Joists should rest on at least 1 1/2 inches of bearing on wood and 3 inches on ___.

Joists should rest on at least 1 1/2 inches of bearing on wood and 3 inches on ___.

• A. Concrete
• B. Brick
• C. Steel
• D. Masonry

Answer: (D)

Joists need a safe bearing surface to transfer their load evenly into the supporting wall. On wood, that bearing depth is 1 1/2 inches. When joists rest on masonry surfaces—such as brick or concrete block—the bearing must be increased to 3 inches. Masonry is the category that covers these common wall types, which is why 3 inches of bearing on masonry is specified. The other options don’t fit because steel isn’t used as a bearing surface for this purpose, and concrete by itself isn’t the general category referenced in this rule—masonry (brick, block) is.

Joists need a safe bearing surface to transfer their load evenly into the supporting wall. On wood, that bearing depth is 1 1/2 inches. When joists rest on masonry surfaces—such as brick or concrete block—the bearing must be increased to 3 inches. Masonry is the category that covers these common wall types, which is why 3 inches of bearing on masonry is specified. The other options don’t fit because steel isn’t used as a bearing surface for this purpose, and concrete by itself isn’t the general category referenced in this rule—masonry (brick, block) is.