Canada · Construction type

What are the building code requirements for wood-frame construction in Canada?

Wood-frame (combustible) construction under the NBC is permitted up to 6 storeys for residential occupancies with sprinkler protection, with prescriptive framing requirements in Part 9 for smaller buildings and engineered design under Part 4 for buildings exceeding prescriptive limits.

Wood-frame construction is the most common building method for residential and small commercial buildings in Canada. The National Building Code sets height and area limits for combustible construction, prescriptive framing rules for houses and small buildings, and fire-protection requirements that increase with building height and occupancy type.

What to check first

  • Part 9 provides prescriptive framing requirements for wood-frame buildings up to 3 storeys and 600 m² building area (with some expansions for sprinklered buildings).
  • Part 3 permits combustible construction up to 6 storeys for Group C residential with sprinkler protection under specific construction types.
  • Fire-resistance ratings, fire separation requirements, and cladding restrictions increase with building height for wood-frame buildings.

Jurisdiction notes

National baseline

NBC Part 3 Subsection 3.2.2 sets building size and construction requirements for combustible buildings. Part 9 provides prescriptive framing, sheathing, and structural requirements for houses and small buildings.

Provincial variations

Some provinces adopted 6-storey wood-frame provisions before the NBC, and may have additional amendments or taller-building provisions for mass timber.

Engineering requirements

Wood-frame buildings exceeding Part 9 prescriptive limits require engineered design by a qualified professional, using CSA O86 for wood structural design.

Not professional advice

CodeCan reports what the published building code says. It is not legal, engineering, or architectural advice, and it does not certify compliance. Building codes are adopted and amended provincially and enforced locally — always verify with your authority having jurisdiction (AHJ) before you build.

Work through it in this order

  1. Determine whether the building qualifies for combustible (wood-frame) construction based on occupancy, height, and area limits.
  2. Classify the building under Part 9 prescriptive rules or Part 3 engineered design requirements based on size thresholds.
  3. For Part 9 buildings, verify prescriptive framing, sheathing, and bracing requirements for the building dimensions and loads.
  4. Confirm fire-resistance rating requirements for floor, wall, and roof assemblies based on the construction type.
  5. Check sprinkler, fire-alarm, and cladding requirements that apply to wood-frame buildings at the proposed height.

Common questions

How many storeys can a wood-frame building be in Canada?

Under the NBC, wood-frame (combustible) construction is permitted up to 6 storeys for Group C residential occupancy with sprinkler protection. The specific limits depend on building area, occupancy, and construction type.

When does a wood-frame building need an engineer?

Buildings exceeding Part 9 prescriptive limits (generally over 3 storeys or 600 m² for residential) require engineered structural design. Buildings with unusual loads, spans, or configurations may also require engineering even within Part 9 limits.

What fire rating is required for wood-frame floor assemblies?

The required fire-resistance rating depends on the construction type. Common wood-frame construction types require 45-minute to 1-hour rated floor assemblies, typically achieved with gypsum board on the underside of the framing.