BEVELBACK WEATHERBOARD CAVITY SYSTEM
Internal corners shall be weatherproofed by the use of corrosion resistant internal corner flashings.
3.0 Installation Information
This section of the literature should be read in conjunction with the installation details.
The selected building wrap and flexible sill and jamb tape system must be installed in accordance with the manufacturer’s instructions prior to the installation of the cavity battens. The building wrap must be installed horizontally and be continuous around corners. Wrap must be lapped 75 mm minimum at horizontal joints and 150 mm minimum over studs at vertical joints. Particular attention must be paid to the installation of the building wrap and sill and jamb tapes around window and door openings to ensure a continuous seal is achieved and all exposed timber wall framing in the opening is protected. All penetrations through the building wrap must be sealed and joints sealed or lapped 150 mm.
The selected cavity vent strip must be installed so a minimum 15 mm drip edge to the bottom of the weatherboards is maintained at all times.
Cavity battens must be installed over the building wrap to the wall framing at a maximum of 600 mm centres where the studs are at 600 mm centres, or at 400 mm centres when studs are at 400 mm centres. Cavibat cavity battens must be fixed in place with 40 x 2.5 mm hot-dip galvanised flat head nails or galvanised or stainless steel finishing brads at 400 mm centres. Refer to BRANZ Appraisal Number 524
for further information. Timber cavity battens must be fixed in place with 40 x
mm hot-dip galvanised flat-head nails at maximum 800 mm centres.
Where the studs are at greater than 400 mm centres, a building wrap support, e.g. polypropylene strap, 75 mm galvanised mesh, galvanised wire, or additional vertical battens must be installed over the building wrap between the cavity battens at maximum 300 mm centres to prevent the building wrap bulging into the drainage cavity.
3.1.1 Aluminium Joinery Installation
Aluminium joinery and associated head flashings must be installed in accordance with the window manufacturer’s instructions. A 7.5 - 10 mm nominal gap must be left between the joinery reveal and the wall framing so a PEF rod and air seal can be installed in accordance with NZBC Acceptable Solution E2/AS1, Paragraph 9.1.6 after the joinery has been secured in place.
Published: September 2009