The Ontario Building Code | Protection from Weather and Insects
9.32.2.2. Protection from Weather and Insects
(1) Openings for natural ventilation other than windows shall be constructed to provide protection from the weather and insects.
(2) Screening shall be of rust-proof material.
9.32.3. Mechanical ventilation
In Plain Language
Natural ventilation openings must be protected from weather and insects, as set out in this article, typically requiring screens and weather-resistant covers.
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.