three timber skyscrapers in Perth and Sydney

Timber skyscrapers reach for record heights and sustainable Australian cities

Timber skyscrapers up to 50 storeys tall may soon dot Australian skylines in a push to decarbonise and revitalise urban construction.

Three separate plans have been submitted to build hybrid timber buildings in Perth and Sydney between 180 meters and 220 meters high.

Each would more than double the height of the current world record-holder, an 86.6-meter apartment building in Milwaukee, USA.

Timber skyscrapers are made possible by hybrid construction, which uses engineered “mass timber” around a concrete core.

Developer James Dibble, whose proposal for a 47-storey apartment building in Perth is before the state development panel, said hybrid technology puts timber on par with concrete and steel.

“There is not really any limitation to height other than the limitation of physics like any other building, to be frank,” he said.

“I think a 350 metre hybrid building is possible, which is almost twice the height [of the Perth apartment building].”

The 180-metre, 40-storey Atlassian headquarters in Sydney is already approved for construction this year. Two other planned timber skyscrapers are before state development panels.(Supplied: Atlassian)

‘You can’t grow concrete’

Cement and concrete manufacturing is estimated to produce about 8 per cent of the world’s natural greenhouse emissions, whereas timber sequesters carbon, even after the tree has been cut down.

Softwood plantation trees like pine grow fastest in their first few decades and can be harvested for construction timber at about 30 years old.

Between growing, harvesting and processing, timber is more expensive than concrete and steel construction, but some developers are willing to pay the premium for its sustainability credentials.

James Dibble estimated his planned Perth tower, which is marketed as carbon negative, will cost “about 9 per cent” more than a wholly steel and concrete structure.

“There’s got to be a recognition that the built environment is one of the three main contributors to climate change,” he said.

“We’ve seen huge evolution in terms of animal agriculture and transport and not very much has been done [in construction].

“And I would remind everyone that you can’t grow concrete. If concrete was a country, it’d be the third highest emitter in the world.”

Besides eco-marketing, timber’s big selling point is its aesthetic value — a natural counterpoint to the sterile grays and whites that dominate urban design.

In 2023, Murdoch University in Perth will open Boola Katitjin, a building that puts its timber on full display inside and out.

a tall timber building
At 180 meters long and four storeys high, Boola Katitjin is WA’s largest timber building.(ABC: Angus Mackintosh)

“Every time we bring people through, be it visitors, be it future staff members — everyone instinctively goes over and touches the surface of the columns,” Multiplex design manager Jamie Cook said.

“It really is a natural material that everyone wants to get up close and personal to.”

What is mass timber?

Mass timber is wood that has been engineered to strengthen it against the structural weaknesses of sawn logs.

Mass timber products like glulam (glued laminated timber), CLT (cross-laminated timber) and LVL (laminated veneer lumber) make it possible to build timber buildings more than a few storeys high.

Likewise, hybrid construction channels structures’ vertical weight through a concrete core, allowing the timber to dominate the interior and exterior living spaces.

“We could not build a 183-meter building out of mass timber only. It’s not technically possible,” Mr Dibble said.

“Where mass timber is superior we used it and where it wasn’t, we didn’t. That ultimately ended up with a hybrid structure that is 42 per cent mass timber.”

a man in a hardhat on the top floor of a wooden construction site
“We are absolutely confident that timber will perform as well if not better [than steel],” Boola Katitjin project director Daniel Price said.(ABC: Angus Mackintosh)

He also said that superiority extended to fire and weather protection.

“Mass timber can out-perform steel in terms of fire. It will self-extinguish.

But to protect against South Perth’s high water table, a concrete base was deemed more suitable.

“That is built with concrete, the core is concrete, the columns are concrete, but pretty much everything else can absolutely be done in timber and in those applications mass timber is superior,” Mr Dibble said.

Timber supply under stress

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