Residential Building Inspector Practice Exam

What is the minimum depth nominal size for which bridging must be provided to support floor joists laterally?

1. 10 inches

2. 12 inches

3. 14 inches

4. 16 inches

The correct answer is: 12 inches

Bridging is essential for providing lateral support to floor joists, preventing them from buckling or twisting under load. The minimum nominal depth at which bridging becomes a requirement is significant because deeper joists are more susceptible to lateral movement due to their increased span and height. The correct choice indicates that for floor joists with a nominal depth of 12 inches, bridging is mandated. This requirement is based on building codes which recognize that joists of this depth and greater need additional support to maintain structural integrity and stability. Bridging helps to distribute loads evenly and enhance the overall performance of the floor system. Joists that are shallower than 12 inches typically have stiffness characteristics that allow them to maintain their form without lateral support, while joists that are 12 inches and deeper become more flexible, necessitating bridging to ensure they remain secure and functional.