Unless otherwise authorized by the building official, what is the minimum distance that trenches must be from the footings of a building?

The correct minimum distance that trenches must be from the footings of a building, unless otherwise authorized by the building official, aligns with the requirement for maintaining structural integrity and safety. Typically, this distance needs to ensure that excavations do not undermine the foundation's stability or cause potential soil movement that could affect the footings.

While the principles of angle and geometry do play a role in determining excavation limits, the specific choice of 45 degrees likely refers to a general standard of ensuring that the excavation is sloped away from the footer to maintain weight distribution and prevent collapse. It's common practice in construction that the trench should remain at a safe angle to prevent undermining structures which could lead to serious safety concerns.

In practical terms, this means that the lateral distance from the base of the footing to the edge of the trench can be calculated based on the angle of repose, commonly reflected in building codes and construction standards. The 45-degree reference should be interpreted in the context of how it provides guidance for safe distance and angle management around footings.

This approach ensures that the necessary precautions are observed to maintain both the integrity of the footings and the overall safety of the construction site.