Insulating Lining paper is 4mm thick providing basic and effective wall insulation and resistance to condensation problems - as with 'Heatsaver', this product is treated with fire retardant. The product is supplied ready laminated to a reinforced liner for easier handling and to provide a basic surface that it is possible to paint directly although overlining is important to achieve a good finish and to improve the durability of the surface.This product is suitable as a localised ‘problem solver’ for cold external walls and is not recommended for use in fire escape routes inside your home unless the surface is further treated with a fire retardant covering. This product is class E fire rated and should not be used for projects such as new builds and extensions where Building regulations are applicable.