Harwal Rigid Polyurethane Spray Foam Insulation is a high-performance, spray-applied polyurethane foam insulation that is used to insulate walls, roofs, and other areas of a building. It is a closed-cell foam that is sprayed into the cavity between the framing members of a wall or roof. The foam is sprayed in a continuous bead and is designed to provide a continuous, air-tight seal.