Lenders reject homes with spray foam insulation

However, the work was not up to scratch, according to a report by Stephen Hodgson, the former boss of the Property Care Association (PCA) who now inspects properties with spray foam and trains surveyors.

After sales stalled and difficult conversations with lenders, Ms Rowe agreed to replace the roof entirely, splitting the cost of nearly £10,000 with new buyers.

She said it has cost the family thousands more in surveyors' and administration fees and utility bills.

The firm that installed the spray foam, SealSixty, gave the family £400 as a gesture of goodwill and said the work met all the requirements set out by the Green Homes Grant scheme at the time.

Ms Rowe said that her family had been "left high and dry".

"It was installed under a government initiative, and you really don’t expect them to turn their back," she said.

Spray foam insulation has been used to stop heat escaping from roofs, lofts and attics for decades and comes in two forms.

Closed cell spray foam is rigid once set. It is a better thermal insulator and was previously sold to stabilise failing roofs. But if it has been used inappropriately or installed poorly, it might put stress on timbers, restrict air circulation and put them at risk of decaying.

Open cell spray foam remains soft once set and is only used for insulation. It is more breathable but is often installed where a highly-resistant underlay like bitumen felt is already present, stopping vapour from escaping.

While a recent report by the Health and Safety Executive highlighted situations where using open cell was low-risk, it cautioned against applying it directly to roof tiles.

But homeowners like Gary Wright feel like they have been "left in limbo".

When his two-year fixed-rate mortgage was up for renewal, he hoped to find a better rate.

But when he applied he was shocked to discover open cell spray foam had been installed in 2009. It had not come up during surveys when he had bought the house.

He decided to remove most of the foam in the loft himself, after receiving several expensive quotes.

A surveyor still recommended a full roof report and Mr Wright felt he had to renew his mortgage with his current lender at a less preferable rate.

"We know that in the next two years, we need to get this fixed, and I can’t afford to right now," he said.

For homes where it is already present, the HOA recommends:

A government spokesperson said it had "consulted lenders about this matter who say they rely on the views of valuers and surveyors on this issue".

They added any measures fitted under government schemes must be done by a Trustmark-registered installer "to the highest standards with issues promptly and properly rectified".

Further information on Trustmark's dispute resolution process can be found here.