The Ontario Building Code | Floor Assembly over Basement
3.2.1.4. floor Assembly over basement
(1) Except as permitted by Sentence 3.2.2.42.(3), 3.2.2.43.(3), 3.2.2.44.(3), 3.2.2.45.(3), 3.2.2.46.(3), 3.2.2.47.(3) or 3.2.2.48.(3), a floor assembly immediately above a basement shall be constructed as a fire separation having a fire-resistance rating conforming to the requirements of Articles 3.2.2.20. to 3.2.2.83. for a floor assembly, but not less than 45 min.
(2) All loadbearing walls, columns and arches supporting a floor assembly immediately above a basementshall have a fire-resistance rating not less than that required by Sentence (1) for the floor assembly.
In Plain Language
A floor assembly directly above a basement must generally be built as a fire separation matching the rating otherwise required for floor assemblies, but never less than 45 minutes, and the loadbearing walls/columns/arches supporting it must match that same minimum rating.
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.