Spray foam insulation removal in Farnborough

Foam off the rafters, then a roofer's look underneath

We remove spray foam from the underside of your roof, then inspect the timbers, felt and battens it was hiding and explain in plain words what we found.

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Spray foam stuck to a rafter and the back of the slates

Signs the foam in your loft needs attention

A surveyor or lender has queried the foam
Foam sprayed straight onto felt or tiles
Dark, damp or soft timber at the edges
Condensation or a musty smell in the loft
Foam cracking or pulling away from rafters

What the foam may be stuck to

Grey single-ply flat roof with roof lanterns and a crane beyond

Roofing felt

Older bitumen underlay, sometimes torn before the foam went on.

Flat-roofed rear extension and garage behind a brick semi-detached house

Breather membrane

Newer underlay, checked for tears and gaps once the foam is off.

Close view of natural slates with copper nail heads and a lead edge

Tiles or slates

No underlay at all, with foam on the back of the covering.

Removal, inspection and repair work we do

Foam removal from rafters
Timber and felt inspection
Underlay and batten repairs
Re-roofing where needed
Loft re-insulation
Before and after record

Removal only, repairs or a new roof?

Removal only

The foam comes off and the timbers and felt underneath are sound.

Removal and repairs

Some battens, felt or timber ends are damaged and are put right in place.

Removal and re-roof

The underlay has failed across the slopes, so the covering comes off too.

Spray foam removal, the figures

Spray foam and your roof, by the published guidance

What RICS said about lenders, what the foam hides, how long the covering above may last, and the re-roofing, ventilation and Part L figures that follow removal, each with its source.

Chapters of this guide and the figure each one turns on
No.	Chapter	The figure it turns on
01	What RICS said about spray foam and lenders	RICS guide: 31 March 2023
02	What the foam hides from an inspection	Timber cannot be fully seen
03	How long the covering above may last	Welsh slate: 100+ years
04	When removal turns into a re-roof	Under 50 per cent of the roof
05	Ventilating the loft once the foam is out	25mm at the eaves, 15° or less
06	Re-insulating the loft to Part L	Improved figure: 0.16

Chapter 01 of 06

What RICS said about spray foam and lenders

3 March 2023RICS press release launching its consumer guide
31 March 2023Published date shown on the guide itself
Equity releaseThe lending sector RICS named as concerned
Ask your lenderCheck whether its lender policy allows these products

Source: RICS press release (03 March 2023) and spray foam consumer guide (published 31 March 2023), accessed 28 October 2026

Spray foam insulation is sprayed as a liquid onto the underside of a roof, where it expands and sets. In a loft it ends up covering the rafters (the sloping timbers that carry the roof), the underlay (the felt or membrane laid under the tiles) and sometimes the back of the tiles or slates themselves. From inside, the roof becomes a single layer of foam, and everything behind it drops out of sight.

In March 2023 RICS, the professional body for chartered surveyors, launched a consumer guide on the subject. Its press release, dated 3 March 2023, said that "there has been concern within specific sectors of the lending market, such as equity release mortgages, which is now having a wider impact on lenders." The guide itself shows a published date of 31 March 2023. Its advice to homeowners is direct: "Do check with your mortgage provider whether their lender policy allows the installation of such products".

What that means if you are selling or remortgaging

The RICS wording describes concern in some parts of the lending market, starting with equity release, and a wider effect on lenders since then. It does not say that every lender turns down a home with spray foam, and the position can differ from one lender and one product to the next. A buyer's surveyor may flag the foam in a report, and a valuer may ask what sits under it. The first step is the one RICS gives: ask the lender concerned what it needs, in writing if you can.

Some lenders and buyers want the foam taken out. Others want evidence about the roof beneath it. Removal answers both, because once the foam is off, the roof can be inspected and recorded. That record lets a surveyor answer the question they could not answer before, and it gives you something to hand over rather than a promise.

Why the roof matters as much as the foam

Taking foam off is half the job. The other half is reading what it was hiding: felt that has torn or turned brittle, battens (the slim timbers each row of tiles is fixed to) softened by damp, nails rusted through, and tiles or slates that have slipped. Those are roofing faults, and they decide whether the loft needs a small repair, new underlay or a full re-roof. We are a roofing firm based in Farnborough, so the inspection and any repair can follow the removal on the same job.

Our guide on why people are removing spray foam insulation goes further into the reasons homeowners across Hampshire and Surrey give for taking it out.

Chapter 02 of 06

What the foam hides from an inspection

The published concerns about foam on a roof
Concern	Published wording	Source
Timber roof structure	Cannot be fully seen or inspected when covered with spray foam	RICS consumer guide
Ventilation	Incorrectly installed insulation can negatively impact it	RICS consumer guide
Moisture	Can result in moisture damage	RICS consumer guide
Foam on a leaking roof	We don't recommend doing this	Energy Saving Trust

Source: RICS spray foam consumer guide (March 2023); Energy Saving Trust roof and loft insulation advice (last updated 8 May 2026); accessed 28 October 2026

Foam across the rafter faces hides splits, staining and soft timber from view.

A roof inspection depends on seeing the timber. A surveyor in the loft looks along the rafters for splits, sagging, staining and the soft surface that points to decay. They check the purlins (the heavy beams that run along the roof and prop the rafters part way up) and the joints where timbers meet. RICS puts the difficulty in one sentence: "If the timber roof structure is covered with spray foam it cannot be fully seen or inspected." A surveyor who cannot see the timber cannot report that it is sound, and that gap in the report is what reaches the lender.

The second concern is moisture. The RICS guide says incorrectly installed insulation "can negatively impact ventilation and result in moisture damage". A pitched roof gets rid of moisture through its eaves, its ridge and its underlay, and foam packed across that route changes how damp air leaves the loft. Timber that stays damp for long spells is open to rot, and with foam over it the first sign can be a stain on a bedroom ceiling rather than anything you would notice in the loft.

Foam also hides the fixings. Every tile or slate hangs from a batten by its nibs or is held by a nail, and those nails rust over time. Under foam, a roof can look tight from inside while the fixings behind it have given up, because the foam itself is holding the covering in place.

Foam sprayed onto a leaking roof

Some foam was put in to stop a leak or to hold slipped tiles in place. The Energy Saving Trust, in guidance last updated on 8 May 2026, says of spraying foam onto a leaking roof: "We don't recommend doing this." The leak does not go away; the water runs behind the foam and into the timber, out of sight. When foam comes off a roof like that, the slipped tile, the cracked slate or the torn felt it was covering can be the first thing we find, and the timber around it is where we look hardest.

Open-cell and closed-cell foam

Spray foam comes in two broad kinds. Open-cell foam is soft and springy, and a thumb pressed into it leaves a dent. Closed-cell foam is hard and rigid, and grips firmly to whatever it was sprayed onto. The kind in your loft changes how it comes away from the timber and how long the removal takes, so we identify it on the first visit and say which it is before we price anything. Some lofts have both, where a later installer added to earlier work, and each part is dealt with on its own terms. Our guide to open-cell and closed-cell spray foam sets out the differences in more detail.

Chapter 03 of 06

How long the covering above may last

Welsh slate100+ yearsRuns past the axis
Spanish natural slate75-100 years
Reclaimed Welsh slate50-80 years
Clay tile60-80 years
Concrete tile40-50 years

Source: HomeBuilding, updated 30 September 2025. Typical ranges, never a promise.

Once the foam is off, the question changes from what was in the loft to how much life the roof above has left. The bars show HomeBuilding's typical working life for the coverings found over lofts like yours. Welsh slate sits at 100+ years, Spanish natural slate at 75-100 years and reclaimed Welsh slate at 50-80 years. Clay tile comes in at 60-80 years and concrete tile at 40-50 years. These are national ranges for a typical roof, never a promise for any one house.

The figures matter because removal can be a good moment for a wider decision. If the slates or tiles are young in their range and the felt beneath them is sound, removal and re-insulation finish the job. If the covering is near the end of its range and the felt has failed as well, it can make more sense to re-roof now than to re-insulate under a roof that will need stripping in a few years. Deeds, the original sales details or a date stamped on the back of a tile can help place your roof within its band.

Clay tile: two published figures

BRE, as quoted by Marley	Minimum life expectancy of 60 years
HomeBuilding	60-80 years

On the survey

We look for age clues on the covering, such as worn faces, flaking slate and moss, and set them against the felt found under the foam.

Reading the covering from inside the loft

With the foam gone, the underside of the roof tells its own story. Daylight between slates, slipped tiles hanging on a single nail, battens split at the fixings and felt that crumbles at a touch all show up from inside. Where the foam was sprayed straight onto the back of tiles or slates with no underlay, we look at whether removal has disturbed them and whether they are still held properly. A slate whose nails have rusted can stay put under foam and then slide once the foam no longer grips it, so we check fixings as we go and refix any that move.

Some marks are left by the removal itself. Foam that has bonded hard to a rafter may leave a thin skin or a rough face on the timber, and that is recorded alongside any real damage so the two are not confused. Our guide on whether spray foam damages roof timbers covers what decay and staining look like once the foam is off.

Repairs we can make from inside and out

The faults found under foam can be ordinary roof repairs. A torn section of felt can be patched, or a run of battens replaced by lifting the tiles above it, and slipped slates can be refixed from outside. Where the roof is tiled or slated and sound, our pitched roofing service covers those repairs, so you are not left waiting for a second firm. Each repair is added to the record of the loft, so the surveyor sees what was found and what was done about it in one place.

Chapter 04 of 06

When removal turns into a re-roof

Under 25 per centof the total building envelope affected
Under 50 per centof the roof affected by the work
15 per centheavier new covering needs Building Regulations approval

Source: Planning Portal, building regulations guidance on re-roofing, accessed 28 October 2026

Removal itself is work inside the loft. The roof only comes into it when the inspection shows faults that need the covering lifted. A few slipped slates, a torn patch of felt or a handful of soft battens are repairs. Felt that has failed across every slope, battens soft along whole courses and timber stained by years of trapped damp are a different scale of job. At that point, patching from inside under a covering that keeps letting water in costs more over time than starting again from the rafters up.

The panel sets out the Planning Portal's re-roofing test. Work stays outside a building control application, normally, while it touches less than 25 per cent of the total building envelope and less than 50 per cent of the roof. Stripping and re-covering every slope takes the job beyond that roof limit, which brings building control in. Separately, if the replacement covering adds 15 per cent or more to the weight on the roof, Building Regulations approval is needed, and the Planning Portal advises getting a structural engineer or surveyor to check before starting.

Who checks the work around Farnborough

For Farnborough and Aldershot addresses, and for Fleet and the rest of Hart, the council service is the Hart and Rushmoor Building Control Partnership, whose team works from Rushmoor's Farnborough offices (01252 398715). A registered building control approver is the other route. For a house in Bracknell Forest, that council lists re-covering pitched and flat roofs among jobs that might call for building regulations approval, so we confirm the position there before any re-roof.

The figure50%of the roof affected: the Planning Portal's line for a building control application25% envelope limit50% roof limitSource: Planning Portal, re-roofing guidance

Why a re-roof can be the cleaner answer

When the covering comes off, the whole roof is open from above. The old felt goes, new underlay is laid over the rafters, new battens go on, and the slates or tiles are refixed or replaced. Any foam still stuck to the back of the old felt leaves with it, which saves scraping it off from below. From inside, the rafters can then be cleaned back and inspected in full daylight, which gives the surveyor the clearest record of all. Our roof replacement service covers stripping, re-felting and re-covering a whole roof.

What drives the cost of removal is the area of foam, how thick and how firmly bonded it is, the room to work in the loft, and what the inspection finds behind it. A loft with low headroom or boarded floors takes longer than an open one, and so does foam packed tight into the eaves. Add any repairs or a re-roof and the figure changes again, which is why we price after the inspection rather than from a description over the phone. Our guide on what decides the cost of spray foam removal goes through each factor.

Chapter 05 of 06

Ventilating the loft once the foam is out

Cold roof ventilation and the loft hatch seal, as published
Set-up	Condition	Eaves ventilation or seal
Cold roof, HR (non-breathable) underlay	Pitch 15° or less	25mm along the eaves
Cold roof, HR (non-breathable) underlay	Pitch more than 15°	10mm along the eaves
LR (breather) underlay	Well-sealed ceiling, third-party certified	3mm fortuitous ventilation via normal eaves
Loft hatch	Approved Document C para 6.12	An effective draught seal

Source: Marley on BS 5250 cold roof ventilation; Approved Document C, 2013 edition; accessed 28 October 2026

A conventional loft is built as a cold roof: the insulation lies across the ceiling joists on the loft floor, and the space above it stays cold and is ventilated so damp air can leave. Spray foam on the rafters turns that arrangement upside down, insulating the slope instead and closing off the air paths at the eaves. When the foam comes out, the loft goes back to working as a cold roof, and it only works if the air can move again.

The table gives the figures Marley publishes under BS 5250, the code for managing moisture in buildings. What a cold loft needs depends on its underlay. Where the underlay is HR, meaning high resistance to vapour and so not breathable, Marley gives 25mm of continuous ventilation at the eaves for roofs pitched at 15° or less, dropping to 10mm once the pitch is above 15°. Where it is LR, a breather underlay, and the ceiling below is well sealed, the small 3mm gaps that ordinary eaves leave are counted as enough, provided the product carries third-party certification. Approved Document C adds a point inside the house: loft hatches should have an effective draught seal, because a gap round the hatch pushes warm, moist air from the landing straight into the cold loft.

Foam is cut back from the eaves so air can move into the roof space again.

Clearing the eaves and checking the underlay

Foam can fill the eaves, the low edge of the roof where the rafters meet the walls, and block any vents or gaps there. As part of the removal we cut it back from the eaves so air can move into the roof space again, and we fit eaves vents or trays where the roof needs them. We also identify the underlay, because the ventilation figure turns on whether it is HR or LR. Felt that has torn or rotted along the eaves may need replacing so the vents do their job without letting rain in, and that is one of the repairs that can only be judged once the foam is off.

Loft conversions and rooms in the roof

Where the loft is a room, the insulation has to stay at rafter level, and that build-up needs its own design for ventilation or vapour control. Approved Document C asks that a roof be built so interstitial condensation, the kind that forms inside the layers rather than on a surface, does not harm its structure or its thermal performance. BS 5250:2021 is the current version of the moisture code and is listed as being under review, so we work to it and check the product sheets for the insulation and membranes we propose. For a loft room, the removal is planned around the plasterboard: sometimes it comes down so the foam can be reached, and it goes back once the new insulation is in. Our guide to the spray foam removal process explains how the loft and the rooms below are protected while we work.

Chapter 06 of 06

Re-insulating the loft to Part L

0.35Table 4.3 threshold for an existing roof
0.16Table 4.3 improved U-value
15 yearssimple payback test in para 4.13
24 March 2027start date of the AD L 2026 edition

Source: Approved Document L Volume 1, 2021 edition incorporating 2023 amendments; AD L 2026 edition; accessed 28 October 2026

With the foam gone, the loft needs insulating again, and there are two routes. In a cold loft the insulation goes back across the floor, between and over the ceiling joists, with the roof space above it ventilated. In a loft room or conversion it goes at rafter level, with the ventilation or vapour control design that chapter 05 describes. Which route suits your house depends on how the loft is used, and that is settled before anything is ordered. Deeper insulation across the floor also means raising any loft boarding, which we allow for when we plan the job.

Part L sets the targets as U-values, the rate at which heat escapes through a square metre of roof for each degree of temperature difference; a smaller number means a warmer roof. For existing elements, Table 4.3 of Approved Document L gives a roof threshold of 0.35 and an improved value of 0.16, and the table also applies to retained parts of a home, for example the roof slopes kept in a loft conversion. Paragraph 4.13 eases the 0.16 target where it cannot be reached in practice, or where the energy saved would take longer than 15 years to pay back. The roof is then brought to the best standard that pays back inside 15 years, and as a rule it should finish no worse than 0.7.

Is re-insulation building work?

The Building Regulations define renovation of a thermal element, which includes a roof, as "the provision of a new layer in the thermal element or the replacement of an existing layer". Whether your re-insulation counts, and what it must reach, is a question for your building control body, which for Farnborough and the Hart towns is the Hart and Rushmoor Building Control Partnership. We ask before we specify. Approved Document L's 2026 edition comes in on 24 March 2027 for work in England, with the existing-element table renumbered 3.3, so the date your work starts can matter.

VAT on insulation

To 31 March 2027zero rate on installed energy-saving materials

From 1 April 2027the reduced 5% rate applies

Source: HMRC VAT Notice 708/6, GOV.UK

VAT and the record for your surveyor

HMRC's Notice 708/6 zero-rates installations of energy-saving materials made between 1 May 2023 and 31 March 2027, with the reduced 5% rate from 1 April 2027. Ask whether your re-insulation qualifies, and check whether any quote includes VAT. When the job is finished you receive a record of the loft before and after, with notes on the timber, felt and battens and a list of any repairs, for the surveyor, valuer or lender who asked about the foam. Our guide on re-insulating after spray foam removal sets out the insulation options for a loft that has just been cleared, and how each one fits with the ventilation the roof needs.

Published guidance this page relies on

RICS, March 2023Spray foam insulation consumer guide
BS 5250:2021Moisture management code, current
AD L 2021Part L, conservation of fuel and power

Find out what is under your foam

We inspect the loft, open up the foam where it is safe to, and give you one written total for removal and any repairs.

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The removal process, start to finish

Tell us what the surveyor said
Loft inspection and photos
Your quote for the work
Removal, record and re-insulation

Spray foam removal: straight answers

How much does it cost to get spray foam insulation removed?

It depends on the area of foam, how thick and how firmly bonded it is, the headroom and access in the loft, and what the inspection finds under it. Re-insulation, eaves vents and any repairs to felt, battens or tiles add to it. We price the removal after inspecting the loft, so the figure reflects your roof.

Can spray foam be removed without damaging the roof timbers?

Yes, with care. The foam is cut and scraped back from the timber by hand, and a thin skin can remain where it bonded hard. That is recorded separately from any real decay or staining, so a surveyor reading the record can tell the two apart. Felt behind the foam can tear as it comes away and is repaired.

Do I have to remove spray foam to sell my house?

Not in every case. It depends on your buyer, their surveyor and their lender. RICS said in March 2023 that some lenders, starting with equity release, had concerns about spray foam. Ask the buyer's side what they need: sometimes it is removal, sometimes evidence about the roof underneath, and removal with a record can answer both.

How difficult is it to remove spray foam insulation?

It is slow, careful work in a confined space rather than a difficult trade. Hard, closed-cell foam takes longer to cut back than soft open-cell foam, and low headroom, boarded floors or stored belongings slow it further. The loft is protected, the waste is bagged and taken away, and the house below is kept clean.

Why are people removing spray foam insulation from their lofts?

Lending is one reason: RICS reported concern among some lenders in 2023, which affects sales and remortgages. Surveyors also cannot inspect timber hidden under foam, RICS warns that poorly installed insulation can harm ventilation and cause moisture damage, and the Energy Saving Trust advises against spraying foam onto a leaking roof.

What will a surveyor want to see after the foam has gone?

Clear rafters and purlins they can inspect, and evidence of the work. We provide photos of each section before and after removal, notes on the condition of the timber, felt and battens, and a list of any repairs made. You can pass that record to the surveyor, valuer or lender who raised the foam.

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Tell us roughly when the foam went in and what your surveyor said, and we will inspect the loft.

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Spray foam insulation removal in Farnborough

Signs the foam in your loft needs attention