Is my Westboro stair rise inside the Ontario range?

To check your rise against the 2024 Ontario Building Code, share the measurement you have and compare it to this: on private stairs within a dwelling unit, each rise must be no more than 200 mm and no less than 125 mm, measured nosing to nosing.

That range is the starting point, but one number is not the whole picture. The Code also requires that no two adjacent risers differ by more than 5 mm, and that no riser anywhere in the flight differs from any other by more than 10 mm. A rise that sits inside 125 mm to 200 mm can still fall short if the risers are uneven across the flight.

A few other dimensions connect directly to the rise. The run must be no less than 255 mm (about 10 in.) and no more than 355 mm, measured nosing to nosing. Each tread must be at least as deep as its run, and no more than 25 mm deeper. Nosing edges are rounded or bevelled between 6 mm and 14 mm. If any of those are off, the rise being correct does not make the stair compliant as a whole.

For the stringer beneath all of this, the Code sets an effective depth of at least 90 mm and an overall depth of at least 235 mm, with stringers spaced no more than 900 mm apart and treads at least 25 mm thick.

There are too few published Ottawa prices for stair work to quote a range. When you ask a carpenter to look at the stair, ask them to put each of these line items in writing: materials, labour, any patching and finishing needed after the work, and disposal of what comes out.