BEVELBACK WEATHERBOARD CAVITY SYSTEM
The finished floor level must have a minimum clearance to paved or unprotected ground as required by NZS 3604:1999.
Hermpac weatherboards must overhang the bottom plate on a concrete slab by a minimum of 50 mm as required by NZBC Acceptable Solution E2/AS1, Table 18.
The bottom edge of the Hermpac Bevelback and Rebated Bevelback Weatherboard Cavity System must finish a minimum of 100 mm above paved surfaces or 175 mm above unprotected ground.
At deck or low pitch roof/wall junctions, the bottom edge of the Hermpac weatherboards must be kept clear of any adjacent surface, or above the top surface of any adjacent roof flashing by a minimum of 35 mm.
Structure & Framing
Timber wall framing behind the Hermpac Bevelback and Rebated Bevelback Weatherboard Cavity System must be treated as required by NZS 3602:2003 Timber and wood-based products for use in building.
Timber framing must comply with NZS 3604 for buildings or parts of buildings within the scope limitations of NZS 3604. Buildings or parts of buildings outside the scope of NZS 3604 must be to a specific design in accordance with NZS 3603 and AS/NZS 1170. Where specific design is required, the framing must be of at least equivalent stiffness to the framing provisions of NZS 3604. Use of timber framing must be in accordance with framing manufacturer’s specifications.
In all cases studs must be at maximum 600 mm centres, with dwangs fitted flush between the studs at maximum 800 mm centres.
In order to achieve an acceptable wall finish, it is imperative that framing is straight and true. Framing tolerances must comply with the requirements of NZS 3604:1999.
Cavity Vent Strip
The Hermpac Bevelback and Rebated Bevelback Weatherboard Cavity System must incorporate a cavity vent strip to close off the bottom of the cavity and provide resistance against the penetration of vermin. The vermin strip must be in accordance with NZBC Acceptable Solution E2/AS1, Paragraph 22.214.171.124. The vent strip must be manufactured from PVC, aluminium or stainless steel, and be punched with 3 - 5 mm holes or slots
Published: September 2009