Cleaning Concrete with Bleach: Pros & Cons

Chlorine bleach has been a staple in household cleaning for more than a century, and is used for everything from sanitizing kitchen surfaces to removing mold and mildew in the bathroom. But did you know you can also use bleach to clean most decorative concrete surfaces, including driveways, patios, and countertops? Not only is bleach a bargain when compared to other cleaning products, it also works like magic to remove many common concrete stains.

However, like most cleaners, using bleach on concrete has its pros and cons. Here’s what to consider before using bleach for a specific concrete cleaning application.

WHAT CONCRETE SURFACES CAN I CLEAN WITH BLEACH?

Many types of concrete surfaces can be cleaned using bleach, including:

• Concrete driveways
• Concrete patios and pool decks
• Concrete countertops
• Concrete basement floors (prone to mold and mildew)
• Concrete pavers
• Concrete garage floors
• Concrete water features

Avoid using bleach to clean polished concrete floors because it can dull the finish. Instead, use only neutral-ph cleaners on polished concrete (see Cleaning Polished Concrete Floors.) You also shouldn’t use bleach to clean painted concrete floors because it can be too harsh and cause the paint to flake away.

HOW DO I CLEAN CONCRETE WITH BLEACH?

For disinfecting and mold and mildew removal, follow these steps:

1. Put on protective gear
2. Mix about 1/3 cup of bleach into a gallon of clean water in a plastic bucket or container
3. Apply the bleach solution using a nylon-bristled brush or broom
4. Scrub thoroughly
5. Leave the bleach solution on the concrete for about 10 minutes
6. Rinse it off by spraying with a garden hose

For spot removal of stubborn stains, such as food stains on concrete countertops, soak a cotton ball or rag with diluted bleach, place it on the stain and let it sit for 5 to 10 minutes, or until the stain has faded. Then rinse the area with water. (See How to Remove Stains from Concrete Countertops.)

You can also use bleach to get rid of moss in between the joints of concrete pavers, using a solution of one part bleach to 10 parts water. Mix the materials in a bucket and then pour over the affected areas. Scrub with a stiff-bristled broom, and then rinse the entire area with water.

Tip: For cleaning exterior concrete, look for bleach products formulated for outdoor use, such as Clorox® ProResults Outdoor Bleach. These concentrated formulas are thicker than standard bleach, so less is required to remove tough outdoor stains.

ARE THERE ALTERNATIVES TO BLEACH FOR CLEANING CONCRETE?

There are a number of environmentally-friendly alternatives to chlorine bleach for removing mold and mildew on concrete, including sodium percarbonate (also called oxygen bleach) and distilled white vinegar (see How to Clean Mold from Concrete). For outdoor concrete surfaces, such as driveways, patios, sidewalks, and pool decks, pressure washing is also an effective method for blasting away stains and mildew growth.

While bleach is great at disinfecting and mildew removal, it’s not the best choice for all concrete cleaning applications. It won’t, for example, eliminate pet urine odors on a concrete floor. And it’s not very effective at removing oil and grease stains on concrete. For these cleaning jobs, you’ll have better success using an enzymatic cleaner or a commercial concrete cleaner and degreaser. (See Choosing the Best Concrete Cleaner and Degreaser.)

All-Purpose Concrete Cleaner Removes sealers and coatings.

Cleaner & Degreaser Starting at $10.95

Brickform Neutra Clean A pH neutral cleaner that combines cleaning and light degreasing

Micro-Degreaser Encapsulates and lifts petroleum-based oil stains

Commercial Surface Cleaners Cuts through grease and grime. Environmentally friendly

Kemiko Neutra Clean Low VOC All Purpose Cleaner. Leed compliant.

PRECAUTIONS TO TAKE WHEN USING BLEACH

Before cleaning any concrete surface with bleach, it’s important to read the warning label and safety data sheet for the product you’re using. The following precautions are particularly important.

• Never mix bleach with ammonia, vinegar, or other household cleaning products, since the combination can produce toxic fumes that are harmful to breathe.
• Because chlorine bleach is corrosive and can irritate or burn your skin and eyes, wear rubber gloves, protective clothing, and safety glasses to prevent accidental contact.
• Always work in a well-ventilated area. Bleach releases volatile organic compounds (VOCs) when used indoors, making it essential to open windows and doors.
• If you’re cleaning a patio or driveway, protect any nearby plants and landscaping by watering them before and after applying the bleach solution. When diluted as directed, bleach will not kill your plants or grass but it can cause leaf burn.
• To prevent bleach residue, make sure you rinse off surfaces as directed. This should be done before the bleach and water solution has a chance to dry.
• When purchasing chlorine bleach, make sure that the bleach concentration is for household use and not for industrial applications. Most liquid household bleach contains sodium hypochlorite (the active ingredient) at a concentration of 8.25%.

WHEN TO HIRE A PROFESSIONAL TO CLEAN YOUR CONCRETE

If your attempts at cleaning concrete with bleach are falling short, it might be time to hire a professional. Working with a concrete cleaning contractor has perks like knowledge and skill in cleaning concrete surfaces effectively. They'll use proper cleaning techniques, know the right products, and avoid potential damage to your concrete surfaces. Additionally, contractors can provide a more thorough and efficient cleaning service, saving you time and effort.

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