Sealing your asphalt driveway is a necessary preventative measure to ensure protection from water. Cracks and potholes from water damage can result in expensive repairs. Here are a few tips for applying asphalt sealant: When sealing your driveway, make sure there is no expectation of rain for up to 72 hours after application. Also, the ground temperature must be above 45 degrees Fahrenheit. Avoid coming into contact with sealant and avoid vapor inhalation. Clean off the surface of the asphalt with detergent and rinse well before you begin. When finished, allow time for the sealant dry completely. Apply the sealant in thin layers, and try to work on one small section at a time. Finally, the sealant will take approximately 24 hours to dry, do not drive or walk on the driveway during this time. More here