Eventually with time, exposure and use, asphalt will crack and decay. When pavement becomes too damaged to repair or salvage it becomes necessary to remove and replace the existing asphalt. All existing blacktop would be removed, leaving the stone base, which may require installation of additional stone and regrading to ensure positive draining. New layers of blacktop are to be installed in lifts according to specifications. Most commercial parking lots require at least 3" - 4", half base blacktop and half surface blacktop.