Milling can save homeowners the cost of repaving an entire driveway. The process removes as much old surface as necessary, typically a depth of one to two inches.
For milling and repair to be effective, the ground underneath or sub-base must be dry and solid. Otherwise, new asphalt laid on top will fail. After milling and cleaning, a tack coat is laid down so new asphalt will adhere.
Milling is also used to lower spots to better drain a driveway, or to scuff it enough to enable new asphalt to bond during resurfacing. After repair, the new asphalt is compacted to restore it to level grade.