Formulated with specialized acrylic latex polymer that forms an elastomeric sealant. It is designed to perform on troublesome roof surfaces and ponded water situations. It is recommended for use on rolled roofing, bonded tar and gravel, modified bitumen, built up roofs, and most asphaltic roof surfaces. It is not required or recommended for metal or coated metal roofs. This product is a heavy duty rubberized undercoating primer and must be topcoated. Primer is light blue in color and designed to improve adhesion of elastomeric roof coatings on troublesome surfaces and prevent leaks. It expands and contracts with your roof. Can be used as a base to convert black asphalt to white. Soap and water clean up while wet. Do not use on roofs with a slope of 1/2" or less per foot. Coverage: 25 to 100 sq. ft. per gallon, depending on surface. Color: Light blue. 5 gallon (actual contents 4.75 gallon).