Intersecting thoughts on Concrete Masonry Walls
Movement found at intersecting walls has always been a concern for contractors and design professionals. Early in my career, intersecting concrete masonry walls would commonly just be toothed together with little or no ability to handle the differential movement. This method allowed for the creation of new cracks and small chips from the concrete masonry units.
One of the first attempts to solve the problem was the additional step of raking the corner joint 3/8 inch and applying sealant as a way to seal the crack that would form. By itself, this method is better, but not a problem solver.
Today, designers are doing an all-together better job of detailing masonry intersections. Commonly the structural slabs are much thicker under the walls than before, the masonry units are much better than the cinder block of days past and reinforcing methods have improved results.
Products on the market today make tying an intersecting wall much more controlled. Wire mesh hardware cloth, lath mesh, intersecting wall wire and “Z” bars have done well to reduce problems.
The “Z” bar is what I see most commonly on today’s projects. The ¼ inch by 1 ½ inch by 28 inch +/- bars have a turn down of 90 degrees at each end. The bar is placed into grouted cells in the intersecting reinforcing joint to tie the walls of the structure together.
My BLOG comments are based on my engineering and masonry contracting experience and travels around the United States visiting masonry projects. I realize masonry practices vary in different geographical locations, so I’d welcome your feedback on different practices.