The review of the foremost Standard in New Zealand for the building and construction industry, Timber framed buildings, NZS 3604:1999, is well underway. Standards New Zealand expects to issue the draft revised NZS 3604 for public comment soon. Public comment will close in mid-to-late February 2010 and publication is scheduled for late 2010/early 2011.
Revision includes major changes
There have been major changes proposed in sections 3, 4, 5, and 10 in NZS 3604 as follows. These proposed changes are within the agreed scope for the project.
- Section 3 – Site requirements. Updating the soils classifications to align with AS/NZS 1170
- Section 4 – Durability. All clauses relating to weather tightness and the building envelope have been removed pending the revision by the Department of Building and Housing of E2/AS1. The corrosion zone maps have been updated to align with AS/NZS 1170 and metal fasteners have been reviewed and updated
- Section 5 – Bracing design. The wind and earthquake zones have been aligned with AS/NZS 1170 and the bracing demand requirements have been reviewed and updated to align with results from the Building Research Association research programme. There has been confusion on the use of section 5 in the past so the committee has reconfigured it to provide more clarity to end users
- Section 10 – Roof framing. This section has undergone a major overhaul to provide more clarity on the design of roof framing. For example, the rafter span tables have been rationalised to reduce the number of tables. Purlins and battens have been reviewed and the use of manufactured trusses has been clarified to reduce the level of confusion between designers, builders, and building consent authorities on the use of trusses in timber-framed houses
Some other changes proposed and agreed by the technical committee are as follows.
- Section 11, the building envelope is to be removed pending the revision of E2/AS1.
- The tables throughout NZS 3604 have been reviewed to reduce their total number in the document and to remove reference to timber that is no longer available in the marketplace.
- The figures throughout the document have been reviewed for clarity and many have been updated.
The technical committee met on 7 to 8 December 2009 and is now aligning the rest of NZS 3604 with the proposed changes to these sections. Subscribe to the keep me up to date service(http://www.standards.co.nz/web-shop/?action=updateWatchList&mod=catalog) to be notified when NZS 3604 is available for public comment.
Thank you
'Standards New Zealand would like to thank all the committee members and nominating organisations that have been involved with the revision of NZS 3604 so far, the end users of NZS 3604 who have provided feedback, and the industry specialists that have assisted the work groups,' says Don Bunting, Chair. 'It's been quite an effort getting to this point.'
'Many issues have been raised and debated and the technical committee and working groups have worked really well together.'
'On behalf of the NZS 3604 review leadership group and technical committee Standards New Zealand would like to wish you a very enjoyable holiday season, and a successful 2010.'
Note: The changes outlined in this article are by no means a full representation of the issues discussed to date by the technical committee or the work groups formed to undertake the project to review NZS 3604:1999 Timber-framed buildings. Nor are they a final representation of decisions made to date. This article presents a summary of the changes made to update readers on the review of NZS 3604:1999.
For more information, please email mani.taare@standards.co.nz, or call 04 495 0934.
Related Touchstone articles