In short
Checkatrade's 2026 guide puts a standard flat roof replacement between £2,800 and £7,500, or roughly £75 per square metre, with felt averaging £65, EPDM rubber £90 and GRP fibreglass £107.50 per square metre plus VAT. The size of the roof and the covering set the base price; stripping the old roof, replacing rotten decking, insulation and scaffolding are on top. We quote after seeing the roof, because the deck underneath is what moves the price.
This is a job for our Flat roofing service.
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The published figures
The numbers below are Checkatrade's, from their flat roof replacement cost guide updated for 2026. They are national averages before VAT and they are a starting point, not a quote.
| Covering | Checkatrade range per m² | Checkatrade average per m² |
|---|---|---|
| Torch-on felt | £50 to £80 | £65 |
| EPDM rubber | £80 to £100 | £90 |
| GRP fibreglass | £95 to £120 | £107.50 |
| Standard flat roof, all types | £50 to £110 | £75 |
The same guide gives a whole-job range of £2,800 to £7,500 for a standard replacement. The gap between those two numbers is the size of the roof and everything that is not the covering.
What moves the price on a real roof
- The deck. This is the one nobody can price from the ground. If the boards under old felt are soft, they are replaced, and on a roof that has leaked for years that can be most of them.
- Stripping the old covering. Checkatrade lists removal of the existing roof as a separate cost, and so do we. Three layers of old felt and chippings is a skip on its own.
- Insulation. Planning Portal's guidance on re-roofing says the work to re-cover a roof should also include improving its thermal insulation, and a cold flat roof on a 1970s extension usually has none. Adding a warm-roof board raises the price and the roof height.
- Details. Every rooflight, outlet, pipe and wall abutment is trimmed by hand. A plain garage roof is quick; a kitchen extension with two rooflights and a parapet is not.
- Access. A single-storey back addition is reached off a ladder or tower. A flat roof over a two-storey side extension needs a scaffold.
Which covering is worth the extra
Felt is the cheapest to lay and the shortest-lived, and it is a flame job on your house. EPDM costs more per metre but goes down as one sheet with adhesive, no flame, and Elevate quote a life expectancy of over 50 years for the RubberCover membrane we use. GRP is the dearest of the three and gives a hard, walkable surface with no joints, which is what we recommend where the roof doubles as a balcony or gets walked on for window cleaning. Cure It's GRP system carries a 20-year materials guarantee from the manufacturer. On a roof you expect to keep for decades, the difference between felt and rubber is a small part of the whole job.
Our price for your roof comes after we have seen it. We measure it, look at the deck from below if there is a ceiling stain, and quote the strip, the deck, the insulation and the covering as separate lines so you can see where the money goes.
