What is the minimum depth that the bottom of exterior footings must be below finished grade?

The minimum depth that the bottom of exterior footings must be below finished grade is 12 inches. This requirement is in place to ensure that footings are placed below the frost line in many regions, which helps to prevent frost heave and maintains structural stability. In areas where soil freezes, footings that are not deep enough can shift and cause cracks and misalignment in the structure above.

Having the footings at least 12 inches deep below the finished grade minimizes these risks, providing a solid foundation that supports the weight of the structure and withstands environmental factors. This depth is critical for the longevity and integrity of residential buildings, particularly in varying weather conditions that can affect soil stability.