Issue 23 – December 2010
The Department of Building and Housing (DBH) is consulting on proposed changes to documents that the majority of designers and builders use day-to-day, and is asking for submissions. There are also proposals dealing with steel-framed and concrete buildings.
Download the DBH Summary of the proposed changes (www.dbh.govt.nz/UserFiles/File/Consulting/pdf/2010/e2-b1-consultation-summary-sheet.pdf), which you are welcome tocirculate to others who may be interested.
Please study the proposals and make submissions. Consultations close 4 February 2011; so please get your submission to DBH underway before the Christmas break.
DBH proposes to: cite the next published version of the widely-used timber-framed buildings Standard NZS 3604 in B1/AS1; cite new Standards for steel-framed residential and low-rise buildings and seismic restraint of engineering systems in buildings in B1/VM1; and delete B1/AS2, an Acceptable Solution for timber barriers.
NZS 3604 is the Standard used to design most timber-framed homes and other low-rise timber-framed buildings such as residential care buildings and commercial offices. The current Standard dates from 1999; Standards New Zealand has consulted the building industry and is updating the Standard to reflect the latest design methods and construction practices. The next version will include changes resulting from AS/NZS 1170: Structural Design Actions.
Other proposed changes to B1 documents are to:
- Delete Acceptable Solution 2 (B1/AS2). This is a design solution for timber barriers. Design loads for residential barriers have increased and timber strengths and stiffnesses have reduced and B1/AS2 is now out of date.
- Amend Verification Method 1 (B1/VM1) to refer to two new documents:
- NZS 4219:2009: Seismic performance of engineering systems in buildings. This deals with restraints for building contents and engineering systems which are critical, or may be a hazard, in an earthquake.
- NASH Standard Residential and Low-rise steel framing Part 1: Design Criteria Version 2: October 2010. This document explains how to comply with the performance criteria of B1 for steel framing of low-rise buildings such as houses and commercial buildings.
E2 (External Moisture)
DBH proposes to: update Acceptable Solution E2/AS1, dealing with weathertightness of timber-framed buildings, and Verification Method E2/VM1; and introduce a new Acceptable Solution for weathertightness of concrete.
E2/AS1 is a key document dealing with cladding and the weathertightness of timber-framed buildings. The Department is proposing to:
- Update the technical content to reflect recent studies and research
- Respond to changes in building practices
- Align E2/AS1 with the next version of NZS 3604.
Minor changes are proposed for E2/VM1 which tests the performance of claddings with drainage cavities on timber framed buildings
DBH proposes a new Acceptable Solution E2/AS3 for weathertightness of concrete and concrete masonry, that would cite the Cement and Concrete Association of New Zealand document CCANZ - S01: Weathertight Concrete and Concrete Masonry Construction which is presently in draft.
For more information on the proposed changes to B1 and E2 documents go to www.dbh.govt.nz/current-consultations (www.dbh.govt.nz/current-consultations) .
People who have already registered for the DBH's recent consultations can make an online submission using their existing login details.
Remember, anyone designing, constructing or altering a building must have a thorough knowledge of the current Building Code. Acceptable Solutions and Verification Methods published by the DBH provide one way of complying with the relevant part of the Building Code. Please become familiar with the proposed changes and have your say.
Summarised from information supplied by Department of Building and Housing.