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Viking StrandSarking is an H3.1 treated strand board; designed by Juken New Zealand, as a substrate for pitched and low-slope membrane roofs.

As StrandSarking is more rigid and spans further than plywood, it reduces the visibility of sheet joins under asphalt shingles and forgives unevenness in the structure creating a flatter and sharper looking roof.

Unlike plywood, the extra length spans an extra truss; resulting in a stronger substrate and less double-nailing at sheet edges.

The manufacture process involves the soaking of individual woodchip strands in the treatment before they are pressed into StrandSarking sheets. This ensures every sheet is fully treated throughout its entire thickness, as opposed to the conventional methods of treating wood, where untreated sheets are merely sprayed post-manufacture with the assumption that the treatment will penetrate to the board's centre. The treatment used for StrandSarking is solvent-free.

StrandSarking has no face grain so it can be laid in any direction (minimising wastage) and can span up to 900mm.

Key Features
  • Solvent-free treated substrate
  • Every strand is individually treated
  • Manufactured in New Zealand
  • Designed for climatic weather extremes
  • More rigid substrate
  • Board dimensions: 3600mm x 800mm
  • Square-edged profile
  • Installed only by a Viking Approved Applicator
  • 15-year product warranty
  • BRANZ Appraised (Appraisal No. 713)(both pitched and low-slope membrane roofs)
  • Declare. ID LMX-1006: Red List Free
NZ-Owned Business
NZ-Owned Business
Scope of Use

StrandSarking has been appraised for use on buildings within the following scope:

  • With timber roof framing designed in accordance with NZS 3604 or NZS 4229, or timber roof members subject to specific design; and,
  • In NZS 3604 Wind Zones up to and including Extra High; and,
  • Maximum eaves height of 10m above the ground; and,
  • Snow loads up to 1kPa; and,
  • Roof pitch of at least 10 degrees; and,
  • With roof trusses or framing at maximum of 900mm centres; and,
  • With roofing materials up to 150kg/m²

See BRANZ Appraisal 891 for full information.


Limitations on Use

Strandsarking has not been appraised for the following situations:

  • As a diaphragm
  • For flat roofs, decks, trafficable areas or roofs with a pitch of less than 10 degrees
  • As a substrate for membrane roofs

Installation shall be carried out by a Viking Roofspec trained and licensed installer. Installation shall be undertaken in accordance with all relevant technical information related to the selected installation method, including information contained within the BRANZ Appraisal No. 891 (2015), BRANZ Appraisal No. 276 (2012) and Viking StrandSarking substrate checklist.

NZS 3604 Wind Zone Extra High suitable
Extra High Wind Zone
Statement of Building Code Compliance

The product will, if employed in accordance with the supplier’s installation and maintenance requirements, assist with meeting the following provisions of the New Zealand Building Code (NZBC):

  • Clause B1 Structure: Performance B1.3.1, B1.3.2 and B1.3.4. StrandSarking meets the requirements for loads arising from self-weight, gravity loads, temperature, snow, wind and creep (i.e. B1.3.3 (a), (b), (c), (g), (h) and (q)).
  • Clause B2 Durability: Performance B2.3.1(b), 15 years. StrandSarking meets this requirement
  • Clause F2 Hazardous Building Materials: Performance F2.3.1. StrandSarking meets this requirement and will not present a health hazard to people

See BRANZ Appraisal 891 for full information

Other Performance Attributes
  • Viking Strandsarking is backed by a 15 year product warranty
  • Solvent-free treatment — the azoles and permethrins used to protect the board against fungal decay and insect attack respectively, are water-based treatments, so no solvents are used. The preservatives used are organic biodegradable compounds.
B1 Structure compliant
B2 Durability compliant
F2 Hazardous Building Materials compliant
Hazardous Building Materials
BRANZ Appraised
BRANZ Appraised
CAD/PDF Details
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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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