Case Study: Open-Cell Spray Foam Removal & Loft Insulation Upgrade – Ascot, Berkshire

A detached family home in Ascot, Berkshire had open-cell spray foam applied directly to the roofing membrane across roughly 60m². With the foam blocking a sale, the owner needed it removed to a surveyor-ready standard — and the loft properly re-insulated afterwards.

The problem

The homeowner’s loft had open-cell spray foam applied directly to the roofing membrane across roughly 60m². As many owners discover, spray foam in the loft is now routinely flagged by building surveyors and mortgage lenders — it hides the condition of the roof timbers and felt, and can trap moisture against the structure. In this case the foam had become a barrier to selling the property: the customer needed it removed to a standard that would satisfy a surveyor, and wanted the loft properly insulated afterwards.

What we did

Our team began by protecting the property with dust sheets and scaffold boards to contain debris throughout the works. We then carefully removed the spray foam from the roof structure, scraping the rafters, hips and apex by hand to fully expose the timber and felt beneath — the standard building surveyors expect to see.

With the membrane exposed, we inspected the felt and carried out minor repairs to small tears. Where felt is perished beyond repair we always notify the client before proceeding — in this case the membrane was in serviceable condition. All foam waste was removed from site and disposed of responsibly under our registered Waste Carrier Licence.

The insulation upgrade

With the loft clear, we supplied and installed an additional 150mm of Knauf mineral wool insulation over approximately 40m², bringing the loft insulation up to a total depth of 300mm — exceeding the 270mm typically recommended and improving thermal efficiency in line with current building regulations.

Because the works involved removing existing insulation and installing approved energy-saving materials in a qualifying residential property, this project was zero-rated for VAT under HMRC Notice 708/6.

The result

The roof timbers and membrane are now fully exposed and inspectable, the loft is insulated to 300mm, and the homeowner received their site audit report and Mortgage Approval Certificate within 48 hours of completion — everything a lender or surveyor needs to see.