How to Deep Clean Your Concrete Patio

Concrete acts like a giant sponge, absorbing everything from motor oil and charcoal soot to moss and runaway mulch stains. While it looks industrial and permanent, porous concrete needs regular attention to prevent deep-set grime from becoming a permanent fixture of your outdoor space. A neglected patio doesn't just look tired; it becomes a breeding ground for slick mildew that turns dangerous the moment it rains. Deep cleaning isn't about scrubbing until your hands ache; it is about choosing the right chemistry for the job and letting it dwell. When done well, the process strips away the grey film, reveals the clean aggregate underneath, and prepares the surface for a fresh coat of sealer. You aren't just washing the patio; you are resetting the clock on your hardscape.

  1. Clear the Space First. Remove all furniture, planters, and debris from the patio. Use a stiff-bristle push broom to sweep away loose dirt, cobwebs, and organic matter.
  2. Target the Trouble Spots. Identify oil spots or deep moss patches and apply a heavy-duty degreaser or specialized concrete cleaner directly to these areas. Let the product dwell according to the label instructions before scrubbing with a wire brush.
  3. Brew Your Cleaning Chemistry. In a large bucket, mix one gallon of warm water with a quarter-cup of liquid dish soap or a dedicated oxygen bleach powder. Avoid using chlorine bleach near grass or delicate landscape plantings.
  4. Work the Grime Out. Pour the solution over the patio in sections and use a stiff-bristle deck brush to work the cleaner into the concrete using circular motions. Focus on high-traffic zones and areas where water tends to pool.
  5. Blast Away the Debris. Use a pressure washer set to a low-to-medium psi to spray away the loosened dirt and soap, working from the highest point to the lowest. If you don't have a pressure washer, use a high-pressure nozzle on your garden hose.
  6. Inspect and Reset. Once the patio has dried, inspect for any remaining spots that require a second application. Allow the entire surface to dry for at least 24 hours before moving furniture back into place.