The major review of NZ Standard 3604 during 2010/ 2011 has provided greater clarity for frame and truss manufacturers around responsibility and reliability, but has also added new layers of administrative work, says FTMA chairman, Robert Grimmer.
“This is a key standard and is considered to be the bible on methods and details for the design and construction of timber-framed structures up to three storeys, not requiring specific engineering design. There have been quite a few changes made to the standard as a result of the review which has impacted on what our members do and how they do it.”
One of the most significant changes has been the passing of some responsibility from the frame and truss manufacturer to the Licensed Building Practitioner, he says.
“Over the years a number of design activities have been carried out at frame and truss level. However the new legislative regime requires the designer or architect on behalf of the builder, to carry out this work. It has more clearly defined the role of the frame and truss fabricator but has added a lot more formality to the process, and increased administrative work.”
Other changes included new timber grading requirements, which state which timber grade can be used and where.
“There have also been some quite technical changes to step up the engineering performance of timber framed buildings, including guidelines for nailing patterns.”
Robert says the other big change impacting the industry over the last three years has been the review of New Zealand treatment standards for timber.
“Previously a wide range of different treatment types could be used. However a standardised treatment regime has now been introduced for the vast majority of timber houses, which has greatly simplified the processes.”
FTMA is also working with the Ministry of Business, Innovation and Employment to establish the frame and truss industry’s position on MBIE’s draft guidance document on Manufactured Building Solutions.
“We are looking at the implications the content may have to our industry, and are reviewing the FTMA Code of Practice to align it with MBIE’s guidance documents. There are some potential liability changes with regards changes to the Building Act and Consumer Guarantees Act, although in most cases our members deal directly with builders and not the end consumers. If members are dealing directly with building owners there could be an increased level of liability.”
FTMA is also undertaking a review of Restricted Building Work (RBW) to clarify the status of pre-nailed wall frames and manufactured roof trusses.