The Ontario Building Code | Required Venting
9.19.1.1. Required venting ="http://thehandyforce.com/interior/bathroom-renovations/" title ="Toronto Bathroom renovation inspiration">venting
(1) Except where it can be shown to be unnecessary, where insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation is installed between a ceiling and the underside of the roof sheathing, a space shall be provided between the insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation and the sheathing, and vents shall be installed to permit the movement of air from the space to the exterior.
In Plain Language
Attic or roof space venting is required as set out in this article, letting moisture and heat escape from this space rather than accumulating and causing condensation or ice damming.
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.