Q: We have an asphalt driveway that over the years has developed cracks and some minor potholes. It has become an eyesore. Can the asphalt be restored? Is this something I can do myself?
A: Old and badly damaged asphalt or blacktop driveways sometimes require resurfacing by a professional asphalt paving contractor. The pros use hot-mix asphalt patch, fillers and sealers. This is the only way to achieve permanent repair. The hot-mix materials and equipment are not available to the do-it-yourselfer. However, many times such driveways can be restored to like-new condition by using cold-mix asphalt patching materials developed especially for the do-it-yourselfer.
Restoring a blacktop driveway is basically a four-step process. The first step is to thoroughly examine the driveway to determine which repair materials are necessary and then to give the surface and base a preparatory cleaning. Loose materials in potholes or crumbled areas should be dug out to the earth base of the driveway. Weeds growing through cracks or holes should be pulled out by the roots. Using a weedkiller is another option.
The entire driveway should be swept clean and hosed down. If you own an air compressor, you can use it to blow loose debris out of the cracks. Wear safety glasses if you use a compressor.
If the driveway has areas where films of grease or oil have accumulated from dripping automobiles, those areas should be treated with a special asphalt-driveway cleaner or scrubbed with a strong detergent and rinsed thoroughly. The basic materials needed for blacktop repair are bagged, pre-mixed asphalt patch material for filling potholes, badly damaged areas and large cracks; asphalt-crack filler; and a surface sealer. You will encounter two sizes of cracks: hairline, which can be filled by applying filler or sealer; and grooves, one-eighth-inch wide or larger, which require the use of crack filler.
The key to successful patching is a clean, solid base. On larger cracks and potholes, dig out any loose asphalt or gravel and make sure the edges of the area to be patched are firm, not crumbling. Keep scraping and chiseling the edges until you have a solid base.
Most manufacturers recommend repairing driveways when the temperature is 55 degrees or more; warmer conditions with low humidity speed drying time.
Once the area is clean and dry and the weather is favorable, you are ready to proceed with the patch. Fill holes within one inch of the top with the asphalt patch mix. Use a 4-by-4 timber to tamp the mixture into the hole. Make sure it's pressed firmly against the edges. Next, add additional patch mix so the filled area is about a half-inch above the level of the driveway. Finally, tamp this area flush using the 4-by-4. If the hole is deep, it should be filled with gravel to within four inches of the surface. Tamp the gravel using a solid piece of lumber.
The repair area should be lightly coated with asphalt sealer. Use a shovel and metal trowel to apply cold-mix asphalt-patching compound in one-inch layers. Each layer should be firmly tamped. Air bubbles can be removed using the tip of the trowel.
The final layer of patching compound should be built up to a half-inch above the surface. Tamp the patched area and lightly dust with sand. For a final tamping, use your car and drive a tire back and forth over the patched area until it is level.
Do not walk or drive on the area for about 48 hours to allow the patch to harden. After filling cracks and patching holes, you have to wait awhile before sealing.
Follow the directions for specific waiting periods and instructions on sealer application; some products require a dry surface, while others recommend a slightly damp one. Before you apply the sealer, sweep the area. The sealer can be applied with a sealing brush or squeegee, an old push broom or a roller.
Don't try to seal the entire driveway at one time; the sealer is likely to start drying before you are able to spread it. Try working in sections of 100 square feet at a time.
If your driveway has never been sealed, it may need two coats. The first usually needs to be completely dry before you apply a second.
While sealers are basically cosmetic, a high-quality sealant will provide some preventive protection against cracking and staining.
Most asphalt driveways are intended to last 15 to 20 years but begin to show aging after just five to seven years. Annual inspection and repair of small cracks and crevices as they appear will help extend the life of your driveway. Done properly, repairs with cold-patching materials will give you good durability. However, often they are not permanent and may have to be repeated.
If cracks and holes are left unattended, water that seeps in and under your driveway will weaken and undermine the asphalt-based surface. In northern climes, damage will accelerate as the surface heaves with the freeze-thaw cycle. The alternative to regular maintenance is eventual resurfacing by a professional, a far more expensive project.
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