The Ontario Building Code | Expanding and Deteriorating Rock
4.2.4.12. Expanding and Deteriorating Rock
(1) Where rock that expands or deteriorates when subjected to unfavourable environmental conditions or to stress release is known to exist, this condition shall be fully investigated and provided for in the design.
In Plain Language
Where rock that expands or deteriorates under environmental exposure or stress relief is present, the foundation design must account for that rock's specific behaviour rather than treating it as stable bearing material.
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.