The four tests
Before committing to a Queenslander renovation, work through four tests in this order.
- Project envelope. What is your maximum total spend including a 15-20% contingency? Not your loan limit. Your spend ceiling.
- Cash flow. Trades invoice mid-project. Can you fund the gap between progress payments and finance drawdowns?
- Decision capacity. Are you in a life stage where you can absorb 12-18 months of weekly project decisions?
- Exit ramp. What does it cost to stop the project mid-build if life intervenes? Trades, securing the site, insurance.
What the Coorparoo project cost as a benchmark
The Coorparoo build-under cost $331,510 over 2018-2020. Brisbane construction rates have risen since, so treat that figure as a directional reference and re-quote against current rates. See the full breakdown.
The hidden costs people miss
- Engineering variations during the build (budget 5-10% of structural scope)
- Council fees, certifier inspection callouts, owner-builder course and permit
- Temporary accommodation if you can't live on site
- Site security and weatherproofing while structure is exposed
- Furniture, curtains and external works that often fall outside the build budget
Realistic owner-builder savings
Owner-building typically cuts total project cost by roughly 33% against a fixed-price builder contract, because it removes the builder's margin. That saving is real, but it costs you time, admin and project risk. Read the owner-builder reality.
Tools
Model your project against the Coorparoo ratios with the budgeting tools, then run the readiness framework before you commit.
