Overall, we recommend Zep Purple Pressure Wash (US$13.98, The Home Depot). Alkaline cleaners are great for lifting oil stains, grease stains, and other petroleum-based stains from concrete. It's an added benefit that you can use it with a pressure washer, making the job that much easier.
In fact, vinegar removes mold from concrete better than bleach. Bleach will only remove the top layer of mold, causing the mold to return.
Vinegar or baking soda: These natural cleaners work well to clean cement patios with stubborn charcoal or rust spots. Mix equal parts vinegar and water, scrub the patio with the mixture, then give it a good rinse. If stains don't dissolve, try undiluted vinegar.
Use Concrete Sealer After Power Washing
Concrete is porous by nature, and the voids deep within fill up with dirt, contaminants, and water, not to mention what's on the surface. Think of your driveway like one big sponge.
Here's a short list of some of the usual chemicals used in commercial pressure washing: Oxalic acid – useful in rust removal and other similar cleaning processes. Citric acid – stain removal and cleaning of concrete driveways or wooden decks. Sodium hypochlorite – disinfects and removes stains.
Use a mild grease-cutting detergent such as Dawn or Ajax dishwashing liquid mixed with water and a natural or synthetic bristle scrub brush to help brighten the patio surface. NOTE: Never use a wire brush as it can leave rust stains and scratch the concrete surface.
Vinegar and Baking Soda
Simply fill a spray bottle with equal parts water and vinegar (or water and baking soda), and add a little bit of liquid dish detergent. Spray the mixture on your concrete surface and let it sit for about 30 minutes. Then scrub and rinse your concrete.
Mix bleach with water and then add dishwashing detergent to the mix and put it into a spray bottle. Spray the solution onto the cement patio, let it sit for a few minutes, then scrub the mix into the concrete with a stiff brush.
Use Bleach
But that's not all; chlorine bleach can also be used for cleaning the concrete driveway. Of course, you should dilute it with equal parts of water or a 1:1 ratio. With the mixture ready, spray it on the driveway, allowing it to sit for 10 minutes. Then, use a stiff brush before rinsing with clean water.
'A homemade cleaning solution for your patio can be made by mixing equal parts water and white vinegar,' says Zak. 'This natural cleaner is effective in removing dirt, mildew, and algae. For stubborn stains, you can add a few drops of liquid dish soap to the mixture.
You can use Simple Green Oxy Solve Concrete and Driveway Cleaner to clean a concrete patio with or without a pressure washer. It removes oil, grease, grime and most stains and discolorations. Its biodegradable formula is safe for lawns and pets.
Another relatively safe and environmentally friendly solution for cleaning concrete is an oxygen bleach product, such as OxiClean. Just be sure to wear rubber gloves, as bleach products can be tough on skin. Sprinkle the powerful solution over the entire patio and scrub it with an ordinary push broom.
Whether your patio is sealed concrete or cement, or even sealed concrete pavers, a bleach and water solution makes it easy to clean away built up soil, stains from leaves and pollen, mold, mildew and algae.
The Liquid peroxide cleans, refreshes, and brightens concrete, tile, and grout without leaving watermarks or residue in contrast to other cleaning chemicals. Powdered peroxide-based formulas are generally high-performance alkaline, tile and grout cleaners and degreasers that are made for use on heavy-duty concrete.
A recipient of the Safer Choice label, Simple Green All-Purpose Cleaner can be used in pressure washers and on all washable surfaces, and easily removes tough dirt and grime without the use of caustic chemicals.
Power Wash Your Driveway: Applying Waterproof Sealer
After the driveway is pressure washed, it helps to eliminate future stains by applying a waterproof sealer to its surface.
Oil leaks, blood, and sticky residues can absorb and result in stubborn stains. However, using a driveway sealant after pressure washing can help prevent these stains from becoming permanent features in your driveway.
You can power wash concrete all year as long as the temperature is about 40 degrees Fahrenheit. Most homeowners and businesses prefer to do it in the spring or summer to reduce the spread and growth of algae and mold. It also reduces pollen, which can affect allergies.