Should I Buy a House with Spray Foam Insulation?

Finding a house you love with spray foam insulation can be a huge headache. While it’s marketed as an energy saver, this type of insulation is a major red flag for mortgage lenders because it can cause severe timber rot and other hidden defects.

It can make a property un-mortgageable and a costly mistake. This guide will help you understand the risks and what you need to do to protect yourself.

Why is spray foam insulation a problem?

Lenders view spray foam as a major risk because it can cause timber rot in the roof. The foam creates an impermeable barrier that can trap moisture and prevent the roof from breathing.

This makes it impossible for surveyors to inspect the roof timbers for rot, damp, and other structural defects. Because the condition of the roof cannot be confirmed, the property's value is uncertain, making it a high-risk asset for a lender.

Major high-street lenders and all equity release providers are particularly strict and will often refuse to lend on a property with spray foam.

The uncertainty of the roof's condition means it is classed as a high-risk property, and it may not meet a lender's criteria. This is why a property with spray foam insulation can be considered unmortgageable.

Open-Cell vs Closed-Cell spray foam

There are two main types of spray foam insulation. Open-cell foam is less dense and is often used in residential properties. Closed-cell foam is more rigid and is generally considered to be more problematic.

Its moisture-trapping nature is a major concern for lenders as it poses a higher risk of timber decay.

Both types can lead to a mortgage refusal, but closed-cell is viewed as the more significant risk due to its dense, rigid structure.

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What to do if a property has spray foam

If you find a property that has spray foam, you need to proceed with extreme caution. The risks are high, but there are steps you can take to protect yourself:

1. Ask the Seller for Documentation: Request the original installation certificates and any warranties.
2. Instruct a Specialist Surveyor: Find a RICS-qualified surveyor who specialises in spray foam. They will need to perform an invasive inspection, which involves drilling into the foam to check the condition of the timbers beneath. You will have to get the seller's permission for this.
3. Be Prepared for a Refusal: Even with a specialist report, be aware that many lenders may still refuse to lend.

How much does it cost to remove spray foam?

The cost of professional spray foam removal can vary significantly, usually ranging from £2,000 to over £5,000, depending on the size of the area and the complexity of the job.

You will also need to budget for a replacement roofing membrane and a new insulation material.

Long-term risks to consider

Even if you can secure a mortgage on a property with spray foam, this may not be a long-term solution. When you come to sell or remortgage the property in the future, you will likely face the same issues.

Your pool of potential buyers may be limited to cash buyers, as a new buyer will likely face the same problems getting a mortgage. This could significantly impact the property's value and your ability to sell it.

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