In Plain Language

A foundation must be excavated down to undisturbed soil as set out in this article, since building on loose or previously disturbed fill can lead to uneven settling.

This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.