FAQ

An airtight membrane forms a continuous air barrier so unintended gaps don’t leak heated or cooled air. Placing it on the warm side of the assembly (inside face in most AU climates) improves comfort and efficiency. Intelligent (variable‑permeance) membranes add moisture safety by being tighter in winter and more open in summer to aid drying.

No. A DPM under slabs/floors is a vapour‑tight barrier to stop ground moisture entering the building; it’s not a breathable wall wrap. Use vapour‑permeable WRBs on walls and roofs, and DPMs for ground moisture control.

Yes. You can retrofit airtightness and moisture control from the inside using intelligent membranes, compatible tapes, and service cavities; external wraps can be added during reclads or reroofs. We offer support for retrofit details so you gain performance without major rework.

No. We supply WRBs, IABs and accessories for any building type, including Passive House. If you’re pursuing certification, we can support your team with PHPP‑ready specs.

Homes that combine a continuous WRB + airtight layer, good insulation, quality windows, and smart orientation to cut energy demand and improve comfort. Passive House is a specific certified subset of high performance; many non‑certified homes still apply the same principles.

A WRB (sarking/building wrap) sheds rain that gets behind cladding and resists wind while still allowing the assembly to dry. In Australia, NCC provisions require vapour‑permeable wraps on the outside of insulation in many climates to manage condensation risk.

It’s the deliberate, unbroken layer that controls airflow through the envelope. We typically place it on the interior (warm) side for easier detailing and service access; rigid Air Barreir options (RAB) are also possible. Intelligent airtightness barriers (IAB) increase drying potential in mixed climates.

A vapour barrier severely limits vapour diffusion. It can be appropriate in extreme hot‑humid or sub‑arctic conditions with one‑directional vapour drive—but in most Australian climates a full VB can trap moisture. If you’re unsure, run hygrothermal modelling (WUFI) before specifying.

Most AU climate zones perform best with vapour‑permeable external membrane (Class 3 or 4 VCMs per AS/NZS 4200.1). Vapour barriers (Class 1–2) are typically not used as external membranes here apart from Hot Humid climates; check your project’s climate and wall build‑up.

Modern monolithic (non‑porous) VPMs let vapour escape while remaining fully waterproof and wind‑tight, avoiding the ‘tent effect’ of older microporous wraps. Premium TEEE‑film wraps provide very high water holdout, high heat resistance and long UV exposure windows during construction.

AS/NZS 4200.1 classifies vapour control membranes (VCMs) by permeance. Class 1–2 are low‑permeance (vapour‑barrier‑like), while Class 3–4 are more permeable (used as VPM/WRB to meet NCC condensation provisions).

A high‑performance home follows best‑practice enclosure design to reduce energy and improve health. Passive House is a third‑party certification pathway that verifies the design with PHPP and checks construction against stringent metrics.

In AU practice, ‘sarking’ is a pliable membrane under roofing or behind cladding. Today, many projects use vapour‑permeable sarking with drainage gaps to manage condensation as well as rain.

Our core products are weather‑ and air‑resistive barriers that protect insulation from wind‑washing and moisture loads (a key cause of lost R‑value) however we do provide woodfibre board which has excellent insulative properties in various thicknesses and low‑expansion perimeter foam around windows/doors to close air paths.

WRB (Weather‑Resistive Barrier): Sheds liquid water that gets behind cladding and resists wind‑driven rain; often vapour‑permeable to allow drying.

VPM (Vapour‑Permeable Membrane, Class 3–4): A type of WRB with tested permeance that lets moisture vapour escape while keeping rain out—used to meet NCC condensation requirements.

ATB/IAB (Airtightness Barrier / Intelligent Airtightness Barrier): The air‑control layer that stops unintended air leakage; usually on the warm (interior) side. “Intelligent” versions vary their permeance to improve drying.

We specialise in WRBs and airtightness rather than wet‑area or below‑grade waterproofing. If you need bathroom/balcony/planter membranes per AS/NZS 4858 or AS 4654.2, we can refer trusted suppliers; our wraps and tapes interface with those systems.