Both eliminate the labor required to construct multiple levels of conventional scaffolding. and mason's preferences.7 to 21. Additional advantages include ability to be lifted easily from floor to floor. These systems deliver 14 to 28 yd3 (10. this decrease in productivity is often offset by large reductions in scaffolding costs. the suspended scaffolds are 104 . The choice depends on the size of the job. Other variables include maximum safe wind exposure. continuous slab. Suspended scaffolds (ref. other trades can also work at the same time. large columns and deep beams may interfere with masonry veneer placement from the interior. Proper alignment of these elements will facilitate the construction process and provide a more appealing completed structure. the interior wythe is steel studs with sheathing. Where space allows. Placing the Masonry Concrete masonry can either be laid from the inside of the building with the masons working on the interior floor area or from the outside of the building with the masons working on scaffolds or work platforms. 7). material delivery must be timed so that the materials can be moved quickly to the place they are needed. 1-95/ASCE 6-95/ TMS 602-95. LLC Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. Herndon. Elizabeth. Florida. 8. The attachment requirements for suspended scaffolds are fairly complex." Masonry Construction." Masonry Construction. 6. 1995. 1995. Uniform Building Code. Kenneth A." Masonry Construction. Suspended scaffolds have the advantage of keeping the lower floors of the building accessible once the work has progressed above this point. Below this height. NATIONAL CONCRETE MASONRY ASSOCIATION 2302 Horse Pen Road. November 1989. Specification for Masonry Structures.ncma. Provided by: Nitterhouse Masonry Products. spurred by the arrival of Disney World produced a market for quality. "A Floor a Week per Tower." Masonry Construction. ACI 530-95/ASCE 5-95/TMS 402-95. economical building systems. REFERENCES 1. Suspended scaffolds typically become cost effective at building heights of seven to ten stories. Rapid growth in areas like that of Orlando. Specification for Design and Construction of Load-Bearing Concrete Masonry. and are typically designed for each project and installed by the scaffold supplier. Keating. National Concrete Masonry Association.org To order a complete TEK Manual or TEK Index. traditional or power mast scaffolding is probably more cost effective. 1997. 2. ACI 530. Elizabeth. 3. CONCLUSION Many economical concrete masonry structures have been built around the country ranging from buildings to over twenty stories in height to fifteen foot high retaining walls. Whittier. Building Code Requirements for Masonry Structures. Concrete masonry construction and the early NCMA Specification for Design and Construction of Load-Bearing Concrete Masonry were ready with the technology to allow engineers and architects to design economical and aesthetically pleasing structures. Mark A. Hooker. Reported by the Masonry Standards Joint Committee. rather than by a powered system. May 1997. innovative construction methods. "Suspended Scaffolds Cut High-Rise Masonry Costs. Keating. They may also be preferable on sloping sites where erection of frame scaffolding would be difficult. "Loadbearing Masonry Rises High in Cleveland. March 1991. 7. 105 contact NCMA Publications (703) 713-1900 . proper engineering design and use of concrete masonry materials. Virginia 20171-3499 www. Most suspended scaffolds are raised and lowered by hand. May 1997. High-rise buildings have seen an unprecedented growth with modern. 1970.adjustable in small increments to keep the platform at the optimum working height for the masons. "Powered Mast-Climbing Work Platforms. Wallace. 5. CA: International Conference of Building Officials (ICBO). 4. Reported by the Masonry Standards Joint Committee. a 4 in. The flashing should be extended past the face of the wall. and below sills and copings. beam pockets and ledger beam details. lintels. they inhibit any water that penetrates the face from wicking to the back of the wall. wall-roofing intersections. Copings. unpunctured flashing and weep holes are to be used at the base of wall above grade. all sills. bond beams.7 (MW11)(9 gauge) wire or one tie per 41/2ft2 of wall area using W2. (25 mm) and should have functional flashing and weep holes. construction techniques. (406 mm) on center would meet this requirement and is often used. A W1. and properly sealed splices at laps. Details covered for this system are base flashing. sealed. Figure 1––Exterior Concrete Masonry in a Residence Proper selection and application of integral water repellents and surface treatments can greatly enhance the water resistive properties of masonry. In addition. and located movement joints when necessary. water repellents. creating a cavity wall. composite wall. be mechanically anchored to the wall. the front facade of these structures is composed of brick to give the building a more residential. or corrosion resistant metal should be used.8 (MW19)(3/16 in. construction techniques. stone. EXTERIOR CONCRETE MASONRY The use of water repellent admixtures in concrete masonry and mortars can greatly reduce the amount of water entering the masonry. One way to construct a brick and block wall is to separate the two wythes with an airspace. the connection detail between the floor system and the wall system is critical for achieving a watertight structure. bay windows. chimneys. 6. (406 mm) vertically. The collar joint between the two wythes should be 100% solid as it is the only defense against water penetration. (102 mm) concrete masonry veneer will shrink over time. This guide is intended to assist contractors and architects to give this building type a modern approach to detailing. lintels. (102 mm) hot-dipped galvanized ladder type joint reinforcement should be placed in bed joints spaced 16 in. 2). 106 TEK 3-13 © 2005 National Concrete Masonry Association . Functional. Much of this TEK will deal with which strategy should be utilized in connecting a wood floor system to a masonry load-bearing wall. Because a 4 in. See TEKs 19-1. sills and chimney caps should project beyond the face of the wall at least 1 in. FLOOR SYSTEM CONNECTIONS When designing low-rise loadbearing structures. These structures come in many forms. INTRODUCTION The current trend of urban renewal and infill has sparked a high volume of new low-rise masonry residences. 3. copings and chimney caps should have a minimum slope of 1:4. Other floor systems are used in low-rise construction that are not addressed here see TEK 5-7A for further information (ref. flashing.7 (MW11)(9 gauge) joint reinforcement @16 in. joint reinforcement. The composite wall consists of an exterior wythe of brick directly mortared or grouted and tied to an inner wythe of CMU. Connection methods covered are joist hangers.NCMA TEK Provided by: Quik-Brik National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONSTRUCTION OF LOW-RISE CONCRETE MASONRY BUILDINGS TEK 3-13 Construction (2005) Keywords: architectural details. copings and chimney caps of solid masonry units.)wire (ref. 19-2A and 19-4A (refs. but they should not be considered as substitutes for good fundamental design including flashing details and crack control measures. & 5) for more information on water resistant concrete masonry construction. weep holes. type S mortar tends to be less workable in the field and should only be specified when dictated by structural requirements. more human scale. BRICK AND BLOCK COMPOSITE WALL DETAILS Quite often. These new buildings are largely derivative of the historic loadbearing masonry “brownstone” or “three flat” structures of old. 2). Compared to type N or O. reinforced concrete. Another is to use a composite wall design. Minimum tie requirements are one tie per 22/3ft2 of wall area for W1. construction details. and should have properly sized. window head and window sill details. at shelf angles. The flashing should have end dams at discontinuous ends. but quite often they employ the use of load bearing concrete masonry walls supporting a wood floor system. Sills. In addition. Flashing should be installed at locations shown on the plans and in strict accordance with the details and industry standard flashing procedures. above openings. The floor system does not interrupt the continuity of the bearing wall. Strap Anchor 2 wythes of 4” (102 mm) CMU Drip Edge Drip Edge Grouted Bond Beam Figure 3 Joist Hanger Non-Bearing Detail Grouted Bond Beam Figure 5 Beam Pocket Non-Bearing Detail 107 . any water present in the wall has an unobstructed path inside the building and has the potential to deteriorate the floor structure. The traditional beam pocket detail still can be effective. (102 mm) CMU Stepped through wall flashing Stepped Through Wall Flashing Strap anchor in head joint.JOIST HANGER DETAILS BEAM POCKET DETAILS The use of a joist hanger system can greatly simplify the bearing detail. Without the flashing. Installation is quicker and easier resulting in a more economical installation. Stepped flashing above the bearing line is critical to the performance of this system. Block & mortar treated with integral water repellent (where required) Stepped Through wall flashing Block & mortar treated with integral water repellent (where required) 2 wythes of 4 in. (102 mm) CMU Inner wythe cut to form pocket Through Wall Flashing Drip Edge Drip Edge Joist Hanger Grouted Bond Beam Grouted Bond Beam Figure 2––Joist Hanger Bearing Detail Figure 4––Beam Pocket Bearing Detail 2 Wythes of 4 in. Below are details for a parapet condition and a window sill condition. The sill detail shows the arrangement of flashing. (76 mm) with continuous sealant at the joint on both sides of the wall.13M @1219 mm) on center or as required for wind resistance. Grouted Bond Beam Figure 6––Ledger Beam Bearing Detail Figure 8––Parapet Detail Joint reinforcement as required Flashing Flashing end dam Through wall flashing Cotton sash weep Drip edge Grouted cell (under flashing) Anchor bolts grouted into bond beam Drip edge Ledger Beam Grouted Bond Beam Figure 7––Ledger Beam Non-Bearing Detail Figure 9––Window Sill Detail 108 . 4 bars at 48 in. The flashing and weep holes will allow the water to exit without damaging the structure. end dam. Any water that penetrates the block with run down the inner cores of the block until it hits the flashing. The parapet is reinforced with No. it should extend down the face of the wall at least 3 in. (No.LEDGER BEAM DETAILS PARAPETS AND WINDOW SILLS The use of a ledger beam which is bolted to a bond beam is also a good option for this bearing condition. weep holes and drip edge and how they all form a watertight Optional: Counterflashing or waterproofing adhered to CMU Block & mortar treated with integral water repellent (where required) Through wall flashing Block & mortar treated with integral water repellent (where required) Metal coping Drip edge Continuous sealant (both sides) Anchor bolts grouted into bond beam Flashing Ledger Beam Bond Beam Reinforcement if required for wind resistance. Through wall flashing is still required to maintain a watertight wall. If a metal cap is used. flashing.8 m)wide] Figure 13––Control Joint at Opening 109 . Notice that the joint reinforcement is discontinuous at the joint. Joint Reinforcing Rebar / Grout Mortar Backer Rod Sealant Joint reinforcing as required Flashing Joint Reinforcing Cotton weep Rebar / Grout Drip edge Mortar Bond beam Backer Rod Sealant Figure 10––Masonry Lintel Detail Figure 12––Control Joint Details Control joint location using masonry lintel Control joint location when using steel lintel Flashing with end dams Joint reinforcing as required Control joint Steel lintels Cotton weep Drip edge Figure 11––Double Angle Lintel Detail Additional control joint [if opening is more than 6 ft. Control joints simply are weakened planes placed at approximately 20 ft. The second detail shows two steel lintels used for spanning the opening. (1. and weep holes. (6 m) on center in concrete masonry walls and at changes in wall elevation/thickness. The first option shows the use of a concrete masonry lintel which is grouted solid and reinforced. Cores are shown grouted adjacent to the joints as well to ensure structural stability in taller walls and/or high load situations. drip edge.WINDOW HEAD DETAILS CONTROL JOINT DETAILS These two window head details show the relationship between the steel lintel. end dams. Drip Edge Figure 15––Level Flashing and Angle Figure 17––Window Sill Detail 110 .COMPOSITE WALL BASE FLASHING DETAILS COMPOSITE WALL WINDOW DETAILS Figure 14 shows a stair-stepped flashing detail with the exposed drip edge and weep holes. The flashing should be turned up on the inner side of the wall to direct water to the outside of the wall. Stepped flashing turned up on the inside. (406 mm) o. Flashing support angle Stepped through wall flashing Continuous collar joint Cotton sash weep @16 in. or the flashing must be self adhesive. The use of a precast concrete or stone sill is highly suggested over using brick rowlock sills. Drip Edge Continuous collar joint Flashing End Dam Cotton sash weep Stepped flashing Drip Edge Steel Lintel Figure 14––Stepped Flashing at Base Figure 16––Window Head Detail Joint reinforcement as required Collar joint Sealant and backer rod Flashing end dam Continuous collar joint Flashing support angle Through wall flashing Cotton sash weep Flashing Drip Edge Grouted solid Cotton weep 16 in. The flashing must be set in mastic on top of the concrete foundation. end dams and weep holes to keep moisture out of the wall.c. (406 mm) o. The sill detail also uses flashing. and folded to form an end dam protects the head condition from moisture. Here steel lintels back-to-back create the above window span. Figure 15 shows a straight through wall flashing detail.c. c. National Concrete Masonry Association.* All joint reinforcement should be hot-dipped galvanized (minimum) 8 in. It is imperative that the veneer have a continuous wire embedded in every other course to control movement. 2003. (102 mm) 2 wire ladder joint reinforcement @ alternate 16 in. (406 mm) o. vertically* 1 in. (205 mm) CMU backup wall. Building Code Requirements for Masonry Structures. 6. National Concrete Masonry Association. Three types of joint reinforcement are shown including tri-rod. NCMA TEK 19-5A. PLAN CONCRETE MASONRY VENEER DETAILING Tri-rod joint reinforcement @ 16in. Design for Dry Single-Wythe Concrete Masonry Walls. Flashing Strategies for Concrete Masonry Walls. Provided by: Quik-Brik Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. 4 in.c. NCMA TEK 19-2A. ACI 530-05/ASCE 6-05/TMS-402-05. (102 mm) 2 wire ladder joint reinforcement@ alternate16 in. National Concrete Masonry Association. 2001. (25 mm) Rigid insulation SECTION Figure 18 shows the detailing of a 4 in. 2004.c. NCMA TEK 19-4A. 2002. Water Repellents for Concrete Masonry Walls. 2. (203 mm) CMU 1 in. contact NCMA Publications (703) 713-1900 . Flashing Details for Concrete Masonry Walls. 5. Virginia 20171-4662 www. 4. vertically* Tab type reinforcement@ 16 in. 4 in. With the other two systems. Herndon. National Concrete Masonry Association. (406 mm) o. Floor and Roof Connections to Concrete Masonry Walls. an additional ladder type joint reinforcement is used to provide this movement control for the veneer. (406 mm) o. 2004. the joint reinforcement satisfies this requirement. Reported by the Masonry Standards Joint Committee. tab and adjustable types.ncma.org To order a complete TEK Manual or TEK111 Index.c. NCMA TEK 5-7A. NCMA does not assume any responsibility for errors or ommisions resulting from the use of this TEK NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 3.c. National Concrete Masonry Association. (102 mm) concrete masonry veneer used in conjunction with a 8 in. NCMA TEK 19-1. With the tri-rod system. (102 mm) CMU Flashing Tri-rod Tab type Adjustable Figure 18––Concrete Masonry Veneer Detailing REFERENCES 1. 2005. (406 mm) o. vertically 4 in. (25 mm) airspace Adjustable joint reinforcement@ 16 in. (406 mm) o. post-tensioning has been used to strengthen and repair existing masonry walls. the two terms are often used interchangeably as they apply to this form of masonry design and construction. called pretensioning. The other type of prestressing. the Figure 1—Open -Ended Concrete Masonry Units 112 TEK 3-14 © 2002 National Concrete Masonry Association (2002) . warehouses and other types of structures. steel prestressing tendons which can be wires. The net area strength of concrete masonry units must be at least 1. This TEK addresses new concrete masonry walls laid in running bond and built with unbonded vertical post-tensioning tendons. Prestressing tendons are either installed during wall construction. proprietary units are also being developed that are specifically intended for use with tendons. 1) addresses the structural design of vertically post-tensioned walls.900 psi (13. Because mortar must be placed on concrete masonry webs adjacent to grouted cores to contain the fluid grout. with the addition of hardware to develop the posttensioning forces. POST-TENSIONING In post-tensioned construction. This initial state of compression offsets tensile stresses from applied loads.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology POST-TENSIONED CONCRETE MASONRY WALL CONSTRUCTION Keywords: construction techniques. Post-Tensioned Concrete Masonry Wall Design. bars or strands. prestressed masonry. Post-tensioned concrete masonry walls have been built for schools. Current design codes (ref. and Type S is a good choice for posttensioned masonry as well. 2). quality assurance. The materials are the same. hollow concrete masonry units are laid conventionally and prestressing tendons are either placed in the concrete masonry cells or in the cavity between multiple wythes. Concrete Masonry Units Open-ended (A. post-tensioned masonry. In either case. Post-tensioning is a specific method of prestressing where tendons are stressed after the wall has been placed. Higher early strength mortars can accommodate earlier stressing. Mortar bedding is a design issue as well. Grouting helps increase cross-sectional area for shear and compressive resistance. manufacturing.and H-shaped) concrete masonry units (Figure 1) are particularly suited to post-tensioned masonry . Because virtually all prestressed masonry built to date has been post-tensioned. 3) typically address post-tensioning of masonry walls laid in running bond. tensioning INTRODUCTION Prestressing is the general term used when a structural element is compressed prior to being subjected to building loads. TEK 3-14 Construction MATERIALS Construction of a post-tensioned wall proceeds similarly to that of conventional masonry. as the section properties of a wall with face shell mortar bedding are different from those of a fully bedded wall. but increases construction cost and time. or access ports are left in the walls so the tendons can be slipped in after the walls are completed. full mortar bedding is sometimes specified when grout is used. stronger units are often specified for post-tensioned walls to utilize the higher compressive strength. Mortar and Grout Type S mortar is commonly used for conventional loadbearing masonry. TEK 14-20A (ref. as these units can be placed around the tendons without having to lift the units over the tendons. highway sound barriers. Because this TEK addresses unbonded tendons only. and sometimes prestressing grout. the tendons are tensioned only after the walls have cured for approximately three to seven days. The cells or cavity containing the tendons may or may not be grouted. While these two-core units are commonly used. In addition.1 MPa) per Standard Specification for Loadbearing Concrete Masonry Units (ref. retail. However. involves tensioning the tendon prior to construction of the masonry. prestressing tendons. strength. grout is still needed for mild reinforcement. Couplers allow the use of shorter bars which minimizes the height of lifting. 2). Tendons in walls with a likelihood of high moisture levels (single wythe exterior walls in areas of high humidity and interior walls around swimming pools. 3) also allows steel strands or wires to be used. Grouting While the need for grouting is minimized compared to conventionally reinforced walls. installing the tendons.000 psi (413 and 690 MPa). Concrete masonry unit Foundation or support Tendon Continuous bond beam (inverted) Foundation or support Cast-in-place anchor 2a—Cast-in-place anchor Anchorages Each tendon is anchored at the foundation and extends to the top of the wall. Prestressing grout is only used with bonded tendons. Thus. such as in bond beams. but they are still considered unbonded. ref. In some instances.000 and 100. selecting and setting the top anchorages. In practice. tendons are usually high-strength bars joined by couplers. similar to Figure 2b. tendons can also begin at an upper floor and not at the foundation.000 psi (1. Cast-in-place anchors are often set by the foundation contractor. and the design documents should indicate the type of protection required. Most tendons currently available in the United States are bars between 7/16 and 1 in. The cast-in-place bottom anchor (Figure 2a) is preferred for shear walls and for fire walls. except for certain shear walls (these must be identified on the design drawings). quality control is a concern with these anchors. In this case. depending on the supplier. It is considered good practice to use additional corrosion protection. CONSTRUCTION Key steps of post-tensioning concrete masonry walls include: selecting and setting the bottom anchorages. Steel strand tendons are generally 270. The foundation anchorage is embedded in the wall or footing while the top anchorage utilizes a special block. a precast concrete spreader beam or a grouted bond beam. etc. The mechanical post-installed anchors can be used for nearly all applications. such as flexible epoxy-type coatings. (203 mm) from tendon) 2b—Foundationless anchor Adhesive anchor 2c—Adhesive anchor Figure 2—Bottom Anchors for Use in Post-Tensioned Masonry 113 .860 MPa). such as hot-dipped galvanizing (ref. While they are the best anchors for capacity. Tendons In the United States. foundation dowels are grouted into the wall to lock it in place. and tensioning the tendons. the contractor must select the anchor appropriate to the conditions. Tendon Bond breaker tape (2) No. Important features of the tendons are their size. Bottom Anchors Bottom anchors are most critical to the proper construction of post-tensioned walls. for tendons in moist environments. although Building Code Requirements for Masonry Structures (ref. not the mason. The mason controls bottom anchor placement when either adhesive anchors are installed in the foundation (Figure 2c). Tendon Corrosion Protection Tendons must be protected from moisture deterioration. while the adhesive type should not be used for fire walls. Alignment is essential to ensure that the tendons are placed exactly as intended. there are no code provisions for tendons which are not steel. with strengths between 60. Encasing tendons in conventional grout restrains the tendons. (11 and 25 mm) in diameter. To date.grout discussed here is conventional grout (ASTM C 476. If the anchor in Figure 2b is used. Tendons are usually placed in hollow cells of masonry units with little or no grouting. Building Code Requirements for Masonry Structures (ref. 6). In addition. cast-in-place anchors are the most difficult to align. or when an anchor is used which does not rely on the foundation for support (Figure 2b). 4 (M #13) continuous Foundationless threaded floor slab anchor Concrete masonry unit Tendon Foundation or support Dowel into slab or wall (locate minimum 8 in. and relaxation characteristics. not prestressing grout. Unless the design documents call out specific bottom anchors. locker rooms. 3) requires that tendons be anchored by mechanical embedments or bearing devices or by bond development in concrete. 3). the open-ended units shown in Figure 1 must be grouted to meet minimum web requirements in ASTM C 90 (ref. anchorages for the tendons. and tendon restraints. the foundationless anchor is used with a bond beam. Tendons can not be anchored by bond development into the masonry. most prestressing tendons are supplied with a hotdipped galvanized coating.) must have corrosion protection in addition to that provided by the masonry cover. Tensioning At the time the tendons are stressed. Positioners may also function as restraints if their capacity is determined by testing. Thus. They may be installed after the masonry is constructed provided the design allows laterally-unrestrained tendons. post-tensioned walls are most economical when the grouting is minimized or eliminated totally in comparison to a conventionally reinforced wall. All other tendons are unbonded.034 MPa) tensile strength. Prestressed masonry design. grouted conventional reinforcement is used in addition to post-tensioning tendons to provide minimum requirements of bonded reinforcement. the cause of the difference must be corrected. The project specification should include either the minimum f 'mi and minimum specified compressive strength of masonry ( f 'm). The anchor should not be supported by mortar. primarily seismic. However. 4) requires that the following two methods be used to evaluate the tendon prestressing force: 1. Specification for Masonry Structures (ref. or the amount of curing required before stressing can occur. t /2 Figure 3—Tendon Coupler and Positioner Post-tensioned walls must be constructed in conformance with masonry standards applicable to conventionally reinforced masonry. Laterally restrained tendons are not free to move within a cell or cavity. the wall performance will not be as good as with laterally restrained tendons. Tendon positioners (see Figure 3) are useful to maintain the tendon location within the wall during construction of the masonry. bonded tendons are also laterally-restrained. The higher cost of the post-tensioning materials is more than offset by the savings of placing fewer tendons compared to reinforcing bars and eliminating most of the grouting. If laterally-restrained tendons are required. the masonry is considered to have its initial strength (f 'mi). use a calibrated dynamometer to measure the jacking force on a calibrated gage. relies on an accurate measure of the prestress in the tendons.for prestressing tendons using bars of less than 150 ksi (1.Tendons Tendons are usually placed concentric with the wall. use load-indicating washers complying with Standard Specification for Compressible-Washer-Type Direct Tension Indicators for Use with Structural Fasteners. Both the prestressing grout inside the duct and the grout around the duct must be cured before the tendons are stressed. If grout encases the tendon either totally or at restraints or bond beams. In addition to these. whether it is accomplished by fully stressing each tendon sequentially or by stressing the tendons in stages. To ensure the required level of accuracy. Laterally-unrestrained tendons are free to move within the cell or cavity and are the simplest to construct. This detail can also be used for interior partitions. t Remove and replace face shell for access to coupler and are generally the most economical to construct. the tendons must be able to slip freely. the tendon placement should proceed simultaneously with the masonry to allow the restraints to be installed unless the cells will be grouted. Figure 4 shows a means for supporting the top of a wall when the top anchor is placed on a bond beam in a lower course. Restraint is accomplished by grouting the full height of the tendon or by providing intermittent restraints—either grout plugs or mechanical restraints—at the quarter points of the wall height. However. ASTM F 959 (ref. The sequence of tensioning. However. Placing tendons is much like that of mild reinforcement. 4) requires the following for posttensioned masonry: 114 . The designer must specify which system will be used. However. a grouted bond beam or a precast concrete unit. is a function of the design specifications. a bond breaker such as poly tape should be used to allow the tendon to slip. tendons should not be placed such that tensile stresses develop in the wall due to the combination of prestressing force and dead load. unbonded tendons may be either laterally-restrained or unrestrained. Specification for Masonry Structures (ref. or 2b. and therefore the structural integrity of these walls. 5). Bonded tendons are encapsulated by prestressing grout in a corrugated duct which is bonded to the surrounding masonry by grout. However. Tendons can also be either bonded or unbonded. they may be placed off-center to counteract bending moments due to eccentric vertical forces or lateral forces from a single direction. In all details. If the two values determined by methods 1 and 2 are not within 7 percent of each other. and either: 2a. For some conditions. measure the tendon elongation and compare it with required elongation based on average load-elongation curves for the prestressing tendons. Walls with laterally-unrestrained and unbonded tendons do not require grouting Grouted cell Mesh grout stop QUALITY ASSURANCE Locate couplers to avoid lateral restraints Bond breaker tape Tendon Positioner t /2 Top Anchors The top anchor must be placed on solid masonry. (10 mm). Virginia 20171 www.1-02/ASCE 6-02/TMS 602-02. Reported by the Masonry Standards Joint Committee. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 2. For cross-sectional dimensions greater than 8 in.ncma. ASTM F 959-01a. Reported by the Masonry Standards Joint Committee. Herndon. (25 mm). ACI 530-02/ASCE 5-02/TMS 402-02. National Concrete Masonry Association. (203 mm). 2002. 5. 2. 2002. REFERENCES: 1.1. 3. (203 mm). Standard Specification for Grout Nut. the tolerance for tendon placement is +1 in. and pilasters with cross-sectional dimensions less than 8 in. (6 mm) for masonry beams. 2001. In the out-of-plane direction. Building Code Requirements for Masonry Structures. 2002. 4 (M #13) continuous Grout cell solid Bond breaker tape Mesh grout stop Figure 4—Top Anchor Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. the Architect/Engi- Soft joint. 4. ASTM International. In the in-plane direction. 115 contact NCMA Publications (703) 713-1900 . 2001.org To order a complete TEK Manual or TEK Index. columns. Standard Specification for Compressible-Washer-Type Direct TenSteel structure sion Indicators for Use with StrucRemove and replace tural Fasteners. walls. the tolerance increases to + 3/8 in. Specification for Masonry Structures. ACI 530. TEK 14-20A. 2001. Standard Specification for Loadbearing Concrete Masonry Units. to bearing plate 6. If tolerances exceed these amounts. ASTM and load-indicating washer International. ASTM C 90-01a. the tolerance for the tendon placement shall be + 1/4 in. face shell for access ASTM International. fire-rated as required Lateral tendon restraint anchor bolted or welded to bottom flange of beam to provide simple support at top of wall Veneer Continuous bond beam Extend tendon such that it is properly engaged with projected tabs of restraint anchor neer should evaluate the effect on the structure. Post-Tensioned Concrete Masonry Wall Design. Bearing plate (2) No. ASTM C 476-01. hardened washer for Masonry. 3. 89 (multiply by 0. productivity rates can vary with unit size and concrete density. 3. economics. 116 TEK 4-1A © 2002 National Concrete Masonry Association (2002) . and 20% to 54% for 12-in. Concrete Masonry Unit Weight (ref. The following sections discuss some of the various factors that can impact masonry productivity. concrete ma- Production. Based on typical hollow concrete masonry units. productivity is typically thought of as the number of concrete masonry units placed per unit of time. mortar workability.000 kg/m3) or denser concrete) 8-in.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology PRODUCTIVITY AND MODULAR COORDINATION IN CONCRETE MASONRY CONSTRUCTION TEK 4-1A Construction sonry unit weight greatly impacts masonry productivity. 4). Because masonry crews are accustomed to laying concrete masonry Keywords: construction techniques. In addition to these. some of which can be controlled by the mason and others which are beyond the mason's Figure 1—Estimated Production Rates Based on control. (305-mm) units (refs. productivity INTRODUCTION For masonry construction. number of units per mason per dayb 550 to 650 135 to 190 80 to 160 Notes: a Values assume: walls are constructed in running bond with standard 3/8 inch (10 mm) thick mortar joints and are of convenient height. based on records of completed jobs. b To obtain square feet of wall per day. and walls incorporate modular layout to minimize cutting. Published productivity rates. modular coordination. multiply the values in the table by 0. Bond pattern can also affect productivity. the use of lightweight concrete masonry units (less than 105 pcf (1. This production rate is influenced by many factors. number and type of wall openings.083 to obtain m2/day). with lighter weight units resulting in higher productivity rates (other factors being equal). amount of reinforcement and wall size. lb Table 1—Typical Concrete Masonry Productivity Ratesa Unit nominal size and description: 4 x 2 x 8 concrete brick units 8 x 8 x 16 standard concrete masonry units 8 x 8 x 16 split face concrete masonry units Productivity. should be used as guidelines only. units per mason per day 250 200 150 100 50 0 10 20 30 40 50 60 Weight of unit. 4) PRODUCTIVITY RATES Ideally.680 kg/m3) concrete) can increase productivity 10% to 18% over heavyweight units (125 pcf (2. (203-mm) units. As illustrated in Figure 1. concrete masonry productivity rates should be compiled by masonry estimators. such as those shown in Figure 1 and Table 1. masonry bond pattern. adequate masonry labor is available. (203 mm) vertically and horizontally. Similarly. These modules provide the best overall design flexibility and coordination with other building products such as windows and doors. Steel congestion in reinforced masonry can slow productivity. For example. Nonmodular layouts may require additional considerations for items such as using nonstandard units or saw cutting masonry units and maintaining bond patterns. Thus. has a modular height. which leaves 2 in. 1.primarily in running bond. with a masonry window opening 8 in.8" (2. Similarly. an 86 in.235 mm) high masonry opening. 36 in. However.184 mm) high door. Typically. 914. If all of the mason’s work is placed into Division 4.083 mm) masonry opening to accommodate the door and frame. 44 in. (102-mm) modules for some applications. the construction manager. concrete masonry elements should be designed and constructed with modular coordination in mind. Modular window heights are any multiple of 8 in. (711. In addition. (203 mm) greater than the height of the window if a 4 in. (51 mm) notch which provides the necessary 6' . the architect/engineer. Placing too many reinforcing bars in too small a space makes it difficult to place the steel and to provide adequate grout coverage. Standard concrete masonry modules are typically 8 in. • included the input of a quality mason contractor.032 mm) doors in masonry walls without the need for cutting the masonry units. 3) requires 1/4 in. such as placement of jamb reinforcement and adequate grout consolidation within small core spaces. masonry opening widths for doors and windows should be 4 in. (2. which fits into an 88-in.4" or 88 in. (2. The end product typically is more difficult to construct. This facilitates good communication prior to the commencement of work and prior to the development of any misunderstandings. Masonry opening heights for windows typically are 8 in. the national consensus standards for masonry design and construction. 2). and 52 in.6 mm) header which would allow a 6' . Concrete masonry structures can be constructed using virtually any layout dimension. (101. (51 mm) above and below for framing and 4 in. This allows for 2 in. and so on in 8 in. Additionally. IMPACT OF QUALITY ON PRODUCTIVITY The overall quality of the project can influence the masonry productivity. Planning and Layout Attention to planning of the building itself and of construction sequencing and scheduling can impact masonry productivity. quality materials. A project with these ingredients will also be conducive to a very productive jobsite. other bond patterns often require more time to lay.. the masonry material suppliers and the mason contractor. ducts. • reviewed the plans. it enhances communication with the masonry team and has a better chance of being properly incorporated into the job. (51 mm) for the door framing. (51 mm) greater than the door height.10" (2. These include precast lintels with a 2 in. Proper Design Quality design means that the designer has: • designed and detailed a project that is constructible. 4. the contractor. and • incorporated all masonry materials into CSI Division 4. (6. (Often.) Similar to the pre-bid and pre-construction conferences. Figure 2 illustrates these opening sizes. pre-bid and pre-construction conferences. Thus. 3. This opening size allows for 2 in. other construction issues may arise. applicable ASTM standards should be included for specifying masonry materials. a modular door height is 2 in. 1118 and 1. 5. Note that products are available in some locations to accommodate 6' . coordinating the placement of pipes. In other areas. stack bond has been estimated to decrease productivity by about 8% over comparable running bond productivity rates (ref. 4). Modular coordination is the practice of laying out and dimensioning structures to standard lengths and heights to accommodate modular sized building materials. door and window widths of 28 in. specifications and structural drawings to eliminate conflicting words and conflicting details.235 mm) high masonry opening. but may also include 4in. (2. for maximum construction efficiency and economy. Specification for Masonry Structures (ref. 2.321 mm). (102 mm) for installing a sill at the bottom of the window. • developed plans and specifications that are sufficient for construction and are complete with the proper code and standards referenced. a comprehensive set of plans and specifications will help enhance productivity because it will reduce or eliminate time spent correcting misunderstandings and errors. A complete set of plans and specifications will include a copy of Building Code Requirements for Masonry Structures and Specification for Masonry Structures (refs. (102 mm) sill will be used.032 mm) door to fit into 7' .. Pre-Bid and Pre-Construction Conferences Pre-bid and pre-construction conferences should be held and attended by all parties involved in the masonry work including the owner’s representative. chases and conduits to align them with hollow masonry cores can reduce the need to saw-cut masonry units. (203 mm) increments. (102 mm) larger than the door or window width. Quality construction includes: 1. door frames are available with a 4 in. Clear communication minimizes delays due to factors such as lastminute changes and errors.4 mm) clear space between the 117 . some mason materials are found in division 7. (51 mm) less than any multiple of eight. produces more waste and is more costly.8" (2. attention to planning and layout. (203 mm) greater than the window height. adequate jobsite and 6 proper installation. (203 mm). proper design. are modular and would not require cutting of the masonry. Masonry opening door heights are 2 in.. (51 mm) on each side of the opening for framing. (51 mm) framing 2 in. Selecting units of all one shade for the sample panel will not accurately reflect the completed work.reinforcing bar and the masonry for fine grout and 1/2 in.22 m) and should contain the full range of unit and mortar colors. cold and wet weather conditions. (102 mm) 2 in. Although masonry construction can take place during hot. Units meeting the ASTM tolerances will be easier to place. sealant application and all other procedures should be performed on the sample panel so that their acceptability can be judged as well. (51 mm) framing 2 in. 4). Cleaning procedures. methods and workmanship acceptable on the job. More detailed information on these construction procedures can be found in All-Weather Concrete Masonry Construction (ref. (102 mm) 2 in. Sample panels reduce misunderstandings and provide an objective indicator of the intended construction practices. Similarly. Instead. Quality Materials Masonry materials have a successful history of meeting applicable specifications and project requirements. (51 mm) framing 4 in. In addition. grout and other masonry materials will help expedite the job. units without excessive chippage (a characteristic also governed by ASTM stan- Masonry opening width = window opening width + 4 in. They help ensure all parties understand the range of materials. (13 mm) clear space for coarse grout. (51 mm) framing Masonry opening height = window opening height + 8 in. The sample panel should remain in place throughout construction as a point of reference. (51 mm) framing Door Openings Figure 2—Modular Wall Openings 118 . schedule masonry work to avoid times of the year particularly subject to freezing temperatures or prolonged rains whenever possible.22 x 1. (102 mm) sill height Window Openings Masonry opening width = door opening width + 4 in. special construction procedures may be warranted in some cases to ensure the masonry quality is not impacted by the weather. units should be randomly selected as they would in the project construction. Sample panels are typically at least 4 ft by 4 ft (1. (51 mm) 2 in. mortar. specify dimensional tolerances for the units. Ensuring that the materials used are as specified helps keep the masonry construction on track. For maximum productivity. ASTM standards for masonry units. timely delivery of the units. (203 mm) 2 in. (51 mm) framing 2 in. (51 mm) framing Masonry opening height = door opening height + 2 in. for example. and allow the mason to more easily maintain level and alignment. This includes having: • undisturbed space for building the sample panel(s). 2002. Building Code Requirements for Masonry Structures. R. National Concrete Masonry Association. REFERENCES 1. 2002. poured concrete foundations or footings which do not meet their tolerances may require the mason to saw-cut the first course of block. newer fork lifts often have increased capacity. V. Products that are easier for the mason to install. 2002. TEK 31C.1-02/ ASCE 6-02/TMS 602-02. All-Weather Concrete Masonry Construction. Kolkoski. Reported by the Masonry Standards Joint Committee. quality installation requires: • an ample number of qualified craftsmen. 2. ACI 530. to compensate. • qualified and sufficient supervision. which include the sand mixed with the appropriate cement.org To order a complete TEK Manual or TEK Index. Premixed mortars. can also impact masonry productivity. Jobsite A quality jobsite helps productivity by including ample space for the mason subcontractor to work and having easy access to the masonry supplies. 1988. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. Craftsman Book Company. • a defined and ample-sized area for materials and supplies. There have been some marvelous developments in products and equipment to assist masons and hence increase masonry productivity. Other equipment advances that can enhance productivity include portable hand-held lasers that work in numerous directions simultaneously. or take some other measure. 119 contact NCMA Publications (703) 713-1900 . Research Investigation of Mason Productivity. In some cases. Masonry and mortar cements provide more consistency because all of the cementitious ingredients are premixed. a single boom which increases visibility. 5. and • the right equipment for the job. have higher load ratings and higher extensions. and • a defined and ample-sized area for sampling and testing procedures as required for the project. Premixed mortars can improve mortar quality control and uniformity and can also increase productivity by eliminating the need for job site mixing. Masonry Estimating. Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. Specification for Masonry Structures. Herndon. such as self-adhesive flashings and pre-formed flashing end dams. work by other trades can also impact masonry productivity. For example. are more maneuverable.dards) allow placement without the need for sorting the product for quality—an activity that reduces overall productivity. For example. electric portable winches and power (crank-up or hydraulic) scaffolding.ncma. National Concrete Masonry Association. are also available in silos or in mixers or blenders. Virginia 20171 www. Choice of mortar can also impact productivity. 3. 1989. Proper Installation In addition to the factors cited above. 4. ACI 530-02/ASCE 5-02/TMS 402-02. Reported by the Masonry Standards Joint Committee. ESTIMATING MORTAR MATERIALS Next to grout. includes about 5% waste 120 TEK 4-2A © 2004 National Concrete Masonry Association (replaces TEK 4-2) (2004) . ESTIMATING CONCRETE MASONRY UNITS Unit Unit face Number of units per type size. (mm) 100 ft2 (100 m2) of wall area conventional 8 x 16 (203 x 406) 119 (1.550) brick 22/3 x 8 (68 x 203) 710 (7.083 m 2). It should be stressed that the information for estimating materials quantities in this section should be used with caution and checked against rational judgment. such as pilaster units. estimating. When using this estimating method. For conventional units having nominal heights of 8 in. or as a general means of obtaining ballpark estimates. construction. mortar INTRODUCTION Estimating the quantity or volume of materials used in a typical masonry project can range from the relatively simple task associated with an unreinforced single wythe garden wall. shapes. this translates to 119 units per 100 ft 2 (9. Often. Including a 5 percent allowance for waste and breakage. (406 mm). Large projects. the area of windows. the rule of thumb methods described in this TEK provide a practical means of determining the quantity of materials required for a specific masonry construction project. the exposed surface area of a single unit in the wall is 8/9 ft 2 (0. mortar is probably the most commonly Table 1—Approximate Number of Concrete Masonry Units Required for Single Wythe Constructiona a based on net area of masonry wall. due to their complexity in layout and detailing.275) half-high 4 x 16 (102 x 406) 238 (2. it can be applied to estimating the number of units required regardless of their width. often require detailed computer estimating programs or an intimate knowledge of the project to achieve a reasonable estimate of the materials required for construction. for smaller projects. corner units or bond beam units are to be incorporated into the project. in.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology ESTIMATING CONCRETE MASONRY MATERIALS TEK 4-2A Costs/Estimating Keywords: concrete masonry units. if varying unit configurations. However. the number of units used in these applications need to be calculated separately and subtracted from the total number of units required. Design issues such as non-modular layouts or numerous returns and corners can significantly increase the number of units and the volume of mortar or grout required. doors and other wall openings needs to be subtracted from the total wall area to yield the net masonry surface. Similarly. to the comparatively difficult undertaking of a partially grouted multiwythe wall coliseum constructed of varying unit sizes. material estimating is best left to an experienced professional who has developed a second hand disposition for estimating masonry material requirements.610) Probably the most straightforward material to estimate for most masonry construction projects is the units themselves. The most direct means of determining the number of concrete masonry units needed for any project is to simply determine the total square footage of each wall and divide by the surface area provided by a single unit specified for the project.) Because this method of determining the necessary number of concrete masonry units for a given project is independent of the unit width. grout. and configurations.550) half-length 8 x 8 (203 x 203) 238 (2. (See Table 1 for these and other values. (203 mm) and nominal lengths of 16 in.29 m2) of wall area. 3 kg) bag 1-3. 1 ton (907 kg) damp loose sand = 25 ft 3 (0. or 1 ft 3 Type S mortar cement. 1 ft 3 Type N mortar cement. 1 ton (907 kg) sandb Preblended mortar: 1-80 lb (36. 1/2 ft 3 hydrated lime.71 m3) For conversion purposes. 3 ft 3 sand Type S 1/ 2 ft 3 portland cement.281 kg/m3) Masonry and mortar cement bag weights vary. or 1 ft 3 Type M mortar cement.028 m3).0 kg) bags. typical density 40 lb/ft 3 (641 kg/m3) Sand: 1 ft 3 is equivalent to about 7 shovelfuls.035 m3). or 1 ft 3 Type M masonry cement. 6 ft 3 sand. Type S masonry cements and mortar cements are packaged in 75 lb (34. based on factors such as the skill level of the mason. 1 ft 3 Type N masonry cement. although commonly: Type N masonry cements and mortar cements are packaged in 70 lb (31.0283 m3. 6 ft 3 sand. Assumes face shell mortar bedding for conventional concrete masonry units and full bedding for brick-sized concrete masonry units. 9 ft 3 sand Mortar cement: Type M 1 ft 3 portland cement.8 kg) bags.3 kg) bags. nonmodular layouts. the following can be used: Portland cement: typical bag volume = 1 ft 3 (0.361 kg) bag Site-mixed mortarc : Portland cement-lime: Type M 1 ft 3 portland cement. 41/ 2 ft 3 sand. Type M masonry cements and mortar cements are packaged in 80 lb (36. 33/4 ft 3 sand Type S 1 ft 3 portland cement. 1 ft 3 hydrated lime. numerous returns and corners. or 1 ft 3 Type S masonry cement. 1 ft 3 = 0.000 lb (1. 3 ft 3 sand Type N or O 1 ft 3 Type N masonry cement. typical bag weight 94 lb (42. 3 ft 3 sand Type S 1/ 2 ft 3 portland cement. 1 ft 3 Type N masonry cement. 41/ 2 ft 3 sand. typical bag weight 50 lb (22. 2 ft 3 hydrated lime. 3 ft 3 sand a b c a Approximate number of units that can be laid using one batch of mortar Conventional CMU: Brick-sized CMU: 240 1.550 38 187 46 225 62 300 93 450 62 31 300 150 46 31 225 150 31 150 62 31 300 150 46 31 225 150 31 150 Number of units can vary from those listed in the table. typical density 94 lb/ft 3 (1. 41/2 ft 3 sand Type N 1 ft 3 portland cement. 6 ft 3 sand Type O 1 ft 3 portland cement. 1 ft 3 Type N mortar cement.506 kg/m3 ) Hydrated mason's lime: typical bag volume = 11/4 ft 3 (0.000 16 420 50 1. 3 ft 3 sand Masonry cement: Type M 1 ft 3 portland cement. 1/4 ft 3 hydrated lime. Values include nominal amounts for waste.Table 2—Mortar Estimation for Single Wythe Concrete Masonry Walls Mortar type & batch proportions Masonry cement: 8-70 lb (31.8 kg) bags masonry cement. 121 . typical density of damp loose sand 80 lb/ft 3 (1. 3 ft 3 sand Type N or O 1 ft 3 Type N mortar cement.6 kg).7 kg). etc. 6) 1.9 (1. combined with numerous other variables can lead to large deviations in the quantity of mortar required for comparable jobs.5 (0.0) 14.2 (1.000 lb (907 and 1. 907 kg) of masonry sand is required for every 8 bags of masonry cement. Portland cement lime mortar One 94 lb (42.8) 11.1 (5.0) 18.3 (1.8 (4. (356 mm) 74.misestimated masonry construction material.1 (11.3) 6.7) 2.7) 2.3 (11.2) 3.7 (1.6 (5.4 (2.6) 9. 75 or 80 lb (31. mortar proportions.6) 18.9 (3.9) 2.0) 5.7 (1.0) 8.1 (0.4 (3.6) 5.6) 9.048) a 6 in.8) Wall width: 10 in. 122 .2) 9.1 (1.0 (0.0) 19.1) 6.642) 112 (2.9) 2. The properties and configuration of the units used in construction can have a huge impact alone.2 (1. (254 mm) 47.5) 4. These general guidelines are as follows for various mortar types.9) 2. sand volumes are often correlated to an equivalent number of shovels using a cubic foot (0.0) 5.3 (1.5 (22.9) 5.8) 10.6 (3.2) 6.2) 14 in.000 and 3. as shown in Figure 1. If more than 3 tons (2.8) 5.6 (2.2 to 36.4) 4.7 kg) bag hydrated lime to 4 1/4 ft 3 (0. This assumes a proportion of one 94 lb (42.6) 4.438) 104 (2. mixed in proportion with sand and lime to yield a lean Type S or rich Type N mortar.5) 12.7 (1. masonry cement or mortar cement.6) 1.361 kg).6) 7.219) 56 (1.2 (1.8 (0.5) 8 in.1) 3.000 lb.7 (1.0 (1.7) 9.7) 37. (mm) 8 (203) 16 (406) 24 (610) 32 (813) 40 (1.7) 5.6 (2.8) 2.8) 7.8) 8.3 (1.5) Assumes two-core hollow concrete masonry units and 3% waste.6) 6. construction conditions.7 (4.6 kg) bag of portland cement to approximately one-half of a 50 lb (22.6 (1. although other weights may be available as well.5) 11. Variables such as site batching versus pre-bagged mortar. in.6) 4.4 (0. (203 mm) 36.2) 15.0) 12 in.6) 4.6 (0.3 (2.3 (1. Packaged dry.0 (14.9 (0.9 (2. Masonry cement mortar Masonry cement is typically available in bag weights of 70. ft3 per 100 ft2 of wall (m3 per 100 m2)a Grout spacing.1 (1. will lay approximately 62 hollow units if face shell bedding is used. For common batching proportions.9 (0.0) 2.5 (2.5 (7.626) 72 (1.5 (9.4 (2.4 (1. (152 mm) 25. hence. ESTIMATING GROUT The quantity of grout required on a specific job can vary greatly depending upon the specific circumstances of the project.9) 7. add 1/2 ton (454 kg) to account for waste.3) 6.8 (7.8 kg) bag of masonry cement will generally lay approximately 30 hollow units if face shell bedding is used.1 (3.0 and 36.7) 14.9 (1.0 (1. simply round up to account for waste.8 (3. For smaller sand amounts.3) 3.6 (7.1) 3.8 (3.9) 5. unit tolerances and work stoppages. the estimates are independent of the concrete masonry unit width.7 (6.8) 12.03 m3) box.2 (1. 34.6 (0.4) 24.6) 4.0) 3. masons have developed general rules of thumb for estimating the quantity of mortar required to lay concrete masonry units. Preblended mortar Preblended mortar mixes may contain portland cement and lime.5) 12.8) 5.829) 80 (2.1 (2.6 (1. Figure 1—Measuring Mortar Sand Volume Table 3—Grout Volume Estimation for Hollow Single Wythe Concrete Masonry Walls Volume of grout.9 (1. and will always include dried masonry sand.235) 96 (2.3 (2.1) 5.4) 4.8 (2.8 (2. For example.422) 64 (1. For ease of measuring in the field.0) 29.3 (2. As such. This equates to about 240 concrete masonry units per ton of sand.3) 4. (305 mm) 58.2 (0.5) 7.0 (1.5 (2.016) 48 (1.3 kg) bags or in bulk volumes of 2.4 (1.4) 4.2) 3. One 70 lb (31.9 (4.8) 2. 1 ton (2.2 (1.6 kg) bag of portland cement.3 (1.7 (1.8 (0.1) 3.721 kg) of sand is used.12 m3) of sand.3) 23. Note that the following estimates assume the concrete masonry units are laid with face shell mortar bedding.9) 8.4 (2.845) 120 (3.8.3) 4.0) 3.3 kg). the mortars typically are available in 60 to 80 lb (27.8 (3.032) 88 (2.9 (18.4) 6.3 (1. 66 ft 3 (0.2 95 1. linear ft (m) 80 lb (36. Note that walls constructed of 4-in. in. Further.8 80 80 lb (36. Table 4—Grout Estimation for Hollow Single Wythe Concrete Masonry Walls. TR 90B. it is not recommended to grout conventional 4-in.361 kg) bag yields approximately 25 ft 3 (0.7 (0. (102-mm) units. Vertical Grouting with Preblended Grouta CMU size.7 110 2.3 kg) bag yields approximately 0. smaller projects may experience a larger percentage of grout waste. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK.0 (0. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive.000 lb (1.488) 60 (18. 3. Although the absolute volume of grout waste seen on a large project may be larger than a comparable small project.000 lb (1. 123 contact NCMA Publications (703) 713-1900 . in.6 150 2.3 kg) bag yields approximately 0. number of cores 80 lb (36. Additional grout may be necessary for horizontally grouting discrete courses of masonry.29) 80 lb (36.000 lb (1.3 kg) bag 3. (102-mm) masonry units are not included in Table 3.71 m3 ) Table 5—Grout Estimation for Hollow Single Wythe Concrete Masonry Walls.019 m3).361 kg) bag yields approximately 25 ft 3 (0. Virginia 20171 www.000 lb (1. Due to the small cell size and difficulty in adequately placing and consolidating the grout.units of low density concrete tend to absorb more water from the mix than comparable units of higher density. Herndon.66 ft 3 (0. the method of delivering grout to a masonry wall (pumping versus bucketing) can introduce different amounts of waste. Brick. REFERENCES 1 .361 kg) bag 3. (mm) 6 (152) 8 (203) 12 (305) a Yield.361 kg) bag 2.823) 100 (30. Annotated Design and Construction Details for Concrete Masonry. Tables 4 and 5 contain estimated yields for bagged preblended grouts for vertical and horizontal grouting. 2 . Horizontal (Bond Beam) Grouting with Preblended Grouta CMU size. Table 3 provides guidance for the required volume of grout necessary to fill the vertical cells of walls of varying thickness.38) 1. National Concrete Masonry Association.org To order a complete TEK Manual or TEK Index.48) 2.019 m3).71 m3 ) Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. respectively. Kreh. D. 2003.609) 80 (24. Building With Masonry. 1998. The Taunton Press.ncma.3 kg) bag 3. (mm) 6 (152) 8 (203) 10 (254) 12 (305) a Yield. Block and Concrete .6 (0. 3. weep holes INTRODUCTION A wall constructed with two or more wythes of masonry can technically be classified in one of three ways. It is generally not necessary for the vertical movement joints in the veneer wythe to exactly align with those in the backup wythe. A true veneer is nonstructural—any contribution of the veneer to the wall’s out-of-plane load resistance is neglected. The primary function of anchored veneers is to provide an architectural facade and to prevent water penetration into the building. (406 mm) on center.100 mm). Most commonly. Bending moments (flexure) due to wind or gravity loads are distributed to each wythe in proportion to its relative stiffness. 1) defines veneer as a masonry wythe which provides the exterior finish of a wall system and transfers out-of-plane loads directly to the backing. glazed. Building Code Requirements for Masonry Structures (ref. incorporating joint reinforcement at 16 in. The continuous airspace behind the veneer. cavity walls. or stone veneer. ground face or scored block. fluted. and is considered appropriate if special precautions are taken to keep the air space clean (such as by beveling the mortar bed away from the cavity or by placing a board in the cavity to catch and remove mortar droppings and fins while they are still plastic). but is not considered to add load resisting capacity to the wall system. A minimum 1 in. (76 mm) veneer units may be available as well. along with flashing and weeps. Building Code Requirements for Masonry Structures Chapter 6 (ref. These include: locating control joints to achieve a maximum panel length to height ratio of 11/2 and a maximum spacing of 20 ft (6. noncomposite or veneer walls. 124 TEK 5-1B © 2003 National Concrete Masonry Association (replaces TEK 5-1A) . As an alternative. and water penetration resistance. These three wall systems are composite. 1) includes requirements for design and detailing anchored masonry veneer.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY VENEER DETAILS Keywords: architectural details. a 2 in. wall openings. See Crack Control for Concrete Brick and Other Concrete Masonry Veneers for more detailed information (ref. specific crack control recommendations have been developed for concrete masonry veneers. including deflection of the backup and any horizontal supports. Wall ties may be joint reinforcement or wire wall ties. The continuous air space. must be detailed to collect any moisture that may penetrate the veneer and direct it to the outside. (25 mm) air space between wythes is required (ref. the structural properties of veneers are neglected in veneer design. TEK 5-1B Details (2003) DESIGN CONSIDERATIONS Masonry veneers are typically composed of architectural units such as: concrete or clay facing brick. split. on the other hand. This TEK addresses concrete masonry veneer with concrete masonry backup. (102 mm). crack control measures should be employed as required for each wythe. proprietary insulating drainage products can be used. although 3 in. provides the wall with excellent resistance to moisture penetration and wind driven rain as well as a convenient location for insulation. as well as where stress concentrations occur. Because the two wythes in a veneer wall are designed to be relatively independent. A masonry veneer with masonry backup and an air space between the masonry wythes is commonly referred to as a cavity wall. depending on how each individual wythe is designed and detailed. Otherwise. The veneer is assumed to transfer out-of-plane loads through the anchors to the backup system. and using Type N mortar for maximum flexibility. or cavity. differential movement between the veneer and backup. Noncomposite walls. construction details. This requires that the two masonry wythes be connected by masonry headers or by a mortar or grout filled collar joint and wall ties to help ensure adequate load transfer between the two wythes. wall ties. As such. Although structural requirements for veneers are minimal. are designed such that each wythe individually resists the loads imposed on it. Although veneer crack control measures are similar to those for other concrete masonry wall constructions. 1). the following design considerations should be accounted for: crack control in the veneer. adequate anchor strength to transfer applied loads. 3). anchored masonry veneers have a nominal thickness of 4 in. provided that the ties allow differential in-plane lateral movement. Composite walls are designed so that the wythes act together as a single member to resist structural loads. (51 mm) air space is preferred. connectors. flashing. parapets. (25 mm) and Figure 1—Parapet a maximum of 4 1/2 in. 1 in.c. 1). bolted to bearing plate (305 mm) of control joints and wall openings to ensure the free ends of the veneer are Bond beam Mesh or other grout stop device adequately supported. Vents can also be installed at the top Drip edge of other masonry veGrade neer walls to provide natural convective air Fill solid flow within the cavbelow flashing ity to facilitate drying. backup must be a minimum of 1 in.c. Because veneers rely on the backup for Insulation. Rational design may allow a The distance between the inside face of the thinner wythe. hot-dipped Structural wythe as ladder type reinforcement is preferred over required by design Notch/pocket truss type. For vented caviConcrete slab ties. a 2 in. min. grout and loose fill insulation. Figure 2—Foundation 125 . Steel bar joist welded or as required support. typ. Extending insulation up the full height of the parapet helps veneer and the outside face of the masonry prevent thermal losses through the parapet. flashing is used or meable nature. as required tuck flashing into (51 mm) wide airmortar joint space is recomAirspace. because the ladder shape Joint reinforcement accommodates differential in-plane and wall ties at movement and facilitates placing vertical 16 in. mortar collection between the cavity partially open "L" device and the exterior of the shaped head joints wall. (203 mm) Concrete Masonry Veneers (ref. This second Anchor bolt Fill solid at anchor feature is particularly important when the two bolt locations wythes are of materials with different thermal Sealant and moisture expansion characteristics (such as Sealant Concrete concrete masonry and clay brick). beself-adhering cause of their imperInsulation. as other.. at the top and bottom Concrete masonry Concrete masonry of the wall to enhance veneer backup drainage and help 1 in. thick when empirical design is used (ref. (406 mm) o. For glazed flashing unless per local practice masonry veneer. More information on ties for veneers can be found in TEK 3-6B. mended with air vents Finish varies (25 mm). leeeward cavities. (813 mm) o. Sealant at top of Vapor retarder. 4). reinforcement.. (114 mm). When horizontal joint reinforcement is grout stop device Roofing membrane used to tie the two wythes together. Reinforcement. wall ties must be placed within 12 in.Wall ties for veneers transfer lateral loads to the Slope to roof Wood nailer structural wythe and also allow differential inwith anchor bolt plane movement between wythes. (25 mm) weeps at Cavity filter or other equalize air pressure 32 in. This helps preas required required Grout vent suction being Note: Local codes may restrict the use of foam plastic insulation below grade in areas where the formed in the hazard of termite damage is very heavy. or in an Cant masonry veneer insulated cavity wall which tends to have Roofing membrane differential thermal movement between the Mesh or other Sealant wythes. it is prudent to create baffles in the Waterproofing or Protective metal cavity at the building dampproofing on flashing foundation corners to isolate the cavities from each Insulation. Notes: Structural wythe of parapet must be a minimum of 8 in. . per local practice Horizontal joint reinforcement at 16 in.Airspace. Drip edge 1 1 2 in. (25 mm). min.c.c. per local practice Insulation. Concrete masonry backup Vapor retarder. typ. 1 in.. 1 in. typ. Flashing Concrete masonry backup Concrete masonry veneer 1 in. (406 mm) o. (38 mm) min. (406 mm) o..c. (25 mm). slope 15° Sealant Upside down lintel unit or solid unit Concrete masonry sill unit or precast concrete sill Flashing Weeps 24 in. as required (b) Sill Figure 3—Window Opening 126 . Vapor retarder. as required Horizontal joint reinforcement at 16 in.c. (813 mm) o. (610 mm) o. Concrete masonry veneer Airspace. Insulation. partially open "L" shaped head joint Concrete masonry lintel Finish varies Drip edge Ceiling support Cavity filter or other mortar collection device Sealant Backer material Lateral support Window frame Finish varies Insulated glass Sealant and backer material (a) Head Window frame Min. min. (25 mm) weeps at 32 in. Virginia 20171 www. Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. the cell adjacent to the door should be filled solid. per local practice Airspace.Concrete masonry veneer Notes: In the backup wythe. Insulation. 2. 2003. Herndon.ncma. (25 mm). TR 90B. National Concrete Masonry Association. as required Vapor retarder. 1 in. min. National Concrete Masonry Association. Crack Control for Concrete Brick and Other Concrete Masonry Veneers. ACI 530-02/ASCE 5-02/TMS 402-02. National Concrete Masonry Association. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. 2001. Annotated Design and Construction Details for Concrete Masonry. 2003. 3. 4. or similar. This is typically accomplished by slushing mortar into the cell as the wall is erected. 2002. A form board. TEK 3-6B. Building Code Requirements for Masonry Structures. 127 contact NCMA Publications (703) 713-1900 . TEK 10-4. For larger cavities where part of the cavity will not be covered by the door jamb. shape varies in mortar joint Form return-cut masonry or pressure treated wood blocking Caulk Concrete masonry backup Fill solid adjacent to door Caulk Fill solid with mortar or grout Figure 4—Metal Door Jamb REFERENCES 1. Reported by the Masonry Standards Joint Committee. masonry units may be cut and mortared into place to provide a solid backing for the door jamb. Concrete Masonry Veneers. is used at the edge of the cavity to confine the mortar or grout fill to the hollow metal jamb.org To order a complete TEK Manual or TEK Index. Anchor. horizontal joint reinforcement to take tension due to concrete masonry shrinkage and help keep any cracks that occur closed. These include movement joints (control joints in concrete masonry and expansion joints in clay masonry). Horizontal joint reinforcement is placed in the mortar joints above and below the band to take stress from the differential movement in that plane. Similarly. and sometimes horizontal joints to allow longitudinal movement. Conversely. they occur in the mortar joint rather than through the unit. clay masonry walls incorporate vertical and horizontal expansion joints to allow the clay to expand without distress. Concrete Masonry Band in Clay Brick Wall Figure 1a shows a two-course high concrete masonry band in a clay brick exterior wythe of a cavity wall. For bands higher than two courses. In veneers. In veneers. which hardens the concrete. architectural details. With this type of construction. clay brick. Therefore. control joints. because it tends to be more flexible than other mortar Types. Type N mortar is often specified for veneers. In general. wall ties INTRODUCTION BANDING DETAILS Masonry is often specified because of its aesthetic versatility. For example. In addition. or concrete masonry is used in clay brick walls as accent bands. several strategies are used to accommodate movement. joint reinforcement. the joint reinforcement and ties should be placed in alternate joints so that one does not interfere with TEK 5-2A © 2002 National Concrete Masonry Association (replaces TEK 5-2) 128 . (305 mm) of the top and bottom of the band to help ensure the surrounding masonry is adequately supported. However. it is particularly important that the band. the following practices are employed to minimize the potential for cracking. (406 mm) on center vertically. all masonry walls should be designed and detailed to accommodate anticipated movement resulting from volume changes in the masonry materials themselves. as any water that penetrates the veneer through cracks between the two materials drains down the cavity and is directed out of the wall via flashing and weep holes. Wall ties should be installed within 12 in. Often. the design goal is to allow the movement to occur (as restraint will cause cracking) while providing appropriate support. vertical control joints and horizontal joint reinforcement can be incorporated into concrete masonry walls to control cracking and still allow horizontal shrinkage of the concrete masonry units to occur without introducing undue stress into the wall. Combining masonry units of different size. combining these two materials within one wythe of masonry requires special detailing due to their different material properties.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CLAY AND CONCRETE MASONRY BANDING DETAILS TEK 5-2A Details (2002) Keywords: architectural bands. joint reinforcement should also be placed within the band itself at a spacing of 16 in. cracking can result. Ideally. When detailing a wall to accommodate movement. exterior concrete masonry walls incorporate clay brick. Without due consideration of these opposing movements. using a lower compressive strength mortar helps ensure that if cracks do occur. Concrete masonry is a hydraulic cement product and as such requires water for cement hydration. the cracking is primarily an aesthetic issue. The bands add architectural interest to the wall and can also help hide horizontal elements such as flashing and expansion joints. clay masonry units are very dry subsequent to firing during the manufacturing process and then tend to expand as they pick up moisture from the atmosphere and from mortar as they are laid. banding. When both clay and concrete masonry units are used in the same masonry wythe. veneer. These can be adjusted as needed to suit local conditions and/or experience. crack control. detailing is required to accommodate concrete masonry shrinkage and clay masonry expansion occurring side by side. In general. as well as the wall panel above and below the band be supported by wall ties. The recommendations that follow are based on a record of successful performance in many locations across the United States. concrete masonry units are relatively wet at the time of manufacture and from that time on tend to shrink as the units dry. color and finish provides a virtually limitless palette. within Figure 1b shows a slip plane incor12 in. (51 mm) which detail has been more successful in preferred a given location. In this case.9 m). It is expansion joint spacing does exceed 20 ft (6. Joint reinforcement. Note that local experience may require reducing the When concrete masonry banding is used over a wood expansion joint spacing to 16 ft (4. per rial in the horizontal bed joints above and 12 in. control Bands only one course high must be detailed to incorjoints should not be used in the concrete masonry band at the porate joint reinforcement and wall ties in the joints above expansion joint locations. (305 mm) local practice below the band. a tie Adjustable ladder Clay brick which accommodates both tie and wire wall tie (hot dipped galvanized) @ 16 in. tom of the band should be raked back and preferred sealed with an appropriate sealant to prevent water penetration at these joints. requires control joints rather than expansion joints. (305 mm) porated into the interfaces between the of band concrete and clay masonry to allow unrestrained longitudinal movement be1a—with joint reinforcement at top and bottom of band tween the two materials. and below the band (see Figure 2). If brick vertical stud backup. Some designers. 129 . Wall tie.1 m). consider imperative that joint reinforcement be used in the concrete placing an additional vertical movement joint through the masonry band. joint required Joint reinforcement reinforcement should be incorporated into the concrete masonry band. per 12 in.7 (9 gage) demonstrated good performance in (MW 11) at Closed cell rigid many areas of the United States. 1 in. (406 mm) insulation. similar provisions apply (see Figure 3). accent band (25 mm). so that any water draining down the Sealant and building cores of the band can be directed out of Closed cell rigid paper or other the wall at that point. Note that this construction is typically Wall tie. particularly if the aspect ratio of the band is high. The continuous should extend through the concrete masonry band as well. Although concrete masonry construction typically masonry shrinks. in the same mortar joint should be used. flashing or a similar mateWall tie.placement of the other. even if it is not used in the surrounding clay concrete masonry accent band near mid-panel with joint brick masonry. min. 1 in. Experience has shown that vertical expansion joints in the clay masonry reinforcement continuous through that joint. within however. within Vapor retarder. as bond break material When slip planes are used. In addition to joint reinforcement. prefer placing joint reinforceVapor retarder. The Air space. and joint reinforcement in this location helps keep the clay brick be placed at a maximum of 20 ft (6. Concrete masonry exposed mortar joint at the top and bot(25 mm). polyethylene. min. contacted for further information on 2 in. (51 mm). there 16 in. (305 mm) more expensive than the detail shown in of band Figure 1a. 1b—with slip planes at top and bottom of band reduced spacing of expansion joints in the wall is recommended to reduce the Figure 1—Multi-Course Concrete Masonry Band in Clay Brick Veneer potential for cracking. accent band 2 in.c. Although the detail in Figure 1a has W1. (305 mm) ment in every bed joint in the concrete local practice of band masonry band. insulation. within 12 in.1 m) along the length of above and below the band from cracking as the concrete the wall.. vertical such as a seismic clip type wall tie. When hollow masonry of band units are used for the band. (406 mm) o. This can be accomplished by placing building paper. Wall tie. the slip plane Seismic clip-type Clay brick below the band should incorporate flashwall tie ing. as are locations where use of bond breaks o.. or equivalent required at the top and bottom of the band is preferred (see Figure 1b) A local maConcrete masonry sonry industry representative should be Air space.c. vertical at 16 in. a full size unit is cut to fit to allow adequate space for the reinforcement and grout.7 (9 gage) (MW 11) at 16 in. (406 mm) o. W1.. On the wall interior. (305 mm) of band Vapor retarder. per local practice Closed cell rigid insulation Air space. W1. min. (305 mm) of band Building paper. (25 mm). 1 in. as required Air space. veneers are laterally supported by the backup and do not require a shear key. (51 mm).c. flashing and weeps are also used. (406 mm) o.. within 12 in. 6 in.. within 12 in. within 12 in. min. as they provide an adjustable wall tie and joint reinforcement in one assembly. 2 in. (406 mm) o. or equivalent Concrete masonry accent band Wall tie.c. as required Air space. Vapor retarder. except it may contain a raked out mortar joint) Figure 4—Multi-Course Clay Brick Band in Concrete Masonry Veneer 130 . (406 mm) o. (25 mm) min. as required Closed cell rigid insulation. 2 in. within 12 in. flashing and weep holes are used above the accent band to facilitate removal of any water that may accumulate in the wall.7 (9 gage) (MW 11) at 16 in. min. or equivalent Clay brick accent band Wall tie. (152 mm) min. per local practice Seismic clip-type wall tie Clay brick of band Concrete masonry accent band Joint reinforcement. reducing the movement joint's effectiveness. (406 mm) o. (305 mm) of band Concrete masonry Joint reinforcement. 1 in. (51 mm). 2 in. 1 in. preferred Clay Brick Band in Concrete Masonry Wall The recommendations to control differential movement for clay brick masonry bands in concrete masonry are very similar to those for a concrete masonry band in clay brick veneer: joint reinforcement above and below the band and wall ties within the band. Seismic clip-type wall ties are recommended.c. (305 mm) of band Closed cell rigid insulation. lap Air space. per local practice Adjustable ladder wall tie (hot dipped galvanized) @ 16 in..c. W1. (305 mm) of band Vapor retarder. (51 mm). 1 in. Mortar in this joint will restrict brick expansion. rather than using reduced thickness units. The use of two reduced thickness concrete masonry units allows flashing to be placed within the wall without causing a complete horizontal bond break at the flashing. With this construction.7 (9 gage) (MW 11) at 16 in.Wall tie. (25 mm). within 12 in. In reinforced walls (Figure 5b). (305 mm) Vapor retarder. or one with equivalent pull-out strength Figure 3—Concrete Masonry Band in Clay Brick Veneer Over Wood Stud Backup Wall tie. In single wythe construction as shown in Figure 5. (25 mm).c. it is imperative that the veneer control joint not contain mortar as it goes through the clay brick band (see Figure 4). per local practice Clay brick Interior finish Sheathing Joint reinforcement. Corrosion resistant 8d common nail. within 12 in. or equivalent Wall tie. Note that although control joints in structural masonry walls must permit free longitudinal movement while resisting lateral or out-ofplane shear loads. preferred Figure 2—Single-Course Concrete Masonry Band in Clay Brick Veneer Wall tie. preferred Expansion joint Adjustable tie Sealant and No mortar backer rod in joint Expansion Joint Plan View for Clay Brick (Control joint in concrete masonry is similar. as required 4 in. Concrete masonry unit. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. (102 mm) thick concrete masonry unit Flashing and weeps at 32 in. (102 mm) thick concrete masonry unit 4 in. (813 mm) o. nominal thickness = wall thickness . Virginia 20171 www. between grouted cells Joint reinforcement Clay brick accent band Concrete masonry unit with one faceshell and part of webs cut off to fit Joint reinforcement Clay brick accent band (a) unreinforced wall (b) reinforced wall Figure 5—Multi-Course Clay Brick Band in Loadbearing Concrete Masonry Wall Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. max.4 in. max.c. Herndon.. (813 mm).org To order a complete TEK Manual or TEK Index. contact NCMA Publications (703) 713-1900 131 .Cavity filter or other mortar collection device Vertical reinforcement.. (102 mm) Flashing and weeps at 32 in.ncma. using a lower compressive strength mortar helps ensure that if cracks do occur. banding. However. Without due consideration of these opposing movements. as any water that penetrates the veneer through cracks between the two materials drains down the cavity and is directed out of the wall via flashing and weep holes. color and finish provides a virtually limitless palette. or concrete masonry is used in clay brick walls as accent bands. control joints. wall ties INTRODUCTION BANDING DETAILS Masonry is often specified because of its aesthetic versatility. exterior concrete masonry walls incorporate clay brick. codes and standards Keywords: architectural bands. Conversely. the cracking is primarily an aesthetic issue. it is particularly important that the band. clay masonry units are very dry subsequent to firing during the manufacturing process and then tend to expand as they pick up moisture from the atmosphere and from mortar as they are laid. These can be adjusted as needed to suit local conditions and/or experience. the design goal is to allow the movement to occur (as restraint will cause cracking) while providing appropriate support. and sometimes horizontal joints to allow longitudinal movement. because it tends to be more flexible than other mortar Types. With this type of construction. cracking can result. Horizontal joint reinforcement is placed in the mortar joints above and below the band to take stress from the differential movement in that plane. Therefore. clay brick. vertical control joints and horizontal joint reinforcement can be incorporated into concrete masonry walls to control cracking and still allow horizontal shrinkage of the concrete masonry units to occur without introducing undue stress into the wall. In general.) on center vertically. In veneers. several strategies are used to accommodate movement. all masonry walls should be designed and detailed to accommodate anticipated movement resulting from volume changes in the masonry materials themselves. Concrete masonry is a hydraulic cement product and as such requires water for cement hydration.) of the top and bottom of the band to help ensure the surrounding masonry is adequately supported. crack control. In general. joint reinforcement should also be placed within the band itself at a spacing of 400 mm (16 in. The recommendations that follow are based on a record of successful performance in many locations across the United States and typical Canadian conditions. In veneers. architectural details. as well as the wall panel above and below the band be supported by wall ties. they occur in the mortar joint rather than through the unit. Type N mortar is often specified for veneers. detailing is required to accommodate concrete masonry shrinkage and clay masonry expansion occurring side by side. When both clay and concrete masonry units are used in the same masonry wythe. Often. horizontal joint reinforcement to take tension due to concrete masonry shrinkage and help keep any cracks that occur closed. When detailing a wall to accommodate movement. These include movement joints (control joints in concrete masonry and expansion joints in clay masonry). Concrete Masonry Band in Clay Brick Wall Figure 1a shows a two-course high concrete masonry band in a clay brick exterior wythe of a cavity wall. the following practices are employed to minimize the potential for cracking. joint reinforcement. Similarly. concrete masonry units are relatively wet at the time of manufacture and from that time on tend to shrink as the units dry. which hardens the concrete. For example. combining these two materials within one wythe of masonry requires special detailing due to their different material properties. For bands higher than two courses. veneer. the joint reinforcement and ties should be placed in alternate joints so that one does not 132 CAN/TEK 5-2A © 2003 National Concrete Masonry Association . Combining masonry units of different size. clay masonry walls incorporate vertical and horizontal expansion joints to allow the clay to expand without distress. Ideally. Wall ties should be installed within 300 mm (12 in. In addition.NCMA TEK National Concrete Masonry Association an information series from the authority on concrete masonry technology CLAY AND CONCRETE MASONRY BANDING DETAILS CAN/TEK 5-2A Details (2003) Addresses Canadian construction practices. The bands add architectural interest to the wall and can also help hide horizontal elements such as flashing and expansion joints. polyethylene.). Although concrete masonry construction typiconcrete masonry shrinks.) o. within Figure 1b shows a slip plane incorpo300 mm (12 in. particularly if the aspect ratio of the Clay brick band is high. Wall tie. consider imperative that joint reinforcement be used in the concrete placing an additional vertical movement joint through the masonry band. (typical) joint in the concrete masonry band. galvanized @ 400 W1. as a seismic clip type wall tie.) rated into the interfaces between the conof band crete and clay masonry to allow unrestrained longitudinal movement between 1a—with joint reinforcement at top and bottom of band the two materials.7 (9 gage) Although the detail in Figure 1a has mm (16 in. Note that local experience may require reducing the When concrete masonry banding is used over a wood expansion joint spacing to 4. In addition to joint reinforcement. per the horizontal bed joints above and below 300 mm (12 in. cessful in a given location. prefer placlocal practice 300 mm (12 in.c. within Some designers. such wall tie (hot dipped Joint reinforcement. joint Joint reinforcement Closed cell rigid reinforcement should be incorporated insulation as into the concrete masonry band. 25 mm sealed with an appropriate sealant to (1 in.interfere with placement of the other.1 m (20 ft). If brick vertical stud backup. below the band (see Figure 2). When hollow masonry units are Air barrier.) more expensive than the detail shown in of band Figure 1a. 1b—with slip planes at top and bottom of band reduced spacing of expansion joints in the wall is recommended to reduce the Figure 1—Multi-Course Concrete Masonry Band in Clay Brick Veneer potential for cracking. Experience has shown that vertical expansion joints in the clay masonry reinforcement continuous through that joint.) ing joint reinforcement in every bed of band Air barrier. Bands only one course high must be detailed to incorpocontrol joints should not be used in the concrete masonry rate joint reinforcement and wall ties in the joints above and band at the expansion joint locations. Vapor barrier. even if it is not used in the surrounding clay concrete masonry accent band near mid-panel with joint brick masonry.c. there are locations where use o. so that any water draining down the cores of the Sealant and building Seismic clip-type band can be directed out of the wall at that paper or other bond wall tie point.) local practice of band the band. In this case. min. min. however.) many areas. Wall tie. 25 mm tion on which detail has been more suc(1 in. The required Concrete masonry exposed mortar joint at the top and botaccent band tom of the band should be raked back and Air space. 133 . the slip plane below the Clay brick (typical) band should incorporate flashing. within Vapor barrier.9 m (16 ft). within Note that this construction is typically 300 mm (12 in. prevent water penetration at these joints.1 m (20 ft) along the length brick above and below the band from cracking as the of the wall. The continushould extend through the concrete masonry band as well. or equivalent Closed cell rigid of bond breaks at the top and bottom of insulation as the band is preferred (see Figure 1b) A required Concrete masonry local masonry industry representative accent band should be contacted for further informaAir space. per Wall tie. (MW 11) at vertical demonstrated good performance in 400 mm (16 in. flashing or a similar material in Wall tie. This can be accomplished by placing building paper. cally requires control joints rather than expansion joints. break material When slip planes are used. a tie which accommodates both tie and wire in the Adjustable ladder same mortar joint should be used. It is expansion joint spacing does exceed 6. ous joint reinforcement in this location helps keep the clay and be placed at a maximum of 6. similar provisions apply (see Figure 3). used for the band.). lap Air space. W1. W1. within 300 mm (12 in.7 (9 gage) (MW 11) at 400 mm (16 in.). 25 mm (1 in.) o. 25 mm (1 in. Vapor barrier. min. In reinforced walls (Figure 5b).c.) min. On the wall interior. within 300 mm (12 in. With this construction. per local practice Wall tie.) of band Interior finish Clay brick Sheathing Joint reinforcement.7 (9 gage) MW 11) at 400 mm (16 in. or equivalent Seismic clip-type wall tie Closed cell rigid insulation as required Air space. 150 mm (6 in.) o. within 300 mm (12 in.) of band Air space. rather than using reduced thickness units. Seismic clip-type wall ties are recommended.) of band Vapor barrier.).vertical at 400 mm (16 in. flashing and weep holes are used above the accent band to facilitate removal of any water that may accumulate in the wall.) of band Corrosion resistant 8d common nail.).c. Vapor barrier. per local practice Air barrier. min. it is imperative that the veneer control joint not contain mortar as it goes through the clay brick band (see Figure 4).) of band Figure 2—Single-Course Concrete Masonry Band in Clay Brick Veneer Sealed air/vapor barrier. flashing and weeps are also used. (typical) Closed cell rigid insulation Air space. The use of two reduced thickness concrete masonry units allows flashing to be placed within the wall without causing a complete horizontal bond break at the flashing. Concrete masonry accent band Wall tie. (typical) Clay brick Concrete masonry accent band Joint reinforcement.) o. or one with equivalent pull-out strength Figure 3—Concrete Masonry Band in Clay Brick Veneer Over Wood Stud Backup Wall tie. 25 mm (1 in..) o. reducing the movement joint's effectiveness. within 300 mm (12in.c. a full size unit is cut to fit to allow adequate space for the reinforcement and grout. Note that although control joints in structural masonry walls must permit free longitudinal movement while resisting lateral or out-ofplane shear loads. 25 mm (1 in. min. within 300 mm (12 in. min. per local practice Air barrier.7 (9 gage) (MW 11) at 400 mm (16 in. W1.) o.c. veneers are laterally supported by the backup and do not require a shear key. Wall tie.c. within 300 mm (12 in. or equivalent Adjustable ladder wall tie (hot dipped galvanized @ 400 mm (16 in.) of band Concrete masonry Clay Brick Band in Concrete Masonry Wall The recommendations to control differential movement for clay brick masonry bands in concrete masonry are very similar to those for a concrete masonry band in clay brick veneer: joint reinforcement above and below the band and wall ties within the band. as required Clay brick accent band Closed cell rigid insulation as required Wall tie. or equivalent Building paper. per local practice Air barrier. as they provide an adjustable wall tie and joint reinforcement in one assembly. Expansion joint Adjustable tie Sealant and No mortar in joint backer rod Expansion Joint Plan View for Clay Brick (Control joint in concrete masonry is similar. (typical) Joint reinforcement. Mortar in this joint will restrict brick expansion. except it may contain a raked out mortar joint) Figure 4—Multi-Course Clay Brick Band in Concrete Masonry Veneer 134 .Wall tie.). In single wythe construction as shown in Figure 5. L0G 1A0 (705) 458-9630. nominal thickness = wall thickness . Masonry Canada. Virginia 20171 www.) o.c. Joint reinforcement Vertical reinforcement. Beeton. as required 100 mm (4 in.100 mm (4in.ca For additional copies of CAN/TEK contact MC or NCMA at (705) 458-9630 or (703) 713-1900.) thick concrete masonry unit Flashing and weeps at 800 mm (32 in.org To order a complete TEK Manual or TEK Index. max. Ontario. between grouted cells Clay brick accent band Joint reinforcement Clay brick accent band (a) unreinforced wall (b) reinforced wall Figure 5—Multi-Course Clay Brick Band in Loadbearing Concrete Masonry Wall ACKNOWLEDGMENT: The following assisted in the development of NCMA CAN/TEK for consistency with the National Building Code of Canada. 135 contact NCMA Publications (703) 713-1900 .. Canada.) max. 4628 10th Line.Cavity filter or other mortar collection device Concrete masonry unit.masonrycanada.) 100 mm (4in. www.ncma. respectively Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive.) thick concrete masonry unit Concrete masonry unit with one faceshell and part of webs cut off to fit Flashing and weeps at 800 mm (32 in. RR 2. Herndon.. Footings should be placed on undisturbed native soil. Undisturbed Footings Footings lie under the basement. The modular nature of concrete. Footings are typically cast-in-place concrete. reinforced concrete masonry. as required Figure 1—Plain Basement Wall 136 TEK 5-3A © 2003 National Concrete Masonry Association (replaces TEK 5-3) . including full basement walls. pressure treated or use moisture barrier sect resistant foundation for all Sealant building types. construction debris and ice concrete masonry allows floor plan and wall height changes Building paper to be easily accommodated as Sheathing well. stem walls and piers. weak or soft. Concrete Masonry Waterproof or dampproof Basement Wall Construction. gravel or and resistance to fire. crawlspace or stem wall and transfer structural loads from the building to the supporting soil. crawlspace wall. energy efficient and inSill. 3. with Mesh or other accompanying text as approgrout stop device priate. basement wall. 2. plain concrete masonry. Similarly.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY FOUNDATION WALL DETAILS TEK 5-3A Details (2003) Keywords: architectural details. respectively). should be removed and replaced with compacted soil. as Concrete Masonry Walls and required Free draining NCMA's Basement Manual for 1 2 in. (13 mm) isolation backfill more detailed design and conjoint Concrete slab struction information (refs. pier. Concrete masonry can be Flashing Floor sheathing used to provide a strong. the soil grade applications. The reader is referred to TEK 3-11. because of its strength. tree roots. residential details. Preventing Water Horizontal joint Backfill Penetration in Below-Grade reinforcement. insects and noise. Anchor bolt Fill all voids This TEK contains details Concrete under flashing masonry wall for various types of concrete with mortar Grade masonry foundation walls. placed beneath the frost depth to prevent damage re- Vapor retarder soil Aggregate base Optional foundation drain Foundation drain Full bed joint Concrete footing Optional footing drain Reinforcement. In this case. Concrete masonry is well suited for below unless this soil is unsuitable. 4. economy. foundation wall. tion wall types. Insulation membrane Concrete masony wall TEK 19-3A. crawlspace walls. duDrip edge rable. stemwall INTRODUCTION Concrete masonry is used to construct various foundasulting from heaving caused by freezing of water in the soil. durability. Several alternate crawlspace constructions are shown in Figures 3 and 4. (51 mm) PVC pipe at 8 ft (2400 mm) on center. footings should be carefully aligned so that the concrete masonry wall will be near the center line of the footing. ACI 318 (ref. the hazard of termite damage is high. Because of this. BASEMENT WALLS Basements are typically built as conditioned space so that they can be used for storage. such as bulldozers or cranes. water penetration resistance is of paramount importance to basement wall design and construction. Following recommended backfill procedures will help prevent basement wall cracking during this operation. as required Grout Backfill Concrete masonry wall Waterproof or dampproof membrane Vertical reinforcement. heavy equipment. Anchor bolt Note that local codes may reReinforced bond strict the use of foam plastic insubeam lation below grade in areas where Vertical reinforcement. (102 to 203 mm) of backfill should be low permeability soil so rain water absorption into the backfill is minimized. Walls should always be properly braced to resist backfill soil loads or have the first floor diaphragm in place prior to backfilling. crawlspaces are typically designed as unconditioned spaces. directly on top of the footing. Footing drains can either be cast into the footing or constructed using plastic pipes through the bottom of the first course of masonry. as required Isolation joint Concrete slab Vapor retarder Optional foundation drain Foundation drain Free draining backfill Undisturbed soil Concrete footing Reinforcement. In most cases. allows water on the interior to reach the foundation drain. vertical reinforcement is positioned towards the interior face of below grade walls to provide the greatest resistance to soil pressures. The optional footing drain shown. 9).should be removed prior to placing footings. should not be operated over Flashing Drip edge Sealant Fill all voids under flashing with mortar Grade the backfill during construction unless the basement walls are appropriately designed for the higher resulting loads. Unless otherwise required. Sill. The foundation drain shown in Figures 1 and 2 can also be located on the interior side of the footing. 5). If warranted. a wall designed to be supported at the top may crack or even fail from overstressing the wall. For reinforced construction (Figure 2). Control joints are not typically used in foundation walls due to concerns with waterproofing the joint and the fact that shrinkage is less significant in below grade walls due to relatively constant temperature and moisture conditions. Otherwise. or on both sides if necessary. Although the top surface of poured concrete footings should be relatively level. ACI 117 (ref. The top 4 to 8 in. Although most building codes require operable louvered vents near each corner of a crawl space to reduce moisture buildup. research has shown that the use of a moisture retardant ground cover eliminates the need for vents in many locations (ref. work or living space. Where only Floor sheathing the top course is to be grouted. Concrete footing design is governed by Building Code Requirements for Structural Concrete. 6). horizontal joint reinforcement can be installed as a crack control measure. the 137 . as required Horizontal joint reinforcement. Similarly. such as 2 in. and concrete foundations are constructed with tolerances conforming to the requirements of Standard Specifications for Tolerances for Concrete Construction and Materials. The drain should be placed below the top of the footing. Finished grade should be sloped away from the building. it should generally not be troweled smooth. as required Figure 2—Reinforced Basement Wall Optional footing drain STEMWALLS FOR CRAWLSPACES Unlike basements. pressure treated or wire mesh or another equivalent use moisture barrier grout stop material can be used to contain the grout to the top course. either vented or unvented. as a slightly roughened surface enhances the bond between the mortar and concrete. reinforcing bars must be properly located to be fully functional. A solid top course on the below grade concrete masonry wall Building paper spreads loads from the building Sheathing above and also improves soil gas and termite resistance. If the crawlspace is vented. A dampproof coating on the exterior crawlspace wall will also help prevent water entry into the crawlspace. (203 mm). PVC or equivalent) is good practice to minimize water migration and soil gas infiltration.15 mm) polyethylene. A 1 in. as required Horizontal joint reinforcement. where applicable. Building Code Requirements for Masonry Structures (ref. as required Grade Bottom of footing minimum 12 in. Stemwalls are typically insulated on the exterior of the masonry. pressure treated or use moisture barrier Finish varies Floor joist Concrete masonry wall Reinforced bond beam. Because the wall is exposed to soil on both sides. 8) allows foundation piers to have a nominal height up to ten times the nominal thickness if the pier is solidly grouted. or four times the nominal thickness if it is not solidly grouted. STEMWALLS FOR SLAB ON GRADE A stemwall with slab on gradesupports the wall above and often also provides a brick ledge to support an exterior masonry veneer. either the walls or the floor above can be insulated. A vapor retarder (typically 6-mil (0. as required Figure 3—Crawlspace Stemwall with Masonry Above Grade floor. FOUNDATION PIERS Foundation piers (see Figure 7) are isolated structural elements used to support the building above. A thicker concrete slab may be desirable. particularly if the crawlspace will be used for storage. (25 mm) air space is considered appropriate if special precautions are taken to keep the air space clean (such as by beveling the mortar bed away from the cavity or by drawing a piece of wood up the cavity to collect mortar droppings). Otherwise. 138 . A 2 1/2 in. respectively. as required Continuous band joist or blocking. Structural design ensures the piers are sized and spaced to carry the necessary building loads. Unvented crawlspaces must have a floor covering to minimize moisture and. with a nominal height not exceeding four times its nominal thickness and a nominal length not exceeding three times its nominal thickness. note that masonry design codes typically require a minimum 1 in. soil gas entry. (ref. If unvented. exposed pipes and ducts are typically insulated. a 2 in. waterproofing or dampproofing coatings are generally not required. (25 mm) clear air space between the masonry and backup to ensure an open drainage cavity. Figures 5 and 6 show concrete masonry stemwalls with masonry and with frame above grade walls. it is important to place insulation in the joint between the slab edge and the foundation wall to avoid thermal bridging. Piers typically are in enclosed crawlspaces. For this case. (305 mm) below grade or below frost line. so recommendations for moisture and soil gas resistance for crawlspaces should be followed for piers as well. If insulated on the interior. Note that the International Building Code. pressure treated or use moisture barrier Termite shield required when no bond beam is provided below sill Anchor bolt Concrete masonry stem wall Install drain for water removal if not higher than adjacent exterior grade for majority of perimeter Vapor retarder Concrete footing Bottom of footing Reinforcement. A stemwall with brick ledge is shown in Figure 6. (64 mm) concrete mud slab is generally used when a more durable surface is desired for access to utilities.Vertical reinforcement. (51 mm) air space is preferred. whichever is greater Floor sheathing Sill. 7) requires a foundation pier to have a minimum nominal thickness of 8 in. as required Anchor bolt Mesh or other grout stop device Grade Isolation joint 18 in. adhered to sheathing Weeps at 32 in. whichever is greater Bottom of footing Reinforcement. pressure treated or use moisture barrier 1 in. Fill solid below flashing Termite shield. (25 mm) is maximum when corrugated ties are used) Joist Continuous band joist or blocking Building paper Anchor bolt Flashing. as required Concrete footing Finish varies Exterior sheathing and finish Stud Floor sheathing Joist Sill. pressure treated or use moisture barrier Termite shield. (813 mm) o. (305 mm) below grade or below frost line. (25 mm) air space. 2 1 2 in. (305 mm) below grade or below frost line. as required 18 in. (64 mm) concrete mud slab Install drain for water removal if not higher than adjacent exterior grade Optional foundation drain Vapor retarder Concrete footing Waterproof or dampproof membrane Bottom of footing minimum 12 in. Drain to daylight or install drain for water removal when below exterior grade Grade Concrete masonry Vapor retarder Bottom of footing minimum 12 in.c. as required Figure 4—Crawlspace Stemwalls with Wood Frame Above Grade 139 . min.Stud Water resistant sheathing Finish varies Brick veneer Wall tie Floor sheathing Continuous plate Sill. for drainage (note: 1 in. (457 mm) min. (457 mm) min. whichever is greater Bottom of footing Reinforcement. as required Figure 5—Slab on Grade Stemwalls with Masonry Above Grade Building paper Flashing Concrete slab on vapor retarder on 4 in. (note: 1 in. as required 6 in. for drainage. whichever is greater Vapor retarder Concrete footing Reinforcement. (305 mm) below grade or below frost line. (305 mm) below grade or below frost line. min. (152 mm) concrete masonry Concrete footing Sheathing 1 in. (813 mm) o. as required in concrete slab Vapor retarder Concrete footing Reinforcement.c. 10 in. pressure treated or use moisture barrier Anchor bolt Flashing (top adhered to backup) Weeps at 32 in. whichever is greater Figure 6—Slab on Grade Stemwall with Wood Frame Above Grade 140 .Concrete masonry wall Concrete masonry wall Concrete masonry header unit Isolation joint Concrete slab on grade with WWF Concrete slab on grade with WWF Control joint. (25 mm) air space. (25 mm) is maximum when corrugated ties are used) Wall ties Drip edge Sealant Sill. (254 mm) solid concrete masonry top course. as required Bottom of footing minumum 12 in. or grouted Bottom of footing minimum 12 in. (102 mm) gravel Perimeter insulation. Concrete Masonry Basement Wall Construction. ACI 117-90. Fundamentals. TR 90A. 2001. Bottom of footing 12 in. 7. 2001. 2000. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 5. ACI 318 -02. National Concrete Masonry Association. ACI 530-02/ASCE 5-02/TMS 402-02. (305 mm) below grade or below frost line. Design and Construction Using Concrete Masonry. Virginia 20171 www. 18 in. Reported by the Masonry Standards Joint Committee. American Society of Heating. 141 contact NCMA Publications (703) 713-1900 . Building Code Requirements for Masonry Structures. International Building Code. TEK 19-3A. Inc. 2001. Preventing Water Penetration in Below-Grade Concrete Masonry Walls. American Concrete Institute. National Concrete Masonry Association. 8. 3. pressure treated or use moisture barrier 8 in. National Concrete Masonry Association. Standard Specifications for Tolerances for Concrete Construction and Materials. Building Code Requirements for Structural Concrete..ncma. National Concrete Masonry Association. 2002. American Concrete Institute. whichever is greater Figure 7—Concrete Masonry Foundation Pier REFERENCES 1.Sill plate Finish varies Strap anchor nailed to girder and embedded in masonry Sheathing Joist hanger Joist Girder Grout at strap anchor locations Sill. 4. Basement Manual. Herndon. min. (457 mm) min. 1990.org To order a complete TEK Manual or TEK Index. TR 149. Annotated Design and Construction Details for Concrete Masonry. TEK 3-11. 2001 ASHRAE Handbook. International Code Council. 2. 2002. Refrigerating and Air-Conditioning Engineers. 9. (203 mm) nominal. 2001. 2002. 6. Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY RESIDENTIAL DETAILS TEK 5-4B Details (2002) Keywords: architectural details. termite resistance. A wide range of architectural styles can be created using both architectural concrete masonry units and conventional units. Architectural units are available with many finishes. as required WALLTYPES Figures 1 through 3 illustrate a few of the construction options available for concrete masonry home construction. design versatility. roof/wall connections. as required Drainage layer Vertical reinforcement as required Concrete masonry wall Stucco Isolation joint Concrete slab Moisture barrier Flashing with drip edge Positive slope Vapor retarder Perimeter insulation. Masonry housing provides a high standard of structural strength. energy conservation. stucco or any number of other finish systems if desired. Insulation. water penetration resistance INTRODUCTION Concrete masonry homes reflect the beauty and durability of concrete masonry materials. ranging from the rough-hewn look of split-face to the polished appearance of groundface units. energy efficiency. Both top plate/anchor bolt and Concrete masonry foundation Concrete footing Reinforcement. It has a high sound dampening ability. is energy efficient. and can be produced in many colors and a variety of sizes. as required Figure 1—Stucco Exterior Finish 142 TEK 5-4B © 2002 National Concrete Masonry Association (replaces TEK 5-4A) . durable and can easily be designed to resist hurricaneforce winds and earthquakes. Concrete masonry can also be finished with brick. some of which are described in more detail below. residential. as required Flashing with drip edge Insulation Horizontal joint reinforcement. fire and insect proof. as required Roof deck + + + + o o Exterior grade sheathing (vent as required) Moisture barrier Embedded strap anchor (alternate: anchor bolt and top plate) Bond beam Standard window system Sill Finish varies Concrete masonry lintel See TEK 19-5A for flashing details Solid unit to support flashing Wood backing. Concrete masonry's mass provides many consumer benefits. economy and aesthetic appeal. as required Backfill Grout. as required Figure 2—Exposed Concrete Masonry Exterior 143 .. (813 mm) o. pressure treated or use moisture barrier Bond beam Anchor bolt Grade Horizontal joint reinforcement. max. as required Solid unit to support flashing See TEK 19-5A for flashing details Flashing with drip edge Solid or filled unit to support flashing 1 in. as required Concrete masonry wall Waterproof or dampproof membrane Isolation joint Foundation drain Concrete slab Vapor retarder Free draining backfill Optional foundation drain Undisturbed soil Optional footing drain Concrete footing Reinforcement. pressure treated or use moisture barrier (alternate: embedded strap anchor) Finish varies Concrete masonry lintel Soffit Wood backing. as required Sill Vapor retarder. between grouted cores Sheathing Wood joist See TEK 19-2A for flashing details Joist hanger Flashing with drip edge Ledger. as required Standard window system Furring and insulation.c.Roof system Roof insulation Top plate. as required Insulation. (25 mm) partially open head joints for weeps at 32 in. as required Vertical reinforcement. Roof system Roof insulation Top plate. (305 mm) concrete masonry wall Sill. as required Vertical reinforcement. as required Standard window system Furring and insulation. as required Horizontal joint reinforcement. as required Concrete masonry wall Subfloor Siding Positive slope Floor joist Anchor bolt Bond beam 12 in. as required Figure 3—Wood or Vinyl Siding Exterior Finish 144 . pressure treated or use moisture barrier Install drain for water Vapor retarder removal if not higher than adjacent exterior grade for majority of perimeter Concrete footing Reinforcement. pressure treated or use moisture barrier (alternate: embedded strap anchor) Finish varies Soffit Concrete masonry lintel Wood backing. as required Vapor retarder. They supply all of the attributes of concrete masonry construction with the thinnest possible wall section. Figure 2 shows a residential wall section with exposed concrete masonry on the exterior and a furred-out and insulated interior. Concrete Masonry Cavity Wall Details. 2001. National Concrete Masonry Association. National Concrete Masonry Association. integral insulation (placed in the masonry cores) can be used as required. A full discussion of options for energy efficient concrete masonry walls is contained in Insulating Concrete Masonry Walls (ref.embedded strap anchor roof connections are shown and can be used interchangeably. Design for Dry Single-Wythe Concrete Masonry Walls. National Concrete Masonry Association. Note that local codes may restrict the use of foam plastic insulation below grade in areas where the hazard of termite damage is high. TEK 6-11. TEK 19-2A. 2002. Figure 3 shows exterior siding with insulation installed between furring. See also TEK 5-7A Floor and Roof Connections to Concrete Masonry Walls and TEK 5-3A Concrete Masonry Foundation Wall Details (refs. 5. Design for water resistance is discussed in detail in References 4 through 6. including a water drainage plane and stucco. 3. Single wythe walls offer the economy of providing structure and an architectural facade in a single building element. is typically attached using exterior wood furring strips which have been nailed to the masonry. REFERENCES 1. 7. Stucco can also be applied directly to the exterior block surface and used in conjunction with integral or interior insulation. 8. TEK 5-1A. Herndon. Flashing Details for Concrete Masonry Walls. 3) for additional alternatives. TEK 19-1. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 6. 2. Concrete Masonry Foundation Wall Details. 145 contact NCMA Publications (703) 713-1900 . Virginia 20171 www.ncma. 8). TR 90A. 2000. two areas in particular need careful consideration during design and construction—water penetration resistance and energy efficiency. National Concrete Masonry Association. 2. 2002. The use of exterior finish systems lends itself to exterior insulation. Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. To enhance the performance of this wall system. 2003. TEK 19-5A. Wood or vinyl siding.org To order a complete TEK Manual or TEK Index. 2002. along with several foundation types. as shown. In this case. National Concrete Masonry Association. Water Repellents for Concrete Masonry Walls. Figure 1 shows an exterior insulation system. Cavity wall details are shown in TEK 5-1A Concrete Masonry Cavity Wall Details (ref. 4. National Concrete Masonry Association. Floor and Roof Connections to Concrete Masonry Walls. 7). TEK 5-7A. 1995. Insulating Concrete Masonry Walls. National Concrete Masonry Association. TEK 5-3A. 2001. Annotated Design and Construction Details for Concrete Masonry. Concrete masonry can be exposed on the interior as well. National Concrete Masonry Association. Because of the inherent material differences between steel and masonry. Concrete masonry walls are popular enclosure systems for metal buildings because of masonry's aesthetic appeal.1 of ASCE 7 (ref. A more detailed discussion of the system. In Serviceability Design Considerations for Low-Rise Buildings (ref. construction details. The CMU wall manual is intended to bridge the gap between the Spandrel engineer who designs the metal building system Bracing and the engineer who designs the concrete masonry walls to unify their respective knowledge. and fire resistance. careful consideration must be given to accommodating differential movement between the two materials and their assemblies. lateral loads. is included in Concrete Masonry Walls for Metal Building Systems (ref. exterior partial-height or wainscot walls. These units can be used for the entire facade or for banding courses to achieve specific patterns or highlight certain design aspects of the building. fire resistance. veneer. supported by a steel spandrel at the top and by the foundation at the bottom. such as colored. connectors. The durability of concrete masonry resists incidental impacts from hand carts and forklifts. See Table 12. impact resistance. Ridge Architectural concrete masonry units. lateral support. as well as superior security. 4) for the allowable story drift for seismic loading. open floor spaces. and noise control. provides maximum protection in disasters such as earthquakes and hurricanes. 2). strength. architectural details. wall movement NCMA TEK 5-5B 146 1 . Figures 2 . and interior loadbearing walls or nonloadbearing walls or partitions. deflection. or scored units.An information series from the national authority on concrete INTEGRATING CONCRETE MASONRY WALLS WITH METAL BUILDING SYSTEMS masonry technology TEK 5-5B Details (2011) typical details used for exterior concrete masonry cladding on a metal building. Most reinforced masonry walls for metal buildings are designed to span vertically. These details may need to be modified to meet individual design conditions. Part of their design flexibility comes from the ability to clad metal buildings with a variety of materials to provide different appearances or functions to the buildings. cladding. metal building. drift. shear walls. Roof System can be used to provide an almost limitless array Gutter of textures and patterns to the walls.6 show some Eave strut Rigid frame column Rigid frame an sp ar e l C Ba ys pac ing Sidewall End wall frame End wall column End wall roof beam End wall End wall corner column Figure 1—Schematic of Metal Building Clad with Concrete Masonry Walls Keywords: anchorage. 1). INTRODUCTION Roof purlin Eave height Metal buildings are used extensively for warehouses and other structures requiring large. DETAILS A typical metal building clad with masonry is shown in Figure 1. split faced. burnished. a lateral drift limit of H/100 for a ten year recurrence wind loading based on main wind force resisting system loads is suggested for low rise buildings with exterior masonry walls reinforced vertically. either with or without a parapet.12. Concrete masonry walls used for metal buildings can include: exterior full-height walls. along with structural design and construction considerations. Footing Design aids are included in reinforcement as Concrete Masonry Walls for required by design Metal Building Systems (ref. However. (51 mm). to ensure that the Concrete masonry wall Rigid frame column joint will behave as assumed. However. and consequently. It is recommended that the number of bars extended across the horizontal joint be minimized. wall segment where required by masonry wall sections used design to maintain continuity and as shear wall segments must resist in-plane overturning forces have vertical reinforcement continuous into the foundaColumn footing as tion as shown in Figure 3. Continuous flashing Two such hinge connections with drip are shown in Figures 2 and 3. assemblies. and that the extension be limited to 2 in. Tape bar above flashing the masonry walls that may result "Hairpin" reinforcement to reduce bond to grout from relatively larger steel frame as required by design deflections at the top of the strucMastic seal around reinforcing bar ture.Wall Base Because of stiffness and deforRigid frame column Concrete masonry mation incompatibilities between wall flexible steel and rigid masonry Flashing adhered to Extend foundation dowel 2 in. as required by design Masonry shear walls are very strong and stiff Foundation dowel-extend past and are often used to resist flashing and lap with vertical reinforcement in masonry shear lateral loads. a “hinge” can be incorporated at the base of the masonry assembly to allow out-of-plane rotation. 1) for in-plane and out-ofplane reinforced masonry walls as well as for lintels Figure 3—Vertically Spanning Reinforced Concrete Masonry and anchor bolts. Therefore. every vertical Lap splice per design bar otherwise required for Flashing adhered to strength at critical sections concrete masonry Continuous flashing does not necessarily need to with drip "Hairpin" reinforcement be extended through the joint. The construction shown in Figure 2 Column footing as Concrete column uses through-wall flashing to required by design break the bond at the base of the wall providing a simply supported Wall strip footing condition allowing shear transfer beyond but no moment for out-of-plane Footing loading. In many cases the shear reinforcement as force can be adequately transferred required by design by friction through the flashed bed joint. it is recommended Figure 2—Vertically Spanning Reinforced Concrete Masonry Side Wall at that a positive shear connection be provided by extending foundaFoundation for Other than Shear Wall Segment tion dowels across the joint. Appendix Side Wall Shear Wall Segment Detail at Foundation C also presents design ex2 147 NCMA TEK 5-5B . to concrete masonry (51 mm) into grouted cell of control the location of cracking in wall. required by design Concrete column Flashing is also incorporated Wall strip footing at the floor level to allow beyond the wall some out-of-plane rotation due to building drift. 0 m) high with metal panel walls extending from the top of the masonry to the roof. easy to use Structural Masonry Design System Software (ref.2 to 3. The masonry provides strength and impact resistance for the portion of the wall most susceptible to damage. Spandrels should be placed as high as possible to reduce the masonry span above the spandrel. A vertical isolation joint should be placed near the building corner and proper consideration should be given to the masonry and steel connections at corner columns. (14 mm) diameter holes at 17 in.) Adjustable anchors Figure 5—Adjustable Anchor Connection to Rigid Frame Column and Control Joint Detail 148 3 . Low Side Wall or Eave (see also Figure 6) For walls designed to span vertically. these walls normally span vertically and are laterally supported by a spandrel at the top of the masonry portion of the wall. For larger building manufacturer lateral loads. rigid frame connection plates and diagonal stiffeners may restrict the spandrel location. Spandrel Detail A typical spandrel detail is shown in Figure 6. (13 mm) masonry anchors is recommended The masonry engineer may choose to place the anchors farther apart than 17 in.c. (432 mm) o. however. (864 mm) o.amples using NCMA’s popular.. or wainscots.) end wall columns is very similar. Reinforced bond beam at spandrel Grout cell at anchor bolt locations Mesh to confine grout Reinforced concrete masonry wall (reinforcement not shown for clarity) Spandrel Note: A standardized punching of 9/16 in. These walls are commonly 4 to 10 ft (1.) Contol joint Sash unit Preformed gasket Rake joint. it is important to properly detail the building corners to accommodate the movements. The spandrel is designed by the metal building manufacturer. Anchorage to Anchor bolt (typ. (864 mm) as this could affect lateral stability of the steel member being connected to prevent torsional buckling (ref. more substantial connec(typ.c. or 34 in. Flexible anchors and/or slotted connections should be used. Column Detail Figure 5 shows the connection of a rigid frame column to concrete masonry sidewalls with a coincident vertical control joint. Depending on the rigid frame configuration used. it is good practice to provide a nominal number of anchors connecting the wall to the colRigid frame column umn to add stiffness and strength to the Vertical reinforcement edge of the wall. these Inside flange brace as as required by wall anchors can assist in laterally bracing required by metal design the outside column flange. are sometimes used. fill with sealant on closed-cell backer rod Grout cell at anchor location (typ. Wainscot Walls Although full height masonry walls provide the most benefit particularly when the masonry is used for shear walls. As shown in Figure 4. (432 mm) o. partial-height walls. 1).c. anchors should not be spaced more than 34 in. If rigid enough.) tions may be required. max.. The Figure 4—Single Wythe Wall Without Parapet at details show vertically adjustable column anchors connecting the wall to the column. Rigid frame Bond beam Anchor bolts at 17 in. If the inner flange of the spandrel needs to be braced. (432 mm) centers for ½ in. the metal building manufacturer will show on the drawings where the braces are required along with the inNCMA TEK 5-5B Shim as required (typ. 3). When the masonry is designed with a base hinge. especially on walls with parapets. Western States Clay Products Association. Minimum Design Loads for Buildings and Other Structures. Serviceability Design Considerations for Steel Buildings. and concrete masonry wall construction. 3. Metal Building Manufacturers Association. Concrete masonry wall Reinforced bond beam at spandrel. 2. (64 mm) min. 4. Coordination between the various trades is essential for efficient construction. CONSTRUCTION SEQUENCE Typically. grout on all sides of anchor which may require a two or more course high bond beam as shown Anchor bolt Spandrel Brace if required by metal building manufacturer (may be under spandrel or on top of spandrel) Section A-A A Shim plates as required Grout cell at anchor bolt for brace Figure 6—Structural Spandrel for Lateral Load Detail REFERENCES 1. 6 in. International Code Council. 2005. American Society for Civil Engineers. however. Note. construction of metal buildings with concrete masonry walls proceeds as follows: concrete footing and column A Anchor bolt Spandrel flange 21 2 in. Concrete Masonry Walls for Metal Building Systems. ASCE 7-05. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 2003. that this sequence may need to be modified to meet the needs of a particular project. For example. steel erection. the steel supported by the masonry is erected after the masonry wall is in place.(152 mm) min. In this case. American Institute of Steel Construction. and the International Code Council. Virginia 20171 www. The steel spandrel should never be pulled to the masonry wall by tightening the anchor bolts. contact NCMA Publications (703) 713-1900 4 149 NCMA TEK 5-5B . The Brick Industry Association. Shim plates should be used at spandrel/masonry connections to allow for camber in the spandrel and other construction tolerances (see Figure 6). National Concrete Masonry Association. 2011. concrete slab placement. placement. NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. Herndon. Structural Masonry Design System Software. 2010. AISC Steel Design Guide #3.ncma. TR 149A.org Provided by: To order a complete TEK Manual or TEK Index. National Concrete Masonry Association. concrete masonry foundation wall construction to grade. Preconstruction conferences are an excellent way for contractors and subcontractors to coordinate construction scheduling and to avoid conflicts and delays.formation needed for the masonry engineer to design them and their anchorage to the wall. this construction sequence changes when loadbearing end walls are used. Sealant and backer Clearance Vapor retarder. concrete slabs or steel members. high rise construction. Shelf angle Rigid insulation board Horizontal joint reinforcement as required Rigid insulation board PANEL WALLS Concrete masonry panel walls are supported at each building story by means of concrete beams. per local practice Air space Flashing Cavity filter or other mortar collection device Steel anchor plate Shelf angle Horizontal joint reinforcement as required Weep holes at 32 in. nonbearing walls. or at prescribed interims. Anchorage between the concrete masonry and structural frame must also account for different construction tolerances for each building material. allowance should be made for differential movement between the shelf angle and the panel wall below due to creep of the frame and/or masonry thermal expansion. Flashing Strategies for Concrete Masonry Walls and Flashing Details for Concrete Masonry Walls (refs. although bolting is often preferred because slotted bolt holes permit adjustments to be made for proper alignment with the masonry. (813 mm) o. curtain walls. Both are designed to resist lateral wind or seismic loads and transfer these lateral loads to the structural frame. Steel supports.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY CURTAIN AND PANEL WALL DETAILS TEK 5-6A Details (2001) Keywords: architectural details. Supports must take into account the strains and deformations in both the concrete masonry panel wall and the structural frame. to ensure proper bolt tension to avoid slipping once positioned. panel walls. construction details.c. allowing a limited amount of movement between the masonry and the frame. Curtain and panel walls differ from anchored masonry veneer in that veneer is continuously supported by a backup material. Care should be taken. Air space Flashing Sealant and backer Clearance Vapor retarder. veneer INTRODUCTION Steel and concrete structural frames often rely on nonloadbearing masonry curtain or panel walls to enclose the structure. 3.c. Curtain and panel walls must be isolated from the frame to prevent the unintentional transfer of structural loads and to allow differential movement between the frame and the masonry. Design for Dry Single-Wythe Concrete Masonry Walls. often in the form of shelf angles. per local practice Figure 1—Shelf Angle Connections to Concrete 150 TEK 5-6A © 2001 National Concrete Masonry Association (replaces TEK 5-6) . 4 & 5) provide detailed information. can be attached to the frame either by welding or bolting. however. They typically do not carry any vertical loads other than their own weight. (813 mm) o. For high-rise construction. bolted connections are inherently more flexible than welded connections. Concrete masonry curtain and panel walls should incorporate flashing and weep holes as for other concrete masonry construction. Panel and curtain walls are distinguished by the fact that a panel wall is wholly supported at each story. This is accomplished by leaving an open (mortarless) space between the bottom of the shelf angle and the masonry below or by filling the space with compressible Anchor bolt Cavity filter or other mortar collection device Weep holes at 32 in. while a curtain wall is supported only at its base. In addition. wall movement. The joint is then sealed with caulking to prevent moisture intrusion. tolerances can potentially affect anchor embedment. The horizontal movement joint below the shelf angle also helps prevent vertical loads from inadvertently being transferred to the concrete masonry panel wall below the shelf angle. CURTAIN WALLS Concrete masonry curtain walls can be designed to span either vertically or horizontally between supports.Rigid insulation board Concrete column Air space Flashing Dovetail slot Cavity filter or other mortar collection device Bolted anchor. the following recommendations should be considered. Adjustable channel slot anchor Sealant and backer Shelf angle Clearance Horizontal joint reinforcement as required Concrete column Vapor retarder. Anchors are required to be embedded at least 11/2 in. 7). consisting of AISI Type 304 stainless steel or galvanized or epoxy coatings. flashing details and available support at the shelf angle. (25 to 51 mm) of mortar into the core of the block above the anchor. it is also recommended that they be embedded in filled cores when using hollow units. construction tolerances for each material need to be accommodated. 1) includes specific corrosion-resistance requirements to ensure long-term integrity of the anchors. per local practice Figure 2—Shelf Angle Connection to Steel Members material. • Use bolted connections with slotted holes for steel shelf angles to allow the shelf angle location to be adjusted to meet field conditions. Anchors used to provide lateral support must be sufficiently stiff in the out-of-plane direction to transfer lateral loads to the frame and be flexible enough in-plane to allow differential movement between the curtain wall and the frame. since construction tolerances vary for different building materials. 1) to prevent failure due to mortar pullout or pushout. welded to steel beam Dovetail anchor Weep holes at 32 in. Because of the magnitude of anchor loads. this can be accomplished by placing a screen under the anchor and building up 1 to 2 in. use shims that are the full height of the vertical leg of the shelf angle for stability. • Provide a variety of anchor lengths to allow proper embedment over the range of construction tolerances. Figure 6 shows an example of a shelf angle connection which is adjustable in all three directions.c. Figures 1 and 2 show steel shelf angle attachments to concrete and steel. wall ties between the exterior and interior masonry wythes should be located as close to the shelf angle as possible. the space between the column and the masonry should be kept clear of mortar to avoid rigidly bonding the two elements together. Flashing and weep holes should be installed immediately above all shelf angles to drain moisture. Shimming is limited to a maximum of 1 in. (813 mm) o. They can also incorporate reinforcement to increase lateral load resistance and the required distance between lateral supports. • Cut masonry units only with the permission of the architect or engineer (this may be proposed when the frame cants 151 . To help accommodate these variations in the field. • When shimming shelf angles. For connections like this. Building Code Requirements for Masonry Structures (ref. (25 mm) (ref. CONSTRUCTION TOLERANCES Tolerances are allowable variations. In multi-wythe panel walls. but establish limits on how far they can vary to help ensure the finished building will function as designed. 2. 7). As an alternative to completely filling the masonry core. (38. either in individual component dimensions or in building elements such as walls or roofs.1 mm) into the mortar bed when solid masonry units are used (ref. For both concrete and steel frames. masonry must be constructed to tighter tolerances than those applicable to steel or concrete frames (refs. such as steel or concrete. In addition. the bottom flange needs to be evaluated for adequate load carrying capability as does the beam for torsion. • Use two-piece flashing to accommodate varying cavity widths. Figure 3—Curtain Wall Connections to Concrete Frames Figures 3 through 5 show curtain wall attachments to concrete and steel frames. Steel shims can be used to make horizontal adjustments to the shelf angle location. When using masonry with another structural system. Construction tolerances recognize that building elements cannot always be placed exactly as specified. Particularly in high-rise buildings. respectively. In general. Fill cells of CMU solid with grout or mortar Horizontal joint reinforcement as required Fill cells of CMU solid with grout or mortar Horizontal joint reinforcement as required Steel column Adjustable anchor 1 in. clearance Concrete slab Horizontal joint reinforcement as required Steel angle welded to beam Concrete slab on metal decking Steel beam Fill head joint solid with mortar Strip anchor installed in masonry head joint (spot weld where anchor engages beam flange) Figure 5—Curtain Wall Connections to Steel Beams 152 . (25 mm) min. (25 mm) min. (25 mm) min. clearance Concrete slab Horizontal joint reinforcement as required Adjustable anchor Adjustable anchor Fill cell of CMU solid with grout or mortar Fill cells of CMU solid with grout or mortar Steel beam 1 in. (25 mm) min. clearance Steel column Adjustable anchor 1 in. clearance Notched steel adjustable anchor (typ) 1 in. clearance Horizontal joint reinforcement as required Fill cells of CMU solid with grout or mortar Horizontal joint reinforcement as required (discontinue at control joint) Steel column Adjustable anchor Figure 4—Curtain Wall Connections to Steel Columns Horizontal joint reinforcement as required 1 in. clearance Preformed rubber control joint Steel column Fill cells of CMU solid with grout or mortar 1 in. (25 mm) min. (25 mm) min. clearance Steel angle welded to beam Concrete slab on metal decking Steel beam Sleeve 1 in. (25 mm) min. 2000. Code of Standard Practice for Steel Buildings and Bridges. Specification for Masonry Structures. 2. TEK 19-2A. 2001. Clip angle adjustability to maintain plumb Adjustability for initial alignment Adjustability to level shelf angle Fig 6—Connection Adjustable in Three Directions REFERENCES 1.ncma. 6. The Aberdeen Group. (ref. National Concrete Masonry Association.org To order a complete TEK Manual or TEK Index. reproduced with permission from Hanley-Wood. National Concrete Masonry Association. • Include instructions for handling building element misalignment in the construction documents. Virginia 20171-3499 www. 5. 7. Building Code Requirements for Masonry Structures. Reported by the Masonry Standards Joint Committee. 2001. Reported by the Masonry Standards Joint Committee. 1999. Design for Dry Single-Wythe Concrete Masonry Walls. Masonry and Steel Detailing Handbook. Flashing Strategies for Concrete Masonry Walls . 153 contact NCMA Publications (703) 713-1900 . 6. Herndon. ACI 530. Laska. TEK 195A. TEK 19-4A.. z Hanley-Wood. 1993. LLC) Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. making the cavity between the two materials too small).towards the masonry. NATIONAL CONCRETE MASONRY ASSOCIATION 2302 Horse Pen Road. Flashing Details for Concrete Masonry Walls. 1999.1-99/ ASCE 6-99/TMS 602-99. National Concrete Masonry Association. 3. 2000. W. American Institute of Steel Construction. ACI 530-99/ASCE 5-99/TMS 402-99. 4. Inc. Fire-Resistance Rating Because fire walls provide a complete separation between adjoining spaces. In addition to these requirements. H-3 . construction details. also see IBC Sections 415. and criteria for protecting openings and joints. As such. a fire wall is generally considered to provide the highest level of robustness and fire safety. protected openings INTRODUCTION FIRE WALLS Concrete masonry. S-1 3 H-1. the provisions are based on the 2003 IBC. fire barrier and fire partition—depending on the level of protection provided for the type of occupancy and intended use. Hence. fire barriers and fire partitions are required to provide the minimum protection necessary to assure that building occupants can evacuate a structure without suffering personal injury or loss of life. It is beyond the scope of this TEK to include every code provision and exception for fire wall design for all project conditions. In addition. In addition. but are included as examples. R-1. 1). International Building Code. fire walls are required to have the minimum fire-resistance rating acceptable for the particular occupancy or use group which they separate and must also have protected openings and penetrations. U 3A B F-1. S-2. under or around the fire wall. 3. 4).4 and 415. each portion of the structure separated by fire walls is considered to be a separate building. R-3. Information on determining the fire-resistance ratings of concrete masonry assemblies is contained in Fire Resistance Rating of Concrete Masonry Assemblies. H-2 or H-3 buildings. Table 1 shows minimum required fire-resistance ratings. I. Potentially significant architectural and economic advantages can be gained from using fire walls since each portion of a building separated by fire walls is considered a separate building for code compliance purposes. the information may or may not conform to local building code requirements and should be carefully reviewed to ensure compliance. fire walls reduce the likelihood of fire spread into the adjoining space. cantilevered fire wall. double fire wall. fire resistance. so certain provisions may be different from NFPA 5000 requirements.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology DETAILING CONCRETE MASONRY FIRE WALLS TEK 5-8B Details (2005) Keywords: architectural details. is well suited to a range of fire protection applications. Fire walls in all but Type V construction must be constructed of approved noncombustible materials. The International Building Code (IBC) (ref. the wall must have sufficient structural stability under fire conditions to remain standing for the duration of time indicated by the fire-resistance rating even with the collapse of construction on either side of the fire wall. By Code (ref. vertical and horizontal continuity. H-4. Table 1—Required Fire Wall Fire-Resistance Ratings (ref. R-4 2 A Walls shall not be less than 2-hour fire-resistance rated where separating buildings of Type II or V construction. B For Group H-1. Generally. E. R-2. 1) Group Fire-resistance rating. thus minimizing major property loss. B. 1) defines three wall types for fire protection— fire wall. hr A. TEK 7-1A and Standard Method for Determining Fire Resistance of Concrete and Masonry Construction Assemblies (refs. Designing and detailing fire walls is a complex task with many facets. 2) building codes. Project-specific needs will dictate the final detailing decisions. it is intended to provide complete separation and must be structurally stable under fire conditions. fire walls. including structural criteria. reliability and superior fire resistance characteristics. fire-resistance rating. Of the three defined fire-rated assemblies. A fire wall must have both vertical and horizontal continuity to ensure that the fire does not travel over. the details shown here are not the only ones that will comply. H-5.5 154 TEK 5-8B © 2005 National Concrete Masonry Association (replaces TEK 5-8A) . H-2 4B F-2. While much of the information in this TEK is applicable to both the IBC and the NFPA 5000 (ref. M. due to its inherent durability. For these reasons. In all cases. Openings for steel electrical outlet boxes are permitted provided they meet the Codespecified requirements. TEK 10-2B (ref. This decreased structural capacity is evidenced by a dramatic increase in the deflection and twisting of steel members. the penetrating item is limited to a 6-in.2 m2). as well as in between. 6). The IBC requires that fire walls be continuous from exterior wall to exterior wall and that they extend at least 18 in. Further. In addition. grout or mortar for the thickness required to provide a fire-resistance rating equivalent to the fire-resistance rating of the wall penetrated. These exceptions require the use of Class B roof coverings (minimum). The full thickness of the fire wall 4 in. Recommendations for locating and spacing control joints in concrete masonry walls also apply to concrete masonry fire walls. as required Concrete masonry fire wall Concrete masonry pilaster Figure 1—Freestanding or Cantilevered Fire Wall with Pilaster 155 . the aggregate width of all openings at any floor level is limited to 25 percent of the wall length. the combustible member must be filled with noncombustible materials approved for fireblocking. protected openings and penetrations. Wood framing may burn. Vertical and Horizontal Continuity The IBC mandates vertical continuity of a fire wall by requiring that the wall extend continuously from the foundation to a termination point at least 30 in. iron or copper pipes or steel conduits and surrounding concrete masonry fire walls may be filled with concrete. The annular space between steel. collapse. Exceptions permitting the fire wall termination at the underside of the roof deck or slab are listed in the Code. and vertical and horizontal continuity are prescriptive.Protected Openings and Penetrations The IBC states that fire walls must have closures such as fire doors or shutters which automatically activate to secure the opening in the event of a fire.22 m) of the fire wall and other criteria for roof assembly protection. Voids created at the junction of walls and floor/ceiling/ roof assemblies must be protected from fire passage by using fire-resistant joint systems tested in accordance with ASTM E 1966 or UL 2079 (refs. (102 mm) above and below. shrink and/or deform under fire exposure and it too loses its load-carrying capability. (102 mm) between the embedded ends of the wood framing. Combustible members. openings in fire walls are restricted to a maximum size of 120 ft2 (11. steel framing undergoes a reduction in strength as the surrounding temperature and duration of exposure are increased. Through-penetrations in fire walls must utilize either fire-resistance-rated assemblies or a firestop system which is tested in accordance with either ASTM E 814 (ref. Control Joints for Concrete Masonry Walls. As with the vertical continuity requirements. 5) or UL 1479 (ref. are permitted to be framed into concrete masonry fire walls provided that. (457 mm) beyond the exterior surface of exterior walls. there are criteria for terminating the fire wall at the interior surface of an exterior wall based on the types and fire-resistance ratings of the intersecting wall constructions and on the presence of an automatic sprinkler system installed per Code requirements.2 (92. DETAILING CONSIDERATIONS FOR STRUCTURAL STABILITY Because most fire wall criteria relating to fire-resistance rating. 9) includes control joint spacing criteria and illustrates control joint details for various fire-resistance ratings. An exception permits larger openings provided both buildings separated by the fire wall are equipped throughout with automatic sprinkler systems. such as wood. concrete masonry fire walls should be designed and detailed to withstand any loading imposed by fire-compromised framing systems or detailed so that those loads are not imparted to the fire wall during a fire. Control joints in fire walls must have fire-resistance ratings equal to or exceeding the required rating of the wall. Structural Stability Under Fire Conditions While concrete masonry remains structurally stable during the extreme temperatures experienced under fire conditions. when framed on both sides of the wall. the designer’s primary challenge when engineering and detailing a concrete masonry fire wall relates to maintaining the structural Grout Vertical reinforcement anchored in foundation Joint reinforcement. This is perhaps the most difficult detailing provision in fire wall design. 8). 7. Buildings located over parking garages and stepped buildings are subject to additional requirements and permitted exceptions. there is at least 4 in. no openings within 4 ft (1. (762 mm) above both adjacent roofs. (152-mm) nominal diameter and the opening is limited to 144 in. Horizontal continuity limits the spread of fire around the ends of a fire wall.900 mm2). As such.6) 6 1/4 (15. Among the systems recommended for use as fire walls are: (a) cantilevered or freestanding walls. Details for cantilevered/freestanding fire walls are similar to those for laterally supported walls (shown in Figures 2. Designing the wall to remain stable under that loading condition may be difficult especially for tall or slender walls. Stagger joists (as shown) as necessary.8) 7 1/2 (19. 2.2) 4 5 (13. Column lines on either side of the wall support the roof framing.9) 7 (17. in. 3 and 4) with the exception that cantilevered walls do not include through-wall ties or break-away connectors. and c) no openings within 4 ft (1. Figure 2—Laterally Supported Loadbearing Fire Wall 156 . (cm) 2 1/2 (6. For this reason. the structural diaphragm on the side of the wall opposite the fire provides the stability. 3. forces Noncombustible roof deck with Class B roof covering 2 Bond beam Table 2—Minimum Clearance Between Structural Steel and Fire Wall (ref . Figure 4 shows a laterally supported fire wall with combustible framing supported by metal joist hangers.3) 3 3/4 (9. so that. 10) Length of bay perpendicular to fire wall ft.1) 2 5 (7. It can be difficult to design a cantilevered single wythe loadbearing fire wall. The fire wall is laterally supported on each side by the framing system. in the event of fire. the connectors on the fire side of the wall will give way before those on the non-fire side. Figure 5 shows design and detailing options for tied fire walls.4) 5 (12. b) roof covering is Class B (minimum). Adequate clearance.6) 3 0 (9.4) 3 1/4 (8.3) Minimum clearance “X” between wall and steel. 30 in.7) 4 0 (12. If the diaphragms occur at different elevations. but rather by the roof structure on the other side Parapet Fire stop material (not shown for clarity) between and around ends of joists Laterally Supported or Tied Walls Laterally supported or tied walls rely on the building frame for lateral stability.stability of the wall under fire conditions.2) 5 5 (16. In Figures 2 and 3. between the framing and the concrete masonry fire wall is necessary to allow framing expansion or deformation without exerting undue pressure on the wall. Top chord bearing wood joists similar. Note that there may be code limitations on the use of combustible framing.7) 5 0 (15. Thermal stresses may cause deformation in steel or wood joists or framing systems which can eccentrically load the top of the fire wall. detailing and constructing fire walls for structural stability during a fire. Joists may be aligned if bond beam width permits proper installation of firestop material between joist ends. cantilevered single wythe fire walls are often designed as nonbearing walls with the primary roof framing system running parallel to the fire wall.7) 5 3/4 (14.5) 4 1/2 (11. Freestanding walls may also be designed to span horizontally between pilasters or masonry columns integral to the wall. There are various methods of designing.1) Concrete masonry unit rated for fire exposure reinforced as required Steel bar joist each side 1 Notes: 1. and (c) double wall construction. (m) 2 0 (6. due to the collapse of the structure on one side of the fire wall are resisted by the structural framework on the other side of the wall. The connections between the roof and wall must be designed to resist these forces. as listed in Table 2. the wall must be designed to withstand the anticipated flexural forces that will be generated as well. Laterally supported fire walls may utilize break-away connectors manufactured with metals having melting points lower than structural steel (generally about 800° F (427° C)). Tied fire walls are a type of laterally supported fire wall where the roof structure is not supported by the fire wall.8) > 60 (18. The wall is cantilevered from the foundation by grouting and reinforcing. (762 mm) parapet is required unless all conditions are met: a) roof deck is noncombustible.22 m) of fire wall. Cantilevered or Freestanding Walls Cantilevered walls (Figure 1) do not depend on the roof framing for structural support. or by prestressing. Joist hanger manufacturers may have alternate details as well. (b) laterally supported and tied walls.1) 3 5 (10. One column is used on each side of the fire wall to support the roof system for that building. preventing fire spread. as required Break-away connector each side "X" each side see Table 2 Vertical reinforcement. Figure 5c shows one steel support column encased entirely within the concrete masonry fire wall. thus the two roof structures are tied together across the fire wall. (102 mm) above. Double Wall Fire Wall Double wall construction (Figure 6) is generally easy to design and detail for loadbearing conditions. each meeting the required fire-resistance rating. 11). It utilizes two independent concrete masonry walls side by side. Fire protection requirements for steel columns are included in Steel Column Fire Protection. TEK 7-6 (ref. Floor and roof connections to each fire wall are the same as for conventional concrete masonry construction. As an alternative to using two steel columns. as required Steel bar joist Steel column each side Concrete masonry fire wall Note: If detailed without breakaway connectors. This system creates a single column line tied at the top of the wall to horizontal roof framing. In this detail. the primary roof framing steel is parallel to the fire wall and supported on fireproofed columns. the other wall remains intact. Figure 3—Laterally Supported Nonloadbearing Fire Wall Parapet Fill full thickness of fire wall 4 in. Grout. Figure 4—Laterally Supported Loadbearing Fire Wall: Wood Framing 157 . below and between wood members with noncombustible fire blocking Concrete masonry rated for fire exposure. Figure 5a illustrates one choice for a “double column” detail which uses a through-wall tie to connect the primary steel on both sides of the fire wall. but the wall must be supported at the top and the connection must be fire protected. especially for taller walls.of the fire wall. Both steel columns and primary support beams/trusses should be aligned vertically and horizontally with the columns and beams/trusses on the opposite side of the wall and should be fireproofed. Detailing the connection of the steel beams to the concrete masonry fire wall varies based on the framing layout. If the primary steel is not parallel to the fire wall Figure 5b shows a through-wall tie which can be used. In the event one wall is pulled down due to fire. reinforced as required Joist hangers bolted to concrete masonry Note: Fire proofing (if required) not shown for clarity. This system is also easy to use when a building addition requires a fire wall between the existing structure and the new construction. These walls are often cantilevered or freestanding but may be tied or laterally supported as well if so detailed and designed. Check with local building codes for fire rating requirements on wood truss and hanger assemblies. fire wall would be nonloadbearing freestanding or cantilevered. Through-Wall Tie Detail: Primary Steel Parallel to Fire Wall Concrete masonry fire wall "X" both sides. see Table 2 Steel beam Angle clip. weld to beam A Angle clip. (762 mm) min. not shown for clarity. Figure 5a—Double Column Method.A Concrete slab Concrete masonry fire wall Figure 5c—Single Column Method Figure 5—Tied Fire Walls (ref. Through-Wall Tie Detail: Primary Steel Perpendicular to Fire Wall Masonry encases steel per building code 30 in. 10) 158 . Figure 5b—Double Column Method. not shown for clarity.Secondary steel Primary steel "X" both sides. see Table 2 Concrete masonry fire wall Note: Beams and columns require fireproofing. weld to beam Steel beam A Section A . concrete masonry parapet A A Steel beam framing into cross beam supported on steel column Steel column encased in fire wall Section A .A Provide clearance Note: Beams and columns require fireproofing. Tests for Fire Resistance of Building Joint Systems. ASTM E 814-02.1-97/ TMS 0216-97. 2005. NCMA TEK 10-2B. Fire Resistance Rating of Concrete bolts and reinforcement Masonry Assemblies. Underwriters Steel bar joist welded Grout stop if wall Laboratory. International Building Code 2003. Underwriters Laboratory. UL 2079. ASTM E 1966-01. continous cleat each side International Code Council. Attachment strip 2. Criteria for Maximum Foreseeable Loss Fire Walls and Space Separation. 2003. Control Joints for Concrete Masonry Walls–Empirical Method. 2003. Building Construction and Safety Code – Wood nailer 2003 Edition. UL 1479. 8. Grout cores solid at anchor 3. American Concrete Institute and The Masonry Society. National Concrete Masonry Association. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. National Concrete Masonry Association. NFPA 5000. 5. 2001. or bolted to bearing below not grouted plate 7. 2003. National Fire Counter flashing anchored to one wall Protection Association. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. Standard Method for Determining Fire beam Parapet flashing Resistance of Concrete and Masonry Construction Assemblies. ASTM Figure 6—Double Fire Wall International. Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. 2000. ACI 216.org To order a complete TEK Manual or TEK Index. NCMA TEK 7-1A. 2004 9. Sealant 2003. 6.ncma. 10. 2002. 2003. 159 contact NCMA Publications (703) 713-1900 . Standard Test Method for Fire Tests of 90° hook Through-Penetration Fire Stops. Bond Cant 4. National Concrete Masonry Association. Virginia 20171 www. ASTM International. Property Loss Prevention Data Sheets 1-22.REFERENCES Sheet metal coping cap with 1. Steel Column Fire Protection. Standard Test Method for Fire-Resistive Joint Systems. 1997. Fire Tests of Through-Penetration Firestops. NCMA TEK 7-6. 11. Factory Mutual Insurance Company. Herndon. then the remaining wall section is filled in. because the actual widths of standard units are 3 5/8. It is essential that the corner be built as shown on the foundation or floor plan to maintain modular dimensions. such as bevelled-end units. modular coordination. special corner details have been developed to accommodate most typical situations. In order to maintain an 8-in. forming a 45° angle with the face of the unit. Corners. while not always required. unit shapes INTRODUCTION A building's corners are typically constructed first. 244 and 295 mm). 5 5/8. (203 mm) 45° angle 45° Outside corner unit Figures 2 through 6 show how corners can be constructed to minimize cutting of units while maintaining modularity of the construction. building the corners requires special care. 9 5/8 and 115/8 in. UNITS Unlike stretcher units. present unique situations. 7 5/8. corners. concrete masonry elements should be designed and constructed with modular coordination in mind. (92. with two closely spaced webs in the center that allow the unit to be easily split on the jobsite. facilitating corner construction. which are used to form walls Double corner or plain-end unit 45° Inside corner unit All-purpose. Other special units may also be available.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY CORNER DETAILS TEK 5-9A Details (2004) Keywords: architectural details. (203-mm) module. 194. Vertical steel. construction details. Because they guide the construction of the rest of the wall. Bay window or 8 in. 143. is often used at corner intersections. In addition. For maximum construction efficiency and economy. however. all-purpose or kerf units are available. units used in corner construction have square ends (see Figure 1). kerf or splitter unit Single corner unit Bevelled or mitered unit Return corner unit Figure 1—Concrete Masonry Units Used for Corner Construction TEK 5-9A © 2004 National Concrete Masonry Association (replaces TEK 5-9) 160 . 7m m) 7 5 (19 / 8in 4m . (203 mm) Wall to 8 in. 5 in 7 / 8 m) m 4 (19 8 in. 7m m) it to t un Cu 12 in. (203 mm) Wall to 12 in. ) 15 mm) 7 (39 35 (92 /8in mm . 5/ 8in 15 mm) 7 . 7m m) . m) 15 5 (39 / 8in. 5/ 8in 11 mm) 5 (29 3 5 (92 /8in mm . 5 8in ) 3 / mm (92 8 in. 5/ 8in 15 mm) 7 (39 7 5 (19 / 8in. 5m m) . 5/ 8in ) 15 7 mm 9 3 ( 8 in. (203 mm) 15 (39 /58in 7m . 5 8in 5 / mm) 3 (14 8 in.12 in. 5 8in 3 / mm) (92 11 5 (29 / 8in. (305 mm) Corner return unit 75 (19 /8in 4m . 5/ 8in 15 mm) 7 (39 Bevelled unit Figure 2—Corner Details. 7m m) Alternate courses . 6m m) . 5/ 8in ) 3 1 mm 6 4 (3 . (203 mm) 5 5 (14 / 8in 3m . (102 mm) thick half-length unit 15 5 (39 / 8in. (203 mm) . (203 mm) Wall Using Standard Units Cut unit to fit or use nominal 14 in. m) . 5/ 8in 15 mm) 7 (39 . m) . 7m m) 10 in. 5/ 8in 15 mm) 7 (39 . 5 8in 7 / mm) 4 (19 . 5 8in 7 / mm) 4 (19 15 5 (39 / 8in. 8 Inch (203 mm) Walls 161 . 5 8in ) 3 / mm (92 fit . (19 7 /58in m) 4m . m) 13 5 (34 / 8in. ) . (254 mm) 7 5 (19 / 8in 4m . 5 8in 7 / mm) 4 (19 15 5 (39 / 8in. 7m m) . (305 mm) Wall Figure 4—Corner Details. (39 5 8in 7 / mm) 4 (19 Corner return unit Figure 3—Corner Details. 6 Inch (152 mm) Walls . (356 mm) units 15 (39 /58in. (356 mm) units 8 in. m) . 4m m) 4 in. (305 mm) 15 5 (39 / 8in. ) . 4 Inch (102 mm) Walls Cut unit to fit or use nominal 14 in. 5/ 8in e 35 (92 /8in mm . 5 / 8 in ) 11 5 mm 9 (2 4 in. 7m (19 7 /58in m) 4m . m) . 5 8i 7 / mm) 4 (19 . 5 8i Cut unit to fit 9 / m) m) or use nominal m 4 9 /5 (24 5 8in. (102 mm) n. 12 Inch (305 mm) Walls 162 . (102 mm) . 5 8in / 15 mm) 7 (39 5 . 5/ 8in 15 mm) 7 (39 . 7 9 (24 /58 in mm) 4m . 5 / 8 in ) 11 5 mm (29 n. 10 Inch (254 mm) Walls 15 (39 /5 8in. m) Alternate courses . (92 x 92 x 194 mm) . m) (19 7 /58in 4m . 5 8in / 15 mm) 7 (39 (for unreinforced corners only) (for unreinforced corners only) 6 in.6 in. mm ) 6 in. 7m . (152 mm) 15 (39 /58in n. m) . 5 8in / 15 mm) 7 (39 3 5/8 x 3 5/8 x 7 5/8 in. m) Alternate courses . (152 mm) 15 (39 /58in . m) 15 (39 /58 in 7m . m) 3 /5 (92 8in. m) 15 n. 14 in. 5 8in / 15 mm) 7 (39 1 5 8 x 5 5 8 x 7 5 8 in. m) . 7m m) . (41 x 143 x 194 mm) 15 (39 /5 8in 7m . (356 / 8 in (24 . (41 x 143 x 194 mm) 15 (39 /58in 7m . 15 mm) Cut unit to fit mm) units 4m 7 9 m) (3 or use nominal 14 in. 5 8i 7 / mm) 4 (19 5 8 x 5 8 x 7 8 in. 5/ 8 in 11 mm) 5 (29 4 in. /8 (29 /5 8in. (356 mm) units (for unreinforced corners only) 11 (29 /5 8in 5m . / in 15 mm) 7 (39 5 8 (19 7 /58in 4m . 5 8i 9 / mm) 4 (24 15 (39 /58in . (152 mm) 15 (39 /58 in 7m . m) . 5 8in 7 / mm) 4 (19 Figure 6—Corner Details. 7m . 15 mm) 5m 7 m) (39 n. 5 8i 7 / mm) 4 (19 15 (39 /58in. 5 / 8 in m) 11 mm) 5 11 (29 5 in. 5/ 8in 15 mm) 7 (39 (19 7 /58in 4m . 5 8in 3 / mm) 2 (9 Figure 5—Corner Details. 163 contact NCMA Publications (703) 713-1900 . Local manufacturers should be contacted for information on unit availability. The Concrete Masonry Shapes and Sizes Directory (ref. National Concrete Masonry Association. 2 . steel connectors. Masonry Institute of America. TR 90B. Reinforced Concrete Masonry Inspector's Handbook. Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. each requiring the masonry to be laid in running bond. 4th edition. Virginia 20171 www. When any of these conditions are not met. 2002. Reported by the Masonry Standards Joint Committee. 4 . and bond beams. 1997. CM260A. including those with architectural surfaces.intersecting at 135° angles. Annotated Design and Construction Details for Concrete Masonry. are often available with the architectural finish on two sides to accommodate corner construction. Architectural units.ACI 530-02/ASCE 5-02/TMS 402-02. Corner construction lends itself to providing shear transfer by relying on running bond. 2) contains illustrations of additional corner units. National Concrete Masonry Association.ncma. Building Code Requirements for Masonry Structures. 3 . Units in adjacent courses overlap to form a running bond pattern at the corner. 4) stipulates three options to transfer stresses from one wall to another at wall intersections. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. These three options are via: running bond. such as those with split or scored faces.org To order a complete TEK Manual or TEK Index. CODE PROVISIONS FOR INTERSECTING WALLS Building Code Requirements for Masonry Structures (ref. REFERENCES 1 . Concrete Masonry Shapes and Sizes Directory. the transfer of shear forces between walls is required to be prevented. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. 2002. Herndon. Running bond (defined as the placement of masonry units such that head joints in successive courses are horizontally offset at least one-quarter the unit length) ensures there is sufficient unit interlock at the corner to transfer shear. 2003. curved walls. In addition. Walls laid up in running bond (with offset head joints). The greater the radius. on the other hand.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY RADIAL WALL DETAILS TEK 5-10A Details (2006) Keywords: construction details. The use of concrete masonry in the design and construction of radial walls presents a unique challenge to the design professional. textures. the width of the vertical head joints at the interior and exterior wall faces and whether the units will be used as is. These projections create a basketweave effect which may or may not contribute to the aesthetic value of the wall. or cut to conform to the desired radius. radius r θ O Concrete masonry units are uniquely suited to distinctive aesthetically-pleasing architectural features. colors and surface treatments has made concrete masonry one of the most versatile and sought after building materials today. The almost limitless variety of sizes.e. beveled at the ends. exhibit a similar geometric configuration at the individual courses with the exception that the ends of units in alternating courses project out beyond the faces of the units immediately above and below (Figure 2). The end result is a series of short chords rather than a smooth arc. Curved walls laid up in stack bond (i. radial walls. projection size for running bond and the effect of cutting the units. mortar joint size. with vertical head joints aligned) possess the geometric properties of a regular polygon (Figure 1). Note that these recommendations apply to S INTRODUCTION β A B Figure 1—Plan View of Radial Wall Laid in Stack Bond (Regular Polygon) p p Figure 2—Plan View of Projections in Radial Wall as a Result of Running Bond 164 TEK 5-10A © 2006 National Concrete Masonry Association (replaces TEK 5-10) .. Where curved walls once were formed from hand-hewn stone carved to fit a predetermined radius. radial walls of concrete masonry are usually formed from rectangular units of fixed shape and dimension. based on factors such as: desired radius. The curvature of these walls depends on variables such as the length and thickness of the concrete masonry unit. such as radial walls. projection. the more closely the surface formed by the chords approaches that of a true arc. shapes. the relatively small unit size lends itself to unique applications. unit size. The bond pattern also impacts the overall appearance of a curved wall section. This TEK contains information to help the designer determine the best way to construct a curved concrete masonry wall. 42 m) Although the equations remain the same. + 1/8 in. 3 = 16/(2 Tan 0. + 3/8 in. Actual unit dimensions are 155/8 in.875o Step 4: Use Equation 3 to determine the minimum wall radius. If the wall surface is to be stuccoed or otherwise covered. Although it is generally recommended that the width of the mortar joint at the interior face not be less than 1/8 in.625)]) = 2 Tan-l (0. based on using either a 3/8 in. (3. (12. note that beveled units or other special shapes may be available to facilitate masonry radial wall construction as well. r = Sl /(2 Tan β/2) Eqn. 1 = 2 (Tan-1 [(16 . The projection of the unit corners for the previous example is found by using Equation 4. n = θ/β Eqn. p = (S1/4) Sin β/2 Eqn.879o Step 2: Use Equation 2 to determine the number of units required.2 mm). reduces the radius as well as the number of units required. 3 Example Nominal 8 x 8 x 16-in.6 mm) DESIGN TABLES Tables 1 through 6 list the minimum radii. (203 mm) long units and 1/4 in.9375) = 16/0. Changing from a 16-in. • Vary the mortar joint width.2 mm) is usually not practical because of construction tolerances. What is the smallest radius the circular wall can be constructed to without cutting the units? Step 1: Use Equation 1 to determine the angle β. 2 = 360/1.5 mm) or 1/2 in. (406 mm) S2 = 155/8 in. 2 r = Sl /(2 Tan β/2) Eqn. (406 mm) long units are considered acceptable. • Shorten the length of the units at the interior face. although cutting only one end of each unit is also an option. to 3/4 in.plain ends Both ends are shown cut. (203 x 203 x 406-mm) concrete masonry units are being considered for use in a circular wall. Although this TEK focuses on the construction of radial walls using conventional concrete masonry units. (194 mm) β = 2 (Tan -1 [(S1 .0327 = 489 in. The width of the interior mortar joint is to be 1 /8 in. and the exterior mortar joint is to be 3 /8 in.75)/(2 x 7. there are several practical methods to vary the minimum radii of curved or circular concrete masonry walls: • Reduce the length of the units. Cutting the units is practical if stretcher units with flanged ends are used.2 mm). it may be desirable to limit the projections of the unit corners beyond the unit faces in the courses above and below for reasons of aesthetics. The designer must ensure any radial wall design complies with all applicable building code requirements. Figure 3—Concrete Masonry Unit Cuts to Facilitate Radial Wall Construction 165 . this may be acceptable under certain circumstances. Generally. (13 to 19 mm) may be acceptable. Sl = 155/8 in. number of units and length of projection for circular concrete masonry walls. = 40 ft. (400 mm) t = 75/8 in.2 mm) for nominal 8 in. (203-mm) long unit will reduce the minimum radius by half.065 in.4 mm) for nominal 16 in. = 16 in. (1. (194 mm) width. (9.the physical limitations and geometry of constructing radial walls. = 153/4 in. MINIMUM WALL RADIUS The minimum radii for curved or circular walls constructed of concrete masonry units is determined through iterations of the plane rectilinear geometric formulae for regular polygons.0164) = 1. 1 n = θ/β Eqn.S2)/2t]) Eqn. n = θ/β Eqn.879o = 191.flanged ends Double corner unit . (3. 4 = (16/4) Sin (0. (6.S2)/2t]) Eqn.9375) = 0. These equations are: β = 2 (Tan -1 [(S1 . (406-mm) long unit to an 8-in. Projections For a curved masonry wall laid in running bond. projections of 1/2 in. Cutting is less practical for double corner units with plain ends (see Figure 3). = 1/16 in.-9 in.5 mm). determine the required angle.6 units Step 3: Adjusting n to be equal to a whole number. 2 192 = 360/β β = 360/192 = 1. (3. Minimizing projections to less than 1/8 in. projections of approximately 1/8 in.15. An increase in the mortar joint width at the exterior wall face. (397 mm) length and 75/8 in. (9. (3. with or without a decrease in mortar joint width at the interior wall face. (13 Stretcher unit . (25 mm) Ext.Table 1—Minimum Radii: 8 in.57) 162 3/32 (2. nominal A Nominal unit width.75) 54 /8 (3.42 (0.96) 293 1/16 (1.59) 40 /16 (4. mortar joint r.50 (1.17 (3.1) 3 3.8) 5 4.08 (0.73) 74 /16 (4. (m) nA p.39) 74 /32 (2.08 (3. ft.79) 25.37) 21 19/32 (15) 6. (m) nA p.84) 13 15/16 (24) 5 4. (mm) 4 (102) 6 (152) 8 (203) 10 (254) 12 (305) 3 /8 in. Both Ends) Ext.08 (4. in. 166 . (406 mm).20) 142 /32 (2.4) 3 3.25) 65 /16 (4.26) 35 /8 (9.00 (0.8) ½ in. ft. mortar joint Nominal width 1 in. (406 mm) Long Cut Units (3/4 in.89) 14 /8 (22) 19 4.79) Table 2—Minimum Radii: 16 in.2 mm) 8 16 in. in. in.79) 20. mortar joint Nominal width 1 in.75 (0. mortar joint r. in.70) 26 /2 (13) 3 7.67 (2.75(12. (mm) 7 13.83 (2.83 (1. in.8) 5 4.67 (4. (m) nA p. (mm) 2.42 (8. multiply n by θ/360.2) 3 6. (mm) 4. ft. (25 mm) Ext. (19 mm) Cuts on Interior Face.75 (0.5 mm) Ext. ft.4) ½ in. in.58 (1.6) 15.30) 20 /8 (16) 1 5. (m) nA p.33 (6.84) 26 /4 (6.2 mm) 8 in.75 (2. (3.07) 33 /16 (4.4) 40.50 (5. mortar joint r.5) 5 8. nominal Nominal unit width. in. (25 mm) Ext. nominal Nominal unit width. (9. nominal Nominal unit width. For θ < 360o.83) 242 1/32 (0.5 mm) Ext.6) ½ in.63) 20 /16 (7. ft.66) 242 1/16 (1.42 (1. in.25 (1.75 (1.37) 42 /32 (4. ft.08 (3.17(18. mortar joint r. (25 mm) Ext. (mm) 4 (102) 6 (152) 8 (203) 10 (254) 12 (305) 3 /8 in.20) 192 1/32 (0. (3.33(15.20) 95 /8 (3. mortar joint r.6) 62.35) 21 /32 (15) 7 5. (m) nA p. in. in.0) Table 6—Minimum Radii: 16 in.67 (7.50 (1.08 (1. (9. (mm) 4 (102) 6 (152) 8 (203) 10 (254) 12 (305) 3 /8 in. in.83 (2. (9. (mm) 3 6.9) 7 3. (mm) 9 2.6) 51.07) 95 /16 (1.48) 293 1/32 (0.25 (0. in.0) 1 5.42 (2.2 mm) 8 8 in.94) 61 /16 (4.2 mm) 8 8 in. One End Only) Ext.08 (1.9) 1 11. mortar joint r. (m) nA p.69) 21 /16 (7.79) 31. nominal Nominal unit width.08 (9. (9. mortar joint r. ft.2 mm) 8 16 in. in.6) 17. (m) nA p. (19 mm) Cuts Interior Face.6) Table 3—Minimum Radii: 8 in.4) 41. in.92 (3. (3.17 (5. (m) nA p.95) 92 /8 (3. (203 mm).4) 3 7.38) 21 /16 (7.72) 42 /16 (4. (203 mm) Long Cut Units (3/4 in. in. (mm) 1 9.2) 3 30. mortar joint Nominal width 1 in.6) 3 3.36) 128 3/32 (2.8) 1 5.6) 20.50 (0. (m) nA p.50 (2.34) 36 11/32 (8.81) 28 /16 (11) 3 7.25 (1. (3. mortar joint Nominal width 1 in.41) 13 /2 (13) 5 2.5 mm) Ext.17 (2.46) 14 /16 (11) 5 1.58 (1. (203 mm) Long Units (Uncut) Ext.80) 43 /16 (7.00 (2.50 (1. (mm) 4 (102) 6 (152) 8 (203) 10 (254) 12 (305) 3 /8 in. mortar joint Nominal width 1 in. mortar joint Nominal width 1 8 in. mortar joint r.55) 48 /8 (3.73) 195 1/16 (1.0) ½ in. (m) nA p. (3.47) 23 /16 (14) 7. (25 mm) Ext.2 mm) 16 in.04) 32 /16 (4. (9. (406 mm). ft.50 (1.9) 1 2.50 (1. mortar joint r.4) 3 12.79) ½ in.14) 33 /8 (9.85) 65 /32 (2.98) 61 /32 (2. (203 mm) Long Cut Units (3/4 in.8) Table 5—Minimum Radii: 8 in.6) 1 20.0) ½ in. in. mortar joint r.83 (1.14) 128 1/16 (1.17) 36 /16 (4.33 (6. (mm) 1 1.4) 34. ft. (3.2) 3 6. in.98) 61 /32 (2. (mm) 7 1.58 (3.5) 5 8.4) 3 13. ft.58 (4. (203 mm). (19 mm) Cuts on Interior Face.4) 1 10.25 (0. (406 mm) Long Cut Units (3/4 in.43) 192 1/16 (1.7) 1 10. mortar joint r. ft. Both Ends) Ext. One End Only) Ext. (203 mm).67(10.74) 23 /32 (7. (406 mm) Long Units (Uncut) Ext.40) 43 /32 (4. ft.4) Table 4—Minimum Radii: 16 in.97) 92 /16 (1.59) 142 1/16 (1.75(12.8) 5 4. (406 mm). (m) nA p.30) 195 1/32 (0.9) 3 3.10) 48 /4 (6.5 mm) Ext.8) 3 15. (m) nA p. (mm) 4 (102) 6 (152) 8 (203) 10 (254) 12 (305) 3 /8 in.17 (9. (mm) 7 2.30) 40 /32 (4.5 mm) Ext.92 (4. in. (9.53) 54 /4 (6.5 mm) Ext.24) 162 1/32 (0.42 (1. (mm) 9 4.92) 28 /32 (5.99) 61 /32 (5. (19 mm) Cuts Interior Face. mortar joint r.2) 27.08) 32 13/32 (10) 5 9.33 (0. (mm) 5 2.6) 13.14) 35 /16 (4.67 (6. (25 mm) Ext.75 (1. (mm) 4 (102) 6 (152) 8 (203) 10 (254) 12 (305) 3 /8 in.92 (0. nominal 8 Nominal unit width. (mm) 1 19.92 (1.92 (2.0) The value of n listed is for a full circle (θ = 360o). Similar data for units cut as shown in Figure 3 are listed in Tables 3 through 6. Tables 1 and 2 present this data for 8 in. in. All tables assume that the interior head joint width is 1/8 in.mm) wide exterior head joint. multiply n by θ/360.50) 101 A 1 /4 in. respectively. 167 contact NCMA Publications (703) 713-1900 . For θ < 360o. Herndon. (m) nA 8 (203) 5'-4" (1. The number of units for the arc should be a whole number.ncma. that the radii provided in the Tables may vary by + 1 in.2 mm). (3. in. These tables list the minimum radii and number of units required to limit projections to 1/8 in. in. (203 mm) and 16 in. (6. (mm) t = actual unit thickness. measured to the midpoint of a unit. in. (203 mm) and 16 in. see AOB in Figure 1. ft-in.84) 25 10'-10" (3. (3. ft-in. projection of masonry unit corners beyond the faces of the units in the courses above and below (see also Figure 2). Table 7 should be consulted when the size of the projection is a prime consideration. NOTATIONS n = Number of concrete masonry units to complete the arc for the central angle θ. p = for masonry laid in running bond. (mm) S1 = length of each side of the polygon forming the exterior face of the wall (length of the unit plus the width of one exterior mortar joint). Using the larger exterior head joint width allows for smaller radii.30) 51 The value of n listed is for a full circle (θ = 360o). (406 mm) long units which have not been cut (as shown in Figure 3). Construction and unit manufacturing tolerances are such Table 7—Minimum Radii for Curved Concrete Masonry Walls to Limit Projections 1 /8 in. (6. degrees θ = central angle subtended for the complete arc of the curved wall (equals 360o for a complete circle). (mm) r. (m) nA 2'-9" (0. (25 mm). (mm) S2 = length of each side of the polygon forming the interior face of the wall (length of the unit plus the width of one interior mortar joint). (406 mm) long units.63) 50 16 (406) 21'-4" (6. in. degrees Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. (3.4 mm) for nominal 8-in.org To order a complete TEK Manual or TEK Index.2 mm) and 1/4 in. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. (mm) r = radius to the exterior face of the wall. Virginia 20171 www. (mm) β = the angle subtended by one side of a polygon (length of one concrete masonry unit). in.4 mm) maximum projection r.2 mm) Nominal unit maximum projection length. design wind speed and roof span. reinforced concrete masonry. 5 (M #16) min. The reader is Shear segment 2 ft (610 mm) min. based on Standard for Hurricane Resistant Residential Construction (ref. In coastal areas. they must be installed according to the manufacturer’s or building code specifications.829 mm) 1 No. Note that water penetration details are not specifically highlighted in the following details. high winds. floors and foundation—are critical to maintaining structural continuity during a high wind event. CONTINUOUS LOAD PATH Connections between individual building elements—roof. at each end of shear segments Beams spanning openings 1 No. 10). at each side of opening having a horizontal dimension greater than 6 ft (1. openings wider than 6 ft (1. construction details. 5 (M #16) min. If one part of the load path fails or is discontinuous. Note that in order for connectors to provide their rated load capacity. building failure may occur. walls. Standard 90° hook at each vertical bar. The critical 1 No. continuous load path. corrosion protection is especially important due to the corrosive environment. Top course reinforced bond beam continuous around perimeter Vertical wall reinforcement at 4 to 32 ft (1. Proper detailing and installation of mechanical connectors is necessary for maintaining continuous load paths. Footing dowel not always required.219 to 9. 3). typ. min.745 mm) o. residential INTRODUCTION High winds subject buildings to large horizontal forces as well as to significant uplift. resulting in the loss of crucial diaphragm support at the top of the wall. High wind provisions generally apply to areas where the design wind speed is over 100 mph (161 km/hr) and over three second gust as defined by ASCE 7 (ref. 5 (M # 16) min.829 mm) and ends of shear segments. The enclosed details represent prescriptive minimum requirements for concrete masonry buildings. at each corner and at each change in wall direction damage to buildings in such events typically occurs due to uplift on the roof. depending on wall height. Reinforced concrete masonry is well suited to resist the large uplift and overturning forces due to its relatively large mass. A primary goal for buildings subjected to high winds is to maintain a continuous load path from the roof to the foundation. This allows wind uplift forces on the roof to be safely distributed through the walls to the foundation. Footing dowels at corners.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology RESIDENTIAL DETAILS FOR HIGH WIND AREAS TEK 5-11 Details (2003) Keywords: architectural details. Figure 1—Typical Reinforcement for High Wind Areas 168 TEK 5-11 © 2003 National Concrete Masonry Association .c. for Grade 40. 48 bar diameters for Grade 60. Since wind suction forces on the leeward side of a building can be 169 . 8 ft (2. overhang Concrete masonry wall Vertical reinforcement. Each of the exterior walls on all four sides of the building and all interior walls designed as shear walls must have at least one 2 ft (610 mm) minimum section of wall identified as a shear segment to resist the high lateral loads. Vertical reinforcement should be placed in the center of the concrete masonry cores to adequately resist both positive and negative wind pressures.c. and where girders or girder trusses bear on the concrete masonry wall (refs. including: at corners and wall intersections.Engineered wood roof trusses or rafters at 24 in. DETAILS 8 ft (2. min.829 mm). See Figure 1 for a summary of reinforcement requirements (ref.4 x W 1. 4).c.050 mm) into slab and at least 6 in. the 40 bar diameter lap splice may still be used. See Steel Reinforcement for Concrete Masonry. a splice length of 40 bar diameters is required by Building Code Requirements for Masonry Structures (ref. max. 1) for Grade 40 reinforcement and 48 bar diameters for Grade 60 reinforcement. 3 ft (914 mm).440 mm) Above Grade Exterior Loadbearing Wall Figure 2 shows a typical loadbearing wall with a floating floor slab.. Bond beam depth and minimum horizontal reinforcement varies with design wind velocity. Reinforcement must be properly spliced to provide load path continuity. and hooked into bond beam Concrete footing Reinforcement. as required 40 bar diameter lap. Grout. max. (6 mm) expansion joint material and sealant Concrete slab Truss anchor rated for vertical uplift and horizontal loads perpendicular and parallel to the wall 24 in. max. at the ends of shear segments. Vapor retarder * Alternate: use No. 3 minimum at 4 ft (M# 10 at 1. maximum extending into slab 10 ft (3. as required Reinforced concrete footing Ceiling height 12 max. 3). W 1. Roof sheathing Bond beam Standard hook extended 6 in. (610 mm) o.438 mm). 1 4 in. (610 mm) max. (152 mm) into masonry bond beam referred to references 7 through 9 for more information on preventing water penetration in concrete masonry walls. as required Concrete masonry bond beam unit with part of interior face shell removed Concrete masonry wall Concrete slab with 6 x 6. on each side of openings wider than 6 ft (1. typ.438 mm) when top of stem wall is tied to slab (see Figure 3) 12 Figure 2—Exterior Loadbearing Wall Horizontal reinforcement.4 (152 x 152 mm. 3. MW 9 x MW 9) WWF*. TEK 12-4C (ref. ceiling height.219 mm) o. extending at least 10 ft (3. Longer shear segments are more effective and are recommended where possible or required by design. vertical reinforcement must be placed throughout a wall to resist the high uplift loads and provide continuity. (152 mm) into bond beam (min. as required Figure 3—Slab Connection for Foundation Wall 3 to 8 ft (914-2. In addition to a continuously reinforced bond beam at the top of the wall around the entire perimeter of the building. however. 5) for standard hook requirements.050 mm) min. roof truss span and spacing of vertical wall reinforcement. If the wall was designed assuming Grade 40 and Grade 60 was used for construction.) at each vertical wall reinforcement. Using allowable stress design. However. Figure 6a shows a continuous masonry gable end wall using either a raked concrete bond beam or a cut masonry bond beam along the top of full height reinforced concrete masonry gable end walls. 3). (13 mm) anchor bolt at 18 to 24 in.. the foundation wall may be extended to 8 ft (2. however. F2 and F3 are forces that must be accommodated in the design of the roof/wall connection. Gable End Walls Because of their exposure. as required Concrete masonry wall Note: F1. the direct embedded roof truss anchor method of connecting the roof to walls is preferred over the bolted top plate and hurricane clip method. Moisture barrier F3 Bond beam Grout stop Horizontal reinforcement.c. Roof Truss Anchor Figure 4 shows a typical roof truss anchor cast into the bond beam of a concrete masonry bearing wall. limitations are placed on the height above grade. gable end walls are more prone to damage than are hipped roofs unless the joint at the top of the end wall and the bottom of the gable (see Figure 6b) is laterally supported for both inward and outward forces. anchor bolt spacing must be reduced (24 in. this results in a weak point at the juncture of the two materials with little capacity to resist the high lateral loads produced by high winds. as it generally has greater capacity and fewer connections. a bolted top plate may be used for the roof to wall connection (see Figure 5). a braced gable end wall can be constructed as shown in Figure 6b by stopping the masonry of the gable end at the eave height and then using conventional wood framing to the roof diaphragm. F2 and F3 are forces that must be accommodated in the design of the roof/wall connection. Bolted Top Plate As an alternate to the roof truss anchor. (610 mm) maximum) because the top plate is loaded in its weak direction. The required anchor load capacity depends on the design wind speed as well as the roof truss span. 2.) 1 2 in. roof slope and roof span (ref. 6). the nail area available for the hurricane clip is limited by the thickness of the top plate. (457 to 610 mm) o. Bond beam Connector may be bent and prenailed on bottom side if additional nailing area is required Pressure treated Southern pine #2 or better top plate. The detail illustrates several different connector types that are commonly used to connect the truss to the top plate. typ. (610 mm) o. Direct embedded roof truss anchor installed per manufacturers specifications F1 F2 Roof truss at 24 in. the anchor must be rated for horizontal forces parallel to the wall (in-plane) and perpendicular to the wall (out-of-plane). 3.essentially as high as the pressure forces on the windward side. max. Figure 4—Roof Truss Anchor Connector (typ. Additionally. As an alternative. However. or as required Note: F1. Figure 5—Bolted Top Plate 170 .) F2 F1 F3 Oversized washer per design. unless the end wall is properly braced to provide the necessary lateral support as shown in Figure 6b. Often. The number and spacing of braces depends on design wind speed.440 mm) above grade (ref.c.. In addition to being rated for uplift. as required (2 x 4 min. if the slab is laterally supported and tied to the concrete masonry foundation wall as shown in Figure 3. 12 in. (305 mm) max.c. (13 mm) anchor bolt at 48 in. 7 16 in. 8d nails 6 in. 8 in. or proprietary anchor Bond beam Note: brace can be similarly used with a sloped beam at the top of a masonry end wall that terminates at the bottom of a vaulted ceiling (i.8d nails each side or 5 8 in.. (1 each side of stud) or as required 5 . ( 152 mm) o. (16 mm) diameter thru-bolt Uplift strap. or as required Facia Soffit Uplift strap.44 kN) at each stud or as required 1 2 in. (610 mm) o. (152 mm) o. (38 x 89 mm) min.c.8d nails each side or 5 8 in. (1. max. (13 mm) anchor bolts Foundation at one-story building or bond beam at multistory 6a—Continuous Gable End Wall Reinforcement 12 in.Standard 90° hook with lap Maintain minimum cover 4 in.8d toenails into brace o.c. (406 mm) 2 . Reinforced cast-in-place or cut masonry rake beam at roof line 2 x 4 in.c. scissors truss) Mesh or other grout stop device Concrete masonry wall with vertical reinforcement as required Joint in gable end wall 6b—Braced Gable End Wall Figure 6—Gable End Wall Construction 171 . (203 mm) 5 . (0. pressure treated or use moisture barrier 8d nails at 6 in. 100 lb (0. wood nailer with 1 2 in.e. (813 mm) o. in field 1 Oversized washer 2 x 6 (38 x 140 mm). at edges.c..c. (813 mm) o. 100 lb. (305 mm) o.c. (16 mm) diameter thru-bolt 2 x 6 (38 x 140 mm) at 16 in.c. 8d nails at 6 in. (152 mm) o. 2 x 4 (38 x 89 mm) continuous nailed 1 to truss webs (one per truss) Double 2 x 4 (38 x 89 mm) at 32 in.219 mm) o. 2 x 4 (38 x 89 mm) at 32 in. (102 mm) min.c.44 kN) at each stud or per design 2 (38 mm) x ladder framing at 24 in. (11 mm) rated structural panels. A 2 3/4 in. A ladder type overhang detail also can be used with the concrete rake beam where the beam is constructed to the same height as the trusses similar to that shown for the cut masonry rake beam in Figure 7b. an outlooker type overhang is shown where the rake beam is constructed 31/2 in. Concrete Rake Beam With Outlooker Type Overhang 12 in. overhang Facia Soffit 2 x 4 (38 x 89 mm) at 24 in. A minimum of height of 4 in. an outlooker type overhang detail can be used similar to that shown for the cast-in-place concrete rake beam in Figure 7a. However. (610 mm) o. 4 in. Figure 7b shows a continuously reinforced cut masonry rake beam along the top of the gable end wall. The beam is formed over uncut block in courses successively shortened to match the slope of the roof. Beam height varies. as required A A Cut masonry rake beam 7b—Section A-A. max or per design Moisture barrier Cut concrete masonry units to match slope. as required Grout. as required Grout. In this detail.c. (1. max. (203 mm) concrete rake beam with 1 No. 172 . max. (610 mm) o. as required A A Grout stop location 7a—Section A-A. (102 mm) min. 2 x 4 (38 x 89 mm) (min.829 mm) o. (102 mm) is needed from the highest projected corner of block to the top of the beam. (89 mm) lower than the trusses so that a pressure treated 2 x 4 (38 x 89 mm) can pass over it.) pressure treated wood nailer Standard hook with lap. (70 mm) deep notch is cut into the tops of the concrete masonry webs to allow placement of reinforcement that is continuous with the bond beam reinforcement in the side walls. 5 (M #16) bar min. (305 mm) max. Notch webs 2 3 4 in.c. (610 mm). Cut Concrete Masonry Rake Beam With Ladder Type Overhang Figure 7—Gable End Wall Gable End Wall Overhangs Figure 7a shows a continuously reinforced cast-in-place concrete rake beam along the top of the gable end wall. A minimum of 4 in. 5 (M #16) or as required Mesh or other grout stop device for cells not reinforced Concrete masonry wall Vertical reinforcement. typ. overhang Roof sheathing Wood roof truss 8 in. (13 mm) anchor bolt at 3 ft. (70 mm) for reinforcement Continuous reinforcement. (102 mm) minimum depth) 90° standard hook Concrete masonry wall Vertical wall reinforcement. 1 No.. (4 in.c. Reinforcement that is continuous with the bond beam reinforcement in the side walls is placed in the top of the beam. max. In this figure. 1 2 in. Facia Soffit 24 in. (102 mm) is needed for the cut masonry bond beam. Masonry units are cut to conform to the roof slope at the same height as the roof trusses.Pressure treated 2 x 4 (38 x 89 mm) at 24 in. a ladder type overhang is shown. 5. National Concrete Masonry Association. Provided by: Disclaimer: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. Building Code Requirements for Masonry Structures. TEK 19-2A. Virginia 20171 www. Flashing Strategies for Concrete Masonry Walls. 1997. Inc. Reported by the Masonry Standards Joint Committee. Herndon. 2002. 10. National Concrete Masonry Association. 2003. 7. National Concrete Masonry Association. 2002. International Code Council. TEK 19-4A. National Concrete Masonry Association. The Guide to Concrete Masonry Residential Construction in High Wind Areas. 2. 2002. Annotated Design and Construction Details for Concrete Masonry. TEK 19-5A.Minimum Design Loads for Buildings and Other Structures . 1999. Southern Building Code Congress International. 2000 International Building Code. SSTD 10-99. ASCE 7-02. Florida Concrete & Products Association. American Society of Civil Engineers. 6.REFERENCES 1. 2003.org To order a complete TEK Manual or TEK Index. 3. 4. Standard for Hurricane Resistant Residential Construction.. 2002.ncma. National Concrete Masonry Association. TEK 12-4C. TR 90B. ACI 530-02/ASCE 5-02/TMS 402-02. 9. Design for Dry Single-Wythe Concrete Masonry Walls. Flashing Details for Concrete Masonry Walls. Inc. 2003.. 2000. Steel Reinforcement for Concrete Masonry. 8. 173 contact NCMA Publications (703) 713-1900 . construction details. Interruption of bond pattern—In addition to the aesthetic impact a change in bond pattern can create. For economy. The heights of masonry openings to accommodate windows are typically 8 in. Masonry openings for doors are commonly either 2 or 4 in.118 and 1. but may also include 4in. Hollow metal frames for doors should be ordered and delivered for the masonry before the other door frames in the project are scheduled for delivery. These modules provide overall design flexibility and coordination with other building products such as windows. TEK 5-12 © 2008 National Concrete Masonry Association Modular Wall Openings The rough opening dimensions illustrated in Figure 1 apply to the layout and construction of the masonry. If the walls are built before the frames are set. When a project does require non-modular layout. 36. and 52 in. Walls incorporating more than a single bond pattern may present a unique design situation. the widths of masonry openings for doors and windows should generally be 4 in. allowing for the door framing as well as the use of a standard-sized door. jobsite decisions must be made—often in haste and at a cost. Locating control joints—In running bond. (51 mm) notch to accommodate 80-in. (51 mm) on each side of the opening for framing. (203 mm) greater than the height of the window if a 4-in. When modular coordination is not considered during the design phase. door heights 2 in. concrete masonry elements should be designed and constructed with modular coordination in mind. Thus. (711. further design and construction issues need to be addressed. To allow for fastening windows and doors to the masonry. This TEK provides recommendations for planning masonry construction to minimize cutting of masonry units or using nonstandard unit sizes. In addition. INTRODUCTION Although concrete masonry structures can be constructed using virtually any layout dimension. Modular window heights are any multiple of 8 in. Similarly.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology MODULAR LAYOUT OF CONCRETE MASONRY Keywords: construction. This opening size allows for 2 in. (51 or 102 mm) greater than the door height. 1. (102 mm) modules for some applications.134 mm) high door.032 mm) doors. (2. metric. (102 mm) larger than the door or window width. the nominal heights and widths of these elements are slightly less. stack bond construction only requires full-size units when control joints are properly spaced and detailed. (102 mm) for installation of a sill at the bottom of the window. with other bond patterns units may need to be cut if specially dimensioned units are not used or are not available. 174 . 914. Modular coordination is the practice of laying out and dimensioning structures and elements to standard lengths and heights to accommodate modular-sized building materials.321 mm) (and so on in 8 in. with a masonry window opening 8 in. For the commonly available 84-in. (2. and other similar elements as shown in Figures 1 and 2. the frames should be set before the walls are built. However. modular coordination. building codes often contain different design assumptions for masonry constructed in running bond versus other bond patterns. however. the laying of units in other than running (half) bond or stack bond interrupts the vertical alignment of unit cells. Modular Wall Elevations Standard concrete masonry modules are typically 8 in. 44. (203 mm). wall openings TEK 5-12 Details (2008) (203 mm) vertically and horizontally. For conventional construction methods. As a result. control joint construction can be accomplished using only full and halfsize units. and partial grouting of walls is virtually impossible. dimensions. precast lintels are available in some areas containing a 2 in. This allows for 2 in. (203 mm) greater than the window height. for maximum construction efficiency and economy. a 4-in. (102 mm) sill will be used. door and window widths of 28. doors. (203 mm) increments) do not require the masonry to be cut. (51 mm) above and below for framing and 4 in. additional costs are incurred to set special knock down door frames and attachments. reinforcement placement and adequate consolidation of grout becomes difficult. (102 mm) door buck can be placed at the top of the opening. Similarly. (51 mm) less than any even multiple of eight can be installed without the need for cutting the masonry. including: Placement of vertical reinforcement—In construction containing vertical reinforcing steel. (9.016 mm) 24 in. The end product is more difficult to construct. it is obvious the aesthetic impact non-modular layouts have on the final appearance of a structure. (203 by 406 mm). (406 mm) Figure 1— Modular Wall Elevations Modular Wall Sections For door and window openings.016 mm) 16 in. (1. Not so obvious is the additional cost of construction. 88.5 mm) (as may be specified for aesthetic purposes or with brick construction).26 m2) net Number of units used in non-modular layout = 122 Number of units used in modular layout = 110 Recommended Construction: The wall elevation shown here reduces the need to cut units by utilizing modular openings and opening locations (i. units align (which facilitates the (1. p l a c i n g a n d consolidating grout in the reduced-size cores of the field-cut units may prove difficult. By coordinating opening sizes and locations. produces more waste. (102 or 203 mm) module is maintained with 3/8 in.38 m2). (1.048 mm) 88 in.016 mm) 12 in. (1. (2. and are available in nominal widths ranging from 4 in. (9. Where mortar joint thicknesses differ from 3/8 in.134 mm) 44 in.87 m2) net Total area of modular layout = 126. (1.77 m2).9 ft2 (8. each dimension shown is evenly divisible by 8 in. consider the following comparison of the modular and non-modular layouts shown here: Total area of non-modular layout = 122. the module size for bond patterns and layout are nominal dimensions. the cells of hollow masonry 48 in. (1.016 mm) 24 in. In addition to these standard sizes. Typically. The designer should always check local availability of specialty units prior to design. Actual dimensions of concrete masonry units are typically 3/8 in.219 mm) placement of vertical reinforcement and consolidation of grout). 48 in.946 mm) 84 in.219 mm) 120 in. and is more costly compared to a similar structure employing a modular layout. (2. (610 mm) 40 in. labor time is reduced and materials are not wasted. (305 mm) = Nonstandard or field-cut units In this example. (1. 52 in. (9. (914 mm) 40 in.7 ft2 (7.7 ft2 (11. (813 mm) 40 in.5 mm) less than nominal dimensions.321 mm) 116 in. heights and lengths may be available from concrete masonry producers. 84. other unit widths. A d d i t i o n a l l y.. concrete masonry units have nominal face dimensions of (height by length) 8 by 16 in. to 16 in. (102 to 406 mm) in 2-in.4 ft2 (11. so that the 4 or 8-in. Figure 3 illustrates this concept. special consideration is required to maintain modular design.235 mm) 32 in.5 mm) mortar joints. (1. (203 mm).118 mm) 36 in. 175 . To further illustrate this concept.Not Recommended Construction: Utilizing non-modular layouts or openings results in unnecessary cutting of the masonry units (shown here as shaded). (2. (51 mm) increments.e. (610 mm) 40 in. (3. 1. (11 mm) 8 in. 7 7 8 in. (51 mm) Framing 2 in. (51 mm) Framing 2 in.Masonry Opening Width = Window Opening Width + 4 in. (57 mm) 2 1 4 in. (102 mm) 2 in. · Appropriate joint thickness selected. (9. (51 mm) Framing Masonry Opening Height = Window Opening Height + 8 in. (51 mm) Framing 4 in. Not Recommended Construction: · Misalignment of bed joints makes installation of wall ties difficult and reduces their effectiveness in transferring loads. 3) Figure 3—Modular Wall Sections 176 . (203 mm) Wall tie 3 in. (32 mm) max. (102 mm) Sill Height 2 in. (203 mm) (197 mm) Wall tie 5 8 in. · May be partially compensated for by the use of adjustable wall ties. (57 mm) Recommended Construction: · Vertical coursing of bed joints of each wythe align. (203 mm) Masonry Opening Width = Door Opening Width + 4 in. (51 mm) Window Openings 2 in. misalignment (refs. (51 mm) Framing Door Openings Figure 2—Modular Wall Openings 8 in. 11/4 in. 2.5 mm) 12 2 1 4 in. (203 mm) 8 in. (102 mm) 2 in. (51 mm) Framing 2 in. (51 mm) Framing Masonry Opening Height = Door Opening Height + 2 in. · Inappropriate joint thickness selected. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. (203 mm) high module. Herndon. 2008. Reported by the Masonry Standards Joint Committee. 2004. The specified dimensions of modular concrete and clay brick are typically 3 5/8 by 2 1/4 by 7 5/8 in. Metric Design Guide for Concrete Masonry Construction. REFERENCES 1. (9. (203 mm). (203 to 406 mm) and height from 2 1/2 to 6 in. Brick most commonly have a nominal width of 4 in. 3. complications can arise if they are incorporated into a structure designed on a 100 mm (3. This allows constructing each course of a wall using only full-length or half-length units. sections and openings. In addition. the overall plan dimensions of a structure also need to be considered.1-05/ASCE 6-05/TMS 602-05.) less than the nominal dimensions to provide for the mortar joints. (64 to 152 mm). National Concrete Masonry Association. Building Code Requirements for Masonry Structures.ncma. 2). Because of their unique dimensions.) metric module. 2. thereby maintaining modular coordination (see Figure 3). (203 mm) module over the length of a wall facilitates the turning of corners. Ideally. 2000. Metric Concrete Masonry Construction (refs. 6) provide detailed guidance for incorporating soft metric units (standard inch-pound units) into a hard metric design project. (11 mm) thick bed joint. Thus. These units are specifically manufactured to turn corners without interrupting bond patterns. (203 mm). Concrete Masonry Corner Details. ACI 530-05/ASCE 5-05/TMS 402-05. (68 mm) for one brick and one mortar joint. ACI 530. 4. the nominal plan dimensions of masonry structures should be evenly divisible by 8 in. TEK 3-10A. TEK 5-9A. As an alternative to cutting units or changing building dimensions. (102 mm). 4) contains a variety of alternatives for efficiently constructing corners. Metric Concrete Masonry Construction. National Concrete Masonry Association. International Code Council. (Note that a 5/12 in. Reported by the Masonry Standards Joint Committee.org To order a complete TEK Manual or TEK Index. Virginia 20171 www. 5. can present unique modular coordination considerations in addition to those present with single wythe construction. (11 mm) thick bed joint is within allowable mortar joint tolerances (refs. the nominal metric equivalent of an 8 by 8 by 16 in. For example. (92 by 57 by 194 mm). 6. whereby half of the units from one wall interlock with half of the units from the intersecting wall. Similar to inch-pound units. common modular brick are laid with a 5/12 in. unit is 200 by 200 by 400 mm (190 by 190 by 390 mm net unit dimensions). Metric Coordination One additional consideration for some projects is the use of standard sized (inch-pound) masonry units in a metric project. TEK 5-9A (ref. 2005. thereby providing a constructed height of 2 2/3 in. 2003 and 2006. 1.) The result is that three courses of brick (including the mortar joints) equals one 8-in. Since inch-pound dimensioned concrete masonry units are approximately 2% larger than hard metric units. masonry units produced to metric dimensions are 10 mm (13/32 in. 2005. Metric Design Guide for Concrete Masonry Construction and TEK 3-10A. but may be available in a wide range of dimensions. Specification for Masonry Structures. which in turn reduces labor and material costs. Provided by: Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible. corner block can be used if available. Modular Building Layouts and Horizontal Coursing In addition to wall elevations. 177 contact NCMA Publications (703) 713-1900 .9 in. International Building Code. 5. length varying from 8 to 16 in. concrete and clay brick are usually laid with bed joints that are slightly larger (or sometimes smaller depending upon the actual size of the brick) than the standard 3/8 in. maintaining an 8-in. National Concrete Masonry Association. NCMA does not assume responsibility for errors or omissions resulting from the use of this TEK. or vice versa. TR-172.Incorporating brick into a project. especially when using units having nominal widths other than 8 in. Concrete Masonry Corner Details.5 mm) mortar joint thickness. either as a structural component or as a veneer. Dead loads include the weight of the door curtain. operator. fire resistance. On doors without windlocks. are covered in Allowable Stress Design of Concrete Masonry Lintels and Precast Concrete Lintels for Concrete Masonry Construction (refs. door jambs.3). to carry the loads imposed on the top of the opening. (305-762 mm). For doors with windlocks. and are heavily dependent on the structural integrity of the door jamb members as they are attached to building walls at jamb locations. reinforcement. LOADS EXERTED BY ROLLING DOORS Architects and building designers should determine the loads that rolling doors exert on the wall around the opening. Changing the door manufacturer's recommended jamb fastener locations may reduce the structural performance of the rolling door or possibly void the fire rating. The rolling door manufacturer can provide a guide data sheet for quantifying the loads imposed by the overhead coiling doors due to the design wind load. The typical masonry jamb detail shown in Figure 3 indicates recommended vertical reinforcement locations 178 TEK 5-13 © 2007 National Concrete Masonry Association . lateral loads. Including these forces in the design of the jamb and its supporting structure can help prevent a jamb failure and allow the building to fully withstand its specified wind load requirements.. etc. as either can negatively impact performance. Calculating the parallel force involves several variables. the rolling doors have been designed for specific wind load applications. wall openings. 1. Live loads result from wind that acts on the door curtain.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology ROLLING DOOR DETAILS FOR CONCRETE MASONRY CONSTRUCTION TEK 5-13 Details (2007) Keywords: construction details. which prevent the door curtain from leaving the guides due to wind loading. 2). the only wind load force that the curtain exerts on the guides is normal to the opening. The door guide wall angles must be mounted to the wall above the opening to support the door. When openings incorporate rolling doors (also referred to as overhead coiling doors or coiling doors). The following conditions need to be considered: • The wall above the door opening must be designed to support the total hanging dead load. • Reinforcement in jambs is recommended to adequately distribute the forces imposed by the door. wind loads on the door are transferred to the surrounding masonry through the door guides and fasteners. It is also important to note that the door must withstand both positive and negative wind loads. The face of wall-mounted doors may extend above the opening for 12 to 30 in. The door is exposed to a additive wind loads. Lintel design. In some instances. from both inside and outside the building. respectively). This load is the catenary tension that results when the curtain deflects sufficiently to allow the windlocks to engage the windbar in the guide. hood. This TEK discusses the forces imposed on a surrounding concrete masonry wall by rolling doors. See also Fasteners for Concrete Masonry (ref. counterbalance. • Reinforcement locations should be planned such that the reinforcement does not interfere with expansion anchor placement. some provision must be made to fasten the top of the hood and hood supports to the masonry wall. wind loads INTRODUCTION Openings in concrete masonry walls utilize lintels and beams to carry loads above the openings. ACCOMMODATING MASONRY REINFORCEMENT AND DOOR FASTENERS Rolling door contractors and installers sometimes encounter reinforcement in walls at locations where door jamb fasteners have been specified. This force acts to pull the guides toward the center of the opening. Rolling doors are available with windlocks. and includes recommended details for jamb construction. Arbitrarily changing either the reinforcement location or the fastener location is not recommended. there is an additional load parallel to the opening (see Figures 1 and 2 for facemounted and jamb-mounted doors. the most prominent of which are the width of the opening and the design wind load. fasteners. that is supported by the wall above the opening. When the door has a hood to cover the coiled door and counter-balance. The Door and Access Systems Manufacturers Association International (DASMA) recommends that vertical reinforcement should be within 2 in. The detail shows a “reinforcement-free zone” to allow for fasteners of either face-mounted or jamb-mounted rolling doors. DASMA recommends that one of the following courses of action be taken: 1. Consult with individual manufacturers for specific guide details and approved jamb constructions. Figure 4 shows a representative jamb construction and guide attachment details for a four-hour fire rated assembly. the following steps should be followed to locate the reinforcement. which would not interfere with the existing reinforcement. (51 mm) of either corner of the wall at the jamb (ref. Another solution may be to bolt a steel angle to the concrete masonry jambs. 5) 179 . One possible solution is to contact the door manufacturer to obtain an alternate conforming hole pattern for the mounting. if it is concluded that the reinforcement will interfere with installing jamb fasteners. Once the steel reinforcement has been located. either drill representative “pilot holes” or use a device similar to an electronic stud locator to determine the steel reinforcement locations. consult a structural engineer to determine a workable solution. which allows the door guides to then be welded or bolted to the steel angle. Force F5 Door opening Door opening B Load Direction 1 Curtain Force F2 Force F3 Load Direction 1 Curtain Force F2 C Force F1 Load Direction 2 Force F4 (a) Without windlock C B A Force F2 (a) Without windlock Force F5 Door opening Force F1 Windbar Load Direction 2 Load Direction 1 Curtain Force F3 Windlock Load Direction 2 (b) With windlock Figure 1—Imposed Forces for Face-Mounted Doors (ref. Note that guide configurations and approved jamb construction will vary with individual fire door manufacturer's listings. to avoid interference: • If structural drawings are available. If an alternate door jamb mounting or alternate door size cannot be accomplished. the doors are mounted on the jambs of a concrete masonry wall intended to replicate field construction. 5) Door opening Force F3 B C Force F1 Force F2 Windlock Force F4 Windbar Load Direction 1 Curtain Load Direction 2 (b) With windlock Figure 2—Imposed Forces for Jamb-Mounted Doors (ref. Existing Construction Before installing fasteners in existing masonry construction. Consider an alternate door jamb mounting or door size to assure that the reinforcement will not interfere with jamb fasteners. The fire door guides must remain securely fastened to the jambs and no “through gaps” may occur in the door assembly during the test.for concrete masonry jambs to provide an area for the door fasteners. rolling steel fire doors must meet the code-required fire rating corresponding to the fire rating of the surrounding wall. • If the building’s structural plans are not available. C B Force F1 A Force F3 2. the project engineer should review the drawings to determine whether or not the jamb reinforcement locations conflict with the specified door jamb fastener locations. FIRE-RATED ROLLING DOOR CONNECTIONS When installed in a fire-rated concrete masonry wall. For fire testing. 4). However. (51 mm) A max. (38 mm) for No. (51 mm) A max. 7) to protect against steel corrosion. (51 mm) max. 7) to protect against steel corrosion. and 2 in. 5 (M#16) bars and smaller. FM Approvals (Factory Mutual) does not allow guides to be welded to steel jambs. clearance A Note that a minimum amount of masonry cover over reinforcing bars is required (refs. Figure 3—Typical Masonry Jamb Detail for Face-Mounted and Alternate Jamb-Mounted Rolling Doors (ref. clearance Vertical reinforcement Grout-filled cell Alternate jamb-mounted door Thickness varies 2 in. (38 mm) for No. See Steel Reinforcement for Concrete Masonry (ref. clearance Vertical reinforcement Grout-filled cell A 2 in. 8)B 180 . DASMA recommends a maximum distance of 2 in. However. (51 mm) for bars larger than No. and 2 in. 4) in order to provide the largest possible clear area for fastener installation. this minimum cover is 11/2 in. 4) in order to provide the largest possible clear area for fastener installation. (51 mm) for bars larger than No. 4) 2 in. this minimum cover is 11/2 in. 6. clearance Face-mounted door A Note that a minimum amount of masonry cover over reinforcing bars is required (refs. See Steel Reinforcement for Concrete Masonry (ref. Figure 4—Approved Jamb Construction for Maximum 4-Hour Fire Rating (ref. B Note: Underwriters Laboratories has approved the welded guide details ONLY AS SHOWN. (51 mm) A max. 5 (M#16) bars and smaller.2 in. 9) for more detailed information on placing reinforcement in concrete masonry. 6. For masonry exposed to weather or earth. (51 mm) from the face of the masonry to the reinforcing bar (ref. DASMA recommends a maximum distance of 2 in. 5 (M#16). (51 mm) from the face of the masonry to the reinforcing bar (ref. 9) for more detailed information on placing reinforcement in concrete masonry. 5 (M#16). clearance 2 in. (51 mm) A max. For masonry exposed to weather or earth. 7. Virginia 20171 www. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive.REFERENCES 1. TEK 12-4D. 2003. 6. TEK 17-1B. TDS-259. Architects and Designers Should Understand Loads Exerted By Overhead Coiling Doors. Door and Access Systems Manufacturers Association International. 2006. 5. 9. 2005. TEK 12-5. International Code Council. National Concrete Masonry Association. National Concrete Masonry Association.ncma. TEK 17-2A. 2005. International Building Code 2006. Allowable Stress Design of Concrete Masonry Lintels. 2005. National Concrete Masonry Association. Metal Coiling Type Door Jamb Construction: Steel Reinforcement In Masonry Walls. International Code Council. 2001. TDS-251. 2005.org To order a complete TEK Manual or TEK Index. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. Herndon. 2006. Common Jamb Construction for Rolling Steel Fire Doors: Masonry Construction—Bolted and Welded Guides. Door and Access Systems Manufacturers Association International. 4. TDS-261. 8. Fasteners for Concrete Masonry. Steel Reinforcement for Concrete Masonry. International Building Code 2003. Door and Access Systems Manufacturers Association International. Precast Concrete Lintels for Concrete Masonry Construction. National Concrete Masonry Association. 3. 2. 181 contact NCMA Publications (703) 713-1900 . 2000. In contrast. found that the FEMA recommendations were overly conservative for concrete masonry for impact resistance. as well as openings such as doors and windows. 9). Concrete masonry walls capable of meeting the ICC-500 requirements are presented. lighting. The reader is referred to the standard (ref. 1. based primarily on providing a continuous load path from roof to foundation. although exposure B is permitted if it exists for all wind directions. and residential shelters. 1) for maps defining these speeds. impact. Research performed at the Texas Tech University Wind Science and Engineering Research Center (ref. • walls and ceiling. When the shelter is to provide shelter from both hurricanes and tornadoes. Therefore. TEK 5-11. Storm shelters are buildings. and do not address storm shelters. Note that wind speeds in ICC-500 are much higher than wind speeds in ASCE-7 (ref. must withstand design wind pressures and resist penetration by windborne objects and falling debris. Residential Details for High-Wind Areas (ref. or parts of buildings. hurricane. 4). ICC-500 WIND DESIGN CRITERIA FOR SAFE ROOM WALLS AND FLOORS General design considerations for storm shelters include: • adequate wall and roof anchorage to resist overturning and uplift. In allowable stress design. the wind load contribution in the load combinations is adjusted accordingly. The newly-developed standard ICC-500. these storms require residents to either evacuate the area or seek protection in dedicated shelters. and • connections between building elements must be strong enough to resist the design wind loads. These are general residential details. 0. the FEMA 361 publication Design and Construction Guidance for Community Shelters. 7) or the International Building Code (refs. reinforced masonry. provides design and construction requirements for hurricane and tornado shelters. where the occupants can safely seek refuge during a hurricane or tornado. as well as the results of impact testing on concrete masonry walls. high winds. and are considered to provide the maximum or ultimate tornado or hurricane design wind speed at a site. Note that this TEK does not address all requirements of ICC-500. resulting in more economical wall designs than those previously recommended by FEMA. testing. Figure 2 shows a typical detail for connecting a concrete roof slab to concrete masonry shelter walls. TEK 5-14 Details (2008) 5). and includes requirements for two types of shelters: community shelters. 6). builders and homeowners seeking storm shelter guidance have used the FEMA 320 publication Taking Shelter From the Storm: Building a Safe Room Inside Your House. Concrete masonry walls have been tested to withstand the ICC-500 criteria. Standard on the Design and Construction of Storm Shelters (ref. egress and fire safety. 2. Prior to the publication of ICC-500. that are designed and built specifically to provide a highly protected space where community members or occupants can seek refuge during these events. 8.NCMA TEK National Concrete Masonry Association an information series from the national authority on concrete masonry technology CONCRETE MASONRY HURRICANE AND TORNADO SHELTERS Keywords: construction details. storm shelters. Hurricanes and tornadoes produce wind pressures and generate flying debris at much higher levels than those used to design most commercial and residential buildings.0W rather than 1. such as hurricanes and tornadoes. can pose a serious threat to buildings and their occupants in many parts of the country. ICC-500 covers both hurricane and tornado shelters. buildings specifically dedicated to provide shelter during a storm. 1).6 W is used as the factored wind load in strength design combinations. which are typically reinforced rooms within a home. provides prescriptive requirements for reinforced concrete masonry homes in hurricane-prone areas. sanitation. 3. using reinforcing bars to provide adequate load transfer. tornado INTRODUCTION Extreme windstorms. or to shelter areas within a home. the most restrictive of the two design criteria should be used for design. 182 TEK 5-14 © 2008 National Concrete Masonry Association . meant to provide temporary protection during a storm. and the NCMA publication Concrete Masonry Tornado Safe Rooms (refs.6W is used instead of W. Wind pressures are to be based on exposure C. and hurricane design wind speeds for applicable coastal areas. however. Hence. ICC-500 defines design tornado wind speeds across the United States. the requirements described in this TEK apply only to dedicated shelters. as well as requirements for ventilation. For example. The standard covers structural design requirements for these shelters. (203-mm) concrete masonry walls with No.1 kg) wooden 2 x 4 propelled at 100 mph (161 km/h).c.) Reinforced lintel above door w/one No.44 m) to reduce vulnerability to overturning. Regardless of the concrete masonry density..8 kg) wooden 2 x 4. (1. For tornado shelters. as follows. walls subject to this 237 mph (381 km/h) design wind speed must be capable of withstanding impact from a 9 lb (4. 4).. can withstand these conditions.8 kg) 2 x 4 propelled at 100 mph (161 km/h) (ref. 5 (M #16) 16 ga. (178-mm) deep bottom chord bearing steel joists infilled with concrete masonry units and Impact rated door max. (152-mm) concrete masonry walls with No. the highest design wind speed in ICC-500 is 237 mph (381 km/h) (with the exception of Guam.83 to 2. metal door frame 8 in. (1. shelter walls and ceilings must be able to withstand impact from flying debris. Although solidly grouted 6-in.219 mm) o. Corresponding walls and ceilings must withstand impact from a 15 lb (6. successfully passed the impact test. (203 mm) CMU. based on a 250 mph (402 km/h) wind speed. the details included in this TEK show 8-in. (152-mm) walls may be adequate for lower wind requirements. ICC-500 defines requirements for tie-down to the foundation and adequate foundation sizing to resist the design overturning and uplift forces. In addition. Ceilings and other horizontal surfaces must withstand impact from the same projectile propelled a 25 mph (40 km/h). These conditions will more than satisfy the less stringent requirements for hurricane shelters. the weight of the grouted masonry assembly provides increased overturning resistance compared to low-mass systems. 4 (M #13) bars at 32 in. max. propelled at 100 mph (161 km/h) and 67 mph (108 km/h). Solidly grouted 8-in.c. they may not have enough weight to resist overturning for the most severe tornado loading.83 to 2.44 m) is optimum for stability 1 ft 6 in. Figure 1—Plan View of Typical Concrete Masonry Storm Shelter 183 . at the top of the wall and in the footing or bottom of the wall. which has a design hurricane wind speed of 256 mph (412 km/h)). size 3 ft (914 mm) (door may swing in or out) Tee anchorage four per jamb 6ft to 8 ft (1. (203-mm) storm shelter walls. (457 mm) No. In addition to these requirements. The engineer will use the masonry weight in the shelter design to resist overturning. 5 (M #16) reinforcement at 48 in. (813 mm) o. the highest design wind speed prescribed by ICC-500 is 250 mph (402 km/h). however. Solidly grouted 6-in.c. 5 (M #16) vertical reinforcement at 48 in. respectively. All weight classes of concrete masonry meet the strength and impactresistance requirements. The ICC-500 design criteria vary with location. min. Several concrete masonry systems have been successfully tested to withstand the 15 lb (6. A ceiling system using 7-in. For hurricane shelters.In addition to being designed for these design wind speeds. 5 (M#16) min. Hence. whose projectile speed varies with the design wind speed. CONCRETE MASONRY ASSEMBLIES FOR STORM SHELTERS A typical concrete masonry storm shelter design is shown in Figure 1.44 m) is optimum for stability 6 ft to 8 ft (1. with one horizontal No. 3 ft (914 mm) Grout solid (typ. The concrete masonry walls tested at Texas Tech were tested at the most stringent of the ICC-500 wind speeds and impact requirements. Grout all cells solid Note: The total height of the shelter (from the top of the floor slab to the top of the ceiling slab) should not exceed 8 ft (2.219 mm) o. Below-ground safe rooms provide the greatest protection. Figures 3 through 5 illustrate typical details for connecting shelter elements to an existing basement wall. that considering the weight of fully grouted concrete masonry. under the following conditions: • the calculated soil pressure under the slab supporting the Do not attach shelter ceiling to floor or ceiling above 4 in. a concrete masonry storm shelter would have required a large dedicated foundation. 5 (M #16) continuous in bond beam Figure 2—Typical Shelter Wall/Ceiling Connection Existing reinforced 8 in. When these conditions are met. but this is contrary to the building code and is highly discouraged. The results of recent testing (ref. Research confirms. with soil the full height of the shelter New masonry shelter walls (see Figures 4 and 5) Figure 3—Retrofit Shelter: Plan View No. (203 mm) o. Residential Retrofit Special consideration must be given when retrofitting a shelter into an existing home. Splice per code A This slab reinforcement is not required when the slab dead load is not required to resist overturning. Figure 4—Retrofit Shelter: Direct-Dowel to Existing Slab 184 .4 A WWF. with a slope no greater than two inches per foot (167 mm/m) for that 3 ft (914 mm) distance. 4 (M #13) reinforcing bar epoxied into floor slab at all corners and each side of doorway. 4 (M #13) bar at 16 in. Accordingly.8 kg) 2 x 4 at 67 mph (108 km/h) protocol (ref. When shelters are located below grade. CL 8 in. thickness existing slab-on-grade w/ 6 x 6 W1. (203 mm) solid grouted CMU min. (406 mm) o.c. with 4 in. 5 (M #16) at 48 in. (203 mm) masonry basement wall. which is designed for a much lower loading. 10). min. as long as they are designed to remain dry during the heavy rains that often accompany severe windstorms.grout to a nominal 8-in. an interior room on the first floor on a foundation extending to the ground or on top of a concrete slab-on-grade foundation or garage floor as good locations for an in-home shelter. a large foundation is not required to adequately resist the uplift and overturning forces. The shelter should be accessible from all areas of the house and should be free of clutter to provide immediate shelter. (102 mm) cast-in-place roof. 4 (M #13) or one No. min. min. 2) suggests a basement. ICC-500 allows concrete masonry storm shelters to be constructed within one and two family dwellings on existing slabs on grade without a dedicated foundation. 31 2 in. (406 mm) o. will not result in a failure of the safe room. the shelter must not be built where it can be flooded.219 mm) o. min. Below-grade ceilings must have a minimum of 12-in. solid grouted with one No. (89 mm) min. each way. the walls do not need to meet the missile impact requirements described above. the soil surrounding the walls can be considered as protection from flying debris during a high wind event. 4) has improved the economy of constructing retrofits.4 (M #13) bar at 16 in. If not within the residence. rather than grout. (1.1 x W1.72 m) of the residence (ref. min.c. In flood prone areas. Sections of either interior or exterior residence walls that are used as walls of the safe room must be separated from the structure of the residence so that failure of the residence. Previously. however. (102 mm) No.c. min. No. Some previous references recommend the use of concrete to fill the masonry cores. 1). as long as the wall is completely below grade and soil extends at least 3 ft (914 mm) away from the wall. Concrete ceiling No. 4 (M #13) reinforcing bars were placed perpendicular to the joists.c. (203 mm) CMU wall. Two No. 8 in. the shelter needs to be within 150 ft (45. RESIDENTIAL SHELTERS The purpose of an in-home shelter is to provide an area where the occupants can safely shelter during a high wind event. FEMA (ref. at 8 in. (305-mm) of soil cover to be exempt from the impact testing requirements. Note that all assemblies were successfully tested using standard masonry grout per ASTM C 476 (ref. (203-mm) depth was also tested and found to withstand the 15 lb (6. 4). . 6.ncma. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. the storm shelter is anchored to the slab at each corner of the structure and on each side of the doorway opening (see Figure 4). Inc. 2002. 185 contact NCMA Publications (703) 713-1900 . Federal Emergency Management Agency. International Code Council. National Concrete Masonry Association. Residential Details for High-Wind Areas.000 psf (95.c. FEMA 361. ASCE 7-02 and ASCE 7-05. 5. TEK 5-11. Design and Construction Guidance for Community Shelters. National Concrete Masonry Association. Taking Shelter From the Storm: Building a Safe Room Inside Your House. 2003. 2003. Standard Specification for Grout for Masonry. NCMA Publication MR 21. FEMA 320. 7. 2006 International Building Code. Minimum Design Loads for Buildings and Other Structures. • at a minimum. 9. but require a larger area and additional features in anticipation of sheltering more people. (406 mm) o. wall. 2008. Epoxy No. 2. ASTM C 476-07. ASTM International. For example. and • the ICC-500 slab reinforcement requirements are waived if the slab dead load is not required to resist overturning. ICC-500. Virginia 20171 www. Investigation of Wind Projectile Resistance of Concrete Masonry Walls and Ceiling Panels with Wide Spaced reinforcement for Above Ground Shelters.. 4 (M #13) dowel at 16 in.6 kPa) for design storm shelter events. 2003 International Building Code. community storm shelters require: signage to direct occupants to storm shelter areas. International Code Council. 2006. American Society of Civil Engineers. 8.org To order a complete TEK Manual or TEK Index. 2004.000 psf (143. 2002 and 2005. Standard on the Design and Construction of Storm Shelters. 4. Federal Emergency Management Agency.storm shelter walls does not exceed 2. (203 mm) masonry wall COMMUNITY SHELTERS Requirements for community shelters are similar to those for residential. min. Herndon. floor and ceiling assemblies with a minimum 2-hour fire resistance rating. Concrete Masonry Tornado Safe Rooms. Provided by: NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. TR 200.8 kPa) for design loads other than the design storm events and 3. Existing reinforced 8 in. 2000. Texas Tech University Wind Science and Engineering Research Center. 10. International Code Council and National Storm Shelter Association. Development length Figure 5—Retrofit Shelter: New Wall/Existing Wall Connection REFERENCES 1. 2003. as well as additional ventilation and sanitation facilities. 2007. 3. reinforced concrete masonry. 4). because the core sizes are also typically the same as for full-height units of the same thickness. half-high bond beam units are typically available with depressed webs to accommodate horizontal reinforcement. Like other concrete masonry units. In addition. half-highs are produced in a variety of sizes. such as corners and bond beam units are also available. Half-high concrete masonry units offer the additional advantages of a veneer-like appearance in economical single wythe construction. finish and appearance. Half-high and other architectural units. Although this theoretically reduces the wall weight. see Refs. Because there are more horizontal mortar joints in a wall constructed using half-high units. considerations for maximum reinforcing bar size as a percentage of the cell area are the same as well. Designers should check with producers about the strength of locally available Related TEK: 3-8A. and the same design aids can be used for both (see Ref. unit configurations. (203-mm) deep bond beam. Grouting two half-high units provides an 8-in. are typically manufactured to a higher unit strength. single wythe construction. such as structural load bearing. 5 for more detailed information. One aspect that may be different for half-high units is the unit strength. colors and surface textures. HALF-HIGH UNITS Half-high concrete masonry units are produced to the same quality standards as other concrete masonry units. integrally colored half-high brick-like units provide enduring strength and lasting resistance to fire and wind while maintaining a virtually maintenance-free façade. as shown in Figures 1 through 3. these walls offer the same finished appearance. As an alternative to a traditional cavity wall. exterior durability and low maintenance coupled with a shorter construction time because of the single wythe loadbearing design. This TEK describes the use of half-high units for single wythe masonry construction. Section properties for half-high units are essentially the same as for full-height units. water penetration resistance 1 186 . durability and low maintenance. 5-7A. construction details. but the top unit need not have depressed webs.An information series from the national authority on concrete DETAILS FOR HALF-HIGH CONCRETE MASONRY UNITS INTRODUCTION Concrete masonry offers numerous functional advantages. ASTM C 90 (ref. f'm.900 psi (13. however. Wisconsin Keywords: bond beam.05 kPa) of those for full height units (see Ref. life and property protection. In addition. flashing. of 1. WALL PERFORMANCE Structural design considerations for half-high construction are virtually the same as those for conventional concrete masonry units. Many designers are turning to half-high masonry because of its economy. Typical nonarchitectural concrete masonry units have a minimum unit strength of 1. with the intent of taking advantage of these higher strengths in their designs when available. 3) governs physical requirements such as minimum compressive strength. corresponding to a specified compressive strength of masonry. Note that the bottom unit of the bond beam should have depressed webs to accommodate the horizontal reinforcement. 6). These attributes are appealing for both new construction and renovations in historic districts. minimum face shell and web thicknesses. As for all concrete masonry units. special shapes. For veneer applications. and dimensional tolerances. 19-2A NCMA TEK 5-15 masonry technology TEK 5-15 Details (2010) units.10 MPa). See Ref. Single Wythe Half-High Construction in Hartland.500 psi (10. 1 and 2. To facilitate the construction of bond beams. there is slightly less concrete web area in the wall overall. in practice the wall weights of walls constructed using half-high units are within 1 psf (0.34 MPa). unit and mortar characteristics. For single wythe masonry. as include potential sources of water. 8-in. (813 mm) o. as required Post-applied surface water repellent Through-wall flashing with stainless steel drip edge. as required Figure 1 shows a proJoint reinforcement at 16 in. drain. See Ref. as required Post-applied surface water repellent * integral water repellent in units & mortar Figure 2—Exterior Loadbearing Wall With Wood Truss Floor (ref. (203-mm) half-high unit* Strap anchor at 2 ft (610 mm) o. Dry Construction with half-highs is very similar to that for conwalls are attained when both the design and construction address ventional units. 7 through 11 for further information. workmanship. As an alternative to supporting trusses by means of a an integral water repellent in both the units and mortar. pocket in the masonry wall or by joist hangers. wythe flashing details using conventional flashing are Mesh or other grout stop included in Ref. well as the difference in bond beam construction noted above. 14. 15 for recommended • both courses fully grouted flashing locations). without compromising the bond at mortar 8-in. See Refs. This also provides continuous non-combustible bearing thickness without the need to stagger the joists. 19) 2 NCMA TEK 5-15 187 . flashing and control considerations are the same as for full height units. as required are a number of generic and • reduced webs for bottom unit: proprietary flashing. and rain screen in. etc. weeps at 32 in. and water repellents. 2 3 in.c. 1 / 2 in 8 in. Single 31/2 in. device Bearing plate detail* Solid grouted single Post-applied surface water wythe walls tend to be less repellent susceptible than ungrouted * Steel bar joists welded or bolted to bearing plate or partially grouted walls to moisture penetration. sealants. (for lateral support) 4-in. Some differences include: an increased number of water movement into.c. 10-in. There • reinforcement. energy efficiency and acoustics of half-high units can be considered to be the same as for similar full height units. 3 in control. is the same as for single wythe masonry walls constructed using full-height units.Performance criteria for fire resistance . weep. (254-mm) half-high units* grouted to form bond beam Mesh or other grout stop device Reinforcement. prietary flashing system that collects and directs water to Flashing and weeps in ungrouted the exterior of the wall and cores over bond beams out weep holes. See Refs. through and out of the wall. Figure 4 shows a unique application where half-high units have been corbelled out to provide bearing for a wood truss floor.c. (406 mm) o. weeps. 13 -18 for more information. age.c. mortar dropping 3 . systems available. (102-mm) half-high unit* Through-wall flashing with stainless steel drip edge. 19) 8-in. since Figure 1—Bearing Detail on Single Wythe Wall (ref. Considerations courses laid per wall height. (for lateral support) 8-in. Reinforcement and grout. As for any single wythe construction. 12 for additional floor and roof connection details. weeps at 32 in. (203-mm) half-high unit* Strap anchor at 2 ft (610 mm) o. (203-mm) half-high units* grouted to form bond beam Mesh or other grout stop device Reinforcement. In addition. as well as a compatible post-applied surface water repellent are Proprietary flashing and weep system recommended.. (203-mm) high bond beam: joints in the face shells (see • two units high Ref. (813 mm) o.c. detailing window openings. door openings. mortar joint tooling. Crack crack control. particular care should CONSTRUCTION be taken to prevent water from entering the building nterior. greater amount of mortar needed. (63 mm) polyisocyanurate = R 22. TEK 10-4. 3 in.ft2.5 h. * integral water repellent in units & mortar Exterior Nonloadbearing Wall Detail Precast Hollow Core Flooring Representative R-values*. (51 mm) concrete topping Precast planks 4-in./2 in. (76 mm) min.0 m2. 2005. 3 in. (254-mm) precast planks 4-in. (51 mm) high soap unit 2 in. (63 mm) polyisocyanurate = R 19. ASTM C 9006b. space for the polyisocyanurate). although they do require other moisture control provisions. (76 mm) bearing "%!2). 2006. solid grouted walls do not require flashing and weeps. National Concrete Masonry Association.. 2. bearing 5-v"%!2). Inc. As a result. TEK 3-6B.K/W) voids and cavities where moisture can collect are absent.. Figure 3—Exterior Wall With Precast Hollow Core Plank Floor (ref.' Wallboard channel v$7# Post-applied surface water repellent Gypsumvwallboard $297!. Flashing 2 in. (38 mm) * Based on insulation 7# channel for R-values of 10. 3.%2 Vapor retarder. (51 mm) high soap unit 2 in.293%!. Post-applied surface 10-in.3 m2. 2001.%#2/5'(). (102-mm) half-high units* Rigid insulation 8-in.4 m2. min. (51 mm) extruded polystyrene = R 13. (203-mm) halfhigh* Bearing pad.oF/Btu (4. such as sealants and water repellents. respectively (plus a reflective air Gypsum wallboard 297!. as required 34!0%$ as R-values may vary slightly. For partially grouted walls. 20).oF/Btu (2. Crack Control for Concrete Brick and other Concrete Masonry Veneers. integral water repellent in units and mortar 1 /2 in. Concrete Masonry Veneers.8."%!2).oF/Btu (3.K/W) 21/2 in. (203-mm) half-high units. integral water repellent in units and mortar /#/#534/- water repellent . (13 mm) rigid insulation Bearing pad. joints taped.ft2. 14. with: 2 in.2 h.. 19) NCMA TEK 5-15 3 188 .ft2.4 . National Concrete Masonry Association. integral water repellent in units and mortar Mesh or other grout stop device 8-in. Check with Rigid4(%2-!87)4( insulation with your manufacturer.Flashing 2 in. as required Generic or proprietary throughwall flashing in ungrouted cells Note that loadbearing corbels are required to be designed (ref. electrical rough-in and 17. (102-mm) half-high units.K/W) 10-in. flashing should be placed in ungrouted cells. grouted to form bond beam. (254-mm) half-high units. (51 mm) concrete topping 2 in.9 h. ASTM International. Standard Specification for Loadbearing Concrete Masonry Units.'0!$ v-). REFERENCES 1.' 1 1. TEK 19-4A. 2008. 2008. National Concrete Masonry Association. TEK 19-1. National Concrete Masonry Association. 2008. National Concrete Masonry Association. 10. 2007. TEK 12-4D. (152-mm) CMU 11/2 in. 19. 2001. Illinois Concrete Products Association.ncma. 15. National Concrete Masonry Association. Reported by the Masonry Standards Joint Committee. Noise Control With Concrete Masonry. 5. Steel Reinforcement for Concrete Masonry. TEK 5-7A. (203-mm) half-high 6-in.Floor and Roof Connections to Concrete Masonry Walls. Design for Dry Single-Wythe Concrete Masonry Walls. 2006. Flashing Details for Concrete Masonry Walls. National Concrete Masonry Association. 9. National Concrete Masonry Association. Intelligent Design. National Concrete Masonry Association. 13. Flashing Strategies for Concrete Masonry Walls. (254-mm) half-high 8-in. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. 20). Half-High Architectural CMU. TEK 6-2B. Joint Sealants for Concrete Masonry Walls. 2008. 18. Concrete Masonry Wall Weights.org To order a complete TEK Manual or TEK Index. 2006.Water Repellents for Concrete Masonry Walls. 2009. ACI 530-08/ASCE 5-08/TMS 402-08. 2008. National Concrete Masonry Association. 16. 2009. TEK 14-1B. (38 mm) channel for electrical rough-in Gypsum wallboard Note: loadbearing corbels are required to be designed (ref.12-in. TEK 19-7. 14. 7. Building Code Requirements for Masonry Structures. TEK 14-13B. 2008. Figure 4—Interior Bearing Wall With Top Chord Bearing Wood Truss Floor (ref. Section Properties of Concrete Masonry Walls. 8. National Concrete Masonry Association. 11. NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication. Virginia 20171 www. 20. National Concrete Masonry Association. 12. TEK 13-1B. National Concrete Masonry Association. National Concrete Masonry Association. National Concrete Masonry Association. 19) REFERENCES (continued) 4. 17. 2007. 2008. Characteristics of Concrete Masonry Units With Integral Water Repellents. TEK 13-2A. Outside-Inside Transmission Class of Concrete Masonry Walls. TEK 19-2A. TEK 19-5A. R-Values for Single Wythe Concrete Masonry Walls. Fire Resistance Ratings of Concrete Masonry Assemblies. National Concrete Masonry Association. contact NCMA Publications (703) 713-1900 Provided by: 4 NCMA TEK 5-15 189 . 2008. TEK 7-1C. (304-mm) half-high 10-in. 2008. Sound Transmission Class Ratings for Concrete Masonry Walls. TEK 13-4. National Concrete Masonry Association. Herndon. TEK 19-6. 6. simple materials can provide unparalleled aesthetic enhancement. code-required construction tolerances are designed to ensure that masonry units are placed such that the completed wall can act structurally as an integrated unit. As discussed below. unit sizes. tradition. not aesthetics. control joints. 8-4A. textures and patterns provide ample opportunity to demonstrate a design technique or overcome design challenges. Within the confines of meeting applicable building codes and specifications. Where appropriate. concrete masonry units. modernity. 10-4. 19-1 NCMA TEK 5-16 Figure 1—Use of Several Unit Colors to Complement the Site Keywords: aesthetics. such as a building entrance. 10-2C. 5-2A. and that unusually high aesthetic standards can be more costly. commensurate with an additional cost for the defined area. on concrete masonry technology TEK 5-16 Details (2011) These requirements assume an understanding of the techniques unique to the nature of masonry. modular coordination. The design and construction team should establish and consistently support ground rules affecting aesthetic interpretations of a project. Inventive patterns. concrete masonry can provide the wall's structure. as well as providing the designer with the ability to develop and present unique aesthetic affects and techniques. When skillfully designed. 2-3A. and surface finishes (split face and standard) can be used in various concrete masonry bond patterns to evoke a sense of strength. and energy envelope. there are some basic requirements relative to aesthetics. color choices (unit and mortar). concrete masonry's modular sizes and range of colors. acoustic insulation. In addition to the architectural finish. or even whimsy. 3-8A. This TEK addresses the proper application of architectural enhancements in concrete masonry wall systems. certain high-profile areas. fire resistance. It is also important for the client to realize the aesthetic standard that the project is based on. may require a custom level of quality. Several state and local masonry associations have developed guidelines for defining aesthetic requirements. sample panel 190 1 . related NCMA TEK and other documents are referenced to provide further information and detail. Related TEK: 1-1E. It is important to realize that code requirements primarily govern structural performance. Communication With Clients Common dilemmas faced by designers are a client’s changing expectations and responses to the project’s changing appearance over time and under varying conditions. In addition. and these can be a good resource for clarifying a project's aesthetic standards. For example. but these are far from comprehensive. 10-3. 5-12. architectural units. banding.An information series from the national authority AESTHETIC DESIGN WITH CONCRETE MASONRY INTRODUCTION One aspect of concrete masonry that has kept it at the forefront of building materials is its ability to incorporate and reflect a broad spectrum of existing architectural styles. architectural masonry. such as Standard Specification for Loadbearing Concrete Masonry Units. which are available in a wide range of colors. The term "architectural concrete masonry units” typically is used to describe units displaying any one of several surface finishes that affect the color or texture of the unit. as well as application of any coatings or sealants. A more laborious method to improve color uniformity is to arrange with the masonry contractor for a presorting of on-site supplied block during certain stages of construction. The sample panel remains in place or at least available until the finished work has been accepted. Figure 2—Effect of Changing Sunlight on Gray Concrete Masonry 191 NCMA TEK 5-16 . Some units are available with the same treatment or pattern on both faces. paint or coating on the units. although local manufacturers should be consulted for final unit selection. Sample panels are a good means to communicate the minimum contract-based aesthetic standard to all parties. should also be demonstrated on the sample panel. and surface finish of the units. See Aesthetics in ASTM C90 (page 4) for more information. concrete masonry walls often interact with changing sunlight in much the same way that natural stone does. Interaction With Sunlight Because it is produced from natural materials. ASTM C90 (ref. Cleaning Concrete Masonry. 4) contains information on the applicability of different types of paints and coatings for concrete masonry walls. partitions. Cleaning procedures. increasing both the economic and aesthetic advantages. Water Repellents for Concrete Masonry Walls. bond pattern. and should in general allow for water vapor transmission. Architectural concrete masonry units are used for interior and exterior walls. With a paint or coating. 3). and in some cases a portion of the work can serve as the sample panel. The sample panel is typically constructed prior to the project. color of units and mortar. as well as the minimum expected level of workmanship. there are various techniques that may be specified to increase the color uniformity in concrete masonry. Other methods are also used to improve color uniformity. The sample panel should contain the full acceptable range of unit and mortar color. (ref. as well as on interior walls. Architectural units comply with the same performance-based quality standards as conventional concrete masonry. 1) for more information on cleaning. Perhaps the best method is to specify the use of mineral pigments in the concrete mix. Using several colors of integrally-colored concrete masonry units in the same 2 wall is an effective technique for producing other visual impacts. TEK 2-3A. the resulting film minimizes the texture of the masonry surface as well as the visual impact of the mortar joints. 2) provides an overview of some of the more common architectural units. (ref. This same attribute can be used to advantage with electric lighting. Pigments provide an integral color throughout the unit and minimize variations in color and texture found naturally in aggregate and sand deposits. TEK 19-1. concrete masonry has natural color variations from unit to unit. Concrete Masonry Unit Color Being produced from natural aggregates. CONSIDERATIONS FOR CHOOSING CONCRETE MASONRY UNITS Architectural Concrete Masonry Units One of the most significant architectural benefits of designing with concrete masonry is its versatility—the finished appearance of a concrete masonry wall can be varied with the unit size and shape. One method is to specify the use of a post-applied stain. Paints and coatings for concrete masonry should be compatible with the masonry. such as two-tone banding or complementary color palates (see Figure 1). Architectural Concrete Masonry Units (ref. terrace walls and other enclosures. since it serves as a comparison for the finished work. allowing the structural wall and finished surface to be installed in a single step. Figure 2 shows how even a conventional gray concrete masonry wall can interact with sunlight to present a range of color. to serve as both exterior and interior wall finish material. When a more monotone appearance is desired. See TEK 8-4A. appearing to change color as the light hits the wall at different angles. For this reason. Mortar Joint Tooling Tooling refers to finishing the mortar joints with a profiled tool that shapes and compacts the surface of the joint and provides a sharper. The vertical flutes also provide an interesting interplay of light and shadow. it can have a significant impact on the overall aesthetics of the completed structure. In addition. Tooling at the proper time allows this initial shrinkage to occur. beaded joints are not recommended for weather-exposed Figure 3—Mortar Joint Profiles NCMA TEK 5-16 192 3 . Engineers. Although technically a tooled joint. In addition. however. The surface shape of the tool determines the joint's profile (discussed in more detail in the following section). as discussed above. Grapevine and weather joints (Figures 3c. mortar joints should be tooled to a concave profile when the mortar is thumbprint hard (refs. As a final step the joints are dressed using a brush. For the cleanest result. 7). because more cement paste is brought to the surface of the joints. Mortar Joint Profiles Traditional mortar joint profiles are illustrated in Figure 3. but do not result in the same surface compaction as concave or V-shaped joints. Tooling mortar joints also helps seal the outer surface of the joint to the adjacent masonry unit. snow to collect. 6. the mortar is compacted against the concrete masonry unit to seal the joint. A consistent time of tooling will minimize variations in the final mortar color. the beaded tooler does not produce the same mortar surface compaction 3g) Squeezed Joint 3h) Struck Joint 3i) Raked Joint as a concave or V-shaped tool. For walls not exposed to weather. Beaded joints (Figure 3e) are formed by tooling the extruded mortar into a protruding bead shape. Joints tooled too early can also subsequently shrink away slightly from the adjacent concrete masonry unit. See also Concrete Masonry Handbook for Architects. the joint profile selection can be based on aesthetics and economics (as some joint profiles are more labor-intensive to produce). improving the joint's weather resistance. Conversely. V-shaped joints 3a) Concave Joint (standard 3c) Grapevine Joint 3b) "V" Joint (Figure 3b) result in sharper shadow lines than unless otherwise specified) concave joints. for example). because of the shape of the tool. Fluted concrete masonry units provide a rich texture and tend to enhance the sound attenuating properties of concrete masonry. Both are used in interior walls to provide strong horizontal 3d) Weather Joint 3e) Beaded Joint 3f) Flush Joint lines. For walls exposed to weather. 5) for information on mortar joints. profiles and color can all impact the overall wall aesthetics. the mortar joint profile can impact the wall's weather resistance. later tooling can produce a darker joint. For white and light-colored mortar. Mortar joints should be tooled when the mortar is thumbprint hard (a clear thumbprint can be pressed into the mortar without leaving cement paste on the thumb). concave joints (Figure 3a) improve water penetration resistance by directing water away from the wall surface. Builders (ref. horizontal mortar joints should be tooled before vertical joints. 3d) provide a water-shedding profile. Plexiglas jointers can be used to avoid staining the joints during tooling. tooled joints that compact the mortar and do not create ledges to hold water are recommended for construction that will be exposed to weather. or similar material. Care must be taken to obtain a straight line with the bead. MORTAR JOINTS While mortar generally comprises less than ten percent of a typical concrete masonry wall surface area. Mortar joint finishing. then restores contact between the mortar and the unit producing a more weather-resistant joint. the protruding bead can allow water. which can be much more dramatic than smooth-faced units. Therefore. Tooling the joints before they reach this stage results in lighter colored joints. ice or Note that not all joint profiles are appropriate for all exposures. Unless otherwise specified. After all joints are tooled. For exterior exposures. cleaner appearance for the wall. any mortar burrs on the wall should be trimmed off with a trowel or other tool (a tool such as a plastic loop is easier to use on a split face wall than a trowel. a piece of burlap. which is stripped off while the concrete is still plastic. On split-faced or ground-faced units. The sample should represent the range of color and texture permitted on the job. EXPECTATIONS FOR UNITS AND CONSTRUCTION Aesthetics in ASTM C90 ASTM C90 provides minimum requirements for concrete masonry units that assure properties necessary for quality performance. is often specified for white mortar. They are formed using a joint raker. If required. During unit manufacture. 9). producing a low-maintenance enhancement that lasts the life of the structure.construction. Consistent batching and mixing procedures also help produce uniform mortar color from batch to batch. the use of cooled water. this surface is either ground away or not exposed (in the case of split-faced units). and may not leave enough mortar cover over horizontal joint reinforcement (joint reinforcement is required to have 5/8 in. as well as appearance. The ASTM C90 specification is described in more detail in TEK 1-1E. The time for product inspection is before placement. Flush joints (Figure 3f) are typically specified when a wall will be plastered. ASTM Specifications for Concrete Masonry Units (ref. limits deleterious substances in aggregates for masonry mortars. Changing the amount of water can significantly change the resulting mortar color intensity. similar to weather joints. Struck joints (Figure 3h) provide a strong horizontal line. Sand can also affect mortar color: sands from different natural sources may have different hues. and maximum linear drying shrinkage. Squeezed or extruded joints (Figure 3g) are made using excess mortar that is squeezed out as units are laid. Note that using a mortar color that matches the surrounding units minimizes the effects of minor mortar staining. 6. that the finished unit surfaces that will be exposed in the final structure conform to an approved sample of at least four units. Silica sand. 10). water repellency. because the mortar is not compacted against the unit (the compaction tends to fill in small surface irregularities along the unit edge). Mortar that is too stiff or older than 2 1/2 hours after initial mixing is to be discarded. but permit minor cracks or chips incidental to usual manufacturing. shipping and handling methods. Standard Specification for Aggregate for Masonry Mortar (ref. however. not the aesthetics of the units nor of the constructed masonry. however because the shape provides a ledge for rain. the finish and appearance criteria. surface features such as scores or flutes. greater care should be used to remove mortar droppings and splatters from the masonry units. Concrete Masonry Construction (ref. the integrally-colored concrete mix is placed into a steel mold. they are not recommended for walls that will be exposed to weather. Excess mortar is simply struck off the face of the wall with the trowel. as well as dimensional and physical requirements such as minimum compressive strength. which removes the mortar to a maximum depth of 1/2 in. Mortar Joint Color Choosing a specific mortar color allows additional creativity by specifying integral color to either provide a visual contrast or to match the unit color. such as shading materials and equipment from direct sunlight. fire resistance rating. and the use of damp. This stripping of the mold draws moisture and coloring pigment to the unit surface. Because the 193 NCMA TEK 5-16 . color and texture should be expected to vary somewhat due to the nature of the material. Raked joints (Figure 3i) provide a dramatic contrast between the units and mortar joints. (16 mm) mortar cover in walls exposed to weather or earth (refs. For this reason there are special methods and equipment. See TEK 3-8A. with a contrasting mortar color.e. 8). It should be noted that the requirements in ASTM C90 are intended to address the performance of the masonry units when installed. i. include acceptance criteria for unit color and surface texture: namely.. 7)). Using a consistent amount of mix water is important to maintain color uniformity for all mortars and especially when using integrally colored mortar. ASTM C144. ASTM C90 does. (13 mm). small imperfections on unit edges can be more noticeable. surface texture. as shown in Figure 4. A better option for exterior surfaces is to specify an integrally colored mortar to provide the visual contrast. then dressed with a brush or other tool. maximum dimensional tolerances. which is more expensive than typical masonry sand. maximum water absorption. Therefore. With raked joints. Considerations for Integrally Colored Smooth-Faced Units Integrally-colored concrete masonry units are available in a wide variety of colors and shades. Qualities that are not included in C90 include color. loose sand piles to reduce excessive 4 retempering. As such. It also includes finish and appearance criteria for concrete masonry units. As a practical matter. Because foreign material in mortar sand can affect the mortar quality. ice or snow. for example. all of the sand for a particular project should come from the same source. which impacts the surface appearance. The specification includes requirements for materials. for further information. density choice. thermal properties and acoustic properties. They may be specified for interior walls. prohibits defects that would impair the strength or permanence of the construction. these properties must be addressed in project contract documents. The mineral oxide pigments are evenly dispersed throughout the concrete mix. The resulting joint is not weather-resistant. in 20 ft. the The International Building Code and Specification for actual location of a masonry element is required to Masonry Structures (refs. Tolerances apply to: plumb. Construction Tolerances As an example. 7) contain site tolerances for be within a certain tolerance of where the element is masonry construction which allow for deviations in the shown on the construction drawings: + 1/2 in. these tolerances are generally adequate for most aesthetic applications as well. these units will have a wider color variation than is seen with split-faced or ground-faced units. alignment. levelness of bed joints. for maximum construction efficiency. However. unless otherwise specified. Understanding this color variation will help avoid possible disappointment that the finished wall does not have the color uniformity of a painted or stained wall. they must be specified in the project documents. concrete masonry elements should be designed and constructed with modular coordination in mind. + 3/4 in. More precise placement dimensions can be specified. economy. and aesthetic benefit. Use of complementary mortar to emphasize pattern Concrete Masonry Construction (ref 9). If tighter tolerances are desired. A full discussion of code-required masonry construction tolerances is presented in TEK 3-8A. The permissible tolerances are intended to ensure that misalignment of units or structural elements does not impede the structural performance of the wall. location of elements. and width of collar joints. Although the tolerances are not intended for the purpose of producing an aesthetically pleasing wall. formed surface is the final exposed surface on smoothfaced units. 194 5 . however. typically at a higher cost. max (+ 13 mm in 6. + 19 mm max). levelness and dimensions of constructed masonry elements.2 m. MODULAR COORDINATION Ground face units with complementary mortar Glazed units with contrasting mortar Figure 4—Examples of Contrasting and Complementary Unit and Mortar Colors NCMA TEK 5-16 Concrete masonry structures can be constructed using virtually any layout dimension. Modular coordination is the practice of laying out and dimensioning structures to standard lengths and heights to accommodate modularlysized building materials. grout spaces and cavities. mortar joint thickness.construction. 6. Aesthetically. The detail shown in Figure 6 has demonstrated good performance in many areas of the United States and is the preferred detail. with different textures. and may require horizontal movement joints as well (see the Banding section. When materials with different movement properties are used in the same wythe (such as clay masonry and concrete masonry). as well as in the band itself if it is more than two courses high. (102-mm) modules for some applications. Crack Control for Concrete Brick and Other Concrete Masonry Veneers (refs. Perhaps the simplest approach is to align the control joint with another architectural feature. 12.or 8-in. 13. control joints typically appear as continuous vertical lines in the field of the masonry walls. or with a combination of these techniques. The architectural effect is very pleasing. such as adjacent to openings. In this case. (305 mm) of the top and bottom of the band and the band itself must contain at least one row of ties. the vertical shadow line provided by the architectural feature provides an inconspicuous control joint location. When control joints are required. but less recommended. but may also include 4-in. locations and construction details can be found in TEK 10-2C. Another. color and finish provides a virtually limitless palette. Horizontal joint reinforcement is placed in the mortar joints above and below the band. They are essentially vertical planes of weakness built into the wall to reduce restraint and permit longitudinal movement due to anticipated shrinkage. 11) provides details of modular wall layouts and openings. CONTROL JOINTS Control joints. etc. (203mm) units. The use of concrete masonry bands in clay brick 6 Figure 5—Banding Example: Split-Faced Bands in Ground Face Field 195 NCMA TEK 5-16 . Designing a concrete masonry building to a 4. Banding can be accomplished with different colors of block. such as the use of a 4-in. proper detailing must be provided to accommodate the different movement properties of the two materials to prevent cracking. Combining masonry units of different size. In this case. In addition. providing a more harmonious looking masonry structure. Control Joints for Concrete Masonry Walls—Empirical Method. Some designers prefer placing joint reinforcement in every bed joint of the concrete masonry band. TEK 10-3. with different unit sizes. TEK 5-12. Several strategies can be used to make control joints less noticeable. (102-mm) high band in a wall of 8-in. as it is economical and maintenance free. and TEK 10-4. 14). a type of movement joint. lateral support (wall ties) are provided within 12 in. for example a smooth-faced band in a split-faced wall (see Figure 5). Standard concrete masonry modules are typically 8 in. this movement difference needs to be accommodated. (203 mm) vertically and horizontally. below). option is to use horizontal slip planes between clay masonry and the concrete masonry BANDING Concrete masonry banding is successfully used in many architectural applications. These modules provide the best overall design flexibility and coordination with other building products such as windows and doors. are one method used to relieve horizontal tensile stresses due to shrinkage of concrete products and materials. and perhaps at other areas of stress concentration. (102.or 203-mm) module will minimize the number of units that need to be cut. Recommendations for control joint spacing. Modular Layout of Concrete Masonry (ref. Control Joints for Concrete Masonry Walls—Alternative Engineered Method. at changes in wall height. concrete masonry requires only vertical control joints. however. veneer has also become very popular. a tie which accommodates both the tie and reinforcement in the same joint (such as seismic clips) should be used. such as a pilaster or recess in the wall. c. per local practice Adjustable ladder wall tie (hot dipped galvanized) @ 16 in. or equivalent Closed cell rigid insulation. At locations of expansion joints in the clay masonry. joints should be continued through the concrete masonry band and the joint reinforcement cut at these locations. 1 in. and/or shade light from directly impinging on the wall surface. diffuse and/or partially blocked light from wall-mounted fixture Unwanted Unwantedlong long shadow shadow Allowable offset from materials.1 m) when concrete masonry banding is used. such as ground 196 7 . because the shadow is intentionally located away from the wall surface.1 m).c. (406 mm) o. there are specialized fixtures adapted for masonry that internally refract. within 12 in. With nondiffuse light. giving the erroneous visual appearance of unacceptably poor materials or workmanship (see Figure 7). it is more typically accomplished with fixtures and devices made for this purpose. and combined movements Low to subliminal light = darkened area: no shadows Figure 7—Use of Diffuse Lighting to Control Shadows NCMA TEK 5-16 band (see TEK 5-2A.7 (9 gage) (MW 11) at 16 in. Often. Diffuse lighting does not concentrate a focused beam but rather spreads the light to provide soft illumination. Certain concrete masonry units. Reference 15). (25 mm). glossy surface treatments and coatings could also inadvertently magnify this problem. (51 mm) preferred Wall tie. min. The maximum spacing of expansion joints in the clay masonry wall should be reduced to no more than 20 ft (6. partially block. diffuse. (305 mm) of band Figure 6—Banding Detail: Concrete Masonry Band in Clay Brick Veneer Light from surface-mounted fixture Offset. including details for incorporating clay masonry bands into concrete masonry walls. construction. deflect. W1. Welldesigned diffuse light can eliminate such concerns. an additional control joint should be placed near mid-panel in the concrete masonry band. No noticeable shadows are cast onto the wall. (305 mm) of band Vapor retarder. TEK 5-2A provides a fuller discussion and additional details for combining these two materials. although the joint reinforcement should not be cut in this location. When wall-mounted light sources are necessary. or generally placed at a distance from the masonry wall assembly. 2 in.. as required Concrete masonry accent band Air space. LIGHTING DESIGN CONSIDERATIONS FOR CONCRETE MASONRY WALLS Masonry has historically been associated with diffuse illumination located on or recessed into ceilings. These concepts are illustrated in Figure 7. When the clay masonry expansion joint spacing exceeds 20 ft (6. vertical Clay brick Joint reinforcement. reflect.Wall tie. Non-diffuse light shining onto a concrete masonry wall from a surface-mounted light fixture or sconce can sometimes cast unwanted long shadows. Clay and Concrete Masonry Banding Details. thus masonry aesthetics are enhanced with a lower lighting intensity and more graceful illumination. the fixture includes additional light diffusers facing away from the wall surface to assist in softly lighting the adjacent area. within 12 in. as step (walkway) fixtures located below the waist. Although this is sometimes accomplished using an array of many individual light sources at a distance. (406 mm) o. 2005. TEK 19-1. TMS 602/ACI 530. 6. Reported by the Masonry Standards Joint Committee. TEK 10-4. TEK 2-3A. National Concrete Masonry Association. Standard Specification for Loadbearing Concrete Masonry Units. 16. 2. 3. 2009. TEK 8-4A. contact NCMA Publications (703) 713-1900 8 197 NCMA TEK 5-16 . 15. International Building Code. 4. can be highly reflective. 7. National Concrete Masonry Association. W. ASTM C90-09. 2002.face (also called honed or burnished). 8. Virginia 20171 www. Portland Cement Association.. Cleaning Concrete Masonry. Farney. ASTM International. 2005. National Concrete Masonry Association. National Concrete Masonry Association. Modular Layout of Concrete Masonry. J. 2010. 11. National Concrete Masonry Association. A. Architectural Concrete Masonry Units. Water Repellents for Concrete Masonry Walls. National Concrete Masonry Association. 2007. Architectural Enhancement. Specification for Masonry Structures. Figure 8 shows a residential project using a custom-fabricated white ground face block. 9. Crack Control for Concrete Brick and Other Concrete Masonry Veneers. NATIONAL CONCRETE MASONRY ASSOCIATION 13750 Sunrise Valley Drive. Engineers. 13. and Panarese. Control Joints for Concrete Masonry Walls—Alternative Engineered Method. Aesthetical Design With Concrete Masonry. ASTM Specifications for Concrete Masonry Units. 12. Concrete Masonry Handbook for Architects.. C. International Code Council. 14. National Concrete Masonry Association. NCMA AIA/CES Provider Program #000530. ASTM C144-04. 2008. National Concrete Masonry Association. The harmonious use of interior lighting combined with exterior overhead (recessed trim) and step lighting is an effective way of solving this challenge. J. Builders. Sixth Edition.1/ASCE 6. TEK 5-2A. Clay and Concrete Masonry Banding Details. TEK 10-3. Control Joints for Concrete Masonry Walls—Empirical Method. TEK 1-1E. Herndon. Standard Specification for Aggregate for Masonry Mortar. National Concrete Masonry Association. Engineering Bulletin 008. 2008.org Provided by: To order a complete TEK Manual or TEK Index. M. 2004. TEK 5-12. ASTM International. TEK 10-2C. The designer used a complementary balance of several lighting fixtures with what might have otherwise been a challenging masonry reflective finish. 2001. 5. Figure 8—Diffuse Lighting With Ground Face Concrete Masonry REFERENCES 1. 2001.ncma. 2003. National Concrete Masonry Association. 2009. Concrete Masonry Construction. Melander. 2008. 2001. 10. TEK 3-8A. National Concrete Masonry Association. NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication.