Douglas Fill and Fix Foam is a polyurethane-based expanding foam used for filling gaps, fixing frames, insulating, and backing. It's an easy-to-use product suitable for general construction and home improvement applications. Use it to fill large, irregular, or awkward gaps where the foam will expand to completely fill the cavity. It's also great for fixing window and door frames, boards, and for 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 works well with all types of sealants.