Driveway Sealer Types

Coal Tar

• Coal tar sealers are made from refined and distilled coal and are meant to seal asphalt driveways. Rubber additives are included to make the coal tar more elastic, and sand and clay make the sealers easier to apply and more durable. The advantages of coal tar include resistance to water, motor oil, gas and the ultraviolet rays of the sun. Problems include the tendency to be accompanied by strong odors and qualities that may cause skin irritation.

Asphalt

• Asphalt sealers offer protection for a standard asphalt driveway because they contain the same or similar materials as the original driveway. Recent improvements have made asphalt sealers more popular, and since they resist water as well as coal tar they are a good alternative. They're not as risky for people with skin sensitivity, and the odor is milder. The main problem with asphalt coatings is that since they're petroleum based they don't do a very good job at protecting driveways from gasoline or oil spills.

Acrylic Sealers

• Acrylic sealers are more expensive than the other two options but are also the best, especially for concrete driveways. These sealers are not yet as widely used for driveways as the other two types, but are very common for use on tennis courts and outdoor basketball courts. They are impervious to sunlight, water and petroleum products, and last for six to eight years before requiring another coating. They also don't build up thick layers over time as happnes with coal tar and asphalt sealers. Due to the long duration of effectiveness, the extra cost can be cheaper in the long run over the cost of the more frequently required sealant types.

Sealing Tips

• There are several tips for effective sealing of a driveway. All debris and vegetation should be removed and the surface rinsed with water. Depressions should be leveled and deep holes patched with cold filler. Cracks larger than a quarter inch should be filed with course sand or acrylic fillers. Oil or gasoline spills should be removed with special cleaners so the sealant will adhere in those spots. Finally, the driveway should be dampened with water to help the sealant bond to the driveway material.

When to Seal

• Depending on the sealant used, a driveway should be re-sealed every three to eight years. Applying a sealer too frequently isn't only a waste of time and money; it can also cause a buildup to occur, leading to peeling and loss of effectiveness. In most cases it's possible to see wear in an existing seal, which is a good indicator of when a new sealant coat is needed.