In FY23, Landcom developed a research partnership with the University of Wollongong’s Sustainable Buildings Research Centre to explore deconstruction of existing buildings as a viable alternative to traditional demolition due to the high volume of construction waste that typically ends up in landfill.
Over FY24, we leveraged ongoing demolition work at our Bulli community, with a case study building, to investigate potential opportunities to preserve value in demolition resources.
The research found that whilst demolition generates large quantities of waste, much of which has inherent value, it was found that current deconstruction practices pose many challenges and barriers compared to traditional demolition practices. This includes:
- safety risks for contractors involved (e.g. unknown contamination),
- additional time and cost pressures on the demolition process (e.g. easier to just knock down and sort after),
- the use of low-quality and low-cost construction materials limiting reuse, and
- site-specific limitations based on the design of buildings and materials involved.
Recycling material however is given high priority, particularly when there is economic incentive to do so, but this does not take full advantage of the value in materials. Optimally, salvage occurs predemolition, however, is hindered by time pressures and lack of market value for those materials. Construction practices also often damage the material, limiting its reuse or resale.
In addition, the research explored the embodied carbon saving potential of reuse and found that in this particular project, the materials by weight did not necessarily correspond to their embodied carbon value. Specifically, brick and tile comprised the bulk of volume by weight (58% and 30% respectively), but only 33% and 21% respectively of the embodied carbon. It was found that glass (1% by weight, but 15% by embodied carbon) and steel (2% by weight, but 15% by embodied carbon) had an oversized contribution to the embodied carbon profile.
What the results of this research suggest for Landcom and our zero waste pathway is a need for:
- A demolition decision making framework that can identify key considerations to help maximise the reuse of construction materials. This would involve the use of a combination recycling, disposal, salvaging, re-use and sorting approach depending on the context of the existing structure;
- Partnerships and collaboration early on with waste management providers, demolition contractors and salvage operators to embed early action with any demolition project and build time and cost implications into the program; and
- Considered action around materials that Landcom uses in construction (e.g. designing for deconstruction) from a cost, reuse potential and embodied carbon perspective.
