Frequently Asked Questions
Question: Will a concrete masonry veneer require horizontal joint reinforcement?
Answer: Yes, concrete masonry veneer should include horizontal joint reinforcement placed in the mortar bed joints including embedded lap splices of at least 6 inches. Because it is concrete masonry veneer, the veneer will undergo net irreversible shrinkage due to 1) “wetting and drying cycles,” 2)carbonation and 3) a decrease in temperature (reversible). Because the net effect is shrinkage, a combination of horizontal joint reinforcement and proper placement of control joints should be employed to reduce the potential for shrinkage cracking. Note that joint reinforcement should be galvanized or stainless steel and placed with at least 5/8 inch mortar cover at the weather exposed face and at the non-weather exposed face 1/2 inch. Typically, the industry suggests the joint reinforcement be placed every 16 inches vertically for 9 gauge wire (W1.7). The joint reinforcement may be separate and placed in alternate joints or connected to adjustable veneer anchors (seismic clip).
NCMA TEK 10-04 Crack Control for Concrete Brick and Other Concrete Masonry Veneers (2001)
NCMA TEK 12-2B Joint Reinforcement for Concrete Masonry (2005)
Selecting the Right Joint Reinforcement for the Job, Masonry Construction Magazine, January 1995, pages 8-14
CMU Veneer Details (Sheets A1-A6), Generic Wall Design Committee, Masonry Institute of Michigan, June 2010
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