Spray Foam Roof Insulation: Should You Get It?

If you're searching "should I have my roof spray foam insulated," you've probably already heard there's a catch — and there is. Short answer: we'd advise against spray foam roof insulation, at least for now, and we're not the only ones saying so. Here's the full picture so you can make an informed decision rather than just take our word for it.

What is spray foam roof insulation?

Spray foam insulation is a liquid foam, applied directly onto the underside of your roof — the rafters and sarking boards — using a spray gun, which then expands and sets into an insulating layer. There are two main types: closed cell spray foam, which sets rigid, and open cell spray foam, which stays soft. On the surface it's appealing — quick to install, strong thermal performance, and it was heavily promoted (and grant-funded under schemes like the Green Homes Grant) throughout the 2000s and 2010s as a fast way to insulate a loft.

Why spray foam roof insulation has become a problem

The issue isn't the insulation performance itself — it's what it does to everything around it, and what that means for your mortgage.

Spray foam bonds directly to the timber roof structure. Once it's in, there's no way to inspect the condition of the rafters and boards underneath without removing the foam first. That matters because trapped moisture and restricted air circulation in the roof space can cause those timbers to rot — and with spray foam in place, nobody can see it happening until it's already a serious problem.

Can you get a mortgage with spray foam insulation?

In many cases, no — or only with real difficulty. Research by the BBC and the HomeOwners Alliance found that only around a quarter of the UK's biggest mortgage lenders will lend on a property with spray foam in the roof. Several, including TSB, Skipton Building Society, Co-operative Bank and Principality, have said outright they won't lend on these properties at all, and no equity release providers will either. It's estimated as many as 250,000 homes across the UK now have this problem.

Is spray foam insulation worth the risk?

If you install spray foam now, you could be creating a real obstacle for yourself (or whoever owns the property next) when it comes to remortgaging or selling — even if it's installed perfectly, by a fully certified installer, with all the right paperwork. Lenders have largely taken the view that it's not worth assessing case-by-case, and simply decline.

The HomeOwners Alliance and the Property Care Association have both gone as far as formally advising homeowners not to install spray foam insulation until there's clearer industry-wide guidance and lender support in place. That's a strong signal, and it's the same advice we'd give.

What if your home already has spray foam insulation?

If your home already has spray foam and you're planning to sell or remortgage, you're not necessarily stuck — but it usually means getting a proper inspection from a PCA-registered specialist, and in many cases, professional spray foam removal before a lender will touch it. It's worth sorting out well before you need to sell, not scrambling once you're mid-sale.

What's the alternative to spray foam loft insulation?

For most lofts, traditional insulation — mineral wool or fibreglass laid between and over the joists — does the job just as effectively for warmth, costs a lot less, and causes none of these problems, since it never touches or hides the roof timbers.

Roof insulation advice across Denton, Stockport, Manchester and Tameside

If you're unsure what's actually in your loft right now, or want an honest opinion on what's worth doing before winter, get in touch and we'll take a proper look — no pressure, just straight advice for your roof, wherever you are across Greater Manchester.