Timber Design Guides Help Standardise Advice On Constructing In Timber

The Wood Processors and Manufacturers’ Association (WPMA) has long recognised the need for standardised, good quality information to help the wider construction sector confidently design with and approve timber structures using the many new engineered timber solutions available today.

Engineered wood turns softer timbers into beams, columns, trusses, portal frames and more that can deliver superior strength, resilience and fire resistance to other materials in the market. The 2011 Canterbury earthquake series and the 2016 Kaikoura events showed that such modern timber construction techniques will allow the built environment to withstand major events including earthquakes and fires comparatively unscathed. Such events have also helped raise awareness within the design community of just how creative it’s possible to be with such a “traditional” construction material; something supported by the regular NZ Wood-Resene Timber Design Awards.

“New Zealand is a leader in timber construction,” explains Andy Van Houtte, CPeng, Manager for the series of 16 Timber Design Guides. The first of the series was published in 2018, and the final ones will be released later this year.

“New Zealand has a lot of intellectual property around designing in timber,” he explains, “and the WPMA is keen to provide a one stop shop for developers, architects, engineers and the wider construction industry, with freely available peer reviewed information. That way, we believe we can provide a clear framework for everyone to understand the relative advantages of different aspects of timber construction, and how to maximise a project’s structural integrity and cost effectiveness while still complying with NZ Standards and the NZ Building Code. To be most useful, we need this to be a trans-industry project that provides a clear path to consenting and construction.”

Industry surveys and market research had confirmed which aspects of timber design that professionals were most interested in learning more about. Each Timber Design Guide was then written by a recognised expert in the field and peer reviewed through a highly qualified working group.

The nine topics covered to date include designing for fire safety, designing for prefabrication, the consenting process for timber buildings, how to cost them, standard connection details, how to work safely with prefabricated frames and trusses, explaining the varied properties of timber species, why timber benefits the environment, and timber’s social and health benefits in construction. Under way are explanations of flooring and cassette systems, acoustics, reinforcing timber beams, post and beam timber buildings, construction guidance, and seismic performance of timber buildings.

As they have been completed, the Guides are uploaded to a dedicated website https://nzwooddesignguides.wpma.org.nz which allows public access through a log-in function. Ultimately, Van Houtte is hoping for 20,000 registrations; about 90 percent of all New Zealand specifiers. The Guides can be supplied in a printed format but he’s finding that most are using the web function as required, and downloading information themselves.

In 2007 the third edition of a single, comprehensive technical manual was announced entitled The Timber Design Guide, published by the New Zealand Timber Industry Federation Inc. and authored by Andy Buchanan, previously Professor of Timber Engineering at the University of Canterbury. That and its updates (last published in 2015) covered the use of timber and wood products in large buildings through 29 chapters.

Andy Buchanan has authored two of the current NZ Wood Design Guides, and continues to be an inspiration to the development of timber buildings, says Van Houtte.

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