2026 Price Guide
Flat Roof Replacement Cost in 2026: EPDM, GRP and Felt Prices
Most UK flat roof replacements cost £2,800 to £7,500 in 2026, with a single garage roof from about £1,000.
A flat roof replacement costs £2,800 to £7,500 for most UK homes in 2026, or £60 to £150 per m² fitted. A single garage costs £1,000 to £2,400, a double garage £2,000 to £4,500 and an EPDM rubber roof £80 to £130 per m². Felt is the cheapest system and GRP fibreglass the dearest.
Four things set the price of a flat roof: its size in square metres, the system you choose, what the old covering has done to the deck underneath, and whether the roof sits over a heated room. A garage re-cover on sound timbers is the cheapest job. An extension roof that needs new boards, a warm roof insulation upgrade and new trims is the dearest. Access, rooflights and gutters add to the bill, and the state of the deck only shows once a roofer is up there.
Flat roof cost per m² by material
| Material | Guide price per m² (fitted) | Lifespan |
|---|---|---|
| Torch-on felt (3-layer) | £60-£100 | 15-25 years |
| EPDM rubber | £80-£130 | 25-50 years |
| GRP fibreglass | £95-£150 | 20-30 years |
| Mastic asphalt | £50-£90 | 20-30 years |
| Lead | £150-£300 | 80+ years |
| Liquid waterproof coating (sound roofs only) | £20-£28 | Extends an existing roof |
Fitted prices including labour. Checkatrade lists its figures before VAT. Lead and asphalt are less common on homes and are shown for comparison.
Free survey, fixed written quote within 48 hours, no obligation.
Garage and extension flat roof costs by material
| Roof (approx. size) | Torch-on felt | EPDM rubber | GRP fibreglass |
|---|---|---|---|
| Single garage (15m²) | £1,000-£1,600 | £1,200-£2,000 | £1,400-£2,400 |
| Double garage (30m²) | £2,000-£3,200 | £2,400-£3,800 | £2,800-£4,500 |
| Single-storey extension (20m²) | £2,400-£3,200 | £2,800-£3,600 | £3,000-£4,200 |
Garage prices are for an unheated garage on sound timbers. The extension row is a roof over a heated room: check the quote includes insulation, which adds £30 to £60 per m² when it is priced separately.
Flat roof replacement cost by roof type
| Roof | Time on site | Guide price |
|---|---|---|
| Porch or bay roof | 1-2 days | £500-£1,500 |
| Dormer roof | 1-2 days | £1,200-£2,500 |
| Single garage | 1-2 days | £1,000-£2,400 |
| Double garage | 2-3 days | £2,000-£4,500 |
| Single-storey extension (20m²) | 2-3 days | £2,400-£4,200 |
| Larger extension (30-50m²) | 3 days to a week | £4,200-£9,000 |
| Large flat roof (70m²) | About a week | £9,800-£12,600 |
Times are days on site for a two-person team once the job starts. GRP adds time for curing.
Guide prices compiled from 2026 UK sources: Checkatrade: Flat roof replacement costs, MyBuilder: Flat roof replacement costs, MyJobQuote: Flat roof replacement cost, FMB: Flat roof replacement cost guide, Planning Portal: Work to an existing roof. Your fixed quote follows a free survey of your property.
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- Free survey and fixed written quote
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EPDM vs GRP vs felt: cost, lifespan and best use
Three systems cover almost every domestic flat roof in the UK. Pick by the room below and how long you plan to stay.
- Torch-on felt, £60 to £100 per m². Three layers of bitumen felt torched together and finished with a mineral cap sheet. The lowest fitted price and the easiest to patch, with 15 to 25 years from a modern system. Best for garages and porches.
- EPDM rubber, £80 to £130 per m². One sheet of synthetic rubber with no seams across the main roof. It flexes with temperature changes, stands up to UV and lasts 25 to 50 years. It only comes in black. Best for extensions, garages and dormers.
- GRP fibreglass, £95 to £150 per m². Resin and glass matting laid wet and cured into one hard shell with no joints, in a choice of colours. Lasts 20 to 30 years and needs dry weather to lay. Best for extensions where the finish is on show.
Over its life, EPDM is the cheapest per year.
Repair or replace your flat roof?
A small split, a lifted edge or one leaking seam is a repair, not a new roof. Patch repairs cost £150 to £500 depending on the material: felt is the cheapest to patch and GRP the dearest. Repair makes sense when the deck underneath is dry and solid and the problem is in one place.
Replace when leaks keep coming back after repairs, when water pools across the roof, when the deck feels soft underfoot, or when the covering is near the end of its life. At that point each repair buys months, not years, and the money is better spent on a new roof with a new guarantee. Get the roof surveyed before you pay for either: a roofer who walks the deck and checks inside for damp can tell you which one you need. We quote the repair when a repair will do. Our roof repair cost guide lists more repair prices.
Signs your flat roof needs replacing
Look at your flat roof after heavy rain and check for these:
- Water still pooling on the surface a day or two after rain
- Splits, cracks, blisters or bubbles across the covering
- Flashings or edge trims pulling away from walls and upstands
- Damp patches, water stains or mould on the ceiling below
- A soft, spongy or sagging deck
- A covering past its expected life: 15 to 25 years for felt, 20 to 30 for GRP
One sign on its own often means a repair. Two or three together, or any sign of a soft deck, point to a replacement, because the boards underneath have taken on water. Leave it and the damage spreads into the joists and the ceiling, which turns a re-cover into a rebuild.
Warm roof insulation and Building Regulations
In England, re-covering more than half of a roof, or more than a quarter of the whole building envelope, needs Building Regulations approval, and the roof is then usually brought up to current insulation standards. A flat roof over an unheated garage or outbuilding does not need insulating. One over a kitchen, bedroom or extension does.
The standard way to meet the rules on a replacement is a warm roof: a vapour control layer on the deck, rigid PIR insulation boards above it, then the waterproof covering on top. The insulation keeps the timbers on the warm side, which stops condensation forming inside the roof. Budget £30 to £60 per m² on top of the covering if the quote leaves it out. Turning a cold roof into a warm roof means stripping back to the deck, and the extra depth means trims, fascias and gutters are reset at the same time. A roofer outside a competent person scheme has to notify building control, and you pay the inspection fee.
How to compare flat roof quotes
Two quotes for the same roof can sit thousands of pounds apart because they price different jobs. Ask for an itemised quote and check each one covers:
- Stripping the old covering and taking the waste away (a skip alone costs £160 to £300)
- Replacing rotten deck boards, and the rate for any found once the roof is open
- Insulation, vapour control layer and firrings to create the fall
- Edge trims, upstands, flashings, gutters and outlets
- Scaffolding or edge protection (£800 to £1,200 if you hire it separately)
- Building control sign-off where the job needs it
- The guarantee, in writing, with its length stated
Labour runs £200 to £350 per roofer per day and most flat roofs are laid by a team of two, so the days on site matter as much as the materials. Get three quotes and keep 10% to 15% aside for anything found under the old covering.
How long a flat roof replacement takes
Most domestic flat roofs are replaced in one to three days. Stripping the old covering takes about half a day, and a single garage in felt or EPDM is done in a day. A double garage or extension takes two to three days, and a large roof up to a week. GRP takes longer than felt or EPDM because the resin has to cure.
Weather sets the timetable more than the calendar. EPDM adhesive will not bond below about 5°C and GRP needs dry conditions to cure, while torch-on felt copes best with the cold. A winter replacement is fine with the right system and a dry spell. Roofers are busiest through summer, so booking your survey in autumn or early spring gives you a wider choice of start dates.
What’s included in an Arkenstone quote
- Free survey with photographs of your roof, no call-out charge
- Fixed written quote within 48 hours, valid for 30 days
- Proper falls so water drains off the roof
- Insulation upgrades and firrings where the regulations require them
- Trims, edges, fascias and guttering tied in to the new roof
- Rooflights set in with EPDM, GRP or felt detailing
- 20-year written workmanship guarantee
What changes the price
- Roof size in square metres and its shape
- The system: felt, EPDM rubber or GRP fibreglass
- The condition of the deck and joists under the old covering
- Insulation needed to meet Building Regulations over a heated room
- Access, scaffolding and edge protection
- Rooflights, upstands, flashings and gutters
Flat roof costs in Peterborough, Lincolnshire and Bath
Our own crews lay EPDM, GRP and felt flat roofs across Peterborough and Cambridgeshire, Spalding and Lincolnshire and Bath and the South West, including Stamford, King’s Lynn, Spalding and Lincoln. Every price starts with a free survey and photographs of your roof, then a fixed written quote within 48 hours, valid for 30 days. Charles Stevens, the owner, calls you back the same day. See our flat roofing page for the systems we fit, and skylights for rooflights set into a new flat roof.
Flat roof cost, your questions answered
How much does a new flat roof cost?
A new flat roof costs £2,800 to £7,500 for most UK homes in 2026, which works out at £60 to £150 per m² fitted. Felt sits at the bottom of that range, EPDM rubber in the middle and GRP fibreglass at the top. A small porch or bay roof starts from about £500, while a large 70m² flat roof costs £9,800 to £12,600.
How much does an EPDM roof cost?
An EPDM rubber roof costs £80 to £130 per m² fitted. That puts a single garage at £1,200 to £2,000, a double garage at £2,400 to £3,800 and a 20m² extension roof at £2,800 to £3,600. EPDM lasts 25 to 50 years, which makes it the lowest cost per year of the three main flat roof systems.
How much does a garage roof replacement cost?
A single garage flat roof of about 15m² costs £1,000 to £2,400 to replace, and a double garage of about 30m² costs £2,000 to £4,500. Felt is the cheapest option and GRP the dearest. An unheated garage does not need insulating, which keeps the price down. Rotten deck boards add to the bill, and roofs built before 2000 can contain asbestos, which needs a licensed specialist.
Do I need Building Regulations approval to replace a flat roof?
In England you need Building Regulations approval if the work covers more than half of the roof or more than a quarter of the whole building envelope, and the roof then has to meet current insulation standards. On a flat roof that means a warm roof build-up. A flat roof over an unheated garage does not need insulating unless the structure changes.
How long does a flat roof last?
Torch-on felt lasts 15 to 25 years, GRP fibreglass 20 to 30 years and EPDM rubber 25 to 50 years. Mastic asphalt lasts 20 to 30 years and lead outlasts all of them. Workmanship matters as much as the material: poor falls, weak upstands and badly sealed edges cut any system's life short, so get the guarantee in writing.
Is it cheaper to repair or replace a flat roof?
A patch repair costs £150 to £500, so repair is cheaper when the damage is in one place and the deck underneath is dry and solid. Once leaks keep coming back, water pools across the surface or the deck feels soft, replacement is the better buy, because each further repair only delays the job while the damage spreads into the timbers below.
Get a fixed written quote
Speak directly to the team. Honest advice, fixed written quotes, and a 20-year guarantee on every job.