Canadian building code question

What are the building code requirements for curtain walls in Canada?

Curtain wall systems in Canada must satisfy requirements across several divisions of the National Building Code of Canada (NBC): structural load resistance, air and water infiltration control, thermal performance, fire stopping at floor lines, and vision glass safety. The exact thresholds depend on building height, occupancy, climate zone, and the edition of the code adopted by each province. CodeCan can cite the precise NBC sections and any provincial amendments that apply to your project.

Curtain walls are non-load-bearing exterior cladding systems that enclose multi-storey buildings. Because they span floor lines, interface with the structure, and form part of the building envelope, the NBC treats them under multiple parts simultaneously — structural, environmental separation, fire protection, and glazing safety. Getting the requirements right requires checking several NBC divisions and any provincial amendments in force for your project location.

What to check first

  • Curtain walls must meet NBC structural load, air barrier, vapour control, and thermal performance requirements simultaneously.
  • Fire stopping at each floor line is mandatory to prevent vertical flame spread through the cavity between the curtain wall and the floor assembly.
  • Vision glass panels must comply with safety glazing requirements, and spandrel panels must meet opaque assembly thermal and fire performance standards.

Jurisdiction notes

National baseline

The NBC establishes baseline requirements for curtain walls under Part 5 (Environmental Separation), Part 4 (Structural), and the fire-separation provisions of Part 3. The 2020 NBC introduced stricter energy performance tiers that affect curtain wall U-value requirements.

Ontario adoption check

Ontario's Building Code (OBC) adopts the NBC with provincial amendments. Ontario has its own SB-10 supplementary standard for energy efficiency that affects curtain wall thermal performance, and the OBC may reference different test standards than the base NBC. Always verify against the current OBC edition in force for your permit date.

Project-specific variables

Building height, seismic zone, wind exposure category, climate zone, occupancy group, and the specific curtain wall system type (stick-built vs. unitized) all affect which NBC provisions apply and at what thresholds.

Work through it in this order

  1. Identify the building's occupancy classification, height, and the provincial code edition in force for your permit jurisdiction.
  2. Determine which NBC Parts apply: structural loads (Part 4), environmental separation (Part 5), fire protection (Part 3), and glazing safety.
  3. Check provincial energy codes or supplementary standards (e.g., OBC SB-10, BCBC Step Code) that impose stricter curtain wall thermal requirements.
  4. Use CodeCan to run the specific question with your project variables and get cited NBC and provincial amendment sections in one place.

Common questions

Does the NBC require curtain walls to have fire stops at every floor?

Yes, the NBC requires fire stopping at floor lines to prevent vertical flame spread through the void between the curtain wall and the floor assembly. The specific construction detail requirements are cited in Part 3. CodeCan can pull the exact section for your project's building type.

Are there different curtain wall requirements for high-rise versus low-rise buildings?

Yes. Building height affects which structural load provisions apply, which fire-protection tier is required, and which energy performance tier is mandated. Taller buildings typically face more stringent requirements across all these areas.

Why doesn't this page give me the exact NBC section numbers?

Curtain wall requirements span multiple NBC Parts, vary by province and code edition, and change with project-specific variables like climate zone and building height. Citing one section without those inputs could lead you to the wrong requirement. CodeCan is designed to take your project context and return the cited sections that actually apply.