Can You Power Wash Concrete Walls?

Water Settings

• Your power washer needs a pounds per square inch, PSI, setting of at least 3,000 to successfully clean debris from concrete walls. The device also needs a flow rate of at least four gallons per minute. If the walls are heavily soiled, a flow rate of 5 to 6 gallons per minute is needed to properly clean your concrete walls.

Nozzle Settings

• Use a rotary nozzle over a fan nozzle on your power washer’s wand to produce a circular pattern. A circular pattern yields a higher water flow speed and breaks up debris quicker than a nozzle that just dispensers water in a forward motion. Start at one end of the concrete wall and work your way to the other end to clean the wall quickly. Spray from top to bottom to keep from soiling already clean areas.

Chemical Solutions

• Pour in a chemical cleaner designed for power washing into your power washer’s cleaner dispenser. Press the “Cleaner” or similar wording button on the device to switch to the cleaner setting and dispense the cleaner after initially washing the walls with plain water. The chemical cleaner breaks up any stubborn stains and debris. Let the cleaner sit on the walls for 15 minutes and then press the “Wash” or similar wording button to switch back from the cleaner setting. Power wash the cleaner off.

Schedule

• Clean your concrete walls on a regular schedule, monthly or quarterly, to keep debris from building up and staining the walls. Do not wait until moss, dirt and grass fragments collect on your concrete walls before deciding to power wash the surfaces. This will only cause frustration and extend the amount of time it will take to clean the walls.