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Viking WarmRoof System

The most commonly accepted definition of a warm roof (for low slope roofs) is 'a roof where the insulation is installed on top of the roof structure' i.e. insulated from the outside of the building. The purpose of a warm roof is to increase thermal efficiency by transferring a building’s dew point to the outside. This prevents dampness of structural materials and negates the need for vents that normally allows air to escape.

Viking’s WarmRoof includes rigid Kingspan Polyisocyanurate (closed-cell foam) sheets that are waterproofed by any one of Viking's membrane options.

Thermal efficiency aside, a Viking WarmRoof is also a practical solution for laying over an existing low-slope roof with weather-tightness or UV resistance issues. The fact the roof doesn’t need to be removed, minimises disruption for inhabitants; protects precious items and protects critical activities. The light-weight nature of the insulation and membrane going on top of the roof, ensures the roof remains well under the 20kg/m2 threshold. Alternatively, this would otherwise require additional engineering of the substrate and supports.

The Viking WarmRoof system negates the need to relocate people or contents and avoids the expensive shrink-wrapping of the building and the environmental cost of waste disposal of uplifted roofing materials.

Components of a Viking WarmRoof System

  • Vapour barrier (for cool stores and regions with extreme climatic variances)
  • Kingspan Polyiso insulation panel (including tapered)
  • Any of Viking's sheet membrane systems

With a correctly designed warm roof:

  • The dew point is on the outside of the building = no damp or rotten materials inside
  • No ventilation of the ceiling cavity is required
  • Thermal bridging is avoided
  • The roof cavity is clear for wiring
  • Savings in air conditioning and heating costs
  • Rigid insulation sheets = structural integrity to the roof
  • Significantly higher R-values are achieved
  • Easily retrofitted onto an existing building
Key Features
  • Polysio board supplied by the world-leading rigid insulation manufacturer
  • Specialised two-part foam adhesive to secure panels to substrate (avoids mechanical fasteners and therefore thermal bridging)
  • Compatible with any Viking membrane roofing product; including torch-on membrane
  • Tapered insulation option — promotes watershed
  • Highest R-Value per thickness — maximum ROI
  • Rigid insulation sheets — dimensional stability
  • Highest possible fire performance rating (Group 1-S)
  • Environmentally friendly
  • Perfect overlay option
  • Installed only by Viking Licensed Applicators
  • 20-year product warranty
  • Full System Warranty Option: 20-years
  • BRANZ Appraised (Appraisal No. 713)
NZ-Owned Business
NZ-Owned Business
Scope of Use

The Viking WarmRoof System has been appraised for use as an insulating roof on buildings within the following scope:

  • the scope limitations of NZBC Acceptable Solution E2/AS1, paragraph 1.1 with regards to building height and maximum floor plan areas; and,
  • on limited access flat roofs with concrete, plywood or steel structural decks subject to specific structural design; and,
  • with roofs constructed to drain water to gutters and drainage outlets complying with the NZBC; and,
  • with roofs constructed to suitable falls (refer paragraph 15.3 and 15.4 of the Viking Warm Roof BRANZ Appraisal); and,
  • with no integral roof gardens; and,
  • situated in NZS 3604 Building Wind Zones, up to, and including Extra High

The Viking WarmRoof System has also been appraised for durability and thermal performance as an insulated roofing systemon buildings that are the subject of specific design with no building height restriction. Building designers are responsible for the building design and for the incorporation of the Viking WarmRoof System into their design in accordance with the declared properties and instructions of Viking Roofspec.

Limitations on Use

The Viking WarmRoof System must be installed by Viking Roofspec Licensed and Trained installers.

Statement of Building Code Compliance
  • Clause B1 STRUCTURE: Performance B1.3.1. The Viking WarmRoof System meets this requirement.
  • Clause B2 DURABILITY: Performance B2.3.1 (b), 15 years. The Viking WarmRoof System meets this requirement. See paragraph 10.1 of the Viking WarmRoof BRANZ Appraisal.
  • Clause E2 EXTERNAL MOISTURE: Performance E2.3.1 and E2.3.2. The Viking WarmRoof System meets these requirements. See paragraphs 15.1 — 15.9 of the Viking Warm Roof BRANZ Appraisal.
  • Clause F2 HAZARDOUS BUILDING MATERIALS: Performance F2.3.1. The Viking WarmRoof System meets this requirement and will not present a health hazard to people.
  • Clause H1 ENERGY EFFICIENCY: Performance H1.3.1 (a). The Viking WarmRoof System will contribute to meeting this requirement. See paragraph 14.1 of the Viking WarmRoof BRANZ Appraisal.
  • Clause C/VM2 FIRE PERFORMANCE (of wall and ceiling linings) — ISO9705, Group 1S = highest possible rating.
Other Performance Attributes
  • BRANZ Appraised No. 713 (2011)
  • Backed by a 20-year product warranty, and for specific projects, is eligible for Viking's Full System Warranty, which covers the product and installation in one document
  • Tapered panel option — maximum watershed
  • The system's thermal performance helps achieve Green Star points for a building
  • Viking Enviroclad and Viking Bituclad both hold CodeMark Certificates and are appropriate membrane systems for Warm Roof
  • Electricity savings from the building's new energy efficiencies can amortise the reroof cost as quickly as 8 years after installation (depending on the polyiso thickness and colour of membrane)
  • The rigid insulation sheets add structural integrity to the roof while the wide-sheet membrane means fewer seams and greater waterproofing integrity
  • Significantly higher R-values are achieved with polyiso panel (uniformly across the entire roof; not just in parts)
  • No CFCs in the manufacture of a Viking WarmRoof
B1 Structure compliant
B2 Durability compliant
C Protection from Fire compliant
Protection from Fire
E2 External Moisture compliant
External Moisture
F2 Hazardous Building Materials compliant
Hazardous Building Materials
H1 Energy Efficiency compliant
Energy Efficiency
BRANZ Appraised
BRANZ Appraised
Membrane Protection Sheet
Product Overview: Viking Warm Roof
Viking Products Material Safety Data Sheets


Masterspec Specification Clause
BRANZ Appraisal 713

713 [2018]

Find an Approved Installer
Maintenance Instructions
Brochure: Viking Enviroclad


Brochure: Viking TorchOn
Brochure: Viking WarmRoof


International Best Practice
Additional Information
Case Study: ASB Civic Centre, Marlborough
Case Study: Commercial Building's New Roof
Case Study: Home with Energy Efficient Roof
Case Study: Hybrid Solution for Nursing Home
Case Study: Innovative Re-roof Solution
Case Study: Re-roof Iconic Auckland Theatre
Case Study: Warm Roof Controls Temperature for Visitors and Plants
Case Study: Warm Roof for St Johns
CAD/PDF Details
Viking WarmRoof Details Full Set

For over 50 years, Viking Roofspec have supplied roofing and waterproofing materials, and combining leading-edge function with design flair to keep water out — for good.

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