Roofline & Maintenance
Spray Foam Insulation: Why We Won’t Install It
Spray foam roof insulation can trap moisture against timbers, block ventilation, and prevent proper structural inspection. An estimated 250,000+ UK homes now face mortgage and resale problems because of it. We do not install it, regardless of the upfront cost saving.
You may have seen spray foam insulation advertised as a fast, modern way to insulate a loft — sometimes through government grant schemes, sometimes through door-to-door sales. We want to be upfront: we don’t install it, and we’d strongly advise against anyone doing so. Here’s the honest reasoning, not just a blanket "no."
What is spray foam insulation?
Spray polyurethane foam (SPF) is sprayed directly onto the underside of roof tiles, felt, or rafters, where it expands and hardens to form an insulating layer. It was heavily promoted across the UK through the late 2010s and early 2020s as a quick energy-efficiency upgrade. It comes in two types: open-cell (softer, more breathable) and closed-cell (denser, more rigid, and the type causing the most serious problems).
Why has it become such a serious problem?
Closed-cell spray foam applied directly to roof timbers creates a real, documented set of issues:
- Trapped moisture — the foam can trap moisture against the timber, encouraging rot and decay that isn’t visible from below
- Blocked ventilation — roofs are designed to breathe; foam can block the airflow that prevents condensation build-up
- Impossible to inspect — once applied, a surveyor cannot see or properly assess the condition of the timbers underneath, which is exactly what a mortgage valuation needs to confirm
The Royal Institution of Chartered Surveyors (RICS) has issued formal guidance advising surveyors to treat spray foam as a flagged risk during valuations. As a direct result, most high-street mortgage lenders now decline or heavily restrict lending on properties with spray foam in the roof space — and reports suggest over 250,000 UK homes may currently be affected.
Can I still get a mortgage if I have spray foam insulation?
In most cases, not without extra steps. A small number of lenders will consider a property if a PCA-registered (Property Care Association) surveyor inspects the foam and confirms, in writing, that it isn’t causing damage — but this depends on the foam type, when it was installed, and whether proper ventilation was maintained. For many homeowners, professional removal followed by a full timber condition report is the only reliable route back to normal mortgage lending.
What if I already have spray foam insulation?
Don’t panic, but don’t ignore it either — particularly if you’re planning to sell, remortgage, or release equity in the next few years. We’d recommend:
- Get a specialist inspection — a PCA-registered surveyor can assess whether the foam is currently causing damage
- Check your installer’s paperwork — if the installation came with a guarantee, you may be entitled to remediation from the original installer or their insurance backing
- Consider professional removal — in most cases, this is what actually restores normal mortgageability, followed by proper re-insulation with a material we’d genuinely recommend
We don’t carry out spray foam removal ourselves, but we’re happy to advise honestly on what we see during any roof survey, and recommend appropriate specialists where needed.
What we install instead
Mineral wool, PIR rigid board, and reflective foil systems — specified correctly for your specific roof type and void shape. None of these carry the moisture-trapping or inspection-blocking risks of spray foam, and all are widely accepted by mortgage lenders and surveyors without complication. See our full roof and loft insulation guide for Merseyside for materials, costs, and area-specific advice.
We won’t install spray foam insulation at any price, regardless of what it might save on the quote. If a company offers it without mentioning any of the above, that’s worth treating as a genuine red flag.
Not sure what your roof needs?
We offer free surveys across Merseyside. We go up, take photos, show you what we find and give you an honest recommendation. No pressure, no obligation.