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How to Clean a Concrete Driveway
When you have stains on your concrete driveway, it’s necessary to treat them with the correct stain remover and clean before applying the sealer. If possible, work on stains while they're fresh. Always follow the directions for using the cleaner. Wear the specified safety gear, especially eye protection. Determining what kind of stains you have will help guide you to the best concrete cleaner for the job.
Before sealing, you should make any concrete repairs if your surface is chipped, cracked or has holes.
Removing Oil and Grease Stains
- Cleaning and getting rid of oil and grease stains can be done in several different ways. From using household product to commercial solvents, spots can be effectively removed from the surface.
- The first step before applying any remover is to try and blot up any excess oil with paper towels or old rags. Rubbing the stain will only drive it deeper into the concrete.
- Household products like cat litter, baking soda and dishwashing soap, or laundry detergent can help absorb and break down the stain. Sprinkle cat litter over the stain and let it sit for several hours, then sweep up the remains. With baking soda and dish soap or powdered detergent, make a paste with water and apply it to the oil spot. Scrub with a brush to help remove the stain.
- With commercial cleaners, apply a degreaser or concrete soap according to the product directions and then rinse with water.
- For older stains, using Trisodium Phosphate (TSP) or WD40 on the stains will help lift them out of the concrete.
- Always scrub the stain with a stiff brush to make sure the solution is worked into the stain. Rinse the area with a garden hose or a pressure washer for the best results.
Removing Paint Spills From Concrete
- Removing paint stains or spills can be a bit tricky depending on the type of paint you are trying to remove. Water-based latex paints will be easier to get rid of than oil-based paints. Also, fresh spills are easier to clean than dried stains.
- Many latex paint stains can be erased with the same methods used for grease stains. Baking soda or TSP mixed with water and applied to the paint spot can work to loosen the stain, followed by scrubbing with a stiff brush. Rinse with water to finish cleaning.
- Oil-based paints may require using a chemical paint stripper. This may necessitate applying the stripper and waiting several hours for the chemicals to react and loosen the spill. You can scrape the loosened paint away with a scraper or putty knife.
- Pressure washing the concrete surface can quickly loosen paint stains from concrete. Older stains and multiple layers of paint may need to be sand blasted for removal. Be cautious as this can be destructive to the concrete surface.
Removing Rust and Dirt Stains
- Rust stains on your concrete will need to be dissolved for proper removal. Household items like lemon juice or vinegar are both acidic and can help dissolve the spot. Apply either directly and let it sit for about 15 minutes. Scrub with a stiff brush and then rinse well.
- Commercial products like rust remover CLR (Calcium, Lime and Rust Remover) or oxalic acid will work well on older and tougher rust stains. Apply CLR to the rust spot, let it sit for the appropriate time, scrub with a brush and rinse. For oxalic acid, mix with water and treat the stain by scrubbing. Rinse thoroughly with water.
- Clay-based soil is especially prone to staining as it has iron oxide particles that give it the reddish color. These fine particles can penetrate deep into the pores of the concrete and make stains hard to remove. Iron oxide is also not water soluble or vulnerable to detergent, which makes clay very stubborn to remove.
- Using a pressure washer is a valuable tool to tackle rust and dirt. The high pressure of the water can loosen persistent stains, saving you time and effort.
How to Clean a Concrete Driveway With a Pressure Washer
After treating stains, you're ready to clean the concrete with a driveway pressure washer. Select the appropriate pressure washer spray tip or nozzle based on how deep your stains are. A 25-degree tip should be good for most cleaning. For heavy-duty cleaning, a 15-degree tip may be needed. Many models come with a specific nozzle for spraying soap and cleaners. If your pressure washer kit doesn't include spray tips or nozzles, you can purchase universal ones.
Wear the appropriate safety gear and clothing: splash-resistant safety goggles, a long-sleeved shirt, long pants, closed-toe shoes and chemical-resistant gloves.
Step 1: Rinse Off the Driveway
Use a garden hose with a spray nozzle to rinse off the entire concrete surface. Removing any loose dirt and debris before applying soap will help the soap reach all areas of your drive.
Step 2: Prepare Your Pressure Washer
Install the soap-spray tip by pulling back on the spray wand collar and pushing the tip into place. Release the collar. Connect a garden hose to the pressure washer and turn on the water. Always operate the machine with a steady flow of water. Insert the pressure washer siphon tube into the concrete cleaner container or add the soap to the detergent tank.
Step 3: Start the Pressure Washer
Start the pressure washer by pulling the starter cord for gas pressure washers or turning on the start switch if you have an electric model. If you pull the starter cord and the motor doesn't start, you may need to squeeze the spray wand trigger to release pressure in the line before pulling the cord again.
Step 4: Evenly Apply the Concrete Cleaner
Thoroughly spray the concrete with cleaner, working the wand back and forth in overlapping strokes. Keep the tip about 8 to 24 inches away from the surface. Let the cleaner soak according to the manufacturer’s instructions, but don’t let it dry out completely. If your drive is partially in the sun, try washing the concrete in manageable sections to better control drying.
Step 5: Flush The Washer Lines
Before rinsing away the cleaner, you need to clear the detergent from the siphon tube, so you don't apply more soap. Turn off the pressure washer and place the siphon tube in a bucket of clean water. Flush the pressure washer for about a minute or until the water comes out clear.
For washers with an onboard tank, fill it with clean water and rinse the system thoroughly until the water runs clear.
It is important to flush the system thoroughly. Allowing chemicals to remain in the pump could cause damage to the system.
Step 6: Clean Your Driveway
Turn the machine off and switch to a low or medium-pressure spray tip. Evaluate the spray on a small section of concrete. If the water etches the concrete, switch to a lower pressure tip. If the test area looks good, continue rinsing away the concrete cleaner. Use the same overlapping strokes as you did above, keeping the tip about 8 to 24 inches away from the surface. You might need to go over some areas twice. Keep the wand moving to avoid etching your concrete.
Do-It-Yourself Driveway Sealing
After the concrete has dried for at least 24 hours, inspect it for cracks, chips, and broken areas. Any of these should be repaired before applying the sealant. You can find concrete repair for fixing and patching to have a smooth surface prior to applying any sealant.
When any necessary repairs have been made, you can apply a concrete sealer. A sealer helps prevent future stains and potential damage from products like ice salts. Some sealers leave the surface with a shiny finish while others have a matte finish. You can also apply a sealer that has a concrete stain included for a new look to your driveway.
Remember to wear splash-resistant goggles and chemical-resistant gloves when applying the sealer.
Newer concrete might already have a sealer that's still in good condition. If it does, it won't accept certain sealants. Test by placing a few drops of water on the concrete. If the water beads up, there’s an active sealer. If the concrete absorbs the water, then it'll accept the sealer.
Step 1: Apply the Sealer
Garden/Tank Sprayer: Add the sealer to the sprayer's tank. Thoroughly cover the concrete with overlapping strokes. Try not to let the sealer build up anywhere. If you do get buildup, remove the excess with a rag. Complete the first coat and let it dry.
Roller and Brush: Apply the sealer just as you'd paint a wall. Start from the garage side and work your way down. You can cover large areas with a roller brush and extension. Use a large paint brush for the edges and seams. Apply a thin, even coat, trying to avoid puddling and over-application. Complete the first coat evenly and let it dry.
Always follow the manufacturer's directions for applying your sealant.
Step 2: Applying a Second Coat
Check the sealer instructions for drying times before starting your second coat. Apply the second coat at a perpendicular direction for more even coverage. Let it cure following the directions for the best concrete sealer.
Now that your concrete driveway is clean and sealed, you’ll want to keep it looking its best. You can see How to Clean Concrete Patio and Remove Stains From Concrete Floors for methods and tips.
