Build-Under Cost Breakdown
Cost guides for Queenslander projects are hard to find. When we were budgeting ours, the best we could find online were vague estimates from builders who wanted a call before they’d give any figures. So here’s our actual breakdown.
All figures are in Australian dollars (AUD). Use the structure as a reference paired with your own current trade quotes. How the figures work →
Cost Reality Check
These figures are project-specific and should be treated as a practical reference point, not a quote. Your final cost will depend on engineering, site access, services, finishes, approvals and builder/trade availability.
Project scope
- 3-bedroom Queenslander, approximately 180m² footprint (upstairs)
- Enclosed habitable build-under of 112.5 m² (plus a newly built carport, carport loft and rear patio and the fully restored rear balcony)
- Coorparoo, inner Brisbane - reasonable access, no extreme constraints
- Owner-builder procurement, all trades contracted directly
Raise and subfloor
| Item | Cost |
|---|---|
| House raising (including temporary works) | $42,000 |
| Structural engineering (raise and subfloor design) | $6,500 |
| Subfloor framing and stumps | $18,000 |
| Subtotal | $66,500 |
The raise quote came in third-lowest of four we received. Cheapest isn’t always best with raisers - we went mid-range with a contractor who had strong references and had worked with our engineer before.
Slab
| Item | Cost |
|---|---|
| Earthworks and excavation | $8,400 |
| Termite barrier (physical, perimeter) | $3,200 |
| Slab formwork and steel | $14,500 |
| Concrete supply and pump | $11,800 |
| Subtotal | $37,900 |
We had a raft slab with deep edge beams designed. The engineer’s specification drove the cost - the site is shale rock with active ground and the reinforcing wasn’t cheap. For the full story see Why our 112.5 m² raft slab took over 20 m³ of concrete.
Framing
| Item | Cost |
|---|---|
| External wall framing (90mm stud) | $18,000 |
| Internal wall framing | $14,500 |
| Carport walls, roof and loft | $22,500 |
| Subtotal | $55,000 |
We used steel beams for the longer spans. It added cost upfront but simplified the framing and reduced future movement. The carport with loft storage was a late add to the scope - it cost $22,500 in framing alone, with the driveway counted separately in external works below.
Rough-in services
| Item | Cost |
|---|---|
| Electrical rough-in (ground floor + upgrade upstairs) | $8,500 |
| Plumbing rough-in (new bathroom, laundry, toilet) | $14,200 |
| Subtotal | $22,700 |
Electrical was the biggest variable. We took the opportunity to bring the upstairs wiring up to current standards at the same time - that added about $5,000 but was absolutely worth it.
External works
| Item | Cost |
|---|---|
| Windows and external doors (ground floor) | $16,000 |
| External cladding (weatherboards, painted) | $7,500 |
| Garage door | $3,400 |
| Driveway and front patio | $14,950 |
| Rear patio | $2,400 |
| Subtotal | $44,250 |
We saved a lot by buying secondhand windows. We used casement hardwood timber windows throughout the new ground floor - these we hand selected to match the upstairs windows.
Insulation and internal linings
| Item | Cost |
|---|---|
| Wall and ceiling insulation | $7,800 |
| Plasterboard supply and install | $22,000 |
| Subtotal | $29,800 |
Fit-out (ground floor)
| Item | Cost |
|---|---|
| Bathroom fit-out (tiles, fixtures, vanity) | $8,500 |
| Kitchen fit-out | $17,840 |
| Laundry fit-out | $3,200 |
| Flooring (polished concrete - ground floor) | $7,600 |
| Painting (ground floor, internal) | $4,800 |
| Electrical fit-off | $7,200 |
| Plumbing fit-off | $11,400 |
| Subtotal | $60,540 |
Permits and professional fees
| Item | Cost |
|---|---|
| Development approval (DA) | $4,200 |
| Building approval | $3,800 |
| Owner-builder permit | $420 |
| Building certifier (inspections) | $3,600 |
| Additional engineering (variations) | $2,800 |
| Subtotal | $14,820 |
Total build-under cost
| Category | Cost |
|---|---|
| Raise and subfloor | $66,500 |
| Slab | $37,900 |
| Framing | $55,000 |
| Rough-in services | $22,700 |
| External works | $44,250 |
| Insulation and internal linings | $29,800 |
| Fit-out (ground floor) | $60,540 |
| Permits and professional fees | $14,820 |
| Grand total | $331,510 |
Items that came in over initial estimates
Electrical (~$5,000 over). We underestimated the cost of the upstairs upgrade. Budget generously for electrical - it’s rarely cheaper than you hope.
Slab variation (~$2,200). The shale on this site varied in depth across the slab footprint. Where one corner went deeper than expected, the engineer specified additional reinforcing. Common slab risk on shale or active ground - budget a variation allowance whenever the geotech report flags variable subsurface conditions.
Where we saved
Owner-builder procurement. Managing the trades ourselves added time and stress, but it saved meaningful money compared to a builder’s margin. We estimate 33% off what a fixed-price contract would have been.
Timing our concreter. We booked three months in advance and got a better rate than the spot price at the time we poured.
Polished concrete instead of flooring. Fewer trades, no moisture barrier issues and genuinely good-looking.
Queenslander build-under costs: common questions
Based on the Coorparoo, Brisbane owner-builder project. Use the structure with your own current trade quotes.
How much does it cost to raise and build under a Queenslander in Brisbane?
Our Coorparoo project totalled $331,510 for a full build-under with 112.5 m² of enclosed habitable ground floor - covering raise and subfloor, slab, framing, services, external works, fit-out and permits. This was owner-builder procurement in inner Brisbane. Treat the breakdown as a structural reference, not a current market quote.
What is the most expensive part of a Queenslander build-under?
On our project the single biggest category was the raise and subfloor at $66,500, closely followed by fit-out at $60,540 and framing at $55,000. If your project includes a higher-spec fit-out or more complex site conditions, those figures will move.
How much does it cost to raise a Queenslander?
The raise itself cost $42,000 including temporary works. Add $6,500 for structural engineering and $18,000 for subfloor framing - $66,500 total for the raise and subfloor stage. Get a current quote rather than relying on this figure as a market estimate.
What were the biggest unplanned costs on this project?
Two items came in over their initial estimates - electrical (the upstairs upgrade added ~$5,000) and a slab variation where the shale went deeper than expected in one corner of the footprint (~$2,200 extra). Both came down to scope or site conditions revealed once work started. Budget a 15% contingency to absorb that kind of variation.
How much can I save as an owner-builder versus using a fixed-price contract?
We estimate 33% less than a comparable fixed-price contract, by avoiding builder's margin and managing trades directly. This saving is real, but it comes at a cost in time and personal legal exposure. Budget the saving in, but do not rely on it to make your project viable.
What is a realistic budget for a Queenslander build-under in Brisbane?
Our Coorparoo project came in at $331,510 for a full build-under with 112.5 m² of enclosed habitable ground floor and standard finishes, owner-builder procurement. Get current quotes from licensed builders or trades for your own scope before setting a budget figure.
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