Reflections on Building the World’s Tallest Timber Building Using CLT

For Lend Lease business manager of cross laminated timber developer Andrew Nieland, there is no better way to summarise the significance of engineered timber in building and construction in Australia and beyond than by quoting drMM founding director and UK architect Alex De Rijke.

If the 19th century was the century of steel and the 20th century was the century of concrete, De Rijke says, “then the 21st century is about engineered timbers.”

“Now he’s not a crackpot, he’s an architect of high standing,” Nieland told a Property Council of Australia conference on sustainability in Melbourne recently.

“When someone of his standing in the construction industry says that, it is incumbent upon all of us to stand up and take notice.”

Indeed, that’s exactly what Nieland and colleagues are doing. Only recently, Lend Lease used cross laminated timber (CLT) to construct the tallest timber building anywhere in the world – Melbourne’s Forté apartment building at Victoria Harbour. Going forward, the company says it expects to use the material on 30 to 50 per cent of its apartment building pipeline.

Based on the results at Forté, there is plenty to be excited about. According to company estimates, the use of CLT provided similar levels of structural integrity as traditional concrete buildings while delivering better thermal performance and reducing the building’s projected life-cycle CO2 emissions by around 1,400 tonnes. Being largely based on pre-fabrication, the CLT construction process involved less material on site and was cleaner, simpler and faster – four months faster, Nieland says.

Asked about the main benefits of CLT use from a project management viewpoint on the Victoria Harbour development, Neiland nominates two key areas.

“Safety is the most important from a Lend Lease perspective. And that’s about a number of things: reduced high risk work, the elimination of injuries associated with formwork and reinforcing. It’s also a better work environment so less dust, vibration noise and obstruction,” he says.

“And commercially speaking, the biggest thing is speed. With it being pre-fabricated, all of the main penetrations were already taken care of, and fixing into timber is a lot easier than fixing into concrete, so for the electricians, plumbers, plasterers and others, it’s a lot easier job [working with a CLT structure] than working with concrete.”

Andrew Nieland

Andrew Nieland. Image Credit: Lend Lease

Nieland says the biggest challenges in dealing with the first building of its kind in Melbourne revolved around the authority space, which involved making sure Lend Lease achieved structural certification and demonstrating compliance with building code requirements on issues such as durability, fire protection and acoustics – much of which was achieved through careful design detailing.

Being a timber-based product, fire protection was an interesting issue. Nieland says Lend Lease needed to do a lot of testing to achieve the fire ratings and work closely with the Melbourne Fire Brigade and the Building Appeals Board in Melbourne to demonstrate that CLT would meet the code requirements.

As a ‘mass wood,’ CLT is different than ordinary timber and has a predictable fire performance (it chars at 0.7 milimetres per minute). Moreover, in terms of fire engineering, required ratings can be achieved by adding additional layers of timber or supplementary materials such as fire rated plasterboard.

Asked about any advice he would give to managers embarking on a project using CLT, Nieland says it is imperative to get the right expertise in place.

“Consider timber as a material from day one and understand that it is not just about replacing other materials with timber, it is about a different construction process which is pre-fabricated,” he says.

“It’s really about understanding what all that entails up front.”

By Andrew Heaton
© 2012 DesignBuild Source. All rights Reserved. Reproduction without explicit permission is prohibited.