Description

White-faced Foil Composite Underlay is intended for use as a roof or wall underlay acting as a vapour barrier with a white light-reflective surface in commercial or industrial building interiors.

It can also be used as a reflective foil within a thermal control layer design for profiled roofs or walls. The product is not absorbent or breathable and should not be considered a condensation control layer.

White-faced Foil Composite Underlay is a synthetic and aluminum foil composite underlay. It is self-supporting over spans up to 1200 mm and is available in rolls measuring 1350 mm by 56 LM, providing a total coverage area of 75.6 m². The Masons identification number or code is FOIL1.35MX75.

Scope

1. White-faced Foil Composite Underlay is certified for use as a roof or wall underlay or as an air barrier on buildings:

• a. Designed in accordance with:
  • i. NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area for timber-framed construction and situated in wind zones (as defined in NZS 3604) up to and including "Very High" when fixed directly to framing, and "Extra High" when fixed over a rigid air barrier, or
  • ii. NZBC Acceptable Solution E2/AS4 with regards to building height and floor plan area for light-steel framed construction and situated in wind zones (as defined in NZS 3604) up to and including "Very High" when fixed directly to framing, and "Extra High" when fixed over a rigid air barrier, or
  • iii. Verification Method B1/VM1 with ULS design wind pressure of up to 2.13 kPa, and
• b. located in all exposure zones as defined in NZS3604, and
• c. in all locations within buildings including when exposed to view in an occupied space but not areas exposed to direct or reflected UV light. such as lean to’s, canopies, over hangs or soffits.

2. White-Faced Foil Composite Underlay shall not be used:

• a. where Building Act Ban 2016/001 applies, or
• b. in buildings that have moisture generating plant or processes such as swimming pools and open liquid containers. where specific measures are needed to manage condensation and moisture generated within the building.

3. White-Faced Foil Composite Underlay shall:

• d. be installed in accordance with White-faced Foil Design and Installation Guide v1.2, Oct 2024, and
• e. be protected from direct sunlight within 14 days, and
• c. If installed without mesh, the pitch/span limitations that can be found in VHP Roof Underlays or the NZ MRM Code of Practice for selfsupporting roof underlays shall be used, and
• d. have a minimum air space of 20 mm between the foil and the underside of the cladding to mitigate dew point condensation.

4. Compliance with H1 established by reference to the heat flows of a reference building as in Verification Methods H1/VM1 or H1/VM2 and the emittance of White-faced Foil Composite Underlay.

5. Care should be taken during installation to keep elements of the building’s electrical fit out separate and insulated from the conducive WhiteFaced Foil Composite Underlay.