Ontario Building Code for Stairs & Railings: What Actually Applies in 2026

Ontario's Building Code was consolidated into O. Reg. 163/24, in force since January 1, 2025, and amended most recently by O. Reg. 242/26 (July 2026). It replaced the old O. Reg. 332/12. If you're reading a guide (including older versions of ours) that cites 332/12 as current law, it's out of date. One nuance: 163/24 keeps transition provisions under which 332/12 can still govern certain construction tied to permits or design work from the 2024 transition period, so an older project can legitimately fall under the previous code. The rules that matter for residential stairs and railings live in Section 9.8, and they're what every project in our St. Catharines shop is drawn against before fabrication starts.

This page collects the requirements we actually work to every week (geometry, guards, handrails, openings, headroom and loads) with the article numbers so you can check them yourself. It is a builder's working summary, not legal advice; your municipality's building department has the final word on any permit.

Stair geometry (private stairs)

Table 9.8.4.1 sets the limits for stairs in dwelling units:

RequirementLimit
Maximum rise200 mm
Minimum rise125 mm
Maximum run355 mm
Minimum run255 mm
Maximum variation between risers5 mm

Two things trip people up. First, the minimum run is 255 mm, not 235 or 220; those older figures predate the 2022 change and still circulate online. Second, the 5 mm uniformity rule applies across the whole flight: an inspector measures every riser, not a sample.

Guards: when you need one and how high

A guard is required wherever the drop exceeds 600 mm. Under 9.8.8.3.(1), guards are a minimum 1,070 mm high. The exception in 9.8.8.3.(3) allows 900 mm for exterior guards serving not more than one dwelling unit, and only where the walking surface is not more than 1,800 mm above grade, a condition people routinely drop when they quote the rule.

Handrails

Handrails on stairs sit 865–965 mm above the nosing line (9.8.7.4.(2)), must be continuous for the length of the flight, and must be graspable. For commercial and multi-unit work, AODA adds continuous-grip profiles (32–50 mm circular), 50 mm wall clearance, and 300 mm horizontal extensions at the top and bottom.

Openings and climbability

Guards must reject a 100 mm sphere (9.8.8.5.(1)), the classic “4-inch ball” rule, so a small child can't pass through any opening. Horizontal elements between 100 mm and 900 mm above the walking surface are not permitted on guards protecting a fall greater than 1,800 mm, because they can be climbed like a ladder.

Headroom

Minimum headroom is 1,950 mm in dwelling units (9.8.2.2.(3)), 2,050 mm in other occupancies, and 1,850 mm is permitted under beams in secondary suites. Measured vertically from the nosing line, not from the tread surface.

Loads on guards (Table 9.8.8.2)

Residential guards are designed for a 1.0 kN concentrated load at the top rail plus a 0.5 kN/m uniform linear load. Commercial occupancies carry higher uniform loads (0.7 kN/m on the projects we engineer). These numbers are why a guard is a structural element: the posts and their fastening, not the glass or spindles, carry the load.

Glass railings and safety glazing

Glass used in a guard must be safety glazing: tempered, laminated, or laminated tempered. In practice we use 12 mm tempered as a minimum, and 13.52 mm laminated tempered (2 × 6 mm glass + 1.52 mm interlayer) for topless systems and anywhere a panel sits above an occupied area. For exterior installations we verify wind pressure and deflection. See our glass railings guide for the system-by-system detail and our glass railings service page for the systems and hardware we install.

How this shows up in a real project

Every drawing that leaves our shop is checked against the clauses above before a board is cut: rise/run and uniformity, headroom through the flight, guard height and infill, handrail position, and the load path for the guard posts. When a permit requires it, we provide stamped drawings. What we won't do is quote a stair that only looks compliant, the geometry is either right on the drawing or it becomes a problem at inspection.

Sources

Frequently Asked Questions

What is the minimum run for a stair in Ontario?

255 mm for private stairs in dwelling units (Table 9.8.4.1). The maximum is 355 mm, with a maximum rise of 200 mm.

How high must a railing be in Ontario?

Guards are a minimum 1,070 mm. Exterior guards serving not more than one dwelling unit may be 900 mm where the walking surface is not more than 1,800 mm above grade. Handrails are 865–965 mm above the nosing line.

Does a glass railing need a top rail?

Not if the glass is designed as the guard and meets the load and deflection requirements, topless systems with laminated tempered glass are common on residential decks. Some building departments interpret 9.8.7 strictly for occupancy uses; we confirm before fabrication.

Which regulation is current: 332/12 or 163/24?

O. Reg. 163/24. It consolidated and replaced the 2012 code, effective January 1, 2025. Any guide still citing 332/12 as current is out of date.

Building or renovating a staircase in the Niagara Region?

We'll measure it, check it against Section 9.8, and give you a written estimate: request a free estimate or see typical pricing.

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