Douglas fill & fix foam is used to filling gaps, fixing frames, insulating and backing. It's an easy to use, polyurethane-based expanding foam for general construction and home improvement applications. For filling large, irregular or awkward gaps where the foam will expand to completely fill the cavity. It's also suitable for fixing window and door frames and boards, insulating between brickwork and cladding, around ductwork and through cavities carrying pipes and cables. Additionally, it can be used as a joint backing material and is compatible with all types of sealants.