'New loft insulation made my home unsellable' More homeowners caught as rogue trading surges in lockdown Caroline Dudley, pictured, had spray foam installed in 2017 Credit: Tony Buckingham When Caroline Dudley, 74, spent £4,500 on spray foam insulation for her Norfolk home in 2017, she thought she was doing her bit for the environment while cutting her energy bills. She never thought the decision would render her home worthless. However, she is one of a number of people who spent thousands on insulation technology only to find out later it had made their homes unsellable. Several banks have become unwilling to lend against properties that have spray foam insulation applied to the underside of roofs, in lofts and against rafters.