![]() In areas where seismic activity is a factor, anchored veneer and its attachments must meet additional requirements to assure adequate performance in the event of an earthquake. In areas where q z exceeds 55 psf (2.63 kPa), the veneer must be designed using engineering philosophies, and the following prescriptive requirements may not be used. These modified provisions are presented in the section High Wind Areas. Modified prescriptive criteria is available for areas with q z greater than 40 psf (1.92 kPa) but not exceeding 55 psf (2.63 kPa) with a building mean roof height up to 60 ft (18.3 m). The following prescriptive criteria apply to anchored veneer in areas with velocity pressures, q z, up to 40 psf (1.92 kPa). Anchors and supports must be noncombustible and corrosion-resistant. Anchors are used to secure the veneer and to transfer loads to the backing. 1, 6, 7).Īnchored veneer is veneer which is supported laterally by the backing and supported vertically by the foundation or other structural elements. More detailed information is contained in TEK 5-1B, Concrete Masonry Veneer Details, TEK 19-4A, Flashing Strategies for Concrete Masonry Walls, and TEK 19-5A, Flashing Details for Concrete Masonry Walls (refs. Additional vents may be installed at the tops of walls to further increase air circulation. For anchored veneer, open weeps can also serve as vents, allowing air circulation in the cavity to speed the rate of drying. If necessary, insects can be thwarted by inserting stainless steel wool into the opening or by using proprietary screens. (25 mm) high and spaced not more than 32 in. Partially open head joints are one preferred type of weep. Flashing and weeps in the veneer collect any water that penetrates the veneer and redirects it to the exterior. Therefore, the backing system must be designed and detailed to resist water penetration and prevent water from entering the building. 5), for further information.įor exterior veneer, water penetration into the cavity is anticipated. See TEK 10-4, Crack Control for Concrete Brick and Other Concrete Masonry Veneers (ref. For veneer, control joints should generally be placed in the veneer at the same locations as those in the backing, although recommended control joint spacing can be adjusted up or down based on local experience, the aesthetic requirements of the project, or as required to prevent excessive cracking. In concrete masonry, control joints and horizontal joint reinforcement effectively relieve stresses and accommodate small movements. Movement may be caused by temperature changes, moisture-volume changes, or deflection. In addition to structural requirements, differential movement between the veneer and its supports must be accommodated. Design criteria are provided in IBC Chapter 16 as well as in TEK 16-4A, Design of Concrete Masonry Noncomposite (Cavity) Walls, (ref. The assembly can be designed as a noncomposite cavity wall where the out-of-plane loads are distributed to the two wythes in proportion to their relative stiffness. The prescriptive requirements relate to size and spacing of anchors and methods of attachment, and are described in the following sections. Masonry veneers are typically designed using prescriptive code requirements that have been developed based on judgement and successful performance. The backing must be designed to support the lateral and in some instances the vertical 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. 2, 3).įor the purposes of design, veneer is assumed to support no load other than its own weight. Unless otherwise noted, veneer requirements are those contained in the International Building Code (IBC)and Building Code Requirements for Masonry Structures (refs. They differ by the method used to attach the veneer to the backing, as illustrated in Figure 1. There are basically two types of veneer-anchored veneer and adhered veneer. Backing material may be masonry, concrete, wood studs or steel studs. Veneers provide the exterior wall finish and transfer out-of-plane loads directly to the backing, but they are not considered to add to the load-resisting capacity of the wall system. Veneer is a nonstructural facing of brick, stone, concrete masonry or other masonry material securely attached to a wall or backing. ![]()
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