How to Remove All Types of Stains From Concrete

Over the years, concrete can accumulate quite a few nasty stains. From oil in the driveway to grill grease on the backyard patio, these stains leave your concrete looking dated and unappealing, especially if they were there when you moved in. No need to worry, though! You can usually remove those stains easily and quickly, depending on how old it is. Here’s how to remove all types of stains from concrete.

Why does concrete stain

Concrete consists of natural materials: water, sand, gravel and cement. While cement doesn’t naturally occur, it is made from limestone, clay, sand and iron ore, all-natural materials. As a result, concrete is porous, just like any other natural material. It absorbs anything that makes its way to its surface.

Because of this, it is important to try to address spills as soon as possible. Soak up as much of the spilled material as you can with paper towels. Or cover the area with an absorbent material like clay or clumping cat litter on the affected area. Work it in with a stiff broom or brush and leave it for at least an hour. (Older stains may take up to 24 hours.) Then, sweep away the absorbent.

This may get rid of new and small stains entirely. If the concrete stain remains, follow the steps below, depending on what type of stain you are dealing with, to rid your concrete of it.

Removing oil stains from concrete

Oil from your car, lawnmower, or other motorized equipment can create particularly difficult concrete stains. If you still have a stain after blotting with a paper towel or using an absorbent material to soak up the oil, you may be able to remove the oil using laundry detergent or a mixture of vinegar, washing soda, and dish soap. However, a degreaser is the most effective approach.

Tip: Never use bleach as it will strip the grey color from the cement leaving your driveway, garage floor or patio with a discolored spot. You should also avoid using steel wool or a brush with hard bristles on your concrete as these can damage the concrete.

To remove an oil stain from your concrete using a degreaser, follow these steps:

Read the degreaser’s instructions and always defer to the information there.
Spray the degreaser onto the stain.
Let it sit for at least five minutes or as directed by the manufacturer’s instructions.
If dealing with a stubborn stain, scrub it with a soft-bristled sponge.
Wipe the degreaser off.
Then, mop to ensure the degreaser is completely removed.
If the stain remains, repeat the process.

Stubborn stains may require extra action. Try mixing one cup of trisodium phosphate (TSP) in a gallon of hot water and pouring this over the stain. Let it soak for at least 30 minutes and scrub with a brush. Wash off with your hose and repeat as necessary.

Removing food grease stains on concrete

Grease from the grill or juices dribbled from a platter being carried across the patio can cause tricky stains. As always with a concrete stain, immediately try to blot it up with a paper towel. If the stain persists or you’re dealing with an older stain, tackle it with the following approach.

Apply laundry detergent to the stain. If you are using dry detergent, add water to make it into a paste.
Make sure to cover the entire area.
Cover the detergent with plastic wrap and secure with tape. This prevents water from washing the detergent away.
Let the detergent sit overnight.
The next morning, scrub it with a soft brush and rinse with water.

Removing paint stains from concrete

Overspray from a project can leave your concrete stained. Depending on how long the paint has been there, you may never fully be able to get the color out of the concrete. However, by following these steps you’ll at least be able to minimize the stain.

Mix TSP in water using a ratio of one cup TSP to one gallon of hot water.
Pour over the affected area and let it soak for at least 30 minutes.
Scrub it into the stain with a soft brush.
Rinse and allow the area to dry for a few hours.
Scrape off the paint with a putty knife or use a pressure washer to get rid of the paint.
Allow the concrete to dry if you pressure wash.
Next, apply paint thinner and follow the manufacturer’s instructions.
Use a scraper or pressure washer to remove paint.
Repeat process as needed.

Removing rust stains from concrete

Whether caused by a forgotten tool exposed to the elements or iron patio furniture, rust stains on concrete are relatively common. You can remove them with minimal effort. A newer stain may only require the use of a common acid like lemon juice or vinegar. Pour juice or vinegar on the stain, let it sit, scrub, rinse and repeat if necessary. For tougher rust stains, you may need a commercial rust remover.

To remove a rust stain using a commercial product, read the manufacturer’s instructions and follow the recommendations for application. Leave the product on for at least 15 minutes or as instructed by the manufacturer. You can scrub the stain with a brush if the stain is particularly tough. Rinse with water, and repeat.

Removing dirt and foliage stains on concrete

Sometimes, dirt and leaves that accumulate on the concrete for long periods can stain it. Removing these brown stains can be just as tricky as any other, especially if they are old. To get rid of these stains, do the following:

Sweep away all debris and dirt.
Mix liquid dishwashing detergent and water in a spray bottle or bucket for larger stains.
Apply the detergent and water mixture to the stain.
Let it sit for 15 minutes.
Scrub with a soft brush.
Rinse the area and repeat if necessary.

Removing pet stains from concrete

If you have a dog run or your four-legged friend has the occasional mishap on the back patio, you may have pet stains to contend with. Not only do those stains look bad, but thanks to the porous nature of concrete, they smell bad, too. As a result, it isn’t enough to deal with how look. You also need to eliminate the odor. Take these steps to rid yourself of both:

Clean the area thoroughly, if it is not already clean.
Mix a solution of 1/8 of a cup liquid dishwashing detergent, ½ cup baking soda, and one gallon of water.
Pour over the stain.
Use a soft brush to scrub the stain away.
Rinse the area.
To get rid of the odor, use an oxygenated enzyme pet stain cleaner.
Follow the manufacturer’s instructions for best results.
Rinse with water.
Repeat as necessary to get rid of lingering odors.

Removing bird droppings from concrete

Birds can make quite a mess, especially if they roost on your roof and make a habit of leaving their waste on concrete. The process of removing bird droppings from your driveway, patio or walkways is similar to removing pet stains. However, if the birds have been eating berries or other foods, the stains left behind may take a few extra steps.

Hose away any droppings on the concrete.
Mix a solution of 1/8 of a cup liquid dishwashing detergent, ½ cup baking soda, and one gallon of water.
Use a soft brush to scrub the mixture into the stain.
Rinse, or use sawdust to absorb the soapy water. Sweep the sawdust away.
Combine 1 tablespoon 12 percent hydrogen peroxide with three drops of ammonia.
Apply this to any remaining stains.
Scrub with a brush until the stains are gone.
Rinse.

How to clean concrete with a pressure washer

You can remove many of the stains above using a pressure washer. If you don’t already own one, you can rent a pressure washer at most home improvement stores. Before you get started, make sure you have the appropriate pressure washer spray tip or nozzle. Narrow-pattern spray trips work best on tough stains but can damage the concrete, so select the tip depending on how tough the stain is.

Dress for the task. Since you are working with chemicals, wear splash-resistant safety goggles, a long-sleeved shirt, long pants closed-toe shoes and chemical-resistant gloves.
Wet the concrete with a hose.
Ready the pressure washer to apply the soap by installing the spray tip you want to use.
Add the concrete cleaner to the pressure washer.
Connect the hose to the pressure washer
Insert the pressure washer siphon tube into the concrete cleaner.
Start the pressure washer.
Apply the cleaner evenly, working back and forth with overlapping sprays.
Let the cleaner soak for three to five minutes.
Place the siphon in clean water, and let the washer run until the water comes out clean.
Spray the concrete with clean water to get rid of the cleaner.

You may need to break this down into sections so the cleaner-sprayed concrete doesn’t dry completely before you wash the cleaner away. If you are pressure washing your concrete to remove stains, you may need to repeat the process several times in difficult areas. Or try one of the stain-specific methods above.

How to seal concrete to prevent stains

Now that you have removed stains, you’ll want to make it easier to keep clean in the future. One way to do that is to seal your concrete. If you have an older home, you first need to remove any existing sealant. Not sure if your concrete already has sealant? Pour water on it. If the water beads, it has a sealer; if it soaks into the concrete, it hasn’t been sealed before. To remove existing sealant:

Clean the concrete. Make sure there is no dirt at all.
If you get the concrete wet while cleaning, allow it to dry for at least 24 hours.
Fill cracks with concrete crack sealer, smoothing with a putty knife.
Follow the manufacturer’s instructions regarding dry time.
Use a roller or paint sprayer to evenly apply a thick coat of stripper to the concrete.
Follow manufacturer’s instructions regarding how long to wait before removing.
Use a long-handled scraper to remove the sealant.
Scrub the floor with TSP and water.
Let dry for 24 hours before applying new sealant.

Once you have removed the old sealant (or let your newly poured concrete cure for 30 days), you’re ready to apply the new sealant. Follow these steps:

Check the weather. You need up to three dry days (the sealant won’t adhere to damp concrete) with temperatures above 50 degrees Fahrenheit.
Follow manufacturer’s instructions for drying times and specifics regarding the application.
Apply the first coat and wait at least two hours before applying the second one.
Paint the second coat at right angles to the first coat. This ensures consistent coverage.
Don’t step or drive on the new sealant until it is completely dry. This can take up to three days.

How to epoxy coat concrete

A good way to keep your garage floor clean is to apply epoxy. (It can also hide stains you’re unable to remove.) Before you apply epoxy, you’ll need to prep it by following the steps above for preparing your concrete for sealant. The concrete needs to be clean and dry. You should also fill in any cracks, and if your concrete is sealed, you’ll need to remove the existing sealant.

With the sealant gone, you’re ready to purchase an epoxy kit. These come in a variety of colors and give you the option to add color flakes, which can hide any imperfections in the concrete. You can also mix in an anti-skid additive that will give the floor a gritty surface that’s a good idea for rainy and icy regions. Once you have your epoxy kit, follow these steps:

Check the weather. Like sealant, epoxy requires temperatures above 50 degrees Fahrenheit, but the temperatures must also be below 80 degrees to prevent bubbling and peeling.
Make sure you have plenty of time. Once you mix the epoxy paint and hardener, you have only two hours to work.
Tape around the edges of the wall just as you would for painting.
Pour the epoxy into a roller tray.
Use a 3-inch paintbrush to paint along the wall, getting into the corners and along the edges.
Roll the epoxy starting in the furthest corner from the exit.
Work in 10-by-10 sections.
Continue until you cover the entire floor.
If you plan to use two coats, allow the floor to dry for 12 to 24 hours. Then, apply a second coat.
If you are using color flakes, apply after every section.
Prepare the topcoat according to instructions.
Apply similarly to the epoxy.
Allow to dry for 24 hours before walking on the floor.
Wait 72 hours before parking a car on it.