Girt
A girt is a horizontal member fixed to columns to support wall sheeting, the wall-plane equivalent of a roof purlin, common on sheds and steel-framed structures.
Ask Chalkline about this →A girt is a horizontal structural member fixed to the columns of a frame to support the wall sheeting. It is the wall-plane equivalent of a roof purlin, and it is common on sheds, garages, and steel-framed Class 10 structures.
In a portal-frame or post-frame shed the loads run through a clear hierarchy: the wall cladding (often profiled steel sheet) spans between the girts; the girts span horizontally between the columns; and the columns carry it all to the footings. Roof sheeting does the same job through purlins; girts are simply the wall version, usually the same cold-formed C-section or Z-section profiles turned on their side.
Girts do two structural jobs:
- carry the out-of-plane wind load on the wall (suction and pressure) back to the columns, which is the governing load for most sheds, and
- provide the fixing line and spacing for the cladding, so girt spacing is set by the cladding’s span capability for the wind classification.
For a builder the practical points are to set girt size and spacing from the manufacturer’s span tables for the wind region and the cladding (closer girts for higher wind or thinner sheet), to fix the cladding to every girt as specified (skipped fixings are a common wind-damage point), and to remember girts often need bridging or fly bracing between them to stop the thin section twisting under load. Treat girts as engineered members, not just “rails to screw the sheets to.”
Also known as: Wall girt, side rail.
Category: Steel framing / Members.
Related
See also
References
- AS 1170.2 Wind actions, Standards Australia (verified 2026-06-03)
Last updated: 2026-06-03. Verified: 2026-06-03. Quarterly review for currency.