The Ontario Building Code | Minimum Number of Risers
9.8.3.2. Minimum Number of Risers
(1) Except for stairs within a dwelling unit, at least three risers shall be provided in interior flights.
In Plain Language
A stairway must have at least the minimum number of risers set out in this article, since a single very tall step, or too few steps, is a common trip hazard.
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.