How to Clean Concrete Floors (Indoor and Outdoor)

By thewriteDuffy •  Updated: 10/29/22 •  5 min read

Concrete is a sturdy material for indoor and outdoor floors. It’s durable, easy to clean, and fairly resistant to stains.

But concrete will stain. It’s porous and will soak up dirt, and spills and harbor mildew. Tough as concrete is, it will need periodic scrubbing.

Here’s how to clean concrete, both indoors and out.

How to Clean Concrete Floors Outdoors

A power washer is the easiest way to clean concrete outdoors.

You should be able to blast away dirt, mildew, and grime in a single afternoon.

If you don’t own one (and I seriously consider getting one for outdoor cleaning, they are invaluable), you can rent one. Either way, read the instructions on how to use your pressure washer before you start your first project with it, and check out my post about techniques for pressure washing brick and concrete.

Power washers do have a lot of power and if used improperly can damage your concrete floor.

Spray the patio surface with a detergent; I like OxyClean Outdoor Multipurpose Concentrated Cleaner (Amazon link) because it works well, doesn’t stink like some others, and is a brand I know and trust.

Next, use a stiff brush to scrub it into the concrete. Never use a metal-bristle brush as the metallic fibers can get trapped in the porous surface of the concrete and rust. I personally like this inexpensive one from Amazon (Amazon link), which has a good stiff brush and a squeegee on the other end for when you need to get the water off to see how it’s going.

Put on safety goggles and gloves. Turn on the pressure washer to the correct setting. Move the wand from one side, using the same motion as you would if you were mopping a floor.

How to Remove Tough Stains from Outdoor Concrete

If you have particularly tough stains on your outdoor concrete, there are many options of cleaners to remove them ranging from household cleaners, natural cleaners, and heavy-duty chemical cleaners.

Here are your options:

Using Bleach or Ammonia to Remove Stains from Concrete

Want to know how to remove stains from concrete? There are several options. You can use bleach, or ammonia (NEVER mix the two), or other commercial solutions if you prefer.

A Natural Concrete Stain Remover Solution from Hydrogen Peroxide

For a more natural solution to stubborn stains on interior concrete floors, mix flour and hydrogen peroxide into a paste roughly the consistency of peanut butter. Spread it over the stained area and let sit overnight. Then, scrape with a plastic-edged scraper tool (like the back of the brush I recommended above).

Using Trisodium phosphate to Remove Tough Concrete Stains

Trisodium phosphate (TSP) mixed with water and scrubbed onto the stained area with a nylon bristle brush can remove REALLY tough stains. Scrub until the stain is gone and rinse with a hose. TSP is available at home improvement stores, or of course on our trusty Amazon here.

Use Muriatic Acid to Eat Away Impossible Concrete Stains

Muriatic acid (like Acid Blue) can be used on outdoor floors to clean the toughest stains, like rust or dried grout. But be warned that it’s a powerful, toxic material that should be used with extreme caution.

Wear protective eyewear and gloves when using it and be sure to follow manufacturer instructions on how to clean concrete with muriatic acid.

Products Recommended for Outdoor Concrete Floor Cleaning

Yocada 2 in 1 Floor Stiff Bristle Scrub/ Scrape Brush
$18.99

55.9" Telescopic Handle brush and squeegee combo.

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12/08/2022 07:03 pm GMT
OxiClean | Outdoor Multipurpose Concentrated Cleaner -
$18.99 ($0.15 / Fl Oz)

Concrete Cleaner to Remove Stains on Driveway, Vinyl, Aluminum, Roof, Wood, Brick & Carpet, Grease and Grime Cleaner (1 Gallon)

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12/08/2022 09:17 pm GMT
Savogran Trisodium Phosphate (TSP)
$28.00

Kelan-Strip Green safer muriatic acid heavy-duty cleaner.

1LB (16oz)

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12/08/2022 08:54 pm GMT
Acid Blue Muriatic Acid by CPDI

Swimming Pool pH Reducer Balancer and Concrete Cleaner.

Buffered, Low-Fume.

1 Gallon Bottle.

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How to Clean Indoor (Polished or Stamped) Concrete Floors

For indoor concrete floors that are polished or stamped, you’ll need to take a gentler approach.

You’ll just use a mop and a bucket of water mixed with a mild cleaner.

Don’t use ammonia, bleach, or any highly acidic substance (like the stain removers I mention above) on polished or stamped floors.

Some good cleaners include Castile soap, liquid dish detergent, stone cleaners and mild floor cleaners. The OxiClean cleaner I mentioned above can work, just make sure to dilute it more than usual.

Mix a solution, apply it to the concrete floor with a wet mop, and then rinse with a mop dipped in clean water.

Products Recommended for Outdoor Concrete Floor Cleaning

Dawn Ultra Dish Liquid
$10.47

Dishwashing Liquid (Original Scent)

2.64 L

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12/08/2022 09:07 pm GMT
Dr. Bronner’s - Pure-Castile Liquid Soap
$36.95

Unscented, Made with Organic Oils

473 mL, 2-Pack

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12/08/2022 09:12 pm GMT
OxiClean | Outdoor Multipurpose Concentrated Cleaner -
$18.99 ($0.15 / Fl Oz)

Concrete Cleaner to Remove Stains on Driveway, Vinyl, Aluminum, Roof, Wood, Brick & Carpet, Grease and Grime Cleaner (1 Gallon)

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12/08/2022 09:17 pm GMT

How to Prevent Future Stains on Your Concrete Floor

To make your concrete floors resistant to future stains, apply a concrete sealant. Use a paint roller to apply it to clean, primed concrete.

There are many specialty concrete sealers for each type of concrete floor you may have, such as stamped, polished, foundation, etc., so choose one that meets your individual needs.

Start in the middle of the area and roll the sealant out to the edges. Floors need to be resealed every two to three years.

Knowing how to clean concrete properly will keep the floors in your garage, workshop, and house looking good as new.

thewriteDuffy

At home, April is a mom, wife, and DIY darling. Among other home projects, she helped her husband Dan renovate their 1986 bungalow and is currently designing and decorating the 2023 custom home they are building themselves. Professionally, April is a writer, author, and online marketer with 15 years of experience writing for newspapers and magazines, building online authority websites, and publishing books.