Pressure washing concrete is a great way to clean off dirt, debris and even oil stains. This process requires only a few tools. You can purchase a pressure washer at nearly any hardware store or rent one from a local tool rental shop.
Step 1: Assess the Concrete
Take a look at the concrete and determine if any preliminary steps should be taken. If the concrete has stains, especially oil stains, then you may want to work those out as much as possible before using the pressure washer.
Step 2: Pre-Clean the Concrete
Using a concrete cleaning agent or a small amount of bleach mixed with water; scrub any areas which contain set-in stains such as oil stains. The stain may not come up completely but the goal is to loosen it enough that the pressure washer can take it out completely or nearly completely.
Step 3: Select the Right Nozzle
Pressure washers come with a variety of different nozzles. Some nozzles are designed to produce a wide stream of water while others produce a directed stream of water. When cleaning concrete you will want 3000 PSI or higher. This nozzle will very likely produce a relatively thin stream of water. Some pressure washer models come with a nozzle specifically for cleaning concrete. Consult your owner’s manual to determine if this is the case.
Step 4: Put on Protective Clothing
Put on a pair of heavy leather gloves and goggles. It is rare but a pressure washer can periodically cause a chunk of concrete to break loose. The goggles will protect your eyes from this situation. The gloves will help to protect your hands in case they come into contact with the stream of water from the pressure washer. Always wear long pants and a long sleeve shirt when operating a pressure washer for added protection.
Step 5: Begin Pressure Washing
Use the pressure washer to slowly work across the entire area of concrete. If the concrete is sloped, you will want to begin at the upper end of the slope. This will allow the water to flow freely down to the bottom of the concrete pad. While using the pressure washer it is extremely important that you avoid hitting objects such as plants, cars, or trees. You need to also avoid hitting your own skin with the stream of water. The pressure produced by the pressure washer could easily cause damage. Once completed allow the concrete to dry completely.
Step 6: Inspect the Work
Check the concrete, especially in areas which contained stains, carefully. If you notice that any of the stains are still fairly noticeable, yuse a scrub brush and a mixture of bleach and water or a concrete cleaning chemical to scrub that area a second time. Then repeat the pressure washing process again.