The Ontario Building Code | Unsupported Excavations
4.2.5.4. Unsupported Excavations
(1) The sides of an excavation in soil or rock may be unsupported where a design is prepared by a person especially qualified in this field of work in conformance with the requirements of Articles 4.2.5.1. and 4.2.5.2.
In Plain Language
Excavation sides may be left unsupported where a design is prepared by a person especially qualified in this field, conforming to the general excavation design requirements set out in this Subsection.
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.