Imagine standing in a supermarket filled with building materials, tasked with collecting the products you will need for your project. Automatically, you turn towards the concrete and steel aisles…but wait, was that wood?
The unassuming middle child, timber is often forgotten when it comes to structural applications, but has the potential to revolutionise the way Australian buildings are being constructed. More specifically, it is engineered timber which can be used in both residential builds and larger-scale, multi-storey projects.
This method of construction is far from new. The Great Buddha Hall of the Todaiji Temple in Nara, Japan is 300 years old and one of the largest wooden buildings in the world. Stadthaus, a nine-storey London building designed by Waugh Thistleton, was previously the tallest timber residential structure in the world – a title recently, and narrowly, claimed by Lend Lease’s Forte in Melbourne.
Stadhaus by Waugh Thistleton architects was constructed from CLT panels. The entire building was completed within 49 weeks. Image: Waugh Thistleton
But projects like Forte, which was constructed with cross laminated timber (CLT), are still a rarity in Australia. Here, the engineered timber industry is only in its infancy, lagging behind Europe, and increasingly the US and New Zealand. There are, however, a few hopeful that the tide will turn sooner rather than later.
Sydney-based Fitzpatrick + Partners (F+P) is one practice which believes there is a compelling case for building ‘tall timber’ and has invested significant research and development into timber applications. Rod Pindar, a principal at F+P, attributes current industry inertia to a lack of demand in investing in new technology within the Australian construction industry.
“All the technologies we use to build these days have been around for decades. We are used to them, we’re experienced with them, and there’s been no need to change,” says Pindar of the reigning concrete and steel.
“There’s the attitude in the industry of ‘we know what we are doing, so why do we need to do it differently?’”
Cross laminated timber. Image: Tilling
An impetus for change (and playing catch up with New Zealand)
Across the Tasman Sea, New Zealand’s building industry has soared ahead in terms of timber construction, but this has only happened within the span of a few short years.
One key driver for this has been the Christchurch earthquakes, which have prompted a dramatic re-think in how buildings are constructed. Seismic engineering is now an integral part of their building design, and engineered timber is well suited to dealing with those challenges. Wood is now front and centre of New Zealand’s building products supermarket.
The Nelson Marlborough Institute of Technology and Arts building in New Zealand by Irving Smith Jack Architects was constructed using the world's first commercial EXPAN Pres-Lam engineered timber structure. Photography by Patrick Reynolds
However, it should not take a disaster to wake Australia from its ‘slumber’, notes Pindar.
“The fact is we do need smarter systems than what we currently have. Contractors are under ever increasing pressure to deliver buildings cheaper and faster, with stringent safety standards and high on-site costs. Traditional methods of construction are struggling to deliver quality outcomes, and I think people are beginning to look to alternative means of construction,” he says.
The impetus for change in Australia, according to Pindar, will therefore not rest solely on the environmental benefits of timber construction. Instead, the shift in culture will be driven by economic and practical advantages.
Stronger, faster, warmer, greener
Typically fabricated off-site, engineered wood products have good strength-to-weight ratio, and are manufactured with millimetre accuracy and sophisticated detailing. This allows buildings to go up on site much quicker and more efficiently than traditional construction.
A keen example is Forte, where walls, floors and ceilings are made from large slabs of timber formed by gluing pieces of timber together. According to developer Lend Lease, this method helped cut construction times by 30 per cent and reduced the number of workers required on site. The reduction in time and noise on site also reduced the impact of construction on local communities.
Forte. Image: Lend Lease
Contrary to popular belief, engineered wood also performs well against fire because of its char factor.
“The analogy is if you are trying to start a fire in your backyard or a barbeque, you don’t put a log on it, you start with twigs and paper. You are not going to start a fire just by striking a match under a log,” explains Pindar.
“You need a large, established fire before that log is going to start to burn, and when it does, it will char and burn slowly. This is measurable and accounted for in the engineering of the timber.”
Large timber beams are therefore able to retain their integrity even after being susceptible to a fire. Compare this to steel, which Pindar says requires costly protective coatings or cladding to protect it in the event of a fire.
Candlebark School Library by Paul Haar Architect is intended to serve as a fire refuge of last resort. Read more about the structural engineering of this project here. Photography by Kristian Laemmle-Ruff
The natural aesthetic of wood is another big advantage of timber construction. A timber building has a warmth to it, soft to touch, and a particular ambience that is calming and inviting. This could be particularly beneficial for commercial buildings with staff and workers who may thrive more in a building made of materials with variance, texture and grain, instead of more sterile, clinical finishes.
A building in Austria under construction using engineered timber technology. Image: UTS
Of course, sustainability remains a key incentive for the use of engineered timber.
A truly renewable resource, timber plantations typically have a 25 year lifecycle, which means there is an endless supply as long as the wood is harvested sustainably and responsibly. Wood absorbs and stores carbon and requires relatively little embodied energy to manufacture.
Timber is also highly recyclable, and at the end of a building’s lifecycle, can be made into other products.
The possibilities of engineered timber are only just starting to enter mainstream building industry consciousness. Following on from the success of Forte, Lend Lease has recently completed another CLT project in Melbourne, The Library at The Dock. The new Netball Centre in Homebush, Sydney, by Scott Carver is being built with large format laminated veneer lumber (LVL) timber beams.
Fitzpatrick + Partners has prepared a concept design for what could be the tallest timber commercial building in Australia using glued laminated timber (glulam), and is exploring the use of hybrid timber and steel or concrete structures in many of its projects.
The tallest timber commercial building in Australia could be constructed with glulam
While Pindar acknowledges that a fully timber building is not always the right solution for every site, he hopes that wood will be seen as a legitimate option alongside steel and concrete:
“I think the question should not be why timber is suited for commercial office design, but why timber is not being used for multi-storey commercial buildings. I don’t think there is a compelling reason for that,” he concludes.
In our following Timber series, we will be looking at the different methods of engineered wood construction, as well as what the industry can expect from manufacturers. Here's a look at the advantage and possibilities of building with cross laminated timber (CLT).