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How to Clean Mold & Mildew Outside With Bleach

Follow these mixing instructions to create a bleach solution to kill exterior mold and mildew, clean mold off gutters, and clean the outside of your house.

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How to Clean Outdoor Mold & Mildew

You’ll need:

  • 5 gallon bucket
  • Clorox® Disinfecting Bleach
  • Measuring cup
  • Rubber gloves
  • Safety glasses
  • Scrubbing brushes (long handle and/or handheld)
  • Garden hose with spray nozzle

Here’s the procedure:

  • Thoroughly water any plants near the area where you will be working. Protect larger plants by covering them with plastic sheeting.
  • Add ⅓ cup Clorox® Disinfecting Bleach to 1 gallon water in the 5 gallon bucket. For larger jobs, use 1 cup bleach added to 3 gallons of water.
  • Pre-wet the surface to be cleaned with water
  • Apply the bleach and water solution to the surface with a scrub brush.
  • Reapply as needed to keep the surface wet for up to 10 minutes
  • Rinse the treated area thoroughly
  • Let surfaces air dry
  • Re-water any nearby plants that may be getting run-off

Any leftover bleach and water solution can be easily flushed down the toilet. Rinse out your brushes and rinse off your gloves and boots with the garden hose, and let everything air dry. You can also use this technique to clean siding, as well as sealed brick and patio stones. Note that you should avoid applying the bleach solution in direct sunlight or to unfinished wood. The solution should not be used for aluminum gutters or windows; rinse thoroughly if any contact occurs. You should also test the bleach solution on the area you want to treat in an inconspicuous area before starting your project. Sure, it sounds easy enough, and really, it actually is! Here’s a picture tutorial to help you see how it’s done.

Mold and mildew builds up a little at a time over the winter. There’s less daylight and lousy weather, making it easier to put off dealing with (until you can’t any longer!).

Use a large plastic tarp to protect the plants.

To make up 3 gallons of the bleach solution, use 1 cup of bleach. This makes it easier to dip a long handled brush into the solution. Measure water into the bucket and mark volume lines on the outside so it’s easy to just use the hose to fill the bucket to the correct volume. No guessing as to how much a gallon is!

Wet the surface with a garden hose. When it’s wet, the discoloration looks even worse.

The less you have to think about what you are wearing while you are working the better. Rubber rain boots and old clothes that you won’t mind getting any bleach splashes on are perfect.

Use a long-handled brush to apply (and reapply by just dipping the brush back in the bucket) the bleach solution to the wall.

Some corners really can only be scrubbed with a hand-held brush. The gloves are really nice to have here:

If you have a large area to clean, don’t try to do it all at once. To stay within the recommended 10 minutes of contact time, work in smaller sections, rinsing the first area before starting again on the next.

Wow — what a difference!

Thanks, Clorox® Disinfecting Bleach! I couldn’t have done it without you!