Timber is no longer just a material used for features, fitout or framing in Australia, with the new engineered timbers taking centre stage in multi-million dollar major projects around the country.
There are three main engineered or mass timber products being used to replace building elements traditionally constructed from concrete and steel – glued laminated timber [glulam], laminated veneer lumber [LVL] and cross-laminated timber [CLT].
While the first projects using CLT such as Lendlease’s flagship Forte apartment building and the award-winning Library at the Dock, both in Melbourne, could only utilise imported CLT, there is now a local CLT produced by XLAM in Wondonga, Victoria.
Since the factory opened earlier this year it has been full-speed ahead, with CLT delivered for projects as far away as Western Australia.
Since the factory opened earlier this year it has been full-speed ahead, with CLT delivered for projects as far away as Western Australia.
There is also a race to the top in terms of the tallest CLT building. The title is currently held by Lendlease’s 25 King Street, which will become headquarters for Aurecon in Brisbane. This project will soon be vertically challenged by Atelier Projects’ 55 Southbank Boulevard in Melbourne, which comprises a 12-storey CLT addition to an existing seven storey commercial building.
According to the project’s Quantity Surveyor and Construction Cost Management consultant, WT Partnership, the use of CLT is resulting in a shorter construction time due to the use of prefabrication and reduced transport costs and associated carbon emissions.
The lighter weight of CLT compared to the concrete and steel alternative also meant the project, which is destined to be a hotel, could achieve additional storeys.
The project’s design engineers, Vistek, believe it will be the tallest timber extension in the world when it is completed.
Sydney-based construction firm Strongbuild has been one of the leaders in the timber construction evolution. Its achievements have included delivering Australia’s largest multi-building multi-residential project, Macarthur Gardens as well as a 10 storey CLT retirement building for Aveo at Bella Vista.
The company has invested in offsite and prefabrication approaches also, opening its own factory at Norwest Business Park in Sydney’s Northwest to support the delivery of projects across all building typologies.
Spokesman for Strongbuild, Shane Strong, tells Jobsite that there is a lot more interest in the market around the use of mass timbers such as CLT, LVL and Glulam.
“The market has picked up,” he says.
Saving on building costs and reducing construction timeframes is one major driver, another is an interest in the sustainability benefits and attributes of mass timbers.
Saving on building costs and reducing construction timeframes is one major driver, another is an interest in the sustainability benefits and attributes of mass timbers.
Strong says the company’s core market of North West is Sydney is particularly cost-conscious, as construction costs in the region are “through the roof” due to the high level of activity.
“For developers to make projects stack up financially [in this area], they need to get their costs down and also the timeframes down,” he says.
While there is a still something of a knowledge gap in some quarters around the benefits of mass timbers in terms of costs and time savings, Strong says that overall there is a growing cohort of educated clients and consultants.
The key to success for projects utilising mass timber is getting the right people onboard early.
Strongbuild preferences an Early Contractor Involvement approach, Strong says.
The company aims to undertake projects where it can “add value”.
In one recent project, the six storey 134-apartment Phoenix apartment development at Rouse Hill, the company examined a few options for the client.
The client originally had a concept for a conventional concrete and steel construction. Strong says his team first modelled a full CLT option as an alternative, which would deliver cost savings. Then it modelled a hybrid approach combining load-bearing steel and CLT, which delivered further savings.
The final solution comprised fully closed prefabricated LVL framed wall panels with CLT floors, lift shafts and fire stairs. The basic elements of walls and floors were pre-finished in Strongbuild’s factory, including the addition of plasterboard lining and insulation. Services conduits were also roughed in.
This meant the elements could be “dropped straight in” on arriving on site. This approach had a dramatic impact on the number of workers and subtrades on site. Strong explains that where a conventional ferro-concrete solution would have seen between 50 and 60 people onsite, Phoenix had around seven or eight.
There are a number of other fundamentals that change with the use of mass timber in addition to time and personnel on site.
Strong explains that the supply chain also changes, and this is also influenced by the source of the mass timber. His company has an exclusive arrangement with Binderholz, which manufactures CLT from European Spruce. This CLT also has slightly different properties to the Australian domestic product now being manufactured by XLAM which uses Radiata Pine as a feedstock.
“It is changing the model of how projects are procured.”
Another difference is the scheduling on payments. In general, using offsite construction for a significant part of the program means there are changes in who gets paid when compared to conventional on-site ferro-concrete projects.
“One of biggest things clients struggle with is how to get the most out of a mass timber structure,” Strong says.
Many suppliers rely on a range of consultants to give them the “right information” to be able to deliver on project requirements and specifications.
Another aspect many in the industry are grappling with is how to get an accurate pricing for a project in the early stages.
“That’s where it helps to get the right people on-board early,” Strong says.
“It is changing the model of how projects are procured.”
Leave a Reply