General Contractor Practice Exam

What is the maximum allowable size of a bed joint in a masonry wall placed directly on the foundation?

1. 1/2 inch

2. 5/8 inch

3. 3/4 inch

4. 1 inch

The correct answer is: 5/8 inch

The maximum allowable size of a bed joint in a masonry wall placed directly on the foundation is established to ensure stability and structural integrity. A bed joint refers to the horizontal layer of mortar between masonry units. A bed joint size of 5/8 inch is often specified as optimal because it balances the need for sufficient mortar to bond the masonry units while also minimizing excessive joint size that could lead to structural weaknesses or issues with moisture penetration. In masonry construction, maintaining consistent joint sizes is crucial for ensuring even distribution of loads throughout the wall. A joint that is too thick may result in settlement issues or variations in the wall's alignment over time. This is especially important when the wall is placed directly on the foundation, as any inconsistencies can be exacerbated by the weight of the structure above. Other options present sizes that exceed the common specifications for bed joints, which could compromise the solidity and reliability of the masonry structure.