Loft Insulation Case Study — Spray Foam Removal From a Pitched Roof, Basingstoke

The problem

Spray foam bonds to whatever it is applied to. Here it had been sprayed straight onto the roof felt and around the rafters, so the roof covering and most of the timber was sealed in and could not be seen or checked.

That is the difficulty with spray foam in a pitched roof. It restricts the airflow the roof was built to have, and it hides the condition of the timbers and the felt behind it, which is why surveyors and lenders so often raise questions about it. There is no treatment or coating that resolves it — the foam has to come off.

The one piece of good news was timing. The foam had only been in place for four years, so there was a reasonable chance the roof underneath had not suffered.

Our assessment

We recommended full mechanical removal, taking the foam back to bare rafters and felt across the whole roof rather than treating sections of it.

The loft was in use for storage and had solar PV equipment installed in it, so protecting the contents and the inverter was part of the job rather than an afterthought.

We also wanted the timbers properly exposed and cleaned down at the end, so the condition of the roof could actually be seen and assessed once the foam was gone.

The removal

The stored belongings and the solar PV equipment and cabling were sheeted and protected before any foam was touched.

The team then worked across the roof in sections, cutting the foam away from between the rafters and stripping it off the timber and the felt behind it.

Residue was scraped and cleaned off the rafters and the felt afterwards, which is the slow part of a spray foam removal — the bulk comes away far faster than the last layer bonded to the surface.

All of the foam was bagged and taken away from the property rather than being left in the loft or disposed of on site.

The result

The roof space is back to bare rafters and felt, with the timbers clean and visible along their full length.

With the foam off, we were able to inspect the roof properly. The rafters and ceiling joists were sound and no remedial timber work was needed, which is a better outcome than many spray foam removals produce.

The loft can now be inspected by a surveyor in the normal way, the roof can breathe again, and the ceiling is ready for conventional loft insulation to be fitted at joist level.