For differential grades, what is the minimum run required for step footings?

The minimum run required for step footings in scenarios involving differential grades is indeed 2 feet. This specification stems from construction practices that ensure stability and structural integrity when dealing with changes in elevation.

Typically, when constructing foundations on sloped lots or uneven ground, step footings are implemented to effectively manage the differing heights. By adhering to a minimum run of 2 feet, builders can support the loads more evenly over the footings. This dimension helps in mitigating issues such as settling or shifting of the foundation, which could lead to structural damage down the line.

If the run were any shorter, there could be a higher risk of instability, especially during ground movement or changes in the weather, thereby compromising the integrity of the building. The 2-foot requirement is a prudent guideline that reflects best practices in foundation engineering and ensures that the structure will be sound for the long term.