Elevator Pit at Perimeter Wall of Building

[PT999]

Does an interior elevator pit (normal heated building - renovation project), right up against the foundation wall have to be built to frost line depth, or can it be higher. As it turns out the foundation wall is above frost line, quite a surprise!

 

[msquared48]

I see no reason why two or three of the walls of the elevator pit can't be stopped at the top of the elevator slab and the footing extend down another foot or so. Any outside sell would have to go to frost though.

Mike McCann, PE, SE (WA)

 

[jike]

It would be impractical, false economy and risky to not carry all the walls to frost or elevator pit depth requirement, whichever is deeper. 2 or 3 walls with shallower depth may cause differential settlement. Why wouldn't you want the elevator shaft to bear on the same material?

 

[DETstru]

Any wall on the exterior of the building must go down to frost depth.

Like msquared48 says, you can turn down the pit slab at the exterior wall or place another concrete element below it at the exterior wall.