The Ontario Building Code | Rating of Supporting Construction

3.1.7.5. Rating of supporting Construction

(1) Except as permitted by Sentence (2) and by Articles 3.2.2.20. to 3.2.2.83. for mixed types of construction, all loadbearingwalls, columns and arches in the storey immediately below a floor or roof assembly required to have a fire-resistance rating shall have a fire-resistance ratingnot less than that required for the supported floor or roof assembly.

(2) loadbearingwalls, columns and arches supporting a service roomor service space need not conform to Sentence (1).

(3) Except for noncombustible constructionrequired by Subclauses 3.2.2.43A.(2)(c)(i) and 3.2.2.50A.(2)(c)(i), if an assembly is required to be of noncombustible constructionand have a fire‑resistance rating, it shall be supported by noncombustible construction.

3.1.8. Fire Separations and Closures