Buying a house with spray foam
Buying a house whose foam appears in no document, bonded to non-breathable felt
Wirral · Recent inspection · Spray Foam Inspection
The house
Detached house with a fully hipped cut-timber main roof, a flat-roof section carrying a solar collector, and a small void over a bay window. About 30 cm of glass-fibre quilt on the loft floor.
The foam
Rigid closed-cell foam, bonded straight to the original non-breathable bitumen felt. Patchy: a few spots unsprayed, and the eaves foamed solid in some runs but open with daylight in others. Its age could not be established.
The paperwork
Nothing found or provided for the foam: no installer, date, product or warranty. The only document in the loft, from 2011, covered a top-up of the floor quilt. The latest energy performance record listed the quilt and solar water heating, but no foam.
Why they called
The purchase was agreed, and the buyer, planning to stay long term, wanted independent evidence on the foam before exchange.
What was measured
- 18 timber readings, 7.6% to 19.3%, none at 20%. The highest were at the ridge board and purlins, in mid-summer.
- Foam 2 inches (about 50 mm) thick at an opening, over about 50 m² of main slope plus about 2 m² over the bay window.
- A bucket part-filled with dark liquid under the solar pipework, with drip marks on the quilt below. Timber at the discoloured foam above the plant read 11.6%.
What it means
The deciding finding was on paper, not on a meter. Undocumented foam has no known installer, product or date, so no warranty is known to call on and there is nothing to check it against. Bonded to non-breathable felt, it is also a set-up PCA guidance says may be treated as high risk. For a long-term home, the report's advice was not to leave it in place on trust.
What happened next
Through the solicitor before exchange: any foam paperwork, any insurance-backed warranty, and the solar system's records. A plumber promptly for the leak, an electrician for exposed wiring. Then removal as a planned job: foam and felt off together, eaves cleared, timbers treated, new breathable membrane, tiles re-laid.
For other homeowners
If you are shown paperwork for the loft insulation, check what it covers: here the only document was for the floor quilt, and the foam appeared nowhere.
Read the guide: Buying a house with spray foam: step by step · Should you buy a house with spray foam insulation?
The honest limit
One summer visit cannot show a cold winter night. Timber behind the bonded foam could not be seen, and the covering, flashings and flat-roof void were not examined close up.