Many Australian builders signed jobs at today’s prices, then watched steel, plastics, timber and diesel climb before they could finish the work. That gap between what was quoted and what it now costs to build is why construction insolvencies are likely to rise again, even as the country falls further behind on homes.
The warning comes from a quantity surveying firm, which argues many builders still price projects on current costs and ignore escalation across a typical delivery period of six to twelve months. Residential margins are thin, roughly 5 to 10 per cent. It does not take much of a cost shock to erase that.
Why fixed-price contracts are the pressure point
A fixed-price contract hands all the cost risk to the builder. If the price of inputs rises after signing, the builder absorbs it. One reported figure suggests 63 per cent of Victorian master builder members hold fixed-price contracts, which gives a sense of how widespread the exposure is.
The input list is long. Reported movements include:
- Steel duties of up to 82 per cent, with rebar duties lifted to the mid-20s per cent in May.
- Plastics up 27 to 36 per cent from April.
- Timber up 8.29 per cent year-to-date.
- Diesel up 41 per cent within a single month.
On a 5 to 10 per cent margin, a few of those hitting the same project can turn a profitable build into a loss. Here’s the catch: the damage often lands months after the contract was signed, so insolvencies tend to lag the cost shock rather than arrive alongside it.
Key numbers
- Residential builder margins: roughly 5 to 10 per cent
- RLB 2026 tender price growth forecast: 4 to 6 per cent across major cities
- Gap to the housing accord target: 94,980 homes
Tender prices say the squeeze is not over
Cost consultancy RLB forecasts tender price growth of 4 to 6 per cent across the major cities in 2026. National work in the pipeline sits at a record $324.8 billion. That is a lot of demand chasing the same trades, materials and machinery, which keeps upward pressure on costs.
So builders face costs rising while the contracts already signed are locked. New contracts can be priced higher, but existing ones cannot. The stress sits in the older, fixed-price jobs still being delivered.
Starts look healthy, but the cycle may be near its peak
June-quarter commencements reached 52,201 dwellings, which looks encouraging on its face. An urban economist cited in the coverage argues the cycle is near its peak, though. August approvals fell 6.1 per cent to 16,953, which is the more forward-looking number.
Approvals feed future starts. If approvals soften while builders are failing, completions slip further behind the housing accord target, with Australia trailing by 94,980 homes. For a closer look at how starts and the pipeline are tracking, see our piece on home building starts and the thinning pipeline.
The link to developer and credit risk
Builder failures do not stay inside the building industry. A developer whose builder collapses mid-project faces delays, replacement costs and, often, a revised budget that no longer fits the loan. That is a direct hit to project economics and to whoever funded it.
This is where private credit enters the picture. Lenders to development projects are exposed when cost blowouts erode the margin that supports repayment. Offshore capital has been moving into Australian property debt, as covered in our look at offshore funds backing a $1b property credit play. More capital in the sector is helpful for supply, but it also means more investors share the downside if builder failures rise.
Treat this as a rule of thumb: the thinner the margin and the longer the build, the more a project depends on cost assumptions staying put.
What happens to supply if failures climb
The mechanics are simple. A builder insolvency pauses or cancels projects, strips out trade capacity, and makes the survivors price in more risk. Each of those reduces how many homes get finished in a given year. With the country already well short of its accord target, there is little slack to absorb it.
None of this is certain. Builders can reprice new work, input prices can ease, and some firms will manage escalation better than others. The base case is more stress, not a collapse. The downside is a cluster of failures that hits completions at the worst time.
A practical next step
If you are buying off-the-plan or contracting a builder, check the contract type and whether it allows any price adjustment. Ask how the builder is funded and how long the project is meant to run. Longer, fixed-price jobs carry more risk of delay. If you want the weekly read on supply and credit, subscribe to the newsletter.
General info, not financial advice.
