What the Code Says
The Ontario Building Code (OBC) sets out strict requirements for cladding systems. For GCs, the priority is not to memorize every clause, but to ensure subcontractors submit the right documentation and build in compliance from day one.
Part 3 – Fire Protection
- Buildings >18 m: cladding must be non-combustible or tested to CAN/ULC-S134.
- Flame spread ≤25, smoke developed ≤50.
- Firestopping at floor lines must maintain a 2-hour rating.
- Spatial separation rules limit materials and openings.
Part 4 – Structural Design
- Cladding connections must resist wind and snow loads per NBCC.
- Importance factor varies with building occupancy.
Part 5 – Environmental Separation
- Cladding must be the first plane of defense against precipitation.
- Systems must include a rainscreen drainage plane.
- The air barrier must remain continuous at transitions and penetrations.
Energy Performance Requirements
Toronto (Zone 6) energy codes require continuous insulation and reduced bridging.
- Walls: RSI 2.97 continuous insulation.
- Max glazing: 40% prescriptive.
- Thermal spacers required at attachments.
- Air leakage: ≤0.25 L/s·m² at 75 Pa.
- WRB installed with minimum 100 mm shingled laps
- All penetrations sealed and booted
- Continuity confirmed at transitions
- Inspection completed before panel staging (third-party where required)
Fire Safety Requirements
Beyond OBC, the Ontario Fire Code enforces cladding performance:
- 18 m: CAN/ULC-S134-tested assemblies, flame spread ≤25, smoke ≤50.
- Firestopping at every floor line.
- Maintain emergency ventilation openings and exit signage visibility.
WSIB Safety Compliance
Cladding installation falls under Ontario Regulation 213/91. As GC, you are responsible for ensuring subcontractors comply.
- Fall Protection: Guardrails or safety nets above 3 m. Where impractical, fall arrest systems with written rescue plan.
- Material Handling: Max manual lift = 23 kg. Mechanical lifts required for heavier panels. Wind speed cut-off ~40 km/h for panel handling.
- Site-Specific Safety Plans: Must document hazards, emergency procedures, and daily safety meetings.
GC Checklist for Code Compliance
- Require submittals for: shop drawings (air barrier, drainage), fire test certificates (CAN/ULC-S134), engineer’s structural calcs, energy thermal modeling.
- Verify inspections: fire stops at floor lines, WRB continuity, insulation coverage, torque logs.
- Enforce safety: fall protection, material handling, wind cut-offs, site-specific safety plans.
- Maintain records: all certificates, reports, and safety logs must be archived for occupancy handover.
