Direct-fix cladding
Direct-fix cladding is fixed straight to the frame with no cavity, so foil sarking behind it is a vapour barrier only, a condensation risk in cool climates (zones 6-8).
Ask Chalkline about this →Direct-fix cladding is cladding fixed straight onto the frame or sheathing with no drained, ventilated cavity behind it, as distinct from a cavity (drained) or rainscreen system that holds the cladding off the frame on battens. Direct fixing is faster and cheaper and is still common on weatherboard and sheet cladding, but it leaves no airspace behind the cladding, and that airspace matters for two things: thermal performance and drying.
Because there is no airspace, a foil-faced sarking behind direct-fix cladding acts as a vapour barrier only; the reflective foil gives no thermal benefit without an air gap next to it. In cool climates (BCA climate zones 6 to 8) that vapour-barrier face is a condensation trap: warm indoor moisture migrates outward, hits the cold back of the impermeable sarking, and pools against the framing. The NCC 2022 condensation management provisions (Volume Two Part H2) and the ABCB Condensation Handbook flag this, and the usual fix is a vapour-permeable membrane (Class 3 or 4 permeance) rather than a foil barrier on the external side.
In hot and temperate climates (zones 1 to 5) direct fix with a vapour barrier is usually fine. Where drying capacity or wind-driven rain is a concern, a drained cavity behind the cladding is the more robust detail. Match the membrane class and the cavity decision to the climate zone, not to habit. See drained cavity and weatherboard cladding.
Also known as: Direct-fixed cladding, no-cavity cladding.
Category: Cladding / Weatherproofing.
Related
See also
References
- AS/NZS 4200.1:2017 Pliable building membranes and underlays, Standards Australia (verified 2026-05-16)
- ABCB Condensation in Buildings Handbook (verified 2026-05-16)
Last updated: 2026-05-30. Verified: 2026-05-16. Quarterly review for currency.