Tile to Colorbond re-roof: a full worked cost example with every line item
An illustrative line-by-line cost build-up for replacing a concrete tile roof with pre-painted steel on an Australian house, including GST, deposit, insurance and finance.
This worked example builds up an illustrative quote for replacing a 40-year-old concrete tile roof with pre-painted steel on a single-storey house, line by line. The total comes to about $31,870 including GST, or roughly $150 per m² of roof surface once gutters and fixed costs are included, within the site's illustrative tile-to-steel range of $90–$160 per m² before gutters. The point is not the final number, which will differ for your house, but the method: measure, list every item, check which ones a real quote leaves out, then apply your state's deposit cap and home warranty threshold.
This guide is part of the roof replacement quote checklist. All prices are illustrative examples, not quotes or market rates.
The house
- Single-storey brick veneer, built 1985, in a suburban area
- Hip roof, concrete tiles, no sarking, a few leaks at the valleys
- Footprint including 600 mm eaves: 18.2 m × 10.8 m = 196.6 m²
- Pitch 22.5°, pitch factor 1.082
- Roof surface: 196.6 × 1.082 = 212.7 m², rounded to 213 m²
- Eaves gutter length: 2 × (18.2 + 10.8) = 58 m
- Four downpipes
- Site: not bushfire-prone, wind classification N2
- No asbestos found on testing of the eaves linings
See measuring roof area for the method.
Line-by-line build-up (illustrative)
| # | Item | Quantity | Illustrative rate | Amount |
|---|---|---|---|---|
| 1 | Strip and dispose of concrete tiles and old ridge capping | 213 m² | $18 per m² | $3,834 |
| 2 | Remove tile battens, supply and fix steel roof battens | 213 m² | $14 per m² | $2,982 |
| 3 | Supply and install insulation blanket with reflective facing | 213 m² | $12 per m² | $2,556 |
| 4 | Supply and install pre-painted steel roof sheets and fixings | 213 m² | $48 per m² | $10,224 |
| 5 | Ridge and hip capping, valleys, wall and penetration flashings | Lump sum | — | $2,400 |
| 6 | New quad gutters | 58 m | $45 per m | $2,610 |
| 7 | New downpipes and connection to existing stormwater | 4 | $280 each | $1,120 |
| 8 | Edge protection hire, installation and removal | Lump sum | — | $1,900 |
| 9 | Skip bins and tip fees | Lump sum | — | $900 |
| 10 | Compliance documentation and administration | Lump sum | — | $450 |
| Subtotal excluding GST | $28,976 | |||
| GST at 10% | $2,897.60 | |||
| Total including GST | $31,873.60 |
Roof-area items (lines 1 to 4) total $3,834 + $2,982 + $2,556 + $10,224 = $19,596 excluding GST, or $92 per m². Including GST that is $21,555.60, or about $101 per m². The full job including gutters, downpipes and fixed items is $31,873.60 ÷ 213 = about $150 per m².
What a real quote often leaves out
Compare your quotes with this list. Common omissions:
- Battens (line 2): some quotes assume the tile battens can be reused. Tile battens are often spaced for tiles, not for steel; ask.
- Blanket or sarking (line 3): leaving it out can save a few thousand dollars and cost comfort, condensation control and noise.
- Gutters and downpipes (lines 6 and 7): sometimes quoted separately or excluded.
- Edge protection (line 8): required for safe work at height; a quote without it should be questioned.
- Rot allowance: our example has none; a real job may find rotten fascia or rafter ends. Ask for a unit rate in advance, for example per lineal metre of fascia.
Enter 213 m² and your own rates in the re-roof cost estimator to see how far each assumption moves the range.
Applying the rules to this example
Licence. At over $31,000 the job is above every state's licensing threshold. See licence thresholds by state.
Home warranty insurance. The job is over $20,000 in NSW and Victoria (Home Warranty for contracts from 1 July 2026), over $3,300 in Queensland, and over $20,000 in WA if a building permit is needed. See home warranty insurance thresholds.
Maximum deposit, using the deposit limit check:
| State | Cap | Maximum deposit on $31,873.60 |
|---|---|---|
| NSW | 10% | $3,187.36 |
| Victoria (contract price $20,000 or more) | 5% | $1,593.68 |
| Queensland ($20,000 or more) | 5% | $1,593.68 |
| WA (Home Building Contracts Act) | 6.5% | $2,071.78 |
Progress payments. A sensible schedule for this job might be: deposit within the cap; a payment when the tiles are removed and battens and blanket are installed; a payment when sheets and flashings are complete; and the final payment after gutters, downpipes, clean-up and your inspection. See deposits, progress payments and contract terms.
If you finance it
Borrowing $28,000 of the total over 5 years at an illustrative 11.5% a year with a $250 fee gives a repayment of about $616 a month and total interest of about $8,950 (roof finance calculator). Interest can add more than a quarter to the price, so compare options in paying for a new roof.
Sensitivity: what moves the total most
| Change | Effect on this example (illustrative) |
|---|---|
| Keep existing gutters | −$3,730 + GST |
| Two-storey house needing scaffold instead of edge protection | +$3,000 to +$6,000 |
| BAL-29 ember sealing and non-combustible sarking | +$2,000 to +$4,000 |
| Asbestos eaves removal | +$1,500 to +$4,000 |
| Rotten fascia replaced, 20 m at $60 per m | +$1,200 + GST |
Frequently asked questions
Is $150 per m² expensive?
It depends on what is included. Our $150 includes gutters, downpipes and all fixed costs. A quote that shows $110 per m² may exclude those. Compare totals for the same scope.
Why is the steel itself only about half the cost?
Labour, removal, battens, flashings, safety and disposal make up much of a re-roof. That is why two quotes using the same steel can differ a lot.
Can I save by buying materials myself?
Possibly, but it complicates warranties, responsibility for defects and insurance thresholds. Most homeowners leave supply with the contractor.
Should GST be on top?
Quotes to consumers should make clear whether GST is included. Check the deposit and threshold calculations against the GST-inclusive total.
Sources
- Queensland Building and Construction Commission — deposit caps and home warranty for Queensland
- NSW Government building and renovating — NSW deposit cap and contract requirements
- Building and Plumbing Commission Victoria — roofing plumbing compliance and Home Warranty insurance
- Australian Taxation Office — GST basics for consumers and businesses
