Lenders have now deemed desktop surveys a thing of the past due to spray foam insulation becoming a significant issue. When installed badly, spray foam insulation can prevent much-needed circulation, which can cause timber decay, and lenders deem this a significant structural risk. Desktop valuations do not consider that a property may have spray foam insulation in its roof space, and this simple error may cost the new homeowner £1000s in the cost of having the spray foam insulation removed. Customers may file complaints against lenders via The Financial Ombudsman Service (FOS).