.9Gallon Kool-Lastik Heavy Duty Primer - Kool-Lastic is a rubberized undercoating that is specially formulated for troublesome, problem roofs and ponded water situations. It will help improve your topcoat adhesion, giving you better leak protection. It has a light blue color, making is easier and more efficient to apply your top coat and can be cleaned up with soap and water while still wet. Should be applied in two coats and Must Be Topcoated! It is recommended for the following roof types - modified bitumen, rolled roofing, bonded tar and gravel, most asphaltic roof surfaces and also for roofs where water ponds. It IS NOT recommended for asphalt/fiberglass shingles. This product is also good for use as a base when converting a black asphalt roof to white. Drying time is approx. 2 hours for dry to the touch and approx. 6 hours until it can be recoated (depending on air temperature and humidity). Coverage is anywhere from 50 to 100 square feet per gallon, depending on the surface it is being applied to. .9Gallon can.