The Ontario Building Code | Required Protection from Precipitation
5.6.1.1. Required Protection from Precipitation
(1) Except as provided in Sentence (2), where a buildingcomponent or assembly is exposed to precipitation, the component or assembly shall,
(a) minimize ingress of precipitation into the component or assembly, and
(b) prevent ingress of precipitation into interior space.
(2) Protection from ingress of precipitation is not required where it can be shown that such ingress will not adversely affect any of,
(a) the health or safety of building users,
(b) the intended use of the building, or
(c) the operation of building services.
In Plain Language
Except in specific cases, where a building component or assembly is exposed to precipitation, it must be designed and constructed to provide adequate protection from that precipitation.
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.