As a key supplier to the residential and commercial membrane roofing sectors, Viking Roofspec spent much of 2022 developing an all-encompassing membrane roofing system that not only exceeds the new H1 (thermal efficiency) requirements, but does so while minimising cost and ensuring the thinnest possible insulation build-up. They’ve named it ‘WarmSpan²’.

Despite MBIE’s more scientific approach of developing six new Climate Zones to replace the previous three, these new zones will ironically become irrelevant when it comes to the thermal efficiency requirements of residential roofs (and commercial roofs under 300m²). The new 5th edition of H1/AS1 will require all new residential roofs to render a minimum R-value of R-6.6 whether that roof is situated in Kaitaia or Stewart Island. This will double the current minimum requirements for the South Island, and more-than-double the minimum requirements for the North Island.

This will be great for lifting society’s health standards over the longer term, however, it poses shorter term challenges in terms of cost and design (added roof assembly thickness).

Viking Roofspec has taken up the challenge of developing a warm roof system to not only: (i) fulfil H1’s new requirements, but (ii) address the cost concerns of the industry as well as (iii) the new design challenges that the new code brings. Engineer-tested in New Zealand by Holmes Solutions of Christchurch, Viking proudly launched ‘Viking WarmSpan²’ in November, 2022.

Viking Warmspan² isn’t just a warm roof — it’s an entire structurally engineered roof build-up; designed from the substrate supports right up to the membrane surface.

With an R-value of R-6.7, the WarmSpan² system can exceed all new residential roof R-value requirements. Featuring a 135mm thick PIR board (the thinnest R-6.7 build-up on the marketplace), Warmspan² frees-up architectural constraints while saving construction time which, ultimately, saves cost.

Warmspan² also has a spanning ability between substrate supports of up to 1.8m and 900mm for the steel tray and plywood substrate options respectively (versus the 400mm centred joists required under a heavy 17mm plywood substrate for a traditional membrane roof). This method, along with the heavily reduced nogging at the tongue-and-groove plywood edges results in 3x less structural timber required by the building code — while still exceeding the structural requirements for snow loading.

Compatible with both Enviroclad and Torch-On membranes, the installation of Viking WarmSpan² mostly reflects that of its predecessor WarmSpan¹, meaning Viking’s Approved Applicators don’t need any new tools or training to install the new system to the professional standard expected by Viking Roofspec.