Residential Building Inspector Practice Exam

The minimum thickness for a spread footing is generally set at 6 inches to ensure sufficient support and stability for the structure it is intended to uphold. This thickness helps distribute the load from the building over a larger area of soil, thereby reducing the risk of settling or shifting that could compromise the integrity of the structure.

Combining a thickness of at least 6 inches with appropriate reinforcement, such as steel rebar, enhances the footing's strength and ability to resist bending and shear forces. The requirement can vary based on the specific building codes in the local jurisdiction, the load of the structure, and the type of soil conditions present.

The options that suggest a thickness of 4 inches, 5 inches, or 7 inches do not align with standard practices. A thickness of 4 inches would generally be inadequate for most residential foundations as it may not provide enough bearing capacity. While 5 inches is closer, it still falls short of what is widely recognized as a safe minimum for load-bearing conditions. A thickness of 7 inches might be considered in specific instances where additional headroom or reinforcement is needed, but it exceeds the minimum requirement. Therefore, 6 inches serves as a reliable minimum standard in many building practices.