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SuperStrand Sarking: Meeting Council Demands for Roof Structures

Councils are the chief influence during the building design process. Ensuring that design elements possess assurances of their compliance with the New Zealand Building Code is imperative if council demands are to be satisfied.

Viking Roofspec recognises this and aims to provide the market with high quality roofing products that deliver outstanding performance whilst fulfilling Building Code and therefore council requirements.

SuperStrand: An Ideal Option

There is no better illustration of this than Viking Roofspec's SuperStrand Sarking which is a treated strand board; engineered as a more robust and user-friendly substrate for supporting shingle roof systems in New Zealand and the Pacific Islands. Its H3.1 treatment goes above and beyond building code requirements, meaning enhanced performance and further peace of mind.

Initially, a Viking pitched roofing system installed on a SuperStrand substrate was classed as a heavyweight roof seeing the combined weight of these two components was slightly over the 20kg/m² threshold. Accordingly, in order to secure consent with this marginally heavier roof, a costly engineer's report; site-specific for every project, was required to demonstrate that the existing support structure was sufficiently robust to support the complete roofing system. This proved prohibitive for building owners who already had the option of using lower spec. alternatives such as untreated 15mm thick plywood which render a combined overall roof weight of below 20kg/m².

So Viking Roofspec sought an official determination in order to reclassify this roof system so that its thicker (16.3mm) treated substrate would not only be the superlative choice, but a compliance-friendly one without the extra cost of an engineer's report.


In 2015 after rigorous testing by BRANZ, a new BRANZ Appraisal for SuperStrand was released (no.891). The updated appraisal deemed any of Viking Roofspec's pitched roofing systems installed over SuperStrand to require no extra structural elements for support in order to meet the Building Code. 

The BRANZ appraisal states:
"Roof systems incorporating Strandsarking weighing up to 25kg/m² may be considered as a Light Roof for design in accordance with NZS 3604."

NZS 3604

NZS 3604, created by Standards New Zealand is recognised as an Acceptable Solution for Building Code Clause B1 Structure. This document is a core resource guide for council members as they determine the compliance of a light timber-framed building. In the construction of 93% of light timber-framed buildings, NZ 3604 is referred to.


The latest BRANZ appraisal meant that specifiers could design a building using high-quality products that would also meet council demands effortlessly by assuring Building Code compliance.

View more information on Viking Roofspec, including contact details.
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September 2016 EBOSSNOW Product News

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