More than seven million tonnes of
construction waste goes to landfill each year – equivalent to enough bricks to build a metre-high wall around Australia’s coastline. So how are engineers rethinking design for circularity?

Words by Chris Sheedy

This article was originally published in the November 2024 issue of create with the headline “Coming full circle”.

Joe Karten’s daughters, aged six and nine, enjoy playing with LEGO. Perhaps unsurprisingly for the children of a core member of the team for developer Built, they regularly spend hours assembling all sorts of creations, which sometimes stand proudly for several days before the girls break them down and pack the pieces into a bucket, ready for their next production.

“Imagine, though, if every time they got bored with one of their LEGO creations, they threw the pieces in the bin, and I had to go out and buy new LEGO sets,” Karten, Built’s Head of Sustainability and Social Impact, said. “If that happened, they wouldn’t be playing with LEGO for very long.

Joe Karten

“And yet, that’s what we do with buildings and fit-outs. We know how to get the very best value out of materials even when we’re children. But as engineering and construction businesses, we need to do a lot better.”

In fact, a spokesperson for the Department of Climate Change, Energy, the Environment and Water told create, circularity is already happening in the construction supply chain. Engineers have to get on board.

“There is no escaping the change towards circular construction,” the spokesperson said. “It’s growing in momentum internationally, and Australia is committed to making this transition.

“It is a growing area of policy focus and the construction supply chain will be expected to deliver materials-efficient, circular solutions.”

Image: Alev-Takil via Unsplash

What is circular construction?

Many consider the idea of circularity anywhere in the economy to have something to do with recycling, or reuse of materials. While these certainly make up a part of the concept, the idea of circular construction covers a lot more ground.

Katherine Featherstone

“It is about keeping things in use for longer, at their highest and best level of use,” Katherine Featherstone, Senior Manager Products and Materials at the Green Building Council of Australia, said. “Circular construction focuses on ensuring that during the design stage, we work together to maximise the lifespan of each element, so it continues to provide value and functionality for multiple uses over time.”

Some of the most important ingredients for success include design for disassembly, meaning welding is out and mechanical fastening is in, and fastidious, digital recording of maintenance of all parts of each building.

“An engineer needs enough information to be able to safely reuse what’s there,” Featherstone said. “We don’t do that well enough right now, and that’s a real roadblock.”

Circular construction involves the engagement of every part of the supply chain, and entirely new processes at the design, construction, maintenance and disassembly stages.

Of course, certain types of construction have long been relatively circular. Some mining businesses are familiar with the need for modular housing for staff during the life of a mine. Military engineers regularly assemble and disassemble portable bridges for mission purposes.

In Canberra during the COVID pandemic, Aspen Medical built a 51-bed surge facility in just 37 days – a building that could pack down into shipping containers for use elsewhere once no longer needed. However, in the mainstream construction arena, and particularly in Australia and New Zealand, examples of circularity are few and far between.

Sophie Degagny

“Because it is still new, businesses aren’t yet working together in the different parts of the supply chain,” Sophie Degagny, Director of Climate Change and Sustainability at KPMG, explained. “We see great examples of circular construction in temporary building projects, but on large buildings we need plans for end of life.

“We will see a lot more green, sustainable procurement in Australia. I moved to Australia four years ago, and in that time I have already seen a lot of changes in relation to the circular economy.”

The one absolute necessity in the move towards circular construction is leadership by engineers, Degagny said.

“Engineers must be deeply involved from the design stage. They need to lead that discussion around how the building is put together to enable it to be disassembled at the end, instead of just knocked down. From an engineering side, if it’s easy to disassemble, it will be a lot easier to repurpose, record and reuse.”

Fitting out

Consider when an office or shop is about to be fitted out. Typically, the walls and floors will be stripped back to bare concrete, steel and brick.

No matter what came before, it is completely cleared out for the new tenants to start afresh. And most of what previously existed is sent to landfill, said Vanessa Cullen, CEO of Forward Thinking Design and Lead Partner with FTD Circular.

“We’ve always undertaken a lot of pro bono work with charities,” Cullen said. “When you have little money to spend, you have to be resourceful. So you design out waste and you reuse, and you procure things second-hand.”

One of Cullen’s areas of specialisation is fit-out. Success in circular fit-out begins with the landlord, who writes policies and guidelines for tenants.

These guidelines then flow on to affect the work of designers, engineers, contractors, certifiers and every organisation in their supply chains.

“The environment did not suffer the impacts of the joinery, which was salvaged from the commercial building going to landfill.”
Vanessa Cullen

“Landlords for most shops and restaurants ask tenants to build false walls within the concrete walls. You’re building a frame and then putting your plasterboard onto that. But why is that being stripped out each time a tenant changes?

“Fortunately, more landlords are appreciating that there are parts of a fit-out that could be retained and used by the next tenant, and then the landlord potentially doesn’t need to give as much of a financial contribution towards the fit-out. This is not just for sustainability; it’s about good financial sense.”

FTD Circular recently worked with a commercial client on tracing and enabling the circular de-fit of a tenancy. At the same time, a charity client was in need of joinery work. The charity’s needs matched what was being removed from the fit-out.

“The commercial clients saved on the landfill, transport and labour fees, and the charity saved around $40,000. There was also great social-impact value because the charity was able to create the space it needed for the people it served; and the environment did not suffer the impacts of the joinery, which was salvaged from the commercial building going to landfill.”

Image: Tom Jersø

This example illustrates an important point in sustainability reporting, said Cameron Kaufman, Circular Economy Specialist at Coreo. In circular construction, Kaufman said, diversion-from-landfill statistics mean little if they’re not backed up by information about where the materials are instead being used.

Cameron Kaufman

“I don’t care about the diversion-from-landfill target,” she said. “Instead, tell me where you are directing those materials to capture and preserve their value. That is the flipping of the switch that we need to see.”

The Circle House project

Circle House is an excellent example of a circular build, Kaufman said.

“Everything is standardised and everything is designed for disassembly. All of the maintenance is recorded in a digital passport. There is a plan for every element of the buildings to be reused in 20 years. That is happening right now.”

In 2020 in Aarhus, Denmark, 60 social housing units – comprising two- and three-storey terraced houses and five-storey tower blocks – were built according to circular principles, with 90 per cent of materials able to be reused without loss of value.

DESIGN: A reuseable structural system – including demountable and reuseable concrete foundations, steel walls, concrete slabs and steel plate connectors – was designed before any physical work began. This system ensured relatively simple disassembly and easy access to all parts for maintenance.

CONSTRUCTION: With clear purpose and a focus on the specific outcome of circularity, traditional building methods were abandoned as modularity rose to the top of the priority list. All parts of the buildings were reused from elsewhere: shingles were made from upcycled plastic waste; the
facades, made from clay and reclaimed wood, are easily disassembled; and reclaimed timber features are found throughout. There is also great consistency of proportion, with just two sizes of wall elements and two lengths of beams.

MAINTENANCE: Every piece of the buildings contains an ID number, a barcode and an embedded RFID chip. This enables a material passport to be kept for each part during each building’s life, and onwards as each piece is used in future builds. Digital maintenance chronicles are kept, ensuring engineers can access records of various maintenance events during the life of the material.

DISASSEMBLY: Clear disassembly plans and processes were drawn up during the design stage, enabling the economic and engineering value of each part of every building to remain intact.

REASSEMBLY: Thanks to the maintenance records, the consistency of dimension of parts and the ease of transport of materials, each segment can be designed into a new build.

Follow the leader

Australia’s federal and state governments are also pushing the economy to go circular, beginning with the construction sector.

In terms of procurement decisions, and governed by the Environmentally Sustainable Procurement Policy, in place from 1 July 2024, the Federal Government encourages circularity through regulation, as do the Victorian, NSW and Queensland governments.

The initial federal focus is on procurement of construction services at or above $7.5 million. Other categories being introduced on 1 July 2025, at or above a value of $1 million, are:

Furniture, fittings and equipment

Information and communication technology goods

Textiles

The policy outlines a number of principles suppliers will be asked to address, including circularity issues such as:

• Waste minimisation

• Use of less materials

• Ability to be deconstructed and reused

• Use of refurbished or reused materials

• Ability to be recycled at the end of the material’s useful life

Public service entities and their suppliers will be required to prove the various environmental claims.

“The circular economy is the big opportunity to decarbonise the built environment sector in Australia,” the DCCEEW spokesperson said. “There’s a bit left to do in terms of electrification, but then it’s all about the materials we’re using and how much carbon is in them. You’ll see a big focus on that, on reusing materials, and on not knocking buildings down, but instead refurbishing and adaptively reusing them.

They’re the big-ticket opportunities for decarbonisation in Australia.”

Further reading