• Masons Roof Underlays are intended for use as a self-supporting roofing underlay
• Assists in moisture control — deflects water and air both during construction and as part of the finished roof
• Temporary weather protection — UV resistance for 21 days — although same-day coverage is strongly recommended

Masons Roof Underlays are certified for use as a roof underlay and air barrier:

• a) on buildings situated in wind zones up to and including Extra High (as set out in NZS3604) with a minimum roof pitch of 3°,
• b) under masonry or metal tile and profiled metal roof cladding,
• c) in all locations including where it is not covered by an internal lining

2. Masons Roof Underlay shall be: 

• a) installed in accordance with Masons Roof Underlay Installation Instructions Version 1.0, Jan 2021, and
• b) installed run vertically or horizontally with or without support for roof pitches greater than 10°, run horizontally with or without support or run vertically with support for roof pitches less than 10°, provided that support is provided where the span is greater than 1200mm, and
• c) protected from sunlight within 21 days of installation (30 days for UNI FR)

• B2 Durability: B2.3.1(a), B2.3.2
• C3 Fire affecting areas beyond the fire source: C3.4(c)
• E2 External moisture: E2.3.1; E2.3.2 (Contributes to)
• F2 Hazardous building materials: F2.3.1

Supporting Info

VHP Ultra underlay is a 180 gsm tri-laminate sheet consisting of two outer non-woven layers which are white and a middle synthetic membrane which is dark grey. Both sides of the sheet have a fine embossing pattern. The sheet is 1.45 m wide and is labelled VHP Ultra Roof Underlay.

Supporting Information about the Intended Use:

Further details regarding the use of the product can be found in Masons Roof Underlay Installation Instructions Version 1.0, Jan 2021

Supporting Documentation for Certification:

• Acceptable Solutions and Verification Methods For New Zealand Building Code Clause B2 Durability (Amendment 12), 28 November 2019
• C/AS1 VM1 Protection from fire Amendment 3
• C/AS2 Acceptable Solution for Buildings other than Risk Group SH for New Zealand Building Code Clauses C1-C6 Protection from Fire, 1st edition, 27 June 2019
• Acceptable Solutions and Verification Methods For New Zealand Building Code Clause E2 External moisture 3rd edition (Amendment 9), 27 June 2019
• Acceptable Solutions and Verification Methods For New Zealand Building Code Clause F2 Hazardous Building Materials (Amendment 3), 1 January 2017
• SCION Report QT8080A "Evaluation of Uni FR FAB to NZS 2295", February 2020
• SCION Report QT8222VHPM "Evaluation of Roof VHP Maxi to NZS 2295", July 2020
• SCION Report QT8222VHPS "Evaluation of Roof VHP Strong to NZS 2295", July 2020
• SCION Report QT8222VHPU "Evaluation of Roof VHP Ultra to NZS 2295", July 2020
• L H Boulton Report 201265 "Assessment of Masons Roofing Underlays for Buildings", 21 October 2020
• Masons Roof Underlay Installation Instructions Version 1.0, Jan 2021
• NZS 2295 2295:2006 Pliable, permeable building underlays
• NZ Metal Roof and Wall Cladding Code of Practice version 3.0