Notice: This site currently shows the 2012/2017 edition of the Ontario Building Code. The current legally effective code is the 2024 edition (O.Reg. 163/24), in effect since January 1, 2025. Confirm current requirements at ontario.ca.

The Ontario Building Code | Clearances

9.19.1.3. Clearances

(1) Except as provided in Sentence (2), where venting ="http://thehandyforce.com/interior/bathroom-renovations/" title ="Toronto Bathroom renovation inspiration">venting is provided to a roof joist space, not less than 63 mm of space shall be provided between the top of the insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation and the underside of the roof sheathing.

(2) Where venting ="http://thehandyforce.com/interior/bathroom-renovations/" title ="Toronto Bathroom renovation inspiration">venting is provided at the junction of sloped roofs and exterior walls and where preformed baffles are used to contain the insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation, the baffles shall,

(a) provide an unobstructed air space between the insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation and the underside of the roof sheathing, that is,

(i) not less than 25 mm in dimension, and

(ii) of sufficient cross area to meet the attic or roof space venting ="http://thehandyforce.com/interior/bathroom-renovations/" title ="Toronto Bathroom renovation inspiration">venting requirements of Article 9.19.1.2., and

(b) extend vertically not less than 50 mm above the top of the insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation.

(3) ceiling insulation shall be installed in a manner that will not restrict a free flow of air through roof vents or through any portion of the attic or roof space.

In Plain Language

Clearances around roof space vents must be maintained as set out in this article, ensuring insulation or other materials don't block the vent opening.

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.