EVO-STIK SYSTEM G Gun Applied Expanding Foam is a durable, one component isolation and construction foam developed to seal between stony construction parts. The polyurethane foam cures under the influence of humidity in the air and substrate. It has excellent thermal and acoustic insulation properties and is damp proof. It expands rapidly to fill and seal holes around window and door frames, or in brickwork, rendering and plaster - then hardens ready to be trimmed, cut, sanded and painted.