Understanding the Quebec Construction Code for Balcony Railings

If you're building in Montréal, Laval, Québec City, or anywhere else in the province, the Code de construction du Québec (CCQ) and the underlying National Building Code (NBC) govern your railing spec. We deal with these every day. Here are the rules that actually matter when you're putting railings on a residential or commercial building in Quebec.

Guard heights

• Residential balconies, decks, mezzanines: minimum 1,070mm (42 inches) above finished floor where the drop is more than 1.8m
• Where the drop is less than 1.8m: minimum 900mm (35 inches)
• Commercial occupancies often require 1,070mm regardless of drop height — check the specific use group
• Stairs: minimum 920mm at the rail (measured vertically from the nosing line)

Picket spacing: the 100mm sphere rule

Vertical pickets must be spaced so that a 100mm (4 inch) sphere cannot pass through. That works out to roughly 4 inches on center for typical 3/4-inch pickets. The intent is to prevent a small child's head from getting through.

Horizontal pickets and cable railings are discouraged in residential buildings because they create a 'ladder effect' that children can climb. Some Quebec municipalities flat-out prohibit them on residential balconies. Glass infill and vertical pickets are the safe specs.

Load requirements

Guards must resist a horizontal point load of 1.0 kN (about 225 lbs) applied anywhere along the top rail, plus an additional uniformly distributed load equivalent to 0.75 kN/m. For commercial spaces with assembly use, the uniform load doubles. Glass infill panels must individually resist 0.5 kN over a 100mm × 100mm area.

If your railing supplier can't hand you a stamped engineering letter showing these calcs, they're not actually meeting code — they're hoping nobody asks.

Stamped shop drawings are mandatory

For any project requiring a building permit, the railing manufacturer must submit shop drawings stamped by an engineer licensed in Quebec (an OIQ member). The drawings must show: section views, attachment details to the structure, load calculations, materials and finishes, and any deviations from the architectural drawings.

Skip this step and you'll fail inspection and have to redo the work. Worse, your insurance won't cover any incidents related to non-compliant railings. Always ask for the stamped drawings — and the engineer's OIQ number — before the railings ship.

What inspectors catch most often

• Picket spacing greater than 100mm (especially at the end-of-run pickets near the post)
• Top rail height shy by 5–10mm due to floor tile build-up the railing supplier didn't account for
• Embed plates not properly anchored to slab rebar
• Glass railings without the required 'No.7' or equivalent safety marking
• Handrails that aren't continuous through stair landings (a code requirement frequently missed by general contractors)