VapourFlex® CW
Class 4 Vapour Permeable Membrane for Commercial and Residential WallsVapourFlex® CW is a vapour permeable, Light Duty wall wrap, designed for use in a wide range of wall systems in both commercial and residential applications.

VapourFlex® CW is classified as a Class 4 Vapour Permeable Membrane and an Air & Water Barrier.
Water vapour absorbs and diffuses through the core non-woven structure, ensuring condensation risk is controlled, while outside liquid water cannot penetrate inwards. VapourFlex® CW is classified as an air barrier, assisting in reducing air infiltration and helping achieve an air-tight building envelope.
Product Advantages
- Class 4 Vapour Permeable
- Up to 90 Days UV Resistance
- Low flammability
- Air & Water Barrier
Applications
Commercial & Residential Wall Wrap and Vapour Permeable Membrane for a wide range of wall systems.
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Product Details
| Product Name | VapourFlex® CW |
| Roll Size | 1500 mm x 30 m (45m2) 3050 mm x 30 m (91.5m2) |
| Duty Rating | Light Wall |
R Values
| Declared Total System R-Values | Summer | Winter |
| Fibre cement and metal clad walls Battened (on the outside of studwork), 90mm frame (no bulk insulation), 10mm plasterboard. | RT0.6 | RT0.6 |
| Brick veneer walls Cavity (on the outside of studwork), 90mm frame (no bulk insulation), 10mm plasterboard | RT0.7 | RT0.7 |
The contribution of this product to the total R value depends on installation and environmental conditions. The R value will be reduced in the event of the accumulation of dust on upward facing surfaces and in cavities that are ventilated.
Product Testing
VapourFlex® CW Summary of Testing Results
| Duty Rating | AS/NZS 4200.1:2017 | Light Wall Duty |
| Vapour Control | ASTM E96 | Class 4 Vapour Permeable |
| Vapour Permeance | ASTM E96 | >1.1403 μg/N.s |
| Water Control | AS/NZS 4201.4:1994 | Water Barrier |
| Air Control | AS/NZS 4200.1:2017 | Air Barrier |
| Flammability Index | AS 1530.2-1993 | Low ≤5 |
| Nominal Material Thickness | <1.0mm | |
| Resistance to UV Exposure | Up to 90 days | |
| Resistance to Dry Delamination | AS/NZS 4201.1:1994 | Pass |
| Resistance to Wet Delamination | AS/NZS 4201.2:1994 | Pass |
| Emittance Value | AS/NZS 4201.5:1994 | 0.9, 0.9 |
Specification Notes
Product Name: VapourFlex® CW
The pliable building membrane to be installed shall be VapourFlex® CW Vapour Permeable Membrane, and shall be installed in accordance with AS/NZS 4200.2:2017 Pliable Building Membranes and Underlays, Part 2: Installation.
Vapour Control Classification: Class 4 Vapour Permeable, >1.1403 μg/N.s
Water Control Classification: Water Barrier
Air Control Classification: Air Barrier
Flammability Index: Low (≤5)
Duty Classification: Light Wall in accordance with AS/NZS 4200.1
Emittance Value: 0.9, 0.9
Emittance Classification: IR Non-Reflective, IR Non-Reflective
Installation Instructions
VapourFlex® CW Vapour Permeable Wall Wrap should be installed in accordance with AS/NZS 4200.2 Pliable Building Membranes and Underlays, Part 2: Installation Requirements.
GENERAL
VapourFlex® CW should be installed horizontally with the printed side facing outward. Fix the product to all framing members, as a continuous membrane, and ensuring any damage or tears to the membrane are repaired.
Fixings should be galvanised clouts or staples for timber frames, and button head or tek screws for steel frames. In high wind areas, it is recommended to install using flat punched multi-point fasteners or cap screws.
When installing VapourFlex® CW, line up bottom of the roll covering the base of the timber bottom plate, ensure the product is level.
Horizontal, vertical and end overlaps must be 150 mm, with top layers of the membrane overlapping the outside of the lower layers to prevent water ingress.
Continue until the top of the wall frame is covered, and seal the membrane with tape to the top plate.
At windows or openings, VapourFlex® CW must be neatly cut, sealed and flashed at all sides to achieve its desired function and facilitate proper drainage to the building flashing. Ensure the membrane diverts water away from the opening.
External cladding should be installed without delay so as not to prolong direct exposure to UV light and other elements.