Rust-Oleum LeakSeal Spray Aluminum 12 Ounce repairs and prevents leaks on a wide range of demanding surfaces. This rubberized coating seals cracks, fills small holes and provides firm-but-flexible protection against moisture and rust on surfaces that need it most. Great for gutters, roofs, flashing, ductwork, PVC, masonry, concrete and more. Seals leaks and cracks water tight. Paintable finish. For best results perform a test spray on cardboard to get a feel for the spray pattern.