How to Clean Flagstone

Share this article to:

We got a question from one of our readers, Loretta, about how to clean flagstone. Loretta said: “I have a flagstone patio which needs some serious cleaning. I have no idea what to use to clean it. Can you please write a guide on how to clean flagstone patio?

How to clean flagston

Yes, Loretta, I can. And if you find yourself in the same predicament as her, then you have come to the right place. Cleaning any type of pavement is a labor intensive work so the best way to clean your flagstone patio of to use a pressure washer. Use a pressure washer and water to clean the flagstone patio on a regular basis, so you won’t have to perform a deep clean. If you have any kind of pavement in your home, a pressure washer is an essential tool to have in your collection. If you cannot afford to buy one, you can often rent one from a hardware store. If you can afford to buy one, I recommend the “Sun Joe SPX3000” or visit this page for a collection of pressure washers.

How to Clean & Remove Mold from a Flagstone Patio

Required Items (for General Cleaning)

  • Dishwashing detergent
  • Scrub brush (use one with a long handle, so you don’t have to squat while scrubbing)
  • Bucket or a large bowl
  • Ammonia
  • kerosene
  • Water

Required Items (for Mold Removal)

  • Boiling water
  • White vinegar
  • Scrub brush
  • Cold water
  • UV light

Steps to Clean Flagstone Patio

Step 1: Add about 3 tablespoons of dishwashing detergent to 2 gallons of water in a bucket. Agitate with your hands to mix thoroughly and for soapsuds to form.

Step 2: Dip the scrub brush into the cleaning solution and use it to scoop some soapsuds off the surface.

Step 3: Use the brush to scrub the surface of the flagstone to remove dirt and grime.

Step 4: Keep working until you’ve covered the area you want to clean. Then rinse off the detergent and loose dirt and grime from the surface of the flagstone. Use a pressure washer to rinse the flagstone if you have one.

Step 5: Check that the surface is clean. If dirt and stains remain on the flagstone patio, add ammonia to the cleaning solution and repeat the process.

Step 6: Rinse the flagstone patio with water when you are satisfied that it is clean.

Steps to Remove Mold from Flagstone

Step 1: Boil water and pour it directly onto the area affected by the mold.

Step 2: Use a scrub brush to scrub the area immediately after pouring hot water on the area. Be careful not to splash the water on yourself.

Step 3: If you don’t want to use boiling water, vinegar is an excellent alternative. Pour vinegar on the area affected by mold and allow it to sit for about a minute. Do not leave the vinegar on the flagstone for too long or it might damage it. Rinse off the vinegar and then scrub the area with a scrub brush. Then rinse the area to remove loose dirt and grime from the patio

Step 4: A UV light can also be used to kill off the mold spores. Hold a handheld UV light over the area of the flagstone affected by the mold to kill the spores.

Method 2: How to Clean a Flagstone Patio Using OxyClean

Required Items

  • OxyClean powder (oxygen bleach)
  • Water
  • Scrub Brush

Step 1: Rinse the flagstone with water. Use a pressure washer if you have access to one.

Step 2: Make a cleaning solution of OxyClean and water. Use about 1 scoop of Oxiclean per gallon of water. Stir the mixture to dissolve the powder in the water.

Step 3: Scrub the area you want to clean with the cleaning solution and allow the solution to sit on the flagstone for about 5 minutes.

Step 4: Rinse the area with water to complete the cleaning process.


  • Ammonia should be handled with care. Always wear protective gloves and a facemask if you have one. Open windows and doors to ventilate the room properly.

Did the above method work for you or do you have any tips on how to clean flagstone? Please share with your fellow readers by leaving a comment below.


Share this article to:

Leave a Reply