About EWI Poorly insulated properties of solid wall construction: The solution There are a great deal of properties in the UK of solid construction. These could be constructed from solid brickwork, concrete or masonry. These properties in the past have been difficult to insulate, which is problematic considering that up to 35 percent of heat loss is through the walls. The best solution to tackle heat loss through the walls is by installing an EWI system. The EWI system comprises of fixing an insulation system to external structure of the property. The EWI system would encapsulate the entire solid wall structure of the property. Effectively cladding it, the insulation cladding will then be rendered to an aesthetically pleasing finish offering minimal maintenance.