For a long time, the built environment has followed a linear model of production and consumption. But in the face of severe global environmental challenges, a new approach is imperative. As Nicola Smith explains, the circular economy involves using less and designing for longevity, disassembly and reuse. The results can be both impactful and awe-inspiring.
Salvaging and repurposing can deeply enrich a project and celebrate the history of the materials without precluding luxury, as demonstrated by Hotel Hotel (now Ovolo) within Canberra’s New Acton precinct, developed by Molonglo Group. The staircase, designed by March Studio, incorporates more than 2,150 pieces of recycled timber.
The European Parliament describes the circular economy as “a model of production and consumption, which involves sharing, leasing, reusing, repairing, refurbishing and recycling existing materials and products … When a product reaches the end of its life, its materials are kept within the economy wherever possible.”1 This is a departure from the traditional, linear economic model, which is based on a take–make–consume–discard pattern.
Circularity requires a shift in thinking that needs to be embedded in our education system and entire building design process, from initial concept through to end-of-life. It involves respecting the intrinsic value of the materials we extract, and the carbon invested in them, throughout their life cycle.
The EU’s Circular Economy Action Plan2 shows the extent to which circularity is a focus in Europe. Further, the new ISO 59040 Circular Economy standard, currently under development, promotes universal Product Circularity Data Sheets (PCDS)3, such as those commissioned by the Ministry of the Economy of Luxembourg, facilitating transparent, reliable, digital product circularity data. Access to comparable data will positively and fundamentally shift the quality and standardization of circular economy information globally – and Australia can’t afford to be left behind.
Thankfully, there’s increasing investor pressure to embrace circularity and move away from a wasteful, consumption-driven mindset to one that considers value. In Australia, built environment professionals must upskill to show leadership, and explore all opportunities to recycle products, materials and “waste,” rather than inadvertently creating assets that are redundant on the day of handover.
Reducing embodied carbon should be an aim and an outcome of circular thinking. This means knowing and accounting for the embodied carbon emissions (CO2e) of all materials and systems we’re designing, and diligently exploring alternatives.4 Helpful resources include the Materials and Embodied Carbon Leaders’ Alliance (MECLA) in Australia, and the US-based Carbon Leadership Forum (CLF) and Carbon Smart Materials Palette.5 “Tally” is a life-cycle assessment (LCA) app that links directly to Autodesk/Revit, a valuable design tool that allows real-time calculation of the environmental impacts of material selections.6
Aiming to use less in the first place (dematerialization), designing for disassembly and deliberately selecting salvaged, recyclable, carbon-sequestering materials with positive end-of-life impacts are three essential strategies.7
Quay Quarter Tower in Sydney’s CBD, designed by 3XN in partnership with BVN, has been repurposed to retain the lower portion of the original 1976 AMP Centre, with the reuse of materials saving in excess of 7,500 tonnes of carbon.
Repairing and adapting (rather than demolishing) existing buildings, designing to combine structural and aesthetic functions to avoid cladding wherever possible, and incorporating only what’s necessary all enormously impact a building’s footprint. These strategies must be embedded in our design approach and form part of every design-stage checklist.
Rather than taking away, these strategies in fact add to a project. Exposing existing and new structure can contribute to richness of palette and foster meaningful connection to place, among other creative outcomes. Eliminating what’s unnecessary means prioritizing elements that truly matter and gaining maximum value.
Nightingale Housing’s approach is a case in point. It utilizes raw brass and metal taps and fixtures, which age better and avoid toxic chrome; open shelving without cupboard doors; exposed services to avoid wall and ceiling finishes; shared rooftop gardens with composting; and green facades, which also are beautiful, to reduce the urban heat island effect. Where finishes are required, Nightingale chooses those that contain fewer volatile organic compounds (low-VOC). As its website states, “It’s about building less, to give more.”8
Beauty and quality are important aspects of built environment circularity. When a project is awe-inspiring in one way or another, it cultivates emotional attachment that then encourages care and preservation, which, in turn, extends the lifespan of component materials and the energy and carbon invested in creating them.
To put buildings together using high-quality, durable, responsibly sourced products in a way that allows easy dismantling requires in-depth materials-recyclability research and a first-principles design approach. In the case of The Recyclable House in Beaufort, Victoria, designed and built by Quentin Irvine of Inquire Invent, this involved stainless steel shower trays, salvaged floorboards, salvaged timber stairs and handrails, and concrete containing recycled aggregate. Only natural paint and oil finishes were used so that the plasterboard and timber remained compostable and biodegradable, and air quality was preserved. The house was designed to avoid the need for silicone sealant wherever possible – for example, benchtops were rebated to create drip lines where the bench meets the sink.
Selecting recyclable materials also means that construction offcuts can be recycled. At The Recyclable House, this was achieved except in the case of the magnesium-oxide board cement sheet, which contains fibreglass that isn’t recyclable because the manufacturer wasn’t amenable, and regular cement sheet that could not be recycled because of Australia’s long history of asbestos-containing cement sheet. As a result of this legacy, most cement-sheet products will not be recycled in Australia because it is impractical and cost-prohibitive to determine which sheets contain asbestos and which don’t – and vast amounts of material are unnecessarily sent to landfill. Alternatives with better recyclability credentials, such as structural insulated panels (SIPs) or eco-ply products, deserve exploration. This is also a good reminder not to take information at face value when specifying, but to drill down for specific details of take-back programs and/or recycling facilities, to maximize recyclability.
The Recyclable House in regional Victoria, designed and built by Quentin Irvine of Inquire Invent, uses both salvaged and new mainstream recyclable materials that have been screwed, nailed and (lead-free) soldered together to facilitate future dismantling, reusing and recycling.
Adopting the cradle-to-cradle mindset needed to truly conserve our natural resources and minimize waste includes finding ways to integrate as many salvaged materials as possible into designs. Salvaging is particularly effective for components not requiring regulatory compliance with standards. Compiling lists of local salvage yards and procuring, setting aside and designing around available products are two good strategies.
Brick lends itself to reuse because it has good durability and thermal mass and retains original features (with lime mortar removed). Without harmful ingredients or harmful emissions, it also results in healthier indoor environments and no bioaccumulation into ecosystems.
Sequestering carbon removed from the atmosphere in building products is a key climate change mitigation strategy. Natural materials such as hemp, mycelium (the root-like structure of fungi), graphene, timber and algae all capture atmospheric carbon and can be used for construction.
Fungi can break down waste, and discarded fibres can be woven into new water-wicking materials or fused with cultivated mycelium to grow moulded composite materials that are zero-waste, lightweight, fire-retarding, buoyant and insulating.
There’s also increasing availability in Australia of products with recycled content. Whether it be recycled aggregate or waste by-products in concrete, the diversion of resources such as timber from landfill to sequester carbon, or new materials created from organic matter or diverted “waste,” these products and technologies are part of the solution.
Circular economy momentum is building. Materials transparency is key to shifting our market, and demand increases supply. Asking the right questions is crucial to understanding the supply chain, where products come from, what’s in them, their end-of-life data, good sources of salvaged materials and valuable new waste streams for recycling.
In the National Construction Code, it should be mandatory, or at least incentivized, to salvage quality materials from demolished buildings for future reuse, to design for disassembly and to specify recycled and recyclable products. We should all advocate for this to be legislated!
Let’s not underestimate the power of the specification in the circular economy. Clearly listing in our specifications all parameters integral to product choices, including circular economy data, helps to embed researched selections into final designs and ensures that any substitutions are truly equivalent and don’t compromise the value-adds that circularity will provide.
As building professionals, we need to drive the circularity groundswell. It’s common sense to design for longevity and recyclability, to choose quality local materials with recycled and/or carbon-sequestered content, and to salvage whatever we can. Leadership in circular economy is the least we can do to value and protect the precious resources we extract from the earth and the carbon invested in materials throughout their life cycle.
1. European Parliament, “Circular economy: definition, importance and benefits,” 3 March 2021, europarl.europa.eu/news/en/headlines/economy/20151201STO05603/circular-economy-definition-importance-and-benefits (accessed 20 April 2022).
2. European Union, Circular Economy Action Plan, 2020, ec.europa.eu/environment/strategy/circular-economy-action-plan_en (accessed 20 April 2022).
3. See positiveimpakt.eu/en/pcds.
4. CO2e denotes “carbon dioxide equivalent” and allows greenhouse gases other than carbon dioxide (CO2) to be expressed in terms of CO2, based on their relative global warming potential.
5. See mecla.org.au, carbonleadershipforum.org and materialspalette.org.
7. For more on some products with positive end-of-life impacts, see holcim.com.au/ecopact, wagner.com.au/main/what-we-do/earth-friendly-concrete/efc-home and epd-australasia.com/epd/reconophalt.
This essay is part of the July/August 2022 issue Architecture Australia, Beyond Sustainability: The power of regenerative design, guest edited by Stephen Choi, Clare Parry and Amanda Sturgeon, on sale 4 July.
Published online: 27 Jun 2022 Words: Nicola Smith Images: Martin Siegner, Nic Granleese, Tom Roe
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Salvaging and repurposing can deeply enrich a project and celebrate the history of the materials without precluding luxury, as demonstrated by Hotel Hotel (now Ovolo) within Canberra’s New Acton precinct, developed by Molonglo Group. The staircase, designed by March Studio, incorporates more than 2,150 pieces of recycled timber.
The Recyclable House in regional Victoria, designed and built by Quentin Irvine of Inquire Invent, uses both salvaged and new mainstream recyclable materials that have been screwed, nailed and (lead-free) soldered together to facilitate future dismantling, reusing and recycling.
Quay Quarter Tower in Sydney’s CBD, designed by 3XN in partnership with BVN, has been repurposed to retain the lower portion of the original 1976 AMP Centre, with the reuse of materials saving in excess of 7,500 tonnes of carbon.
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