The Ontario Building Code | Supported Excavations
4.2.5.3. supported Excavations
(1) The sides of an excavation in soil or rock shall be supported by a retaining structure conforming with the requirements of Articles 4.2.5.1. and 4.2.5.2., except as permitted in Article 4.2.5.4.
In Plain Language
The sides of an excavation in soil or rock must generally be supported by a retaining structure conforming to the excavation design requirements, with limited exceptions described elsewhere in this article.
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.