The Ontario Building Code | Crawl Spaces
3.2.2.9. Crawl Spaces
(1) For the purposes of Articles 3.2.1.4. and 3.2.1.5., a crawl space shall be considered as a basement if it is,
(a) more than 1 800 mm high between the lowest part of the floor assembly and the ground or other surface below,
(b) used for any occupancy,
(c) used for the passage of flue pipes, or
(d) used as a plenumin combustible construction.
(2) A floor assembly immediately above a crawl space is not required to be constructed as a fire separation and is not required to have a fire-resistance rating provided the crawl space is not required to be considered as a basementby Sentence (1).