Douglas Fill and Fix Foam is a polyurethane-based expanding foam designed for general construction and home improvement applications. It's easy to use and can be applied to fill large, irregular, or awkward gaps where it will expand to completely fill the cavity. This foam is also suitable for fixing window and door frames, insulating between brickwork and cladding, and backing as a joint backing material. It can be used with all types of sealants and comes in a 750ml size.