What is the requirement for the thickness of masonry unit bed joints for the second course?

The requirement for the thickness of masonry unit bed joints for the second course is established to ensure proper bonding and structural integrity of the masonry wall. The specified thickness of not less than 1/4 inch and not more than 1/2 inch strikes a balance by allowing adequate mortar for adhesion while preventing excessive joint thickness that could compromise strength or lead to moisture penetration issues. This range supports the traditional practices used in masonry construction, aligning with industry standards that facilitate effective load distribution and minimize the potential for cracking or settling in the masonry wall over time. Adhering to these guidelines provides a robust framework for achieving durable and stable masonry applications.