How to Clean Concrete

Durable, low-maintenance, and inexpensive, there’s a reason concrete is a homeowner’s go-to material when it comes to basement floors, patios, and driveways.

Of course, that doesn’t mean concrete is impervious to stains—it does require a good cleaning now and then. Whether you’re doing spring cleaning or have a problem stain, here’s how to clean concrete floors so they look their very best.

General Maintenance of Concrete Floors

Concrete floors should be cleaned at least once a year to keep them in tip-top shape. Before starting, remove any items from the area—if it’s an outdoor patio, remove all potted plants, furniture, and decorative items. Do a spot test by testing your cleaner in an inconspicuous area to ensure your method will not cause any additional discoloration or damage to your concrete.

To clean a concrete floor in your basement, you may need to do it in sections by moving everything from one side of the room to the other, and then switching back to finish the job.

Inspect your floors for cracks or chips and make any necessary repairs before beginning the cleaning process.

Steps for Cleaning Concrete

What You’ll Need:

• Broom, leaf blower, or vacuum
• Stiff nylon brush
• Spray bottle
• White vinegar
• Baking soda
• Laundry detergent
• Safety goggles
• Pressure washer

Step 1: Remove Loose Dirt and Debris

Sweep or vacuum loose dirt off the surface of your concrete, with one exception: if you have a mold or mildew problem. in your basement. Follow the instructions below for tackling these potential household toxins.

If you are cleaning a patio or driveway, remove and treat any weeds with a string trimmer that may have infiltrated cracks.

Step 2: Spot Treat Stains

One of the most budget-friendly ways to spot-treat stains is with liquid laundry detergent and water. Target the area by pouring the soap directly onto the stain; use a stiff nylon brush to scrub the area (avoid wire-bristle brushes as metal can scratch concrete), rinse with water and allow to dry.

Step 3: Repeat if Necessary

If the stain doesn’t disappear, boost your cleaning solution with a mixture of white vinegar and water, or baking soda and water, and tackle the stain again, rinsing it well with a bucket of water or garden hose.

Step 4: Enlist a Power Washer

If the stain persists, try a pressure washer. You can buy attachments that convert your garden hose into a power washer or rent a machine from your local hardware store. If you rent a machine, step up the pressure carefully as needed, so you don’t inadvertently damage the concrete. Don’t forget to don safety goggles and protect windows, plants, and the like, as the water pressure can damage them.

For more specific concrete stains, follow this guide:

Grease and Oil Stains

To clean oil from concrete, sprinkle sawdust, cornmeal, or baking soda directly onto the stain to absorb as much of the spill as possible. Once the spill is absorbed, brush away the remaining powder with a broom.

If a stain remains, sprinkle more baking soda (if you don’t have baking soda on hand, you can use powdered laundry detergent) and scrub the stain with a nylon brush and a little bit of water. Not all is lost if the oil stain is old or has penetrated the surface; to help remove residual grease stains, try a degreaser and follow the manufacturer’s instructions.

Rust Stains

White vinegar and a little scrubbing with a brush is a very effective, eco-friendly way to remove rust stains from concrete—even those that are decades old. Pour the white vinegar directly onto the stain, allow the liquid to penetrate the area for 20 minutes, and scrub with a stiff-bristled brush.

Then thoroughly rinse the area with clean water. Let dry, and if needed, repeat. If the stain persists, a cleaner like Singerman Laboratories’ Concrete Rust Remover is an industry favorite for removing rust stains from concrete floors.

Water Stains, Mold, and Mildew

Cleaning concrete floors in a basement that is has a mold or mildew problem is different from cleaning a concrete patio with the same issue. If you have a mold or mildew problem on your basement floor, do not sweep the area—you’ll end up spreading mold spores around the basement, causing a much bigger problem.

Open any windows and allow fresh air to circulate while cleaning. Spray the problem area with a solution of mold-killing detergent and water (or a combination of bleach and water if you aren’t worried about potential discoloration), scrub the area with a brush, and rinse with a clean wet mop.

Once the area is completely dry, examine it to determine if you need to repeat the process.

To remove water, mold, or mildew stains from concrete patios and driveways, use a hose or pressure washer. If stains persist, mix a solution of one-quarter bleach to one gallon of hot water and scrub the area with a brush, watering down nearby foliage first to prevent damage from runoff. Rinse thoroughly with clean water.

Stubborn Concrete Stains

Before calling in a pro or scraping the concrete in a final effort to remove stains, there are a couple of last-resort options to be aware of: Muriatic acid and Trisodium Phosphate (TSP).

Muriatic acid should only be used with extreme care as it can cause severe burns and permanently damage your skin, eyes, and lungs. Make sure to read all the manufacturer’s instructions and wear heavy-duty protective clothing, including thick long sleeves and pants, acid-resistant gloves, safety goggles, and a respirator to prevent inhalation of toxic fumes.

Trisodium Phosphate (TSP) is another strong cleaning agent known to cut through grease and mildew stains and effectively remove paint from concrete. TSP is highly caustic and has been banned in some states, so check your local laws before purchasing. Or, better yet, try an environmentally-safe TSP alternative that can provide the same cleaning action without the harmful effects.