Told to remove it, or holding a removal quote
Holding a removal quote: the right foam, with ten departures from its product approval
Essex, London fringe · Recent inspection · Spray Foam Inspection
The house
Detached rendered house with a pitched tiled roof. One main loft, with no insulation on the ceiling. No ridge vents, and at a 23.65° pitch and 5.25 m span guidance does not call for them.
The foam
Open-cell foam, sprayed in 2021 straight onto a breathable membrane, as its approval document permits. Slopes only. Depth ran from bare membrane to about 254 mm at the eaves, with an empty bay beside an overfilled one.
The paperwork
Supplied: contract with a ten-year workmanship warranty, the product approval document and a 25-year product warranty. The installation departed from that approval document in ten places. The contract set no thickness, so there was never a figure to build to; the 25-year warranty covers replacement product only, not removal or labour.
Why they called
The homeowner had been told the foam was installed incorrectly and held a removal quotation. The installer had since entered liquidation.
What was measured
- Loft air held a 3.8 g/kg excess over outside air, nearly twice the 2.0 g/kg of the room below.
- At the ridge, moisture rose from 10.0 to 11.4 g/kg during the visit.
- Nine timber readings, every one 11.6%, including beside the chimney. No rust on any accessible fixing.
- Both eaves filled with foam over 100% of their 8.2 m run, against guidance of roughly 0.082 m² of opening per side.
What it means
The 3.8 g/kg gap between loft and outside air decided this one. In a loft that breathes, the two are normally close; this one was collecting moisture it could no longer clear. With no ridge vents, the roof depends on air crossing between the two eaves, and both were sealed. On what could be measured, that is a ventilation problem to fix, not damage to repair.
What happened next
Restoring ventilation comes first. The report set out options, not one answer: reopen both eaves and fill the bare bays; remove the foam and return to a ventilated cold roof; or re-measure in winter before deciding.
For other homeowners
Holding a removal quote? Ask why removal rather than completing the installation: here the product, surface and area were all correct.
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
One sunny summer afternoon, 23.0 °C outside; the riskiest time is typically a cold winter night. Foam-encased timber could not be measured, the lower roof was not entered, and with the covering not seen from above, water getting in could not be excluded.