The C6, Australia's first hybrid timber building, C6 is due for Perth

James Dibble’s Grange Development recently announced his $350 million hybrid timber tower in Perth, Western Australia – claimed to be the tallest of its kind in the world – had finally been approved.

But the news was met with scepticism from the industry, as you’d expect from a project that claims to exceed regular sustainability outcomes such as the “first carbon negative residential building.

We asked for clarification and data. Here’s what our questions elicited.

According to the development team including architects Fraser & Partners, the project was approved by the Joint Development Assessment Panel.

The idea behind the C6 tower, is to inspire future developments to aim higher with environmentally conscious designs.

To do this, the team has committed to openly sharing all research design and construction documentation for the building.

James Dibble, Grange Development’s founder and director, who was a presenters at The Fifth Estate’s Tomorrowland 2022 summit is particularly keen to pursue the opportunities for mass timber.

“The built environment industry, frankly, is doing very little,” he told the Tomorrowland audience.

“Thirty-nine per cent of global emissions now come from the built environment, which we’re a part of; 28 per cent of that is from emissions originated from operational activities, and 11 per cent from embodied carbon in materials,” Dibble said.

In a separate article he said: “The intent of C6 has always been, at its core, a straightforward proposition. Our aspiration with C6 is to shift the focus towards a more climate-conscious approach to our built environment, rooted in science and engineering.”

“There were more challenges than just getting it across the line”

According to Dibble, the building will consist of 42 per cent mass timber. The remaining components will consist of concrete and glass curtain walls. The external façade will be steel-clad in mass timber, making a majority of the project a mix of mass timber, concrete, and glass.

Dibble said that while trying to put a date to the planning framework and timeframe had been the most challenging part of the proposal, closely followed by the need to accelerate the detailed engineering analysis on each material.

“We did not sign up to the idea of using wood for wood’s sake; we used mass timber where it made sense,” Dibble told The Fifth Estate on Thursday.

“Ultimately, the result is as it should be — a quite simplistic, repeatable and transparent engineering solution that is elegant and outperforms the benchmark.”

And change is already happening

Since ideation, Dibble said two factors had changed – the cost escalation and developers adopting hybrid buildings.

He admits that cost escalation had increased by about 21 per cent since the development application was submitted, but the project remains viable.

“This is not an easy challenge to navigate, as evidenced by the roughly 10,000 apartments on hold in Perth – and the similar situations Australia-wide – due to this factor alone,” Dibble said.

“It will take time for revenue to catch up and for escalation to stabilise, or decline, for the number of projects to progress through the system.”

Meanwhile, the good news, Dibble said, is that the company had experienced significant inquiries and proposals for other similar ideas that he might be able to consult on.

“It seems that C6 has really struck a chord as a viable alternative to our built environment, and that pleases me to no end.”

Addressing the sceptics

Some comments on LinkedIn expressed scepticism about claims the building would be carbon negative.

“Would like to see the calculations justifying carbon negativity being made available to back up the claims,” one comment said.

Dibble said that the carbon-negative result was related to the upfront carbon in the structure.

“It’s a comparison of cross-laminated timber and a hybrid build as opposed to concrete and steel, and as per the Slattery Carbon Accounting, this demonstrates a saving of 10,497,600 kg/ CO2eq,” Dibble said.

He claimed the emissions were equivalent to 4885 economy-class seat flights from Perth to London.

“Cross-laminated timber (CLT) is just one type of mass timber that will be found in C6, and while there are a number of factors that influence its carbon neutrality – timber source, location, and energy use in production, for example – it’s a well-known fact that mass timber is regularly recognised for its ability to sequester carbon.

“Based on our assessment, and considering this building as a whole, to transition from carbon-neutral to carbon-negative will also require nature-based offsets costing circa $500,000 that are already accounted for in the feasibility.”

Chart provided by Grange

Key factors around C6

Upon completion, the project will create 237 residences across 50 storeys, targeting 6-Star Green Star and 7-Star NatHERS ratings with additional net zero plans, energy modelling and commitment to 100 per cent green energy network and carbon neutral certification.

The company has also committed to funding 80 new Tesla Model 3 vehicles (with capacity for self-driving capabilities) to ensure residents can access transport without contributing to carbon emissions.

Other building statistics include:

  • a 50 per cent reduction in energy usage
  • 11.2 per cent of energy generated on-site
  • 90 per cent of water captured and reused
  • 30 per cent reduction in upfront carbon emissions
  • 20 per cent of the development will be for public use
  • 3524 sq m of landscape

The building will also feature a 3500 square metre edible garden on the rooftop, dining and entertainment spaces, 942 sq m of community wellness amenities and 437 sq m of public space on the ground floor. Each apartment will also be granted 18 sq m of communal area, three times state planning controls. There will also be an additional urban farm and children’s timber playscape among the amenities.

Slattery Table provided by Grange

What’s the construction timeline?

“Construction start dates are a moving target,” Dibble said.

The company is currently targeting sales launch towards the end of the second quarter or the beginning of the third quarter in 2024.

“We expect the construction timeframe to be 22 months.”

Dibble adds that he was grateful to his team of consultants for designing the building with ESD in mind and is excited to see a positive response to the project.

“On a personal level, the number of beautiful emails and messages I receive daily is almost overwhelming, and that is what makes these kinds of projects worth the extra work.”

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