Case Study: Roof Replacement & Open-Cell Foam Removal After a Failed Removal – Near Woking, Surrey

A homeowner near Woking, Surrey had already paid another company to remove spray foam from their loft — but the job was never properly finished. Behind a layer of vapour foil, foam was still bonded to the roof structure and the membrane had perished. The honest fix was a full roof replacement alongside removal of the remaining 52m² of open-cell foam.

The problem

This homeowner had already paid another company to remove the spray foam from their loft — but the job was never properly finished. When we inspected, we found open-cell foam still bonded to the roof structure and a perished membrane, concealed behind a layer of vapour foil. To a casual glance the loft looked clear; behind the foil, the problem was still there.

Because the membrane was perished beyond repair, the honest solution was a full roof replacement alongside the spray foam removal of the remaining 52m² of open-cell foam.

What we did

We erected a two-lift scaffold with debris netting to protect the neighbouring properties, then carefully stripped the existing tiles and removed the battens with the foam still attached. The remaining foam was stripped from the roof structure, with the rafters, ridge boards, hips and apex scraped and cleaned back to sound, fully exposed timber — the standard surveyors and buyers need to see. The structure was then prepared for a universal 5-star wood treatment.

With the roof stripped back, we rebuilt it properly: new over-fascia vent strips and felt support trays at eaves level, a new premium breathable membrane, new sawn treated battens, and new large concrete interlocking tiles installed to the manufacturer’s recommendations and the Code of Practice for Slating and Tiling, finished with half-round concrete ridge tiles on a vented dry ridge system.

Inside the loft, we boarded working areas to protect the ceilings and installed new Knauf mineral wool insulation to a minimum depth of 300mm, satisfying current Building Regulations. The job was completed with a full gutter clean and site clean-down, signed off by our lead roofer, with all waste disposed of under our registered Waste Carrier Licence.

The result

Every trace of foam is gone, the roof has been rebuilt from the rafters up, and the loft is insulated to 300mm. The homeowners received an LABC completion certificate, a mortgage approval certificate with photographic evidence of the work at every stage, and a 10-year insurance-backed guarantee.