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)
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)