Anyone who has been told that the foam under their roof may need to come out will ask the same thing first: how much? A fair answer starts with a published range and then explains why a single roof can land anywhere inside it. This page does both. The figures are national, taken from the August 2026 update of MyBuilder's price guide for removing foam. Treat them as guide figures from elsewhere, never as our quotation, because nobody can set a real price for your house without looking at the roof void.
Spray foam removal is not one job. It is a bundle: an assessment, the stripping itself, disposal of what comes off, and then repairs and new insulation so the roof is not left bare. Each part has its own range and its own cost drivers, so we take them in turn. How long the work runs is a separate question, covered in how long spray foam removal takes. For the full service, start at spray foam insulation assessment and removal.
The per-m2 band and what it buys
MyBuilder's guide puts removal at £20 to £50 per m², with an average job landing at about £1,500. That is a labour-and-method price: the roofer's time, the tools, and the care taken not to damage what lies underneath. It is quoted per square metre of roof surface covered in foam, which means the area is the first number we need, and it is the one most owners have never measured.
The band is wide because foam is not a single product behaving in a single way. A thin skim of soft foam on clean timber can come away quickly. A thick, dense layer that has fused to rafters, roof boards and the back of the tiles needs patient, careful work, and the price sits towards the top. Nothing in a national guide can tell you which of those you have, which is why the survey comes before any figure that is worth relying on.
What the rate does not include
The per-m² rate is for taking the foam off. It does not cover the assessment beforehand, the disposal of the waste, any scaffold, any timber that turns out to be damaged, or the new insulation that goes back afterwards. Those are all costs a sensible quote allows for, and we cover each below. If two quotes for one roof sit hundreds of pounds apart, check first that both cover the same tasks.
A worked example from the published figures
Suppose a roof void has foam over 30 m² of rafters and boards. That figure is an illustration, not a typical house. At the published £20 to £50 per m², stripping alone would come to between £600 and £1,500. Add an assessment at the guide's £100 to £200, disposal at £150 to £400, and repairs and new insulation at £500 to £3,000, and the same job spans a much wider range than the headline rate suggests.
| Line | Typical UK range | On 30 m2 (illustration) |
|---|---|---|
| Assessment | £100 to £200 | £100 to £200 |
| Foam removal | £20 to £50 per m² | £600 to £1,500 |
| Disposal | £150 to £400 | £150 to £400 |
| Repairs and new insulation | £500 to £3,000 | £500 to £3,000 |
| Total of the four lines | Sum of the ranges | £1,350 to £5,100 |
The total is simple addition of the published ends, so it shows the outer limits and not the likely price. Few real jobs hit every top figure or every bottom one. Ranges: MyBuilder, updated August 2026.
Why show the spread at all
Because the alternative is a single comfortable-sounding number that hides the spread. The spread is real, and most of it sits in the last line, where the amount of repair work depends on what is found once the foam is off. We would rather you saw that before the survey than after it.
Assessment: the cost of knowing before you commit
MyBuilder's range for a spray foam assessment is £100 to £200. It is worth treating as its own item rather than a free extra, because it is the step that decides whether removal is needed at all. The RICS consumer guide describes the risk of uncontrolled condensation, and a surveyor's flag in a report is a prompt to look, not a sentence on the roof. What the assessment produces is evidence.
What the visit looks at
In the loft we identify the foam, measure how thick it is, check what it is stuck to, and use a moisture meter on the timbers we can reach, with photographs of your own roof throughout. The result is a written note you can hand to a surveyor, a lender or a buyer. Its worth is highest where the answer is that the roof is sound, because then the largest cost on this page never has to be spent. The reasoning behind that sits in our answer on whether spray foam always has to be removed.
Disposal, access and the things behind the foam
Disposal has its own published range of £150 to £400. Foam comes off in awkward pieces and fine debris, and all of it has to be bagged, carried down and taken away. The volume depends on how thick the layer is as well as on its area, so a deep layer over a small roof can cost more to dispose of than a thin layer over a large one. We clear the site and take the waste away as a normal part of the work, never as an afterthought.
Access to the roof void
Access moves the price in ways a national guide cannot capture. On steep lanes and terraced hillsides around Stroud, getting equipment and bags to and from a loft hatch can be slow, and a roof void with little head room makes every square metre take longer. The route in and out is noted at the survey and planned for, rather than found out halfway through.
Scaffold and lifted coverings
Most foam is stripped from inside the roof, so many jobs need no scaffold. Where foam has been sprayed onto the back of tiles or slates and has to be dealt with from outside, or where the covering has to be lifted to reach it, scaffold and re-laying become part of the bill. Published scaffold figures for a re-roof are about £1,125 (MyBuilder, updated August 2026) and £700 to £1,300 (Checkatrade, October 2026). Those are for a full re-roof and are only a guide to scale. Tiles or slates lifted for access are priced on survey, because the type, age and condition of the covering decide what is possible.
If foam has fused to the back of old tiles or slates, taking it off can cost more than the roof covering is worth in places. That is a conversation to have with photographs on the table, before work starts.
Repairs and new insulation afterwards
The widest published range is the last: £500 to £3,000 for repairs and new insulation. A roof void that has been under foam cannot simply be left bare. Once the foam is off, someone has to look at the timbers, replace anything decayed, and then close the roof again with insulation that suits it.
Timber repairs are priced on survey
What timber repairs cost depends on how much wood has decayed, and that cannot be judged until the foam is off and the wood can be inspected. The national guides above fold it into the wider repair and insulation range. In the quote, any allowance for it is marked as provisional. If the timbers are sound, the line comes out. If they are not, you see the actual cost and the photographs that explain it. The inspection side is covered in checking timbers under spray foam.
New insulation
What goes back depends on the roof construction and on what the RICS guidance asks for by way of ventilation and condensation checks. A breathable build-up costs differently from a plain layer of quilt, and the choice affects the price as well as how the roof behaves. Our guide to re-insulating after spray foam sets out the options.
VAT on the two halves
GOV.UK's VAT Notice 708/6 sets two rates. Ordinary roofing work attracts the standard 20%. The insulation put back under the roof of a dwelling is zero-rated until 31 March 2027, and the quote states the VAT that follows that split. For a job that mixes the two, an accountant or HMRC is the right adviser.
What pushes a quote up or down
Pulling the threads together, a handful of features decide where in the published bands your roof falls. None of them is guesswork once the survey is done.
Features that push towards the top
Closed-cell foam that is thick and stuck fast to rafters and boards. A large, complex roof with hips, valleys or dormers that break up the surface. Foam sprayed onto the back of the covering. Low head room, a narrow hatch or a long carry from the door. Hidden damage found only after the foam comes off. Our guide to open-cell and closed-cell foam explains the first of those.
Features that push towards the bottom
A thin layer of open-cell foam on clean timbers, a simple pitched roof with clear access, no foam on the covering, and a roof void in good condition when the foam comes off. Partial removal can also bring the cost down where only some of the foam is a problem, though it is a decision to make on the evidence, not on price alone.
The cost of not acting
It is fair to say that a lender or buyer reacting to foam can cost you more than the work does, because a stalled sale or a refused remortgage has its own price. We make no promise about how any particular lender will behave, and the position is covered in spray foam and mortgages. What we can do is give you the figures, so that the decision is made with the real numbers in front of you.
What reaches you after the survey is a written document covering assessment, stripping by area, disposal, any lifted covering, provisional timber repairs and new insulation, plus photographs of your own roof. The work carries our 10-year workmanship guarantee, in writing.
Comparing quotes fairly
If you collect more than one quote, lay them side by side and check six things before looking at the totals. Is the foam area measured, and is the measurement the same in each? Is the disposal included? Is anything shown for the timber? Does the quote say what goes back in the roof afterwards, and how it will be ventilated? Is any scaffold included? And is it clear who notifies building control where the work is notifiable?
Notification and approval
The Planning Portal sets two thresholds for roof work: under 25 per cent of the building envelope and under 50 per cent of the roof. A job under both limits does not normally need a building control application, but one over either limit can bring Building Regulations approval, and Part L may add a thermal upgrade. We tell you which side of those lines your roof falls on, and send the notification ourselves where the work is notifiable. The details are in our answer on Building Regulations for spray foam removal.
Cheaper is not always a smaller job
A low quote may leave out the things that cost money later: a bare roof void, a missing ventilation path, or waste left on site. Compare like for like. The published ranges give you a sense check, and the written quote shows what the figure covers.
If you would like to start from the figures, send us your address, a few photographs of the foam and the area it covers, and tell us whether a surveyor or lender has flagged it. From those we can tell you where the survey should begin.