Masons VHP Maxi Roof Underlay

VHP Maxi Roofing Underlay is a 220gsm premium roofing underlay. It is fire retardant, very high performance and highly breathable

Manufactured from synthetic multi-laminate spun-bonded, non-woven polypropylene membranes it has the following benefits:

• Premium performance and fire retardant
• Assists in moisture control - deflects water and air both during construction and as part of the finished roof
• Affordable
• Self-supporting and very strong
• Highly breathable - transforms water vapour at higher rates than bitumen impregnated paper
• Temporary weather protection - UV resistance for 21 days
• Codemark Certified

Intended Use

Masons Roof Underlays are for use as a self-supporting roofing underlay

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 

Conditions and Limitations of Use:

1. 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).

Health and Safety

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

Supporting Info

VHP Maxi underlay is a 220 gsm tri-laminated 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 Maxi 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:

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