Told to remove it, or holding a removal quote
Urged to remove the foam: the main loft needed action, the smaller section did not
near Wigan · Recent inspection · Spray Foam Inspection
The house
Single-storey home, T-shaped tiled roof on trussed rafters: a 9.7 × 7.0 m main loft and a smaller south section. Soffit vents at side and rear; tile vents added after the foam.
The foam
Open-cell, fitted in 2022 on finance, sprayed onto a membrane where seen, and over the gable walls. Depth varies: short of the rafter face in places, almost 4 in proud of it in another.
The paperwork
Supplied: product warranty, approval document, installer letter. Missing: contract, workmanship warranty, credit agreement, pre-installation timber readings, condensation risk analysis. The approval document rules out foam over cables or ventilation gaps, and gaps in the layer; photographs show all three.
Why they called
After repeated unsolicited approaches recommending removal, the homeowner wanted an independent view on whether the foam could stay.
What was measured
- 14 timber readings: all 11 in the main loft at 18% or more, three at 20.0%, 20.0% and 20.2%; all 3 in the south section below 18%.
- Loft air 1.5 g/kg wetter than outside on average, up to +2.8 g/kg; 10.4 g/kg, against 10.6 in the room below.
- Dew point 14.6 °C, coldest surface 16.0 °C at the eaves: a 1.4-degree margin.
- Eaves filled with foam at every point photographed, against the report's reference of about 0.24 m² of opening per side.
What it means
The telling line is the loft air, almost as moist as the living space. In the report's reading, moist air from the house is reaching the loft and staying, because foam has sealed the eaves. Two of the three wettest timbers were ceiling joists above the rooms, while the valley where water once came in read 18.1%: pointing to moisture from inside, not a leak.
What happened next
The main loft should not be left as it is: remove the foam, or keep it and deal with the causes. An electrician for the cabling, a roofer to confirm the valley repair if unrecorded, then repeat readings in colder weather.
For other homeowners
If you are urged to remove foam, find its approval document first: it says how the foam must be fitted, so the work can be checked against it.
Read the guide: Do you need to remove spray foam? Removal, costs and what to check first · Spray foam cold calls and removal scams: how to check a caller
The honest limit
Timber behind the foam could not be seen, the roof was seen from the ground only and the valley repair not at all, the room below was read with the hatch open, and one sunny day cannot show the coldest nights.