The Ontario Building Code | Stairs, Ramps, Landings, Handrails and Guards for Dwelling Units
3.3.4.7. Stairs, Ramps, Landings, handrails and Guards for Dwelling Units
(1) Except as required by Article 3.3.4.8., stairs, ramps, landings, handrails and interior guards within a dwelling unit shall conform to the applicable requirements in Section 9.8.
(2) Except as provided in Sentence (3), exterior stairs, ramps, landings, handrails and guards serving a single dwelling unit shall conform to the applicable requirements in Section 9.8. and Sentence 3.1.20.1.(1).
(3) Loads on exterior guards serving a single dwelling unit shall comply with Part 4.
In Plain Language
Stairs, ramps, landings, handrails, and interior guards within a dwelling unit itself can follow a more relaxed set of dimensional requirements than the general exit stair rules, since they're used only by the unit's own occupants rather than the public.
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.