The term 'roof coating' refers to a protective layer applied to the surface of a roof in order to protect it from the elements. The most common type of roof coating is TAR, which is a three-letter word. TAR is a dark, viscous liquid made from the distillation of coal, wood, or petroleum. It is used to waterproof and protect roofs from the sun's ultraviolet rays, as well as to prevent corrosion and rust. TAR is also used to seal cracks and seams in roofs, and to provide a durable, long-lasting finish.