VapourFlex VPM™

Class 4 Vapour Permeable Membrane
VapourFlex-VPM™ is a vapour permeable, Light Duty wall wrap, designed for use in a wide range of wall systems in both residential and commercial applications.

VapourFlex-VPM™ is classified as a Class 4 Vapour Permeable Membrane and a 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.

Product Advantages

  • Class 4 Vapour Permeable
  • Up to 90 Days UV Resistance
  • Low flammability
  • Water Barrier


Residential & Commercial Wall Wrap and Vapour Permeable Membrane for a wide range of wall systems.

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Product Details
Product NameVapourFlex VPM™
Roll Size2740 mm x 30 m (82.2m2)
1370 mm x 30 m (41.1m2)
1500 mm x 30 m (45m2)
Duty RatingLight Wall
R Values
Declared Total System R-ValuesSummerWinter
Fibre cement and metal clad walls
Battened (on the outside of studwork), 90mm frame (no bulk insulation), 10mm plasterboard.
Brick veneer walls
Cavity (on the outside of studwork), 90mm frame (no bulk insulation), 10mm plasterboard
This calculation complies with the requirements of AS 4859.2.
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 VPM™ Classifications in accordance with AS/NZS 4200.1.

Duty RatingAS/NZS 4200.1:2017Light Wall Duty
Vapour ControlASTM E96Class 4 Vapour Permeable
Vapour PermeanceASTM E96>1.1403 μg/N.s
Water ControlAS/NZS 4201.4:1994Water Barrier
Flammability IndexAS 1530.2-1993Low ≤5
Nominal Material Thickness<1.0mm
Resistance to UV ExposureUp to 90 days
Resistance to Dry DelaminationAS/NZS 4201.1:1994Pass
Resistance to Wet DelaminationAS/NZS 4201.2:1994Pass
Emittance ValueAS/NZS 4201.5:19940.9, 0.9
Specification Notes
When specifying, state the following:

Product Name: VapourFlex VPM™

The pliable building membrane to be installed shall be VapourFlex VPM™ 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, 4.208 µg/N·s
Water Control Classification: Water 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 VPM™ Vapour Permeable Wall Wrap should be installed in accordance with AS/NZS 4200.2 Pliable Building Membranes and Underlays, Part 2: Installation Requirements.


VapourFlex VPM™ should be installed horizontally as a continuous membrane by fixing to all framing members with the printed side facing out. VapourFlex VPM™ should extend from the top plate to the bottom plate on concrete slabs or bearers in timber construction. Fixings should be galvanised clouts or staples for timber construction and tech screws for fastening to steel constructions. In high wind areas, it is recommended to install using non-rip caps on clouts, staples or tech screws. Horizontal, vertical and end overlaps must be 150 mm, with all top layers overlapping the outside of lower layers to prevent water ingress. Stagger any vertical overlaps. Any damage made to VapourFlex VPM™ during installation including holes and tears must be repaired. VapourFlex VPM™ is not designed to withstand prolonged direct exposure to UV light and the elements. Outer cladding should be installed without delay.