Sarking
Sarking is a reflective or vapour-permeable membrane installed behind roof tiles or wall cladding to manage condensation, moisture, and draught. Required under NCC 2022.
Ask Chalkline about this →Sarking is a flexible membrane installed immediately behind roof tiles, cladding, or wall lining to manage moisture movement, draught penetration, and thermal performance. In roof applications it runs under the battens and over the rafters, shedding condensation or any water that gets past the tiles toward the gutters. In wall applications it sits behind the external cladding (weatherboard, fibre cement, brick veneer cavity) and forms part of the drainage plane that directs incidental water out of the wall cavity.
NCC 2022 requires sarking in certain climate zones and roof configurations, and under NCC 2022’s condensation management provisions (introduced for higher energy efficiency requirements) correctly specified sarking vapour permeability is now a compliance element. The requirement for reflective foil sarking versus vapour-permeable (breathable) sarking depends on climate zone and wall construction type.
At window openings, flashing at the head and jambs must correctly integrate with the sarking layer using the shingle principle (upper layers overlapping lower). This junction is a common defect point on site.
Category: Building envelope / moisture management
Related
See also
- Flashing, the impervious strips that work with sarking at junctions and openings
- Vapour barrier, a related membrane type used in floor and wall assemblies
- NCC, the code that mandates sarking requirements by climate zone
Last updated: 2026-05-08. Verified: 2026-05-08.