The Ontario Building Code | Unrated Wood Door Frames
9.10.13.3. Unrated wood door Frames
(1) doors required to provide a 20 min fire-protection ratingor permitted to be 45 mm solid core wood shall be mounted in a wood frame of at least 38 mm thickness where the frame has not been tested and rated.
In Plain Language
Unrated wood door frames may be used under the conditions set out in this article, clarifying when a standard frame is acceptable alongside a rated door.
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.