Spray foam insulation is a material sprayed into roof spaces, walls or floors to seal gaps and keep heat in. It comes in two types:

• Closed-cell, which is rigid, dense and creates an airtight barrier
• Open-cell, which is softer and more flexible, allowing some airflow

It had been marketed as an energy-efficient option for years, but it’s now at the centre of growing concerns in the housing market.

Here’s where it gets tricky. Spray foam might help with heat loss, but lenders and surveyors often see it as a red flag. Why?

• It can trap moisture, leading to hidden damp or timber rot.
• Once applied, it’s hard to inspect the roof structure, so surveyors can’t always confirm if the timbers are sound.
• Some installers cut corners, leaving behind poor-quality work.

Because of all this, many lenders simply refuse mortgages on properties with spray foam. So, while it isn’t “bad” in itself, it makes selling harder because it scares off buyers.

In many cases, yes. Spray foam can knock a significant chunk off your property’s value because it shrinks the pool of potential buyers. A report by the BBC suggests a quarter of the UK’s biggest mortgage providers will not lend against homes with spray foam in the roof. If lenders won’t touch it, a cash buyer will likely be your best bet, but will pay less for the certainty and convenience.

Exactly how much your house is devalued depends on the size of the property, the extent of the foam and whether it’s open-cell or closed-cell. But expect buyers to push for a discount to cover either removal or the risk.

Here’s the sting: removal isn’t cheap. Professional removal can cost anywhere from £2,000 to £4,000, depending on how much foam you’ve got and how easy it is to get to. In some cases, removal may involve replacing roof timbers too, which adds even more to the bill.

It’s not a quick DIY fix, either. Removal is messy, time-consuming and needs specialist equipment. Some owners find the best solution is turning to a quick house buying company like House Buyer Bureau. We buy any property in any condition, without the hassle of negotiations or disappointment of sales which fall through.

Unless you’re able to find a buyer who’s happy with spray foam insulation (which is very unlikely), you’ll have to remove the spray foam before selling. While this can be costly it opens the door to more potential buyers. You can also look at selling at a reduced price to reflect the hassle and cost of removal.