Ruscoe's 12-1 Seam Sealer is recommended for sealing openings less than 1/8 inch. It can be used as an effective sealant against water, chemicals, air and dirt for sealing seams in gutters, downspouts, roof and chimney flashings, animal feeders and troughs, wood, concrete, ceramic, brick, metal, stone, masonry, marble and glass. Ruscoe's 12-1 Seam Sealer is recommended for sealing horizontal seams only.