Can expanded metal achieve the 2026 National Building Code of Canada’s updated fire-safety ratings for high-rise cladding?
The 2026 edition of the National Building Code of Canada tightened the screws on exterior cladding for high-rise buildings, making non-combustibility and demonstrable fire-resistance ratings harder to satisfy with conventional composite panels. That shift has sent architects and facade engineers back to their material libraries, and expanded metal is surfacing as a serious contender. It is non-combustible by nature, it ventilates beautifully, and it carries a fraction of the weight of solid sheet. But nature and weight are not what the building inspector signs off on — the inspector wants a CAN/ULC-S101-18 Level 1 rating tied to a specific assembly. This article looks at whether expanded metal can actually deliver that rating, and what has to happen around the mesh for the wall to pass.
What Changed in the 2026 NBC Canada for High-Rise Cladding?
The 2026 code does not merely recommend non-combustible cladding above a certain height — it mandates it for exterior wall assemblies in high-rise residential and assembly occupancies. The benchmark test is CAN/ULC-S101-18, and the target is a Level 1 fire-safety rating. In practical terms, that means the cladding system must resist flame spread, maintain structural integrity under standard fire exposure, and limit heat transmission for a duration that matches the building’s required fire-resistance rating.
Specification Checklist for Architects and Engineers
| Item | What to Verify | Where It Shows Up in the Submittal |
|---|---|---|
| Alloy and gauge | Match the tested assembly exactly; do not substitute aluminum for steel or change strand thickness without a new test | Mill certificates and structural calculations |
| Mesh opening and strand width | Affects airflow, debris intrusion, and the mesh’s ability to shield insulation from flame | Product data sheet and test report drawings |
| Cavity insulation type and density | Must be the same product, thickness, and attachment method as the tested assembly | Insulation manufacturer’s fire-test letter |
| Fire-stop locations | Every floor line, panel perimeter, and penetration | Detail drawings and fire-stop product data |
| Attachment system | Non-combustible clips, brackets, and fasteners at spacing tested | Structural and fire-test documentation |
| Coating or finish | If specified, must be included in the tested assembly; some powder coatings are combustible and will void the rating | Finish manufacturer’s test inclusion letter |
The Bottom Line
Expanded metal can absolutely achieve the 2026 National Building Code of Canada’s updated fire-safety ratings for high-rise cladding — but the rating belongs to the assembly, not the mesh. The metal itself is non-combustible, strong, and thermally favorable, which is why it passes the material-level tests without drama. The real work is in the cavity behind it: the insulation, the air-gap control, the fire stops, and the edge details. Design teams that treat expanded metal as a system component rather than a standalone solution will find that it delivers compliance, durability, and aesthetics in one package. Those that specify the mesh and hope the rest sorts itself out will find themselves in the revision loop longer than necessary.
