Where to look
Spray foam is applied to the underside of the roof slope — between the rafters, and often sprayed over them so the timber is buried. Stand in the loft and look upwards at the roof itself, not down at the floor.
Insulation on the loft floor is a different thing entirely. Mineral wool rolls and loose fill laid between the ceiling joists are standard loft insulation and are not the subject of this guide.
What spray foam looks like
It looks like a continuous sprayed layer that follows the shape of the roof. Colours are usually cream, yellow, off-white or pale grey.
The surface is rarely flat. Expect an uneven, bubbled or lumpy finish. The layer is bonded to the roof structure rather than resting on anything.
Open cell vs closed cell
Open cell foam is softer and spongier, lower in density, and usually applied in a thicker layer. Closed cell foam is rigid, dense and hard.
The distinction matters because it affects how the roof breathes and how difficult removal would be. A homeowner cannot reliably determine the type by eye alone.
Things that are commonly mistaken for spray foam
- Sprayed roof membrane coatings — a thin liquid-applied coating over the felt or slates, not an insulating foam layer.
- Older blown fibre treatments — loose fibres blown into the roof void, held in place by adhesive rather than sprayed as a solid skin.
- Rigid board insulation cut between rafters — pre-formed boards with flat, straight-cut edges, mechanically fitted rather than sprayed.
These are different products with different implications for ventilation, moisture and any future sale. Treating one as the other leads to the wrong decision.
If you can't see your roof structure
Boarded lofts, plasterboarded room-in-roof conversions and lofts with no safe access all hide the roof slope from view.
In these cases visual identification from inside is not possible, and an inspection is the practical route to a documented answer.
The paperwork trail
Installer guarantee documents, handover packs and paperwork from a previous sale often name the product and the company that fitted it. That is the quickest confirmation available.
An EPC records that insulation is present, but it does not reliably identify spray foam specifically. An EPC alone should not be treated as confirmation either way.
Why it matters
Spray foam in a roof void can raise questions during a house sale, and buyers' surveyors and lenders frequently ask for evidence about it. If that has already happened to you, read more on spray foam and mortgage or sale problems.
Depending on the installation, foam can also create ventilation and moisture risks in the roof. Whether it has is a question of fact, established by looking at the roof itself.
Before you go up there
- Do not cut, drill, scrape or pull at the foam to test it.
- Do not attempt to remove any of it yourself.
- Loft spaces contain unsupported ceilings between the joists — take care with your footing and take a proper light.
- If access is difficult or unsafe, do not attempt it.
What to do next
There are two routes, depending on what you found. Reports are delivered within 48–72 hours as standard, with a 48-hour turnaround available for an additional £50.
Not sure what's up there
Loft Condition Report
From £175 — a documented snapshot of the loft, photographed and recorded.
Loft Condition Report — from £175Confirmed spray foam
Spray Foam Inspection
£295 fixed — foam type, adhesion, timber condition and calibrated moisture readings.
Spray Foam Inspection — £295