Sealing your driveway is an important part in maintaining an asphalt driveway and extending the life of it. Sealing prevents water from working its way into surface cracks and underneath the asphalt. Once water gets underneath an asphalt driveway, it can quickly begin to undermine the integrity of it. The water can cause erosion, which eventually will lead to sinkholes in the asphalt. In addition, during winter months, melting snow and ice water can work its way into the asphalt driveway cracks during the day and then freeze underneath the driveway when the temperatures drop. This situation leads to heaving, settling and eventual crumbling of the driveway. Sealing your driveway also prevents weeds growth and protects it from oil spills. It also protects the asphalt from the sun's ultraviolet rays, which break down the binding material in the asphalt.
Though you can pay someone hundreds of dollars to seal your driveway, you can easily seal your own driveway for a fraction of the cost with as little as a half-day's worth of work. That said, a newly poured asphalt driveway needs three to six months to fully cure prior to sealing it. This allows time for the hydrocarbon oils in the asphalt to evaporate and the asphalt to fully harden.
Prior to sealing your driveway, make sure to repair any cracks or holes in it by using either a cold patch or an asphalt driveway crack sealer. Asphalt driveway crack fillers are made from a synthetic rubber and come in either a tube that you apply with a caulking gun or in jugs where you simply pour the filler into the crack or hole. Once you've applied the crack filler, allow several weeks for it to fully cure prior to sealing your driveway.
To actually seal your own driveway, you'll need 5-gallon containers of coal tar driveway sealer. I recommend buying coal tar driveway sealer over asphalt based sealers due to the fact that coal tar driveway sealer does a better job of protecting the asphalt from oil and gasoline spills. The amount of driveway sealer containers required will depend upon the size of your driveway and the amount of square area each container covers. Typically, a 5-gallon container will cover 350 to 400 square feet. Calculate the area of your driveway and then divide it by the amount of area each container can cover. This will determine how many containers of driveway seal you'll need.
Apply the driveway sealer to your asphalt driveway on a warm day so that it spreads easily. To actually spread the driveway sealer, use a long handle squeegee or broom that is specifically made for sealing driveways. Prior to actually pouring the driveway sealer onto your driveway, make sure to thoroughly stir each container well. Make sure when applying the driveway sealer that you do not put it on too thick. Otherwise, it might take much longer to cure, and it would be susceptible to peeling.
After sealing your driveway, make sure not to walk or drive on it for a few days. Typically, a driveway sealer needs a couple of warm dry days prior to driving a vehicle on it. If the weather is less than perfect, you may need several more days to allow it to properly dry and harden.
Finally, keep in mind that sealing a driveway is not a once-in-a-lifetime event. To ensure a long asphalt driveway life, you should plan on sealing your driveway every two to four years.