Material waste is eroding profitability in home building, and the numbers are bigger than anyone expected.
Australia’s construction sector is heading toward a material waste crisis of unprecedented scale. A new industry report estimates that over the next five years, the sector could discard up to $64 billion worth of unused building materials. The majority of this will come from residential construction.
The Australia’s Waste[d] Opportunity 2025 report, led by circular economy specialists Coreo in partnership with the Green Building Council of Australia, reveals that the average home build in Australia wastes roughly 22 per cent of its material inputs. For the average 250 square metre detached home, that’s over $19,000 in materials sent to landfill, offcuts skipped without reuse, or product damaged before installation.
The cost isn’t just environmental. It is commercial. For builders managing tighter margins, increased compliance, and labour pressure, this is waste they can no longer afford to ignore.
Everyday waste, multiplied by millions
While the benchmarking project drew much of its data from commercial and mixed-use sites, the lessons translate directly to residential construction.
Over-ordering remains the primary driver. Most builders apply a buffer of 5 to 10 per cent on material orders to reduce risk of delay. However, this margin regularly goes unused and unsalvaged. Combined with damaged product, changes during construction, or lack of on-site reuse, it becomes a hidden line item undermining profitability.
When extrapolated across Australia’s housing targets — including the 1.2 million new homes planned by 2029 — the report estimates that material waste could cost the sector between $29 billion and $64 billion.
What’s being wasted?
The report identifies the most commonly wasted materials by volume and cost. Topping the list are mixed concrete and masonry, followed by timber, soil and rubble fines, insulation, cardboard, plastic and plasterboard.
In the average new build, over 140 kilograms of material is wasted per square metre. Put another way, for every square metre of new home delivered, builders are effectively throwing away the equivalent weight of a fully-stocked household fridge.
For a 250 square metre family home, this equates to around 35 tonnes of waste materials. Much of it was paid for, transported, and stored before ever being used.
The illusion of recycling
Builders are often reassured that their site waste is being recycled. However, the report challenges that assumption, pointing out that industry-standard waste reporting only measures what is collected for recycling — not what is actually repurposed or reused.
In reality, a significant proportion of materials placed in skip bins are not recycled in a meaningful way. Plastics, for example, can only be mechanically recycled a limited number of times before their value degrades. Many mixed-material loads are ultimately incinerated in waste-to-energy facilities, a process that generates emissions but is still counted toward landfill diversion statistics.
This creates a false sense of circularity. While 90 per cent diversion from landfill may sound impressive on a sustainability report, it does little to solve the underlying issue: materials are being ordered, wasted and lost from the value chain altogether.
What residential builders can do
There are practical steps that small to mid-size home builders can take immediately to reduce waste, improve efficiency, and retain more value on every build.
Track waste by square metre
Move away from vague diversion rates and begin measuring waste in kilograms per square metre. This allows for project comparisons and identifies where excess is occurring. The Green Building Council of Australia provides a free Building Materials Reporting Tool that can help.
Set clear waste allowances
Start with your estimating team. Instead of applying generic ordering buffers, assess actual usage by material category. Over time, this reduces unnecessary product on site and reduces the temptation to dump excess.
Reclaim and store offcuts
Establish a clean, covered storage zone for leftover bricks, sheeting, timber and fastenings. These can be redeployed in future projects, especially in similar builds, or offered to subcontractors for finish work.
Review supplier agreements
Engage with suppliers to create tighter delivery windows or order in smaller batches. For example, if you’re consistently discarding half-packs of plasterboard, rework your volumes and request pack splits.
Train supervisors and trades on material handling
Site damage is a major contributor to waste. Education and basic process improvements can significantly reduce discarded product. Pair this with clear signage and reinforcement at toolbox talks.
Tell the story in your marketing
Clients are increasingly aware of waste and sustainability. Builders who can confidently say they are reducing waste and actively reusing materials can stand out in tenders and sales conversations.
The business case for action
Cutting waste is no longer just a sustainability goal — it is a commercial strategy. As interest rates tighten, clients expect more value, and builders look to protect margins, waste presents one of the most immediate opportunities for bottom-line improvement.
It also aligns with evolving government regulation. By 2027, Green Star will require more detailed waste reporting on new projects. Builders who start improving their systems now will be better prepared — and better positioned — when those requirements arrive.
While the $64 billion figure may feel abstract, the day-to-day reality is not. This is offcut timber on the skip. It is gyprock broken in transport. It is pallets of bricks left over at frame stage. And it is money walking off site with the bin truck.
In a time when efficiency matters more than ever, reducing waste is no longer a nice-to-have. It is a competitive advantage.
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