Beacon Basingstoke Roofing

Spray foam insulation in Basingstoke

If spray foam has been sprayed onto the underside of your roof, we assess what it has done to the timbers, remove it where it needs to come off, and re-roof or re-insulate around it. Before anything is touched you get a free visit, photographs taken in your own loft and on your own tiles, and a single fixed written quote. Rafters and battens behind the foam are checked with a moisture meter through small test cuts.

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The underside of a pitched roof in a loft showing rafters and old spray foam insulation

What we do about spray foam on a roof

  • A surveyor with a torch and moisture meter checking roof timbers in a loft

    Assessment of a foamed roof

    We look at the foam, the timbers it covers and the ventilation around it, photograph what we can reach, and say whether it can stay, needs testing or should come off.

  • House roof stripped to battens during a roof replacement

    Spray foam removal

    Foam is cut, scraped and shaved from rafters, battens and underlay by hand, with the dust contained. The timbers are then checked, dried or replaced before anything goes back.

  • Clay tiled pitched roof gable on a red-brick house

    Re-roofing and re-insulating

    Where foam is bonded to tiles and battens, a re-roof has to deal with it. After removal we fit insulation and ventilation that the roof can live with and the next surveyor can inspect.

Signs your foamed roof needs a proper look

  • A buyer's surveyor or lender has queried the foam under your roof
  • Rafters you cannot see or touch because they are buried in foam
  • A musty smell or damp patches on a landing or bedroom ceiling
  • Slipped or cracked tiles that cannot be lifted and refitted
  • Foam sold at the door, with no paperwork left behind

How a spray foam job runs

  1. 1Free surveyOne of us goes up on the roof and into the loft, and records the foam type, depth and condition.
  2. 2Report and written pricePhotographs of your own loft, our recommendation with the reasons, and a single written price that will not move.
  3. 3Remove, repair and re-insulateWe take the foam off, treat or replace damaged timber, then refit insulation and ventilation to suit the roof.
  4. 4HandoverMoisture readings from the rafters are shown to you, and the paperwork for the new insulation goes into your file.

The spray foam long read

What we find under foamed roofs around Basingstoke, and what to do about it

Spray foam insulation is a two-part liquid that expands as it cures, sprayed onto the underside of the roof so that it sticks to tiles, battens, underlay and rafters alike. It looks tidy and it does stop draughts, but it changes how the whole roof behaves, and it can hide the timbers you would normally inspect. The useful move is to find out what is behind the foam. Below are the questions we are asked by owners in Basingstoke and the villages around it: homes with a mortgage offer in doubt, homes that were foamed after a cold call, and roofs that now need tiles or timbers dealt with. We cover what the foam does, how to tell whether it has caused harm, what removal involves, what it costs, and how a re-roof works around it. The detail on each sub-topic sits in our guides, starting with spray foam removal.

Chapter 1: What has spray foam done to the way my roof works?

What we find

A traditional pitched roof in this part of Hampshire is a cold roof. The insulation lies on the loft floor, the loft above it stays cold, and the underlay and tiles are kept dry by air that drifts through the eaves and out at the ridge. That moving air carries away the damp that leaks up from the house below. It is a simple arrangement and it has looked after roofs for generations.

Foam sprayed onto the underside of the roof turns that cold roof into a warm roof. The RICS consumer guide on spray foam describes exactly this. The insulation now sits at the slope itself, the loft becomes part of the heated envelope, and the eaves vents and ridge vents that used to ventilate the space are often sealed by the foam. Whether that is a problem depends on the quality of the application, the condition of the roof beneath, and whether any moisture remains in the timbers when the foam goes on. On 1960s and 1970s estates round Basingstoke, we meet roofs with bitumen felt underlay that cannot pass water vapour at all. Foam applied over felt can leave no way out for moisture from the house.

What we fix

The first step is a survey. We look at the roof from outside, noting the tile type, the age of the underlay if we can see it, and the state of the eaves and ridge. Then we go into the loft and see what has been sprayed: how deep the foam is, whether it is soft and open-celled or hard and closed-cell, whether it covers the rafters entirely or just fills between them, and whether any gaps expose bare timber.

The question we try to answer is whether this roof can function as a warm roof. That needs a sound structure, a vapour path that suits the underlay, and some assurance the foam was applied by someone accountable. If so, the foam can sometimes stay, with monitoring. If not, we explain why, show you the photographs, and quote for removal. Where the evidence says the roof is fine, the foam stays. A pitched roof with no foam on it stays under our pitched roofing work, and the comparison between a warm and a cold loft is covered in our guide to warm loft versus cold loft.

Chapter 2: How do I know whether the rafters behind the foam are wet or rotten?

What we find

This is the hardest question about a foamed roof, because the answer sits behind the foam. The RICS guide is clear that timbers can look dry on the exposed face while being wet behind the foam. The visible surface tells you very little. A rafter may have a clean, pale face inside the loft, with its upper edge and the sides bedded in foam holding water against the wood.

The trouble starts in the way moisture moves. Warm air from the rooms below carries vapour upward. In a cold roof that vapour is carried out by the ventilation. Under foam, any vapour that reaches a cold spot condenses, and the water has nowhere to go. A small leak at a cracked tile or a failed flashing can add to it, and foam sprayed into the gaps around a chimney or a valley can soak up that water and hold it against the rafters and the battens. Trading Standards guidance on spray foam notes that reduced ventilation increases the risk of condensation, mould and potentially timber rot. You may notice a musty smell on the landing, or staining on the ceiling below, or nothing at all.

What we fix

We assess it with the tools a roofer has. A moisture meter pushed through a small test cut gives a reading on the timber behind the foam. Where we are allowed to, we cut a few inspection windows in the foam at the low points of the roof, around chimneys and at valleys, since those are where water collects first. We probe the exposed wood with a bradawl: sound timber resists, decayed timber crumbles. Photographs go in the report so that you see what we saw.

If the timber is dry and sound, you have reasonable grounds to keep the foam, and the report is useful evidence for a future buyer or surveyor. If the readings are high, or the wood is soft, we recommend taking the foam off the affected area at least, then letting the timber dry, treating it where it is merely damp, and replacing the sections that have decayed. Replacing a rafter foot or a short length of batten is a modest job. Letting rot continue under foam until a tile slips or a ceiling falls costs far more. Our guide to spray foam problems with condensation, timber and ventilation goes into the mechanisms in more detail.

Before: Crumbling mortar under a clay ridge tileBefore
After: House roof stripped to battens during a roof replacementAfter
Typical of what we find and what we leave behind. Every survey includes photos of your own roof.

Chapter 3: A surveyor or lender has flagged the foam on my loft. Do I have to remove it?

What we find

Not always, but you will need to answer the surveyor's concern with evidence, and some owners find it quicker to remove the foam than to argue. The reason is that foam can hide the condition of a roof, and a lender lending against the property wants to know the roof is sound. Some lenders have declined mortgages on homes with spray foam under the roof, and others judge each case separately. Those positions vary and change, so check the current position with your own lender or broker rather than relying on anything you read here.

The reports we see from sellers usually follow the same pattern. A buyer's surveyor opens the loft hatch, sees foam on the rafters, and writes that the roof structure cannot be inspected. The lender's valuer then asks for a specialist report, or declines to proceed. The sale stalls while a buyer who was happy with the house waits for paperwork the seller does not have, because the foam was installed years ago by a firm that may no longer trade, or by a previous owner. What lenders and valuers generally want is certainty that the foam was installed properly and that someone is accountable for it.

What we fix

There are two routes, and the survey tells you which suits your roof. The first is to keep the foam and prove the roof is sound. We inspect it, take moisture readings at test cuts, photograph the rafters in the places the foam allows, and write up what we found. That report can sit alongside any installer paperwork you hold, and it helps a surveyor following an inspection protocol for spray foam homes. The second route is removal. Once the foam is gone, the timbers are visible, any damage has been repaired, and the roof can be insulated conventionally in a way a surveyor recognises.

Which is cheaper depends on what the test cuts show. If the timber is sound and you have documents, an assessment may be all you need. If the timbers are damp, or the foam is closed-cell stuck hard to the tiles with nothing in writing, removal is the cleaner answer. For the sale side, see our guides on spray foam and mortgages and selling a house with spray foam.

Chapter 4: How is spray foam actually taken off a roof?

What we find

Removal is slow, physical work and nothing about it is glamorous. Foam has expanded into every gap, bonded to rafters, battens and underlay, and in many roofs it has pushed itself up between the tiles and the battens. How hard it comes off depends on the type. Open-cell foam is soft and sponge-like, and can be cut and scraped away. Closed-cell foam is dense and rigid, and clings tightly to whatever it touches. It has to be shaved, chiselled and scraped off in layers.

Roofs differ in how the foam was applied. Where it was sprayed onto the back of the underlay, the underlay may come away with it, so the roof covering above is exposed in places. Where it was sprayed directly onto the tile undersides, as sometimes happens on older roofs without any underlay, the foam is stuck to the tiles themselves, and taking it off means taking the tiles off. The work generates a lot of fine dust and offcuts, so the loft has to be contained before anyone starts, and the people doing the work wear respiratory protection.

What we fix

The sequence is the same on every roof, with variations for access and foam type. We clear and protect the loft and the rooms below, and set up dust control. We then take the foam off, working from the ridge down, by hand with scrapers, shavers and chisels, and bag the waste as we go. We sweep and vacuum the timbers and take them back to bare wood.

Then we inspect what the foam was hiding. Sound timber gets treated if it was damp, and left to dry before anything covers it again. Rotten sections are cut out and replaced. If the underlay was damaged or came away with the foam, it is renewed, and if tiles were damaged taking the foam from them, we replace those too. Only then does insulation go back. All of it is carried out of the house, and the loft is left clear. Our guide to spray foam insulation removal covers the process step by step, and who should remove spray foam explains how to judge a firm that offers the service.

You should expect a clear explanation of the method before work starts, because spray foam removal is usually one job in a larger repair.

Before: Water ponding on a domestic flat roofBefore
After: New EPDM flat roof on a brick extensionAfter
Typical of what we find and what we leave behind. Every survey includes photos of your own roof.

Chapter 5: What decides the price of removing spray foam?

What we find

Removal is priced by area first and condition second. The area is simple to measure: the roof slope covered by foam, in square metres. The condition is what the survey exists to find out. Foam stuck to bare timber with accessible rafters comes off faster than foam stuck to the back of old felt, to tiles, or around chimney breasts and hips. A tall loft with room to stand is quicker than a low cut-up roof where the operative crawls on a board.

Added to that is anything the foam was hiding. Rafters with surface damp need only treating. Rafters with rot need cutting out and replacing, which brings scaffolding into the quote on some houses. If tiles have to come off with the foam, the job becomes a partial re-roof. Waste disposal also adds up, since foam is bulky and light and fills a skip quickly. The prices reported across UK cost guides vary widely, partly because of these differences and partly because the guides are written by lead-generation sites rather than by roofers. They give you a range to hold in mind.

What we fix

This is why we quote after the survey. We measure the foamed area, note the access, look at the timbers through test cuts and tell you what is likely to need repair on top of removal. The fixed written quote then covers the whole job as we have described it, with no figure added later for rot we could have found at the survey. If something unforeseeable turns up behind the foam, we stop and explain, with photographs, before anything changes.

Removal alone is rarely the whole story. Re-insulating afterwards is part of the cost, and so is any new ventilation. You can read how we think about that in how to insulate after removing spray foam, and the cost guide spray foam insulation cost compares removal with other options. The table below lists the reported UK figures for removal only.

Chapter 6: My tiles are failing and there is foam stuck to them. Can the roof still be repaired or re-covered?

What we find

This is a different problem from a damp rafter, and it catches owners out because it looks like a standard job. A slipped tile is normally a ten-minute repair. You lift the tiles around it, slide a new one into place and clip it down. When foam has been sprayed onto the underside of the tiles, the tile you want to lift is glued to its neighbours, to the batten and to the foam itself, so lifting it breaks the tile or pulls the foam and batten with it.

The same applies to a full re-roof. The old tiles cannot be stripped and stacked for reuse, because they come away covered in foam, and the battens and underlay beneath are bonded to the foam too. In some houses the foam has pushed out between tiles at the eaves or ridge. Foam has also been sprayed over the top of old slipped or cracked tiles as a supposed repair, which does nothing for the tile and makes the roof harder to mend. A leak near a chimney can run into foam and spread sideways, so the stain on the ceiling is far from the hole.

What we fix

Where only a small area is affected, we can often cut the foam back around the damaged tile, repair or replace the tile and batten, and leave the rest alone. The assessment tells us how far the foam has spread and whether a spot repair will hold.

Where the roof is failing as a whole, the better route is removal and a full re-cover in one operation. We strip the tiles and battens together with the foam, remove the foam from the rafters, and then fit new underlay, battens and tiles, or reuse sound tiles that have been cleaned. Tile weight matters: a much heavier covering can bring in Approved Document A and strengthening of the roof, so we compare weights before choosing. Re-covering a roof can also trigger the insulation upgrade in Approved Document L, and on the Planning Portal you can check the thresholds below which a building control application is not normally needed. Where an application is needed we make it for you. Our guide to re-roofing a house with spray foam sets out the sequence.

Chapter 7: What goes in the roof once the foam has come out?

What we find

Once the roof is bare the job continues, because the reason the foam went in is usually still there. Somebody wanted the loft warmer, or the house cheaper to heat, or a cold-caller persuaded them it would solve a problem it did not. Taking the foam out without a plan puts you back where you began, with a draughty loft and no insulation to speak of.

What goes back has to suit the roof you have. A cold roof with insulation on the loft floor needs a clear air path through the eaves to the ridge, and if the foam sealed the soffit vents, they need to be reopened. A roof that will be used as living space needs insulation at the slope, with a gap or a breathable layer chosen to let moisture escape, and the right vapour control layer on the warm side. A loft conversion adds its own rules: on a two-storey house, escape from the loft must be by a protected stair, and a roof window only counts as an escape window for storeys within 4.5 m of the ground. Without these details, the new insulation can fail the same way the foam did.

What we fix

For a normal loft, the answer is almost always mineral wool laid between and across the joists on the loft floor, with the eaves ventilated and the hatch insulated and draught-proofed. It is cheap, it can be inspected at any time and a surveyor knows exactly what it is. Our guide to loft insulation alternatives to spray foam compares the options, and the reasons for each are in warm loft versus cold loft.

Where you want a warm roof, perhaps for a converted loft, we fit rigid boards between and over the rafters, with a ventilated gap above them or a breathable underlay specified for the build-up. Here each layer is installed where it can be checked, photographed and signed off.

When the work is finished, you get photographs of the finished roof and a clear note of what was fitted, so a buyer or surveyor can see in a minute what a stack of paperwork rarely explains. If a Building Regulations application applies, we deal with it for you, through the council or a private approver of your choice. The guide to what paperwork to keep for spray foam shows what a good file contains.

If a surveyor or lender has already named the foam, send us that paragraph of the report with a photo of the loft. It tells us which question has to be answered, and that is usually whether the rafters behind the foam are dry. We test them, and you then choose between keeping the foam with evidence to support it, or removal with repairs and new insulation in one fixed price. Whichever you pick, we give a 10-year workmanship guarantee on our work. Call 01256 213956 or use WhatsApp.

Spray foam insulation guides and answers

More guides

Quick answers

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Spray foam insulation: questions we get asked

Is it safe to go into a loft that has been sprayed with foam?

Once the foam has cured, the loft is generally fine to enter for a quick look, and you can use the hatch as normal. The risks come from disturbing it: cutting, sanding or scraping foam makes dust, and wet or damaged timbers can be unsafe to stand on. Rafters and ceiling joists are not always visible, so keep to the boards and do not lean on the ceiling. If you want to know what is behind the foam, we do the inspection with the right protection.

A cold-caller says my roof needs foam to stop it leaking. Is that right?

No. Foam does not stop a roof leaking, because a leak is water getting in through a cracked tile, a failed flashing or a bad valley, and foam is insulation, not a roof covering. The leak needs a roofer to find it and repair it. Ask for any quote in writing, take time to compare, and do not sign at the door. Our guide to spray foam cold calls explains the usual hard-sell tactics.

Can you remove spray foam from only one section of my roof?

Often, yes. If the foam covers the whole slope but only one area is damp, we can open that area, remove the foam, repair the timber and re-insulate it conventionally. The join between old foam and new insulation needs care so that vapour cannot reach cold timber at the edge. Whether a partial job is sensible depends on the test-cut readings, and our guide on partial spray foam removal sets out when it works.

Will taking the foam off damage the tiles and underlay?

It can. Foam bonds to whatever it touched, so on some roofs a few tiles or a length of underlay are damaged when the foam is scraped away. We tell you at the survey where we expect this, and the fixed quote includes replacing what the removal breaks. Where foam has been sprayed straight onto tile undersides with no underlay, we plan the job as a partial re-roof instead of trying to save every tile.

What documents should I look for if I think foam was fitted years ago?

Start with the original invoice, any guarantee, and any certificate or technical approval the installer gave you. Look through old solicitor's paperwork, estate agent particulars and any energy performance certificate in your file. If nothing exists, that does not mean the foam is faulty, but it does mean a roof inspection becomes your evidence. Our answer on what paperwork you should hold for spray foam lists what to ask for.

Do I have to replace the roof after the foam is removed?

Not necessarily. If the tiles, battens and timbers are sound once the foam is off, the roof can stay as it is with new insulation and ventilation below it. We replace only what the removal damages or what the inspection finds failed. Where the covering was already near the end of its life, you can choose to re-cover while everything is open, and we price it as a separate line so you can see the difference.

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