Canada's code: decks 24"–71" above grade need a 36" (915 mm) railing; higher decks need 42" (1070 mm). Height table, baluster spacing, and provincial rules.
Quick answer: In Canada, the minimum deck railing height is 36 inches (915 mm) for decks between 24" and 71" above grade, and 42 inches (1070 mm) for decks higher than 71" (1800 mm). A railing is required on any deck more than 24" (610 mm) above the ground.
| Deck height above grade |
Min railing height |
| Up to 24" (610 mm) |
No railing required |
| 24"–71" (610–1800 mm) |
36" (915 mm) |
| Over 71" (1800 mm) |
42" (1070 mm) |
Key Takeaways:
- Railing required when deck is more than 24 inches (610 mm) above ground at any point
- Minimum railing height: 36 inches if deck is 24"–71" above grade; 42 inches if higher than 71" (5'-11")
- Balusters max 4" (100 mm) spacing — a 4" sphere must not pass through
- No horizontal members that act as a ladder (under 36" climbable)
- Provincial codes can be stricter — Ontario, Quebec, BC have additional rules
National Building Code (NBC) Requirements
The 2020 NBC (adopted by all provinces with amendments) sets the minimums shown in the table above: no railing below 24", 36" (915 mm) from 24" to 71", and 42" (1070 mm) beyond that.
Stairs follow a different rule: handrail height between 34"–38" measured from the nosing.
Baluster (Picket) Spacing
The "4-inch rule" — no opening in the railing system can allow a 4-inch (100 mm) sphere to pass through. This applies to:
- Vertical baluster spacing
- Bottom rail clearance to deck surface
- Top rail to bottom of any horizontal member
For glass railing, the glass panel itself satisfies this — but the gap between glass and post must still meet 4".
Post Spacing & Structural Requirements
| Material |
Max post spacing |
Min post size |
| Wood |
6 ft |
4×4 (rated PT) |
| Aluminum |
6 ft |
2" SCH 40 |
| Composite/PVC sleeve over wood |
6 ft |
4×4 wood core |
| Cable railing |
4 ft (tension) |
4×4 minimum |
Posts must be bolted, not screwed to the rim joist (per NBC) — typically 2× ½" through-bolts with washers.
Provincial Variations
| Province |
Notable amendment |
| Ontario (OBC) |
Above 71": 42" minimum, glass must be tempered/laminated |
| Quebec (CCQ) |
Climbable horizontal members specifically prohibited |
| British Columbia (BCBC) |
Higher seismic loads on tall railings |
| Alberta |
Follows NBC closely |
| Atlantic |
NBC + wind exposure category |
Always verify with your local building department — municipalities can add rules.
Common Code Violations We See
- Railing too low on second-story decks (homeowner used 36" for a 9' deck — needs 42")
- Decorative horizontal slats under 36" that act as a ladder
- Glass railing posts spaced 8 ft (max is 6 ft)
- Stair handrail height wrong — measured from tread, not from deck surface
- No graspable handrail on stairs (top rail too thick to grip)
Getting It Right
We pull the deck permit, build to the latest code edition, and call for rough-in and final inspections. The inspector signs off — that's your evidence the railing meets code, which matters for insurance and resale.
Read about deck permit requirements next.
See also: glass railing options • aluminum railing options
