What is a WarmRoof?

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.

We offer two WarmRoof Systems - Viking WarmRoof and Viking WarmSpan

Christchurch Botanical Gardens Visitors Centre With Viking Warm Roof

Energy efficient roof insulation system

In 2007, the Department of Building and Housing introduced “H1” – the code requirement for building insulation; the aim of which was to decrease the amount of heating energy required by 30%, to achieve healthy indoor temperatures.

Despite approximately 300,000 homes still being inadequately insulated, New Zealanders are looking increasingly closer at energy efficiency. There has never been a better time to invest in a “warm roof”…

Viking Warm Roof Creates Tidy Finish

What are the benefits of a 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 be retrofitted onto an existing building

CodeMark NZ Certified

Product certification (CodeMark) is a voluntary scheme that provides an easily-understood and robust way to show that a building product or system meets the requirements of the New Zealand Building Code.

A CodeMark certified product or construction method must be accepted by any building consent authority as complying with the Building Code, as long as it is used as specified.

Our WarmRoof system and our engineered WarmSpan system, with the CodeMarked Viking Enviroclad or Viking Bituclad membrane, provides the most assured pathway to compliance.

To find out more about CodeMark check out the MBIE website.

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WarmSpan - Insulation on Steel Tray

What is Viking WarmSpan?

It is a proprietary warmroof-on-steel tray system. It is made up of a wide-spanning steel tray roof deck, which also forms the vapour barrier with its flashing system.

The Kingspan Polyisocyanurate (PIR) rigid insulation panels are adhered over top and the system is completed with any of Viking Roofspec’s sheet waterproofing membrane systems.

Viking WarmSpan avoids using unnecessary components, removing the cover board and extra vapour barrier used in other warm roof systems to produce a simple, energy efficient, three-layer system.

Check out the video on the left to see Viking WarmSpan in action.

Cavity Wall Upstand Website image.jpg

Integrated Vapour Barrier

The Viking WarmSpan system has an integrated vapour barrier.

Viking WarmSpan’s steel-tray with its air-tight flashing system forms the integral vapour barrier in contrast to other systems that have a separate peel-and-stick membrane which is punctured with thousands of mechanical fasteners.

To access the CAD details (like the image on the left) click here.

Warmspan Testing

No Cover board

The intention of a cover board is to provide superior wind resistance and trafficability.

A cover board is not required with Viking WarmSpan as the system exceeds the ‘Extra High’ wind rating and foot traffic requirements of the building code for an ‘unrestricted access’ roof – the highest rating, as tested and verified by nationally-recognised Holmes Solutions.

No Mechanical Fasteners

Viking WarmSpan uses F.A.S.T. adhesive technology rather than mechanical fasteners. The use of a fully adhered system using F.A.S.T. technology has some strong advantages over the use of mechanical fixings.

Mechanical fixings penetrate the insulation and the vapour barrier, which results in thermal loss and thermal bridging, reducing the efficiency of the system.

The F.A.S.T. adhesive system also rivals the wind uplift resistance of any mechanical fastener, and is part of the system tested by Holmes Solutions.

Cost effective solution

WarmSpan compared to a traditional warmroof through:

  • Removal of unnecessary components

  • Significant savings in materials used for the substrate compared to traditional warm roofs (e.g. timber);

  • Spanning capability of Viking's Metcom 7 steel profile (up to 3.6m between purlins) meaning less framing is required; and

  • As well as these material savings, the significant labour savings achieved by not having to install these extra materials.This all contributes towards making Viking WarmSpan the most cost-effective warm roof system in New Zealand.

WarmSpan in Action

We have developed a time lapse video from a residential home in Wanaka which features a WarmSpan roof as part of the roof design.

The WarmSpan section of the roof is only 60sqm and covers theLiving/Kitchen area of the home.

Check out the video on the left to how simple and clean the installation is!

VK RS Warmspan Table 2048X1536

What are the other benefits of WarmSpan?

  • Highest possible fire rating - Group 1S Fire Rating from the ISO9705 'room test';

  • Spanning ability - up to 3.6m between purlins;

  • Less weight than a traditional warm roof - e.g. loading on building reduced by 2/3 over timber;

  • Tapered panel option - maximum watershed;

  • Highest R-Value - maximum ROI;

  • Polyiso sheets: 25mm, 50mm, 75mm thick, 1.2m wide x 2.27m long.

Drain Or Overflow VWS08

Specification Made Easy

We have an extensive range of Specification documents, CAD details, Product Technical Statement, Brochures and an BRANZ certificate available on our Cad & Resources section.

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Quality Installation

Just like all of Viking Roofspec's systems, Viking WarmSpan can only be installed by a Viking Approved Applicator. A system is only as good as its installation, so we take the time and care to ensure all our applicators are trained to properly install our systems.

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Quality Assurance

Viking WarmSpan is backed by a robust 20-year product warranty.

If the end-user wants further assurance, Viking WarmSpan may be eligible for a Viking Full System Warranty, which covers both the product and installation in one warranty document.

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BRANZ Appraisal

Viking WarmSpan is covered under Viking WarmRoof's BRANZ Appraisal. This means it has been independently tested by BRANZ to determine its ability to deal with New Zealand's environment and meet the Building Code.

WarmRoof - Insulation Roofing system

St Johns High Res RHS

Why a Viking WarmRoof?

  • F.A.S.T. adhesive option available to secure panels to substrate (Avoids mechanical fasteners and therefore some thermal bridging)
  • Wide sheet membrane = less seams
  • Craft paper facer can be torched to for torch-on membrane option
  • Thermal performance helps towards achieving green star points for a building
  • RANZ appraised to meet NZ building code requirements
  • Full System Warranty option* = peace of mind
  • Highest R-Value = maximum ROI
  • Rigid insulation sheets = dimensional stability
  • Highest possible fire performance rating (Group 1-S)
  • No CFCs in manufacture = environmentally friendly

  • Perfect as an overlay option = avoids re-roofing

How is a Viking WarmRoof Constructed?

The best way to show you how a Viking WarmRoof is constructed is to check out the video we have created by clicking on the image of the right.

For any further questions give us a call on 0800 729 799

The Overlay Option


A WarmRoof is a perfect, practical solution for overlaying over an existing low-slope roof with weather-tightness issues (of any substrate including metal). The fact the roof doesn’t need to be removed has many benefits:

  • No need to relocate people and contents

  • Avoid the expensive waste disposal of the existing roof and scaffolding/shrink wrap covering required to maintain weather tightness during replacement.

Viking Warm Roof Countdown Installation Underway
  • In the case of existing low-slope metal roofs, a WarmRoof overlay can avoid the expensive carpentry involved in re-pitching the roof plane up to the minimum 3 degree slope requirement.
  • Electricity savings from the building’s new energy efficiencies can amortise the entire re-roof cost as quickly as 8 years after installation (depending on the thickness used and colour of membrane installed on top.
Cavity Wall Construction -ECW08

Specification made easy

We have an extensive range of Specification documents, CAD details, Product Technical Statement and an BRANZ certificate available on our Cad & Resources section.

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Kingspan Therma Insulation

Kingspan is one of the world’s leading suppliers of panel-based insulation systems. Represented in 70 countries, energy efficient systems are their reason-for-being.

Kingspan Insulation has a sales office in Auckland, from where their New Zealand Manager (mostly in a technical capacity) works in partnership with Viking Roofspec to assist all key project stakeholders to ensure their products are utilised in the best way to get the best results.


High Thermal efficiency

If a building does not meet the minimum requirements for insulation in each of its categories (roof, walls, floor etc.), calculations can be used where well insulated areas can compensate for low insulation areas to achieve an acceptable aggregate R-value for the building.

With its very high thermal efficiency, a Viking Warm Roof can assist in this way with architectural designs that have a disproportionate amount of glazing (thermally inefficient) to make the most of a view.


Quality Installation

The waterproofing sector is possibly the most litigious of the construction industry. There are no second chances. So Viking products can only be installed by a Viking Approved Applicator

This is all about taking care of the detail and working with our team of professional, trained applicators to ensure that a watertight finish is achieved. There are no cowboys here!

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Quality Assurance

We stand behind our product and Viking WarmRoof is covered by a robust 20 year Product Warranty. It is also eligible to be a part of a Viking Full System Warranty, which includes both installation and product, covered in one process.

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Ease of Approvals

Viking WarmRoof is BRANZ appraised.

What does this mean? Well, it has been independently tested in New Zealand, by BRANZ, to ensure it can handle New Zealand's harsh conditions and complies with the New Zealand Building Code.

Current BRANZ appraisal 713 applies to single ply membranes only. The intention is to update it to an all-encompassing appraisal.



Accessory information for WarmRoof and WarmSpan can be found as PDFs on their Cad/Resources sections



Thanks for contacting us. We will be in contact soon to discuss setting up a presentation with you. Rest assured that in working with Viking Roofspec we will assist you in choosing the right roofing or waterproofing solution to protect your (or your customer's) most important assets.

In the meantime feel free to call us on 0800 729 799.

Kind regards

The Team at Viking Roofspec

Book a presentation

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Thanks for contacting us. We will be in contact soon to discuss your project. Rest assured that in working with Viking Roofspec we will assist you in choosing the right roofing or waterproofing solution to protect your (or your customer's) most important assets.

In the meantime feel free to call us on 0800 729 799.

Kind regards

The Team at Viking Roofspec


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