The Ontario Building Code | Clearance to Combustible Framing
9.22.9.3. Clearance to Combustible Framing
(1) Not less than a 100 mm clearance shall be provided between the back and sides of a solid fuel-burning fireplace and combustibleframing, except that a 50 mm clearance is permitted where the fireplace is located in an exterior wall.
(2) Not less than a 50 mm clearance shall be provided between the back and sides of the smoke chamber of a solid fuel-burning fireplace and combustibleframing, except that a 25 mm clearance is permitted where the fireplace is located in an exterior wall.
In Plain Language
A minimum clearance to combustible framing must be maintained around the fireplace assembly, as set out in this article, protecting nearby wood structure from the fireplace's heat.
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.