The Ontario Building Code | Firewalls in Detached Garages
9.10.11.4. Firewalls in Detached garages
(1) Where a garage is detached from the dwelling unit but attached to another garage on the adjacent property, the party wall so formed shall be constructed as a fire separation having a fire-resistance ratingof not less than 45 min.
Note: On July 1, 2017, Sentence 9.10.11.4.(1) of Division B of the Regulation is amended by striking out "Where a garage is detached from the dwelling unit" at the beginning and substituting "Where a garage is detached from thehouse or the individual dwelling unit it serves". (See: O. Reg. 139/17, s. 107)
9.10.12. Prevention of Fire Spread at exterior Walls and Between Storeys
In Plain Language
Firewalls in detached garages have adjusted requirements set out in this article, reflecting the smaller scale and lower occupancy of these accessory structures.
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.