Leanne Walkden
"Very happy with our new flat roof! Liam and the team were prompt, very clean and very good at what they do! I now have a roof that doesnt hold water! Thank you so much!"
Published UK figures · Checked 5 November 2026
Flat Roof Cost UK
(2026 Guide)
What a new or replacement flat roof costs in the UK, by system and by job, from the main price guides with each one named. Flat roofing is our specialism, and your own price comes after a free home visit.
Get Your Free Quote
Free home visit for garage, extension and dormer roofs.
How Much Does a Flat Roof Cost in the UK? The Short Answer
It depends which guide you read, and the gap is large. Checkatrade's replacement guide (its price table is dated December 2024, the page itself 2026) puts a standard flat roof replacement at £2,800 to £7,500. MyJobQuote, updated in October 2026, gives an average of £2,400 within a range of £1,500 to £6,000. The Federation of Master Builders (FMB), in March 2026, gives an average of £8,000.
None of them is wrong. They are pricing different roofs, and the section below on why the guides disagree explains how. These are published figures, not our prices.
Every figure here names its source and was checked on 5 November 2026. We have not averaged them. They are answering different questions.
Want a Figure for Your Flat Roof?
We measure up, check the deck and price it on a free visit.
Flat Roof Cost per m² by System
The three guides that price by area agree on the order: felt is cheapest, EPDM rubber sits in the middle and GRP fibreglass costs most of the three. They disagree on the numbers and on what they include, so here they are side by side, installed per square metre.
| System, per m² | Checkatrade (table 12/24) | MyJobQuote (10/26) | BookaBuilderUK (04/26) |
|---|---|---|---|
| Felt | £50-£80 | £80-£120 (3-layer) | £60-£100 |
| EPDM rubber | £80-£100 | £110-£160 (listed as rubber) | £80-£120 |
| GRP fibreglass | £95-£120 | £120-£180 | £100-£160 |
| Asphalt | £50-£70 | £60-£90 | Not listed |
| Green roof | £75-£110 | About £150 | Not listed |
| Lead | Not listed | £250-£350 | Not listed |
| Liquid plastic coating | £20-£28 | Not listed | Not listed |
Checkatrade's column is marked plus VAT; the other two columns are installed prices.
Checkatrade also gives £50 to £110 per m² for a standard flat roof and £3,000 to £4,500 to convert a flat roof to a pitched one.
Felt is torch-applied in layers and is usually the cost-effective route on smaller roofs. GRP goes on as a liquid over a prepared deck and cures into one continuous skin with no joints. EPDM is a synthetic rubber membrane laid in sheets.
We fit GRP and felt. EPDM is in the table because the guides price it and you may be quoted for it elsewhere, so it helps to see where it sits.
Flat Roof Cost by Job
Most people are not pricing square metres, they are pricing a garage or an extension. MyJobQuote works through a single garage of about 15 m² by system.
| Single garage, about 15 m² | Typical UK range |
|---|---|
| Asphalt | £900-£1,350 |
| Felt | £1,200-£1,800 |
| Rubber (EPDM) | £1,650-£2,400 |
| GRP fibreglass | £1,800-£2,700 |
| Lead | £3,750-£5,250 |
| Other jobs | Typical UK range |
|---|---|
| Shed | £200-£420 |
| Porch | £400-£1,200 |
| Bay window (about 4 m²) | £450-£970 |
| Extension roof | £800-£3,500 |
| Dormer | £900-£1,800 |
FMB prices by area instead, for a full replacement from the deck up.
| Roof area | Typical UK range |
|---|---|
| 20 m² | £2,800-£3,600 |
| 30 m² | £4,200-£5,400 |
| 50 m² | £7,000-£9,000 |
| 70 m² | £9,800-£12,600 |
Why Published Guides Disagree
FMB describes a full build-up: the deck, a vapour control layer, insulation, a cover board, the membrane, then trims and gutters. Its size bands start at 20 m² and run to 70 m². MyJobQuote spends most of its guide on smaller jobs such as sheds, porches, garages and dormers. One is pricing a whole new roof system on a big extension, the other is often pricing a new covering on a garage.
That is why two quotes for what sounds like the same job can be thousands apart. Ask any roofer for a written list of what is included and what is not. If one quote has new decking and insulation and the other does not, they are not quoting for the same roof.
What Changes the Price
Size. The biggest single factor, which is why every guide prices by area or by job type.
The deck. If the boards under the covering have gone soft, they need replacing first. Covering over a rotten deck is how flat roofs fail early, and it is where our own carpenters come in before the new covering goes on.
Insulation. FMB gives insulation boards from £25 per m². BookaBuilderUK gives £40 to £100 per m² for an insulation upgrade. The spread is the difference between a board and a full warm-roof upgrade.
Falls, outlets and edges. A roof that holds water needs its falls corrected, and outlets and edge trims are part of the job. Rooflights and lanterns add to it.
Access and waste. FMB gives about £400 a day for scaffolding and a six-yard skip from £160. BookaBuilderUK gives £500 to £1,500 for scaffolding on small and mid-sized jobs, £2,500 and up for complex ones, and £150 to £400 for waste.
Labour and location. MyJobQuote gives £250 to £350 a day, or £35 to £45 an hour, usually for a team of two, and notes rates are higher in London and the South East.
Repair or Replace?
Plenty of flat roofs do not need replacing. A split, a failed joint or a blister can often be repaired properly. MyJobQuote's roof repair guide puts a flat roof patch at £200 to £700, and Checkatrade's Essex page puts the average flat roof repair at £1,000, ranging from £592 to £1,705.
If a repair is all your roof needs, we say so and do the repair. If the covering is finished, we tell you that and quote for a replacement. For the wider picture on pitched roofs too, see our guide to roof repair costs, and for repairs we carry out see repairs on pitched and flat roofs.
Flat Roof Costs in Essex
Checkatrade's page for flat roof installers in Essex gives county figures. They are undated, and they come in lower than its national replacement range, so read them as a guide to typical Essex jobs rather than a fixed price.
| Essex job | Average | Range |
|---|---|---|
| Flat roof installation | £2,013 | £1,414-£2,893 |
| Felt flat roof | £1,453 | £972-£2,182 |
| Rubber flat roof | £2,181 | £1,595-£3,027 |
| Fibreglass (GRP) flat roof | £2,924 | £1,903-£4,521 |
| Flat roof insulation | £2,052 | £1,400-£3,022 |
| Flat roof repair | £1,000 | £592-£1,705 |
We are based in Chelmsford and take flat roof jobs within a 50-mile radius. Our Chelmsford roofing team covers the city, and we also take work further out in Essex and into London.
How Our Free Home Visit and Quote Work
Call or message us with what the flat roof is doing and where it is. On the free home visit we look at the falls, the outlets and the joints, and check the deck where we can, before recommending anything.
Tell us your budget and we will recommend felt or GRP honestly, not whichever is pricier. You get a free written quotation with no obligation. The detail on both systems is on our page about GRP and felt flat roofs in Chelmsford.
What Customers Say
From a customer with a new flat roof, in her own words.
Where These Figures Come From
Each guide was read on 5 November 2026. Guides change through the year, so use them to judge a quote and use the quote after a home visit as the real number.
- Checkatrade, Flat roof replacement costs in 2026, price table last updated December 2024.
- FMB, Flat roof replacement cost guide for UK homeowners, March 2026.
- MyJobQuote, How much does a flat roof replacement cost in the UK? (2026), last updated 20 October 2026.
- MyJobQuote, How much do roof repairs cost? (UK), last updated 6 October 2026.
- BookaBuilderUK, Cost to replace a flat roof UK 2026, April 2026.
- Checkatrade, Flat roof installers in Essex (undated).
Flat Roof Cost FAQs
How much does a flat roof cost in the UK?
Checkatrade puts a standard flat roof replacement at £2,800 to £7,500. MyJobQuote gives an average of £2,400, and FMB an average of £8,000 across its sizes. The size of the roof, the system and the access decide where yours lands.
How much does a garage flat roof cost?
MyJobQuote prices a single garage of about 15 m² at £1,200 to £1,800 in felt and £1,800 to £2,700 in GRP. Its asphalt range starts at about £900 and its lead range reaches £5,250.
Which is cheaper, felt or GRP?
The guides put felt lower per square metre. Checkatrade gives £50 to £80 for felt against £95 to £120 for GRP, and MyJobQuote gives £80 to £120 against £120 to £180. We recommend a system on the visit based on the falls, the size and your budget.
Is it better to repair or replace a flat roof?
If a repair will hold, we say so and do the repair. If the covering is finished, we tell you and quote for a replacement. For reference, Checkatrade's Essex page puts the average flat roof repair at £1,000.
Is the quote free?
Yes. The home visit and the written quote are both free, with no obligation to go ahead.