What spray foam is, and why it was sold
Spray foam insulation is a liquid that is sprayed onto the underside of a roof, usually between and over the rafters, where it expands and sets. It was widely marketed as a quick way to make a loft warmer and, in some cases, as a fix for loose tiles or a draughty roof.
There are two broad types. Open-cell foam is softer and spongy, and lets some moisture vapour through. Closed-cell foam is denser and harder, and acts much more like a barrier. Both are bonded to whatever they're sprayed on, which in a loft means the rafters, the battens, the membrane, and sometimes the back of the tiles or slates themselves.
Why surveyors and lenders raise it
Many surveyors and lenders raise questions about spray foam, and it has become a common point in home buyer reports. The concern isn't the foam itself so much as what it prevents: a proper look at the roof structure. When a surveyor can't see the rafters, battens or underlay, they can't comment on their condition, so they note it.
What happens next varies from case to case. Sometimes buyers want more information, sometimes the lender asks questions, and sometimes the sale simply takes longer. We can't tell you what any particular lender will decide, but we can tell you what's actually going on in your roof.
What it can hide
A roof needs to breathe. Moist air from the house rises into the loft, and in a traditional roof it escapes through gaps and ventilation. Cover the whole underside in foam and that air movement can stop. Moisture may then condense where it can't dry out, against timber that sits in the dark for years.
The things foam can conceal include:
- Damp or decayed rafters and battens.
- A torn, perished or missing membrane under the tiles.
- Corroded nails and fixings holding the tiles or slates.
- Old leaks that were never properly repaired.
None of this is guaranteed to be there. The point is that nobody can say either way while the foam is in place.
Why it can't easily be inspected
Because the foam is stuck to the surfaces it covers, you can't peel back a corner and have a quick look. Cutting small inspection holes shows a few square centimetres at best. From outside, a roofer can check the tiles, ridges and flashings, but the structure underneath stays out of sight. In practice, the only way to see the whole roof is to take the foam away.
Your options
If foam has been flagged, the usual route is removal followed by a proper check of what was hidden. We carry out spray foam removal across Somerset and Devon, and once the foam is off we look over the battens, membrane and timbers so you know where the roof stands. If you're wondering what the work involves price-wise, our guide to spray foam removal cost explains what changes the figure.
Repairs after removal
Sometimes the roof underneath is fine. Sometimes there are a few battens or patches of membrane to replace, which is ordinary roof repair work. Occasionally, the roof covering and structure are in poor enough shape that a full strip and re-roof makes more sense. Either way, you'll get a free written quote setting it out before anything goes ahead.
Call Jason on 07399 680142 (Mon to Fri 8am to 5:30pm, Sat 8am to 3pm) or send details through the contact page.