Products / CertainTeed SMARTCOAT 301 Fibered Acrylic Mastic

Water-based, fiber-reinforced 100% acrylic elastomeric roof mastic for sealing seams, fasteners, penetrations, splits and tears before a SMARTCOAT 400 or 401 acrylic coating is applied. CertainTeed lists it for metal, asphalt, modified bitumen, concrete and most single-ply roofs. It is white, comes in 3.5 gallon pails, dries in 4 to 8 hours and covers about 12 to 13 sq ft per gallon at 1/8 in thick.