The Ontario Building Code | Required Firewalls
9.10.11.1. Required Firewalls
(1) Except as provided in Articles 9.10.11.2. and 9.10.11.4., a party wall on a property line shall be constructed as a firewall.
In Plain Language
Firewalls are required at the locations set out in this article, providing a robust fire barrier capable of stopping fire spread even if the building on one side collapses.
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.