Should You Pressure Wash Asphalt Before Sealing?

Not always. For most asphalt driveways, a thorough sweep, a leaf blower, and spot-cleaning oil stains are enough prep before sealing. Pressure washing helps when there's caked-on dirt, moss, algae, or grime a stiff broom can't lift. But asphalt is softer than concrete, and aggressive washing can blast loose fine stone and roughen the surface. If you do wash, use a wide fan tip, moderate pressure, keep the wand moving, and then give the driveway plenty of time to dry completely, often a full day or two in good weather, before sealing.

How to sealcoat → Sealcoating a wet driveway →

Why Surface Prep Matters

Sealer needs to grip clean asphalt. Dust, dirt, leaves, oil, and moss all create a barrier. Poor prep is one of the most common reasons sealcoat peels, flakes, or wears early. Our guide on driveway sealer peeling lists the usual causes.

Should You Pressure Wash Asphalt Before Sealing? When It Helps

Pressure washing makes sense when:

• Moss, algae, or mildew has built up in shady areas
• Caked mud or clay has dried onto the surface
• Heavy grime from years without cleaning won't come off with a broom
• Chalky residue or dirt is packed into the surface texture

When to Skip It

You can usually skip the pressure washer when:

• The driveway was sealed within the last few years and is only dusty
• A stiff broom and blower get the surface clean
• The asphalt is old, rough, and raveling, where high pressure could loosen more stone
• There's no time for the driveway to dry fully before your sealing window

Some sealcoating contractors say asphalt should only be pressure washed where there's heavy moss, algae, or dirt that brooms can't handle, because too much pressure can strip the surface.

How to Pressure Wash Asphalt Gently

1. Sweep first. Remove loose debris so the washer isn't pushing it around.
2. Pre-treat stains. Scrub oil and grease spots with an asphalt-safe degreaser and rinse. See our guide on removing oil stains.
3. Choose a wide tip. A wide-angle fan nozzle spreads force out. Avoid pinpoint and turbo nozzles.
4. Use moderate pressure. More isn't better on asphalt. Start low and increase only if needed.
5. Keep a distance. Hold the wand back from the surface and keep it moving in overlapping passes.
6. Work downhill. Push water and dirt toward the street or lowest edge.
7. Stay away from edges and cracks. Blasting into cracks can wash out base material and loosen crumbling edges.
8. Rinse thoroughly. Leftover detergent can interfere with sealer bonding.

Wear eye protection and closed-toe shoes. Pressure washer spray can cut skin, so never point it at people or pets.

How Long to Wait Before Sealing

This is where many DIY jobs go wrong. Asphalt holds water in its pores and cracks. Sealer applied over damp spots can bubble, peel, or dry blotchy.

• General guide: At least 24 hours of dry, warm weather, often more
• Longer: In shade, cool temperatures, humidity, or after heavy washing
• Check cracks and low spots: They dry last

A simple moisture check: tape a small square of clear plastic to the pavement in a shady spot and leave it for an hour or so. If moisture collects underneath, wait longer.

Many people wash one day and seal a day or two later, weather permitting.

Alternatives to Pressure Washing

• Stiff push broom for general dirt
• Leaf blower to clear dust, sand, and fine debris after sweeping. This step is easy to skip but makes a big difference
• Garden hose with a spray nozzle for a lighter rinse
• Scrub brush and cleaner for spot stains
• Edger or scraper for grass and weeds along edges

Don't Forget Cracks

Clean and fill cracks before sealing. Blow out dirt, pull weeds, fill with the right crack filler, and let it cure per the label. Our asphalt crack filler guide walks through it.

A Sample Prep Schedule

Here's how a DIY weekend might look when the driveway truly needs washing:

• Thursday evening: Pull weeds from cracks and edges, sweep, and scrub oil spots.
• Friday morning: Pressure wash gently, working from the garage toward the street. Let the sun do its work.
• Saturday: Blow out cracks, fill them, and let the filler cure. Check shady spots with the plastic test.
• Sunday: If the surface is dry, the filler has cured, and the forecast is clear, seal.

If Friday turns cloudy and cool, push everything back a day. Waiting costs nothing, while sealing a damp driveway can mean redoing the job.

Hiring a Pro

Most sealcoating contractors include cleaning in their price. Ask how they clean, whether they pressure wash, how they handle oil spots, and how long they wait before sealing. If they plan to wash and seal the same day, ask how they ensure the surface is dry.

Bottom Line: Should You Pressure Wash Asphalt Before Sealing?

Should you pressure wash asphalt before sealing? Only when sweeping and spot-cleaning can't get it clean. If you do, use a wide tip, moderate pressure, and steady movement, avoid blasting cracks and edges, and let the driveway dry completely before sealing.