Why timber towers triumph
It’s quicker, safer and more sustainable. And when time is money, timber comes up trumps, says WoodSolutions’ lead program development manager for mid-rise construction Gerry Neylan.
Neylan is championing the use of lightweight engineered timber structures in Class 2, 3 and 5 buildings up to 25 metres in height, following changes to the National Construction Code’s ‘deemed to satisfy’ provisions.
“When I talk to developers about timber they all ask the same thing: is it cheaper and is it faster?” Neylan says.
Engineered timber products like cross-laminated timber (CLT), glulam and laminated veneer lumber (LVL) have been hailed as the ‘new concrete’. Engineered timber has similar strength to concrete and steel but at a fraction of the weight. Manufactured and flat packed off-site, the material reduces build time and costs too.
Neylan says WoodSolutions’ analysis has found that the material costs of engineered timber buildings in CLT are currently “about the same” as concrete or steel. The real savings are found in the “programming”, Neylan explains. Faster construction means savings on equipment, employees, financing and even site sheds.
“When you use timber there’s no propping or formwork, no wet trades and smaller cranes – all of which reduces your labour costs,” Neylan says, pointing to Lendlease’s Forté apartment development in Melbourne as an example.
“Forté’s structure was built with a team of five, including two apprentices. It’s not uncommon to see projects that would demand a workforce of 60 using traditional construction methods being completed with just six people on site, when timber is used.
“You don’t need all the site sheds for a large labour force. And the sites themselves are very quiet – there’s no cutting and welding, and a lot less dust, noise and waste.”
When Lendlease’s nine-storey office at 25 King Street in Brisbane opens later this year, it will be the world’s tallest engineered timber office building based on gross floor area. It will also be the developer’s fifth foray into timber construction.
Lendlease recently made a public commitment to construct in timber on all its development precincts across Australia. The company’s chief executive of building, Dale O’Connor, told the Australian Financial Review that timber is “the way of the future” and that his team is “working out the limits to what this material can do”.
Other companies are also testing the outer limits of engineered timber. Hume Partners’ adaptive-reuse of 55 Southbank Boulevard in Melbourne is a prime example. Using CLT will enable a 10-storey Adina hotel to be built on top of an existing commercial office.
Neylan says the existing concrete frame was designed to take just six additional levels of a traditional concrete-framed structure.
“But because CLT is 75 per cent lighter than concrete and per cent of the weight of steel for the equivalent performances, 10 storeys are possible. And being able to construct more floors is gold on any development.”
Other benefits include less waste, fewer emissions, less disruption to the community and enhanced safety on site. “Lendlease recorded not one hour of lost time due to injury on its International House project,” Neylan explains.
So, why aren’t more developers embracing timber? Neylan says it comes down to the fear of the unknown.
“It’s a relatively new approach to construction, and change is not something the market can be confident with initially.”
But with Australia’s first CLT plant, operated by XLam, which opened in Wodonga this year, a robust supply chain for engineered timber is beginning to emerge. XLam’s facility will produce 60,000 cubic meters of CLT each year – enough to construct the equivalent of the 10-storey Forté apartment every week.
Neylan says quantity surveyors also now have a better understanding of how to cost timber, and builders are beginning to jump on board. Lendlease, Strongbuild and Multiplex may be ahead of the pack, but it won’t be for long, Neylan adds.
“It’s early days – but there will be more savings to be realised as the market gains confidence in timber.”
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