Renovation cost blowouts are back in the news. realestate.com.au reports that Victorians planning a renovation may need an extra $20,000 buffer on top of what they expect to spend, a warning aimed at homeowners but one every builder and tradie should read closely. When the property press starts telling your clients to pad their budgets, it changes the conversation you walk into. The homeowner sitting across the kitchen bench has already been told your quote will probably be wrong.
That is the real story here, and it cuts both ways. A client who expects overruns is easier to talk to about honest allowances. A client who expects overruns is also primed to blame you when they happen.
Why renovation cost blowouts keep happening
The buffer warning is not a mystery to anyone on the tools. Renovation work carries risk that new builds mostly do not:
- You cannot see behind the wall. Rot in the frame, dodgy old wiring, plumbing that was never to code, asbestos sheeting where the plans say plaster. Nobody prices what nobody can see.
- Material prices moved and stayed moved. Construction input costs climbed steeply from 2020 and have settled at a permanently higher level rather than falling back. The ABS producer price indexes track this quarter by quarter, and a quote priced off last year's supplier list is a quote priced wrong.
- Scope creep. "While you're here, could you just…" is where reno margins go to die if it is not written up as a variation.
- Provisional sums treated as guesses. A PC item for tapware based on nothing, a provisional sum for excavation plucked from the air. When they blow out, the client hears "blowout" even though the contract said "estimate" all along.
In Victoria this all sits inside the domestic building contract rules, which control deposits, variations and how cost estimates must be presented. If you work on renos there, the exact current requirements are on the Consumer Affairs Victoria site and they are worth rereading before your next contract, not after your next dispute.
The builder's move: make the buffer visible before the client does
The wrong response to this story is quoting lower to win the job and making it up on variations. That is how you end up as the case study in next year's blowout article.
The better response is to put the buffer in the quote where everyone can see it:
- Price the knowns tight, name the unknowns. Separate firm-priced work from provisional sums, and put a realistic number on each provisional item with a one-line note on what would move it. "Restumping allowance $X, confirmed after subfloor inspection" reads as professional. Silence reads as a trap.
- Quote GST-inclusive totals for homeowners. A reno client comparing your ex-GST number against someone else's inclusive number will draw the wrong conclusion, and not in your favour.
- Variations in writing, priced before the work, signed before the saw comes out. Every time. The five minutes it takes protects the relationship as much as the margin.
- Requote anything older than 30 days. Supplier pricing does not sit still, so your quotes cannot either.
None of this is new advice. What is new is that your clients are being told to expect a five-figure buffer, which means the builder who shows exactly where the risk sits and what it costs is now the one who looks trustworthy, not expensive.
Tighten the admin so the numbers hold
Most blowouts are not bad luck, they are bad paperwork: a take-off done on the back of a delivery docket, a variation agreed on-site and never invoiced, an allowance nobody rechecked. The fix is boring and it works. Do proper take-offs, keep quotes, variations and job records in one place, and check quantities with real numbers instead of gut feel, whether that is a concrete bags calculator for a slab pour or a full estimate. If you are still running jobs from a spreadsheet, it is worth seeing what dedicated tools do now. We have written up the best construction estimating software in Australia and the best construction project management software if you want the lay of the land.
The buffer headlines will keep coming while costs stay high. Builders who quote in the open, paper their variations and keep their numbers current will not just avoid the blowout stories. They will win the jobs from the builders who star in them.
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