VHP Strong Roof Underlay

Manufactured from synthetic multi-laminate spun-bonded, non-woven polypropylene membranes.

• Premium performance and fire retardant

• Assists in moisture control - deflects water and air both during construction and as part of the finished roof

• Economy price

• Self-supporting and strong

• Highly breathable - transforms water vapour at higher rates than bitumen-impregnated paper

• Temporary weather protection - UV resistance for 21 days

• Codemark Certified

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

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

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

Codemark Certified

NZ Building Code Provisions

• 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 

Compliance with any manufacturer’s installation instructions, maintenance, OH & S statements, MSDS and other Health and Safety declarations will provide the necessary Health and Safety Information pertaining to the product. 

VHP Strong underlay is a 140 gsm tri-laminate sheet consisting of a white non-woven top layer with black printing, a white non-woven back layer and a dark grey synthetic membrane centre layer. Both sides of the underlay sheet have an embossed pattern. The sheet is 1.45 m wide and is labelled VHP Strong Roof Underlay. 

• 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