The Ontario Building Code | Protection from Weather and Insects
9.32.2.2. Protection from Weather and Insects
(1) openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">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.