Hermpac Board and Batten Cavity System
- Abbreviation
- Appraisal number 828 (2020)
- Amendment
- 18/07/2022
- Valid from
- 27/05/2020
- Information provider
- BRANZ Limited,
- Information type
- BRANZ Appraisal,
- Format
- PDF,
Description
The Hermpac Board and Batten Cavity System is a cavity-based vertical timber weatherboard external wall cladding system for residential and light commercial type buildings where domestic construction techniques are used.
The system consists of vertically fixed Hermpac weatherboards and battens, ventilated cavity battens, flashings and accessories and is finished with an exterior grade premium penetrating oil, stain or an exterior grade paint system to Hermpac specifications.
The system incorporates a primary and secondary means of weather resistance (first and second line of defence) against water penetration by separating the cladding from the external wall frame with an 18 mm drained cavity.
Scope
The Hermpac Board and Batten Cavity System incorporating stain finished boards and battens and paint finished DuraLarch and Ashin-Dura boards and battens has been appraised as an external vertically fixed wall cladding system for buildings within the following scope:
- the scope limitations of NZBC Acceptable System E2/AS1, Paragraph 1.1; and,
- constructed with timber framing complying with the NZBC; and,
- with a risk score of 0-20, calculated in accordance with NZBC Acceptable Solution E2/AS1, Table 2; and,
- situated in NZS 3604 Wind Zones up to, and including Extra High.
The Hermpac Board and Batten Cavity System incorporating stain finished boards and battens has also been appraised for weathertightness and structural wind loading when used as an external vertically fixed wall cladding system for buildings within the following scope:
- the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area; and,
- constructed with timber framing subject to specific engineering design; and,
- situated in specific design wind pressures up to a maximum design differential ultimate limit state (ULS) of 2.5 kPa.
The Hermpac Board and Batten Cavity System incorporating paint finished cedar boards and battens has been appraised as an external vertically fixed wall cladding system for buildings within the following scope:
- the scope limitations of NZBC Acceptable System E2/AS1, Paragraph 1.1; and,
- constructed with timber framing complying with the NZBC; and,
- with a risk score of 0-20, calculated in accordance with NZBC Acceptable Solution E2/AS1, Table 2; and,
- situated in NZS 3604 Wind Zones up to, and including Medium when dwangs or structural Vertibat cavity battens are at maximum 480 mm centres, and NZS 3604 Wind Zones up to, and including Very High when dwangs or structural Vertibat cavity battens are at maximum 400 mm centres.
The Hermpac Board and Batten Cavity System must only be installed vertically on vertical, flat surfaces.
The Hermpac Board and Batten Cavity System is appraised for use with aluminium window and door joinery that is installed with vertical jambs and horizontal heads and sills. (The Appraisal of the Hermpac Board and Batten Cavity System relies on the joinery meeting the requirements of NZS 4211 for the relevant Wind Zone or wind pressure.)