Desktop surveys are no longer considered by lenders because spray foam insulation has become a major problem. When installed incorrectly, spray foam insulation stops much-needed circulation which can lead to timber decay. This is considered a major structural risk by lenders. Desktop valuations don’t consider that a property might have spray foam insulation on its roof space. This simple mistake can cost your new homeowner thousands of pounds in the cost of spray foam insulation removal. You can file a complaint via the Financial Ombudsman Service (FOS).