Alcolin Filla Foam is a one-part moisture curing expanding polyurethane foam, which is used to fill, seal, and insulate. It cures to a durable, semi-rigid structure, is non-shrinking and has outstanding insulating properties. It has exceptional adherence to most construction materials and is suitable for interior and exterior applications. AAlcolin Filla Foam is weatherproof and damp proof. It is non-toxic and will not expand, shrink or decay once cured.