How to remove mold from concrete patios

Updated February 21, 2017

Mold is a real problem for homes in warm and humid climates. Many homes' roofs, vinyl siding, brick, driveways and patios show signs of mould and mildew. These unsightly green or dark brown or black stains can be difficult to remove and even dangerous to your health at times. As luck would have it, however, concrete patios are one of the easier surfaces to clean of these ugly mould stains and make your patio beautiful again.

Mix the hot water and bleach until well blended in the bucket. A mixture of three parts water to one part bleach works best to kill and remove mould. One gallon is 16 cups, 1/4 of which would equal 4 cups of bleach.

Pour a small amount of the bleach mixture, about 1 cup, directly on the stain. Be careful not to pour too much as the runoff can kill plants, grass, insects and animals and damage many types of surfaces.

Scrub in a circular motion with the scrub brush over the stain, spreading around the bleach mixture as much as possible over the mould. The mould should begin to discolour and break away within a few seconds.

Dip the scrub brush into the bleach mixture just enough to coat the bristles. Continue scrubbing over the stain, repeating the dipping procedure as needed, until the stain is removed.

Rinse away the bleach solution with plenty of water. Use a hose for several minutes if possible. Also, filling the bucket with clean water and splashing it over the bleach solution repeatedly will work to remove any residue.


The water and chlorine bleach mixture will ruin clothing. Either wear clothing that can be damaged or wear an apron or other type of cover. Wear gloves and eye protection to avoid splashes and possible injury.


Never mix chlorine bleach with any other household chemical. The fumes that can occur can be dangerous and possibly fatal. Make sure the area you are cleaning has been rinsed thoroughly if you have already attempted to clean it with something else and also after using the bleach mixture to clean.

Things You'll Need

  • Bucket
  • 1 gallon water, as hot as possible from the tap
  • 4 cups chlorine or oxygen bleach
  • Hard bristled scrubbing brush
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About the Author

Jesse Futch began writing professionally in 2008. He writes for various websites, including eHow, specializing in topics such as family, technology, travel, history and science. Futch is self-taught in the field of writing. He studied U.S. history, software engineering and missile and space systems at U.S. Air Force Technical College.