What is the minimum depth for the bottom of exterior footings below finished grade?

The minimum depth for the bottom of exterior footings below finished grade is 12 inches. This requirement is established to ensure that the footings are adequately situated to prevent frost heave and other issues associated with soil movement. In North Carolina, where seasonal temperature changes can cause ground freeze, footings need to be placed deep enough to remain below the frost line, thus preventing structural damage to the foundation over time.

12 inches is considered a standard practice as it provides a solid base and helps distribute loads effectively from the structure above. This depth also contributes to the overall stability and longevity of the building, which is critical for safety and durability in construction. Knowing the appropriate footing depth is essential for anyone involved in residential construction, as it can affect the entire structure's integrity.