Wind classification
Wind classification (N1 to N6, C1 to C4) sets the design wind pressure for housing under AS 4055:2021, used to select compliant windows, doors and roof fixings.
Ask Chalkline about this →Wind classification is the site-specific wind speed category assigned to a dwelling under AS 4055:2021 (verified 2026-05-10). It translates the site’s geographical wind region, terrain category, topographic multiplier, and shielding conditions into a single label that drives the structural design of roofs, walls, windows, and doors.
Non-cyclonic classifications run from N1 (lowest, sheltered sites in low-wind regions) to N6 (highest, fully exposed sites on the coast or elevated terrain). Cyclonic classifications run from C1 to C4, applicable in tropical north Queensland, WA north of Latitude 26.5S, the NT, and parts of northern SA (verified 2026-05-10 via AS 4055:2021).
The wind classification determines:
- Design wind pressure for structural elements (AS 4055 Table 2.1)
- The required performance rating for windows and glazed doors under AS 2047
- Roof batten and fastener selection under AS 1684.2 or AS 1684.3
- Tie-down hardware specification
For residential doors and windows, the purchaser nominates the wind classification when ordering the assembly from the manufacturer. Products must carry a current AGWA accreditation certificate confirming compliance with AS 2047 at the required wind pressure.
Also known as: wind group, wind rating
Category: Structural / site assessment
Related
- AS 2047: windows and external glazed doors
- External doors: selection, installation and tolerances
- Metal roofing installation
See also
- Wind region, the geographic zone that anchors the classification
- Wind shielding, a modifier that can reduce the design pressure
- BAL (bushfire attack level), a parallel site-specific hazard classification
- NCC 2022 Vol 2 overview
Last updated: 2026-05-10. Verified: 2026-05-10.