The best asphalt driveway sealer is one that contains polymers and other additives that increase the range of protection offered by the product. These sealers offer protection against oil and gas spills in addition to protection from the effects of weathering. They also contain a high percentage of filler material that sinks into small gaps and cracks to create a solid surface.
Most asphalt driveway sealers are not able to withstand the damage caused by oil and gasoline unless they contain additives. Oil and gasoline dissolve asphalt. Coal tar driveway sealers are better than standard asphalt sealers at providing this protection. Many manufacturers, recognizing this problem, have added polymers to the standard mixture to offer additional protection.
Asphalt driveway sealers have the distinction of being environmentally friendly. They do not emit gases that harm air quality, and they are less likely to irritate the skin.
Most sealers are rated for residential or commercial use. Though sealers designed for commercial use are able to withstand higher traffic volumes, manufacturers create their own labels for these products, with no standardization of the grades between manufacturers. The best way to determine the durability of a driveway sealant is to check the manufacturer's warranty. Cost of the sealer is generally another indication of quality.