How to Clean and Seal an Asphalt Driveway

Planning Your Driveway Sealing Project

Sealing an asphalt driveway is one of the most cost-effective ways to protect your home's curb appeal and extend the life of the pavement. Over time, UV rays, water, road salt, and vehicle fluids break down the asphalt binder, causing the surface to become brittle, crack, and fade. A fresh coat of sealant fills small cracks, blocks water penetration, and restores that rich, black finish. This project is best tackled over a long weekend — plan for one day of cleaning and prep, one day for filling cracks, and one day for applying sealer, plus drying time between coats.

Begin by evaluating the condition of your driveway. Lightly worn surfaces with small hairline cracks are ideal candidates for sealing. If you have large potholes, major alligator cracking, or areas where the asphalt has sunk or heaved, structural repair may be needed first. For most homeowners, a standard two-car driveway (roughly 20 feet wide by 30 feet long) requires about 500 square feet of coverage. Buy a commercial-grade coal tar or asphalt emulsion sealer — avoid cheap water-based products that may not last through two winters.

Mistakes to Avoid

Many first-timers skip thorough cleaning and end up with sealer that peels within months. Pressure washing is essential: remove all dirt, oil, and old flaking sealant. Do not apply sealer if rain is forecast within 48 hours — water spots ruin the finish. Another common error is applying the sealant too thickly. Thick coats take days to dry and may remain tacky, trapping dirt. Always apply two thin coats rather than one thick one. Also, avoid sealing during extreme temperatures. If the surface is too hot, the sealant bubbles; if too cold, it never cures. Finally, do not rush the drying time after the final coat. Keep vehicles and pets off the driveway for at least 48 hours, and ideally 72 hours in cooler conditions. Driving on a partially cured sealant will leave tire impressions that are permanent.

Safety

Sealants and crack fillers contain chemicals that can irritate skin, eyes, and lungs. Always work in a well-ventilated area — outdoors is fine, but avoid enclosed spaces like garages. Wear rubber gloves, safety glasses, and long pants and sleeves. If you are using a coal tar-based sealer, consider a respirator rated for organic vapors. Keep children and pets away from the work area until the sealer is fully cured. Dispose of any rags or applicators used with sealant according to local hazardous waste regulations — do not throw them in the trash wet, as they may auto-ignite. Pressure washers are powerful; never point the spray at people or pets, and wear sturdy boots to avoid slipping on wet pavement.

Step-by-Step Instructions

The steps below assume a clean, average-condition driveway. Adjust the time for drying and curing based on your climate and the specific products you buy. Always follow the manufacturer's instructions on the sealer and filler labels — they are tested for that specific product.

1. Clear and Inspect

Remove all vehicles, furniture, potted plants, and toys. Sweep thoroughly. Mark cracks and stains with chalk. If you have weeds growing through cracks, pull them and apply a weed killer a few days before sealing to prevent regrowth. Do not skip this step — weeds will push through fresh sealer.

2. Pressure Wash

Use a pressure washer with at least 3000 PSI and a 25-degree nozzle. Work in overlapping passes from the high side of the driveway down. Keep the nozzle moving to avoid etching. For oil stains, apply degreaser and scrub with a stiff broom before rinsing. Let the surface dry completely — this takes at least 24 hours in good weather. In humid conditions, allow 48 hours. The surface should look light grey when dry; if it still seems damp, wait longer.

3. Treat Oil Stains

If after pressure washing you see dark stains, treat them with a commercial oil stain remover or a paste of cat litter and dish soap. Scrub, let sit, then rinse. Repeat if needed. Do not apply sealant over an oil stain — the sealer will not bond and the stain will bleed through.

4. Fill Cracks and Potholes

For cracks up to 1/2 inch wide, use a rubberized crack filler in a squeeze bottle. Force the nozzle deep into the crack and fill until it overflows slightly. Use a putty knife to level the excess. For potholes or wide cracks, fill with cold patch asphalt compound, tamp it down firmly, and allow to cure per the label — usually 24 to 48 hours. The filler must be fully hard before sealing.

5. Mask and Protect

Apply painter's tape to concrete curbs, garage floor edges, and any decorative borders. Lay drop cloths over grass, plants, and walkways adjacent to the driveway. Sealant drips are difficult to clean, and they kill grass. Also tape over any drainage grates or utility covers.

6. Apply First Coat of Sealer

Mix the sealer thoroughly with a stirring stick or drill mixer. Do not thin unless the product instructions say so. Pour sealer into a roller tray or bucket. Use a thick-nap roller designed for rough surfaces, attached to an extension handle. Start at the top of the driveway and roll the sealer in a thin, even layer. Work in sections about 3–4 feet wide, overlapping each pass slightly. Use a squeegee or a wide brush to get into edges and corners. Avoid puddles — they will not dry correctly and may peel. The goal is a uniform coat that covers the grey without being thick enough to hide the surface texture.

7. Let Dry and Apply Second Coat

Allow the first coat to dry for 12 to 24 hours, or as directed. The sealer should be dry to the touch and not sticky. If the color looks blotchy, proceed with a second coat. Apply the second coat the same way, perpendicular to the first for best coverage. Two thin coats last longer than one thick coat.

8. Remove Tape and Cure

Peel off the tape and drop cloths while the second coat is still slightly tacky — this avoids pulling up dried sealant. Now comes the hardest part: leaving the driveway alone. No foot traffic, pets, or vehicles for at least 48 hours. In cooler weather, wait 72 hours. If it rains during the curing period, check for water spots after the surface dries — they often disappear on their own.

Final Check

After the sealant has fully cured, inspect the driveway for any missed spots or thin areas. A properly sealed driveway should have a uniform, matte black appearance. Drive slowly and avoid sharp turns for the first week to prevent tire marks. With annual cleaning and touch-ups, a good seal job can last three to five years before reapplying.

By taking the time to do the prep work — cleaning thoroughly, filling cracks, and applying sealer in proper conditions — you will extend the life of your driveway and keep it looking great for years. This is a project that any motivated DIYer can complete in a weekend, and the payoff in curb appeal and protection is well worth the effort.