Government support could help overcome barriers to reuse and recycle building materials

With the construction sector responsible for 18 per cent of Australia’s carbon footprint, finding ways to reuse and recycle building materials waste generated when buildings are constructed or demolished is essential.  However, there are deep institutional barriers to recycling and reusing this waste, new AHURI research reveals. The research, ‘Building materials in a circular economy’, undertaken for AHURI by researchers from RMIT University and University of Wollongong, analyses the life cycles of building materials as they are used in construction and then disposed or recycled when the building is demolished so as to assist the residential housing industry to reduce greenhouse gas (GHG) emissions.

‘Although much of the waste generated through construction or demolition can be recycled or be used as a resource in other ways, in general, construction businesses are reluctant to do so,’ says research author,  Professor Tony Dalton from RMIT University. ‘Instead they find that the cost of reusing materials is higher than using new materials; there isn’t an established market for waste materials; they’re hesitant to use available technological and practical knowledge to reduce the waste; and there is a broad perception that Australia has abundant supplies of natural resources so they don’t really need to bother.’

Over the last 50 years, the GHG emissions embodied in residential building materials used each year have almost doubled from 3.2 million tonnes to 5.7 million tonnes in 2020. Analysis of the industry over the period 2007–2019 shows that the use of new building materials is more than double the flow out of waste materials, which shows the consumption of new materials is growing rapidly.

‘Our research established that 27 industries deliver products and services to the building site when a house or apartment building is being constructed,’ says Professor Dalton. ‘Because residential building projects are time-limited, one-off projects, these supply chains are being continuously dismantled and remade for each new project, which limits the ability of the suppliers to introduce changes to materials or their use.’

‘We found that policy development should focus on creating incentives for construction companies to reuse materials, as well as encouraging other ways to reduce embodied energy through material selection and the use of local products that require less transportation. Government regulation can target low carbon building methods and materials, including supporting reuse, rethink, repurpose or remanufacture.’

It is also important to recognise that investment decisions can support the decarbonisation of materials manufacturing and stimulate demand for recycled materials. In particular, when government building contracts require the appropriate use of recycled or low embodied-carbon building materials it can support the reduction in carbon intensive building practices and materials.

‘Ultimately, the idea that carbon is embodied in building materials is a new concept for most people involved in the residential housing system,’ says Professor Dalton. ‘Providing education and training on the benefits and practicalities of building with the circular economy in mind is a high priority.’