What rise and run should my Stittsville deck stairs use?

For exterior stairs serving a single dwelling unit, the 2024 Ontario Building Code sets the rise between 125 mm and 200 mm, and the run at a minimum of 255 mm and a maximum of 355 mm. Each rectangular tread's depth must be no shallower than the run and no deeper than the run plus 25 mm.

Those are the outer limits. Where your stairs actually land within that range depends on a few things specific to your deck.

The height from your deck's walking surface to the ground and the space available below it shape the stair design, and your designer or builder works that out on the drawings. For applications deemed complete on or after March 11, 2026, both Zoning By-law 2008-250 and By-law 2026-50 apply, with the most restrictive provisions governing, so confirm with the City how the rules treat the stairs on your lot.

A permit is required if your deck's walking surface is more than 600 mm (24 in.) above adjacent grade and the deck is attached to or adjacent to the house, or if it is an elevated deck providing principal access to the building. Where a permit applies, the City of Ottawa asks for drawings that show stair construction and location, rise and run dimensions, and guard and handrail information. The City requires three inspections: Excavation/Foundations, Framing, and Final, booked 48 hours in advance.

On handrails: exterior stairs serving a single dwelling unit with three risers or fewer do not require a handrail under the 2024 Ontario Building Code. More than three risers requires one handrail, and it must sit between 865 mm and 1 070 mm above the stair. If the stairs have a guard, the guard height on the stair is measured vertically from the top of the guard down to a line drawn through the tread nosings, and openings in that guard must prevent the passage of a 100 mm sphere. The triangle formed by the riser, tread and bottom rail must prevent the passage of a 150 mm sphere.

Before any footing holes are dug for the stair stringers or posts, submit a locate request through Ontario One Call at least five business days ahead. It is free and required by the Ontario Underground Infrastructure Notification System Act, 2012.

A few things worth confirming with your builder or designer before the drawings are finalised: the exact number of risers given your measured total rise, where the bottom landing sits relative to your property lines, and who is responsible for submitting the permit application and booking the three City inspections.

Make sure you have the permit in hand, a complete set of signed drawings showing the rise, run and stair location, and a written contract that spells out the full scope and price before any work begins on site.