When you find a gap or crack that’s a real monster, Great Stuff Big Gap Filler is the stuff. Big Gap Filler is a ready-to-use, expanding polyurethane insulating foam sealant that fills, seals and insulates gaps up to 3 inches (76 mm). Forms a long lasting, weather-tight seal to reduce drafts for greater comfort and lower energy bills. It will adheres to wood, drywall, metal, masonry, glass and most plastics and has elasticity that allows for movement and shifting within a structure.