Question

Concrete masonry and clay brick masonry differ in that one needs a control joint and the other needs an expansion joint. Which needs which kind of joint, and why?

Answer

Clay brick masonry expands over time, while concrete masonry shrinks more than it expands. Expansion joints are typically used to accommodate thermal and moisture expansion in clay brick masonry. Control joints are typically used in concrete masonry to reduce the occurrence of shrink-related cracking.