The Ontario Building Code | Access Openings
9.18.2.1. Access openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings
(1) An access opening of not less than 500 mm by 700 mm shall be provided to each crawl space where the crawl space serves a single dwelling unit, and not less than 550 mm by 900 mm for other crawl spaces.
Note: On July 1, 2017, Sentence 9.18.2.1.(1) of Division B of the Regulation is amended by striking out "single dwelling unit" and substituting "houseor an individual dwelling unit in a house". (See: O. Reg. 139/17, s. 122)
(2) Access openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings shall be fitted with a door or hatch, except when the crawl space is heated and the access opening into the crawl space is from the adjacent heated space.
9.18.3. ventilation
In Plain Language
Access openings to a crawl space are required as set out in this article, ensuring the space can be reached for inspection, maintenance, or utility work.
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.