Flex Seal Liquid is an easy-to-use rubberized coating that starts out as thick liquid, seeps into cracks and holes and dries to a watertight, flexible, rubberized coating. Flex Seal Liquid creates a super strong, protective rubber coating that blocks out air, water and moisture.Once cured it forms a watertight, weatherproof, non-slip barrier that is resistant to rain, snow, sun, wind, hail, air, moisture, UV degradation, extreme temperatures and natural weathering.It is mildew and chemical resistant and helps prevent rust and corrosion. Perfect for DIY projects, crafts and hobbies. Can be used on concrete, glass, brick, stucco, masonry, wood, PVC and so much more.