For anchoring a wood sole plate at an exterior wall on a monolithic slab, the bolts must extend into concrete by at least how many inches?

For anchoring a wood sole plate at an exterior wall on a monolithic slab, the bolts must extend into concrete by at least how many inches?

• A. 7 inches
• B. 5 inches
• C. 9 inches
• D. 6 inches

Answer: (A)

The key idea is that anchor bolts must be embedded deep enough in concrete to develop proper withdrawal and shear resistance for a mudsill attached to a monolithic slab. The minimum depth used in standard practice is seven inches. This ensures the bolt reaches solid concrete rather than just the surface, giving reliable holding power to resist wind uplift and other loads on the exterior wall. Shallower depths, like five or six inches, wouldn’t meet the required resistance and could allow the connection to fail under load. A depth of nine inches would work, but it’s beyond the minimum that codes and good practice require. Seven inches provides the necessary combination of safety, code compliance, and practicality for installation with typical bolt sizes and hardware.

The key idea is that anchor bolts must be embedded deep enough in concrete to develop proper withdrawal and shear resistance for a mudsill attached to a monolithic slab. The minimum depth used in standard practice is seven inches. This ensures the bolt reaches solid concrete rather than just the surface, giving reliable holding power to resist wind uplift and other loads on the exterior wall. Shallower depths, like five or six inches, wouldn’t meet the required resistance and could allow the connection to fail under load. A depth of nine inches would work, but it’s beyond the minimum that codes and good practice require. Seven inches provides the necessary combination of safety, code compliance, and practicality for installation with typical bolt sizes and hardware.