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. For an eco-friendly cleaner, we recommend Oil Eater cleaner degreaser (US$15.74, Amazon).
Bleach. If your concrete is dull and sprouting weeds or mold, bleach is your best option for cleaning and brightening concrete. Mix a cup of bleach into a 5-gallon bucket of warm water, then spray or pour over concrete. Rinse thoroughly with water.
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.
After the concrete has dried for at least 24 hours, you can effectively apply a concrete sealer. A sealer helps prevent future stains and potential damage from products like ice salts.
If you're simply trying to clean your driveway or walkway, then power washing alone will be sufficient. However, for long-lasting results and to prevent mold and mildew from penetrating the surface, sealing is necessary.
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.
To maintain the lighter color of a concrete driveway, many homeowners turn to cleaning with bleach, but you should not power wash with bleach because it can damage your pressure washer.
Greenworks Surface Cleaner – Best Home Use. If you're looking for a pressure washer surface cleaner to use for driveways, sidewalks, patios, and decks, the Greenworks Surface Cleaner is a great choice.
Neutral pH neutral cleaners are ideal for cleaning sealed concrete surfaces free from embedded dirt and deep stains. They can also be used on unsealed indoor or outdoor concrete surfaces that only require a mild cleaning. Alkaline concrete cleaners have powerful degreasing capabilities.
If you have leaf and/or acorn stains on your driveway, the only way to remove those stains is to use a pre and post treatment. Typically these stains will not come up with a general pressure wash cleaning and will need additional chemicals (chlorine in this case) to remove the stains.
Keep fertilizers away from concrete
Fertilizers often contain ammonium nitrate and ammonium sulfate which are harmful chemicals that can disintegrate concrete. Avoid using these on our near your concrete during its first year.
The inorganic compounds which are useful as concrete dissolvers generally include inorganic acids such as hydrochloric, phosphoric, hypochlorous and carbonic acid. Salts of these acids and alkalies such as sodium-hydroxide, sodium bicarbonate and ammoniumsulfate are also eifective.
In fact, vinegar removes mold from concrete better than bleach. Bleach will only remove the top layer of mold, causing the mold to return.
Best for Driveways: Zep Driveway and Concrete Cleaner
Zep Driveway and Concrete cleaner is suitable for removing concrete stains, dirt, and oil marks. It's a budget-friendly choice coming in a four-pack of 1-gallon jugs. To use Zep Driveway and Concrete cleaner, mix the solution per the package directions.
Stains on concrete are not only unappealing, but can also weaken the surface of your driveway. For outdoor cleaning, a pressure washer is fast and efficient. Pressure washers are portable and can run on either electricity or gas.
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.
Both power washing chemicals should be diluted with water in order to be effective and not damage the surface. Bleach is great for killing mold and moss, ensuring it doesn't come back. Chlorine is a solid option for getting rid of grease stains on concrete.
As a gentler cleaner, bleach can't harm concrete's durable material. Aside from being an effective cleaner and stain remover, it also acts as a disinfectant to the concrete surface.
How often should you pressure wash your driveway? Generally, you'll want your concrete driveway pressure washed at least once a year. This lets you treat sunbaked dirt, grime buildup, and stubborn oil stains, making regular cleaning in between professional washes much more manageable.
Pressure Washing with Bleach
Mix ¼ gallon of bleach and 1 gallon of water. Apply the bleach on the surface by a pressure pump. Let it sit for 15 to 30 minutes. Pressure wash the surface with water and rinse it again if necessary.
While you know that using a power washer can almost magically erase built-up dirt, debris and stains from practically any surface, you might wonder: Can power washing damage concrete? The quick answer is yes, power washing can degrade a concrete surface.