When the code requires a railing
- Edges with a drop: walking surfaces — decks, porches, balconies, landings — more than 600 mm (24") above the adjacent level generally need a guard.
- Stairs: exterior stairs with more than three risers generally need a handrail; open sides of stairs with a drop need guarding too.
- Balconies: always — they're high by definition, and almost always in the 42-inch height class.
Required heights at a glance
| Location | Minimum height |
|---|---|
| Guard, surface ≤ 1,800 mm above grade | 900 mm (36") |
| Guard, surface > 1,800 mm above grade | 1,070 mm (42") |
| Stair handrail (above nosings) | 865–965 mm (34"–38") |
Deck railings: the details
The 600 mm (24") trigger does the sorting: a deck surface at or below it generally needs no guard; above it, one is required. Right at the line, measure carefully. Walkout-basement decks are almost always over 1,800 mm and land in the 1,070 mm (42") class. And watch the bench trap: height is measured from anything standable beside the guard, so a built-in bench at the deck edge raises the required guard height — a classic inspection catch. What this means for your project: deck railings · deck railing cost.
Openings, climbability, strength
Residential guard openings generally can't pass a 100 mm (4") sphere — the picket-spacing rule that keeps small kids on the right side. Between about 140 and 900 mm above the walking surface, guards can't offer footholds; vertical pickets and glass panels pass automatically, horizontal-rail designs don't. And guards must resist real loads at the top rail and infill, which comes down to anchoring into structure — rim joists, concrete — not surface material.
Glass guards: the special rules
Glass in a guard must be safety glass — tempered or laminated — and glass guard designs in Ontario generally require professional engineering, because the panels (and in frameless systems, the mounting hardware) carry structural load. The practical takeaway: buy a glass railing as an engineered system, not as panels from a supplier and a weekend plan. Our framed and frameless systems are both tempered safety glass built to these heights. Ask us what engineering documentation applies to your job before material is ordered.
Pools are extra
Pool enclosures are governed by municipal bylaws on top of the building code — typically 1.2 m minimum height, self-closing/self-latching gates, and no climbable features. Covered on our pool railing page and in the permit guide.
What inspectors actually check
Height from the walking surface, the 100 mm sphere at the widest opening, post solidity (they push), climbability, and — for glass — that it's safety glass in an engineered system. Build to those five and inspections are boring, which is the goal. Every railing we install — aluminum picket included — is specced to pass before the truck leaves the shop.
Plain-language summary of common residential OBC requirements — not a code document or legal advice. Confirm specifics with your municipal building department.