What is the minimum thickness for a spread footing?

The minimum thickness for a spread footing is set to ensure that the foundation can adequately distribute the weight of the structure above it while preventing excessive settlement and maintaining stability. A thickness of 6 inches provides a solid base that effectively supports the loads imposed on it without risking structural integrity or failure.

This choice aligns with the standards established in building codes, which prioritize safety, load distribution, and performance of the foundation system. Thicker footings may be required in certain conditions, such as on weaker soils or for heavier structures, but for standard applications, a 6-inch thickness is considered a minimum requirement.

Other thickness options may be specified for different scenarios; however, 6 inches is the baseline that meets the code's requirements for typical residential construction.