Closed-cell vs open-cell spray foam removal

Spray foam in UK lofts is usually one of two types. Knowing which you have helps you understand the survey, the quote and what your lender is likely to say.

Open-cell foam

Open-cell foam is the less dense type and is common in homes. As a rough guide, it feels soft and spongy if you press it.

Closed-cell foam

Closed-cell foam is denser and rigid, and feels hard. It forms a barrier that can trap moisture against the timbers, and buyers' guides describe it as carrying a higher risk of timber decay.

How lenders see each type

Either type can lead to a mortgage refusal. Closed-cell is generally treated as the more significant risk because it is dense and rigid. Equity release providers are particularly strict about both.

What it means for removal

• Open-cell usually comes away from the timbers more easily, so jobs tend to be quicker.
• Closed-cell bonds firmly, so expect the job to take longer and cost more. Ask how the firm will protect the roof membrane, and whether a new membrane might be needed.
• With either type, rot or damage found once the foam is off adds repair work.

Firms that say they handle both types are marked in the directory. See removal costs for typical prices.