CLICK HERE for the instant Price Calculator
Ontario Residential Deck Regulations Guide
Permit Requirements
When is a permit required?
Exempt (No Permit)
Decks under 600 mm (24″) in height AND less than 10 m² (107 ft²) in area
Permit Required
Decks exceeding either of the above thresholds
Note: Attached decks may require permits regardless of size in some municipalities
Zoning Bylaws
| Requirement | Standard | Notes |
|---|---|---|
| Front Setback | 4.0 – 6.0 meters | Varies by municipality |
| Side Setback | 0.5 – 1.5 meters | Minimum 0.5m for narrow lots |
| Rear Setback | 1.0 – 3.0 meters | Often 10% of lot depth |
| Lot Coverage | Maximum 20-40% | Including all structures |
Site Plan Requirements
Most municipalities require a site plan showing:
- Property lines and dimensions
- Location of deck relative to property lines
- Distance to existing structures
- Proposed materials and height
Ontario Building Code (OBC) Requirements
Structural Requirements
Footings
- Minimum depth: 1.2m below finished grade
- Width: Minimum 350mm diameter
- Location: Within 1.0m of posts
- Reinforcement: Minimum 2 pieces of #15 rebar
Posts
- Minimum size: 38x89mm (2×4) or 140mm diameter round
- Maximum spacing: 1.8m apart
- Connection: Must be anchored to footings
Joists & Beams
- Joist spacing: Maximum 400mm on center
- Beam size: Minimum 38x235mm (2×10)
- Fasteners: Galvanized or stainless steel
Safety Regulations
Guardrail Requirements
Guardrail Height
Minimum 1070mm (42″)
Guard Strength
50 lb/ft load
Post Spacing
Maximum 1.8m apart
Baluster Spacing
Maximum 100mm gap
Guard Construction
- Top rail: 900-1070mm above deck
- Mid-railing: Required for children safety
- Materials: Must resist corrosion
- Attachment: Structural connection required
Attached vs. Detached Rules
| Requirement | Attached Decks | Detached Decks |
|---|---|---|
| Permit Exemption | Rarely exempt (even if under size limits) | Exempt if under 600mm and 10m² |
| Ledger Attachment | Must use proper flashing and lag bolts | Not applicable |
| Insulation Requirement | May require insulation at house connection | Not applicable |
| Stair Requirements | Must meet stair code if accessing home | Only if stairs exceed 3 risers |
Inspection Requirements
Mandatory Inspection Phases
- Footings (before pouring concrete)
- Post installation (before framing)
- Guardrail installation (before final inspection)
- Final occupancy inspection
Common Municipal Requirements
- Site plan review (pre-approval)
- Proof of soil testing (for footings)
- Engineered drawings for complex designs
- Material specifications (pressure-treated lumber)
- Proof of compliance with EPA regulations (if near water)