Binder (also known as basecoat) and Topcoat are types of asphalt paving material, made from hot asphalt cement and aggregate. Depending on the specified use the percentages and sizes of aggregate vary. Typically a “Binder” Course also known as the load bearing coarse contains mostly 3/4” aggregate (The stone in the asphalt is larger), and is applied first at a thickness, depending on the application. “Finish” or “Top” coat contains mainly 3/8” Aggregate (the smooth topcoat that you see on most asphalt surfaces) for a smoother finish and is applied over the binder; its thickness is engineered, dependent on job specs.