Effective and easy to use, Great Stuff™ Pestblock insulating foam sealant blocks insects and pests from entering the home by sealing gaps, cracks and holes while improving energy efficiency all around the home. Great Stuff™ Pestblock insulating foam sealant is a ready-to-use foam sealant that expands up to 1 in to take the shape of gaps, creating a long-lasting, airtight and water-resistant seal that blocks out spiders, ants, cockroaches, mice and more from entering the home without the use of pesticides.