Read this when quotes arrive and do not match. It gives the published range, explains what moves a flat roof price up or down, and shows how to compare quotes by what they cover rather than by the total alone.
Two flat roofs of the same size can be priced a long way apart, and neither quote has to be wrong. The covering differs, the deck beneath may need work, the edges may be simple or complicated, and some quotes include things others leave out. That is why a homeowner gathering prices for a flat roof in Thanet can end up holding figures that cannot be compared.
Every price on this page is a national typical range, credited to its cost guide and month, and none is a quote of ours. Which? and HomeBuilding each warn that London and the South East cost more than the national picture, and East Kent falls inside that region, so read a national range as a starting point rather than a forecast.
The aim here is to leave you able to read a quote, not to estimate your own bill. A flat roofing survey is what turns a range into a price for your particular roof, because the deck, the edges and the access only show when someone is standing on it.
What the published figures say
MyJobQuote, in October 2026, puts a flat roof replacement between £1,500 and £6,000. The gap between the two ends is the point: a small porch roof and a large rear extension are different jobs, and one number cannot describe both. For EPDM, the synthetic rubber membrane, MyJobQuote gives around £60 per square metre, from a separate page dated October 2026.
| What it measures | Typical UK figure |
|---|---|
| Flat roof replacement | £1,500 to £6,000 |
| EPDM, per square metre | Around £60 |
These are national ranges for the job and nobody's price list. Prices in Kent can sit higher, and the figures say nothing about a particular deck or approach to the roof. Treat the range as a way to spot a quote that is far outside normal, in either direction, and ask that quote what it includes.
A figure at the bottom of the range often reflects a small, simple roof with easy access, and one near the top a large or awkward one. A quote well below the range for a large roof deserves a question about what has been left out. A quote well above it deserves one about what is being added.
Both figures are dated, and costs move. Check the month on any guide before you rely on it, and be wary of a figure quoted with no month at all.
Why one roof can have several fair prices
Price follows what has to be done, and a survey is what shows that. The things that move a flat roof price most are these.
- Size and shape. A larger roof costs more, and a roof with many corners, upstands and rooflights has more edges to finish than a plain rectangle.
- Covering. Rubber, glass-fibre, bitumen felt and lead sheet are laid differently and priced differently, and a lead roof is a craft job of its own.
- The deck. Sound boards can stay. A soft, wet or sagging deck has to be replaced before anything goes on it.
- Insulation. A warm roof adds insulation boards, and renovation work can bring in the insulation rules in Approved Document L.
- Falls and outlets. A roof that holds water may need tapered insulation or new outlets to drain it properly.
- Access. A roof reached through the house or over a narrow side passage takes longer to work on than one reached from open ground.
Scaffolding, waste removal and any skip are priced after a survey, since they depend on the site. A scaffold on the pavement needs a highways licence from Kent County Council, which the scaffolding firm requests; that adds a step to the programme as well as the bill.
Each of these is a fair reason for a quote to move. None is a reason to expect a high price on its own. Together they explain why the range is wide, and why a survey of your roof counts for more than a rate from a website.
What a per square metre figure can and cannot say
A per-metre rate looks like a way to price your own roof, and it is not one. The MyJobQuote figure of around £60 per square metre for EPDM is a fully installed average, worked from a roof about the size of a single garage. It is not a rate that scales neatly with area, because much of a flat roof job does not change with size.
Several parts of the work are present on every roof, large or small:
- setting up access and protecting the building
- preparing the deck and checking it is sound
- forming the edges, upstands and outlets
- clearing the site and taking the waste away
A small roof therefore costs more per square metre than a large one, and multiplying a rate by an area gives a number that looks precise and is not. This is why MyJobQuote's replacement range runs from £1,500 to £6,000 rather than following a single line on a graph.
The same holds for the repair rates quoted in some guides. They apply to small patches, up to a few square metres, and cannot be stretched to cover a replacement. If a figure on a website is quoted per square metre and your roof is large, do not multiply it into a total.
This is also why an online calculator that asks only for the roof area returns a number that looks neat and means little. It leaves out the very things that separate one roof from another.
What a per-metre figure is good for is a rough check on whether a quote is in the right region, once you know the covering. It cannot replace a survey.
Where the deck and the build-up change the price
The surprises on a flat roof job arrive when the old layers come up. The survey looks for them in advance, with a look from the loft or ceiling below and at the edges, but the deck is only fully seen when it is open.
The build-up is the stack of layers on the roof, and each can change the price:
- The deck. Plywood, boards or concrete. A deck that has been wet can go soft and has to be renewed in the affected areas.
- The vapour layer and insulation. These matter where a heated room lies below.
- The membrane. The covering itself, laid as one piece or in joined sheets.
- The edges. Trims, drips and upstands, where water is shed or the roof meets a wall.
An overlay, which is a new membrane laid over the old one, can cost less than a strip, but only where the old layers are dry and flat. Our guide to overlaying an old flat roof sets out when it is allowed and when it is a mistake.
Replacing a flat roof's waterproof layer can also bring in the Building Regulations, since renovation of a flat roof is covered by Approved Document L, which can add insulation to the job. Ask the roofer whether the quote allows for it.
A quote that explains how the deck will be treated if it turns out soft is more useful than one that is silent, because the second leaves the question to be settled later.
Comparing quotes fairly
Citizens Advice says to get written quotes from at least 3 different traders before you decide. The total at the foot of a page matters less than what sits above it. Put the quotes side by side and check that each says the same things.
Check that each quote names:
- the covering, and its thickness or type where that applies
- whether the old covering is stripped or overlaid
- how the deck will be dealt with if it is soft or wet
- the insulation, if any, and the fall the roof will have
- the edge trims and the outlets
- whether VAT and scaffold are included
- who clears the waste
A quote that leaves several of these blank is not comparable with one that fills them in, even if the totals look alike. The total on its own is the least useful number on the page.
Our own quotes are one total written price, given after the survey, so you see what the job costs without a stack of separate figures. The survey comes first because the deck, the edges and the access decide the price.
Do not rush a decision to catch a price. A flat roof that is leaking can be made safe in the short term while you compare. Cost is one input; the other is what the roof is expected to deliver in years. Our guide to flat roof lifespan by material sets the two side by side, and the page on whether to repair or replace a flat roof covers the case where mending beats renewing.
Your cancellation rights after a survey
A flat roof contract is often signed at your home after the survey. The Consumer Contracts Regulations 2013 treat a contract signed anywhere other than the trader's own premises as an off-premises contract, and give the consumer a cancellation period of 14 days. Citizens Advice says the cooling-off period begins the day after you enter the contract.
Some details matter when money is at stake:
- If the trader did not give you the cancellation information, the period can extend by up to 12 months.
- Work should not start inside the 14 days unless you ask for that in writing, on a durable medium such as email.
- There is no cancellation right where you specifically asked the trader to visit for urgent repairs, such as an active leak.
Section 49 of the Consumer Rights Act 2015 adds that the work must show reasonable care and skill. If something goes wrong, the Citizens Advice consumer helpline is 0808 223 1133.
Keep the paperwork too. The signed quote, any email that confirms the start date, and the survey photographs form the record of what was agreed. If a start date has to move because of weather or a licence, a short message that confirms the new date saves argument later.
None of this changes the price. It is a reason to read the quote and its cancellation terms at the kitchen table before you sign, and a reason not to feel hurried by a good weather forecast.
