Asked on Oct 01, 2017

How can I get black "mold" off my wood deck?

Nancy Rion
by Nancy Rion
  22 answers
  • Janet Pizaro Janet Pizaro on Oct 01, 2017

    use wet and forget

  • Cindy Hagemann Cindy Hagemann on Oct 01, 2017

    Pressure wash it and then cut back trees to allow some sun on the stairs to prevent it from happening in the future.

  • Karen Tokarse Karen Tokarse on Oct 01, 2017

    Spray with 50/50 Clorox and Water, work in wood with an old broom or brush, then hose off. When the Clorox soaks into the wood, it will hinder the mold from coming back.

  • Fauxgal Fauxgal on Oct 01, 2017

    We pressure wash our deck with Clorox and water.... Once it is very dry, you can consider sealing it... But we like the natural look.

  • Pat Pat on Oct 01, 2017

    In Florida we use a gallon of white vinegar to a large bottle of hydrogen peroxide and spray

  • Harold Clayton Harold Clayton on Oct 01, 2017

    a pressure washer will do the trick. However if that’s too don’t laugh but easy off oven cleaner should do the trick. I use in the shower on tile, and it’s great for eaning wire window screens

  • Weepnseoul Weepnseoul on Oct 01, 2017

    2X/yr my stepfather would bleach clean the decks, while one of us kids would stand by with hard bristled long broom & scrub. Let it dry, sand it down & treat it with an oil-based wood sealer.

  • Ellis Ellis on Oct 02, 2017

    Wet and Forget should work, and it's not harmful to the wood. You just mix the product with water in a sprayer, spray on, and leave it. You can repeat the process again in a while, according to the instructions on the label. A pressure washer can really damage the wood, so avoid it if you can.

  • Clyde Small Clyde Small on Oct 02, 2017

    Clorox. Spray it on while trying not to breathe in the fumes. Many people develop chemical pneumonia when using any form of chlorine product including the dry products like Comet for the kitchen sink. Clorox will definitely kill the

    mildew though. Just spray it on, let it work its magic, then wash it off with water.

    Allow it to dry, hopefully in the sun which will also help to kill the mildew.

    We have always used Clorox to keep our motor home, travel trailers etc

    free of mildew, and the wooden trellis keeping the jasmine vines neat gets cleaned twice a year. So far, I think we've probably saved many hundreds of

    dollars by not having to replace rotten wood. Hope this remedy will help you as well. Julia

  • Lauren Lund Lauren Lund on Oct 02, 2017

    We've used only a 10% bleach solution. 1 part bleach to 9 parts water in a spray bottle. No need for higher strength with overwhelming fumes. No need to scour. Spray and let dry. Repeat daily until gone.

  • Diana Deiley Diana Deiley on Oct 02, 2017

    Before you purchase Wet & Forget, please read the entire label!

    We use pool chlorine with water. Spray then power wash. Living in Florida we have to wash the exterior of our homes & fences frequently. Works great. Less toxic and very budget friendly. Best of luck.

  • Kay Wormington Kay Wormington on Oct 02, 2017

    Bleach will kill the mildew and mold, you'll need to scrub with a stiff brush, to get it down in the grooves of the wood. We also use it in a pump up sprayer ($7-$10) mixed with water to take mold off of vinyl siding. Let it set a few minutes and rinse well with water.

  • Cheryl A Cheryl A on Oct 02, 2017

    Zep makes a cleaning solution to remove mold from wood decks

  • Lisa S. Lisa S. on Oct 02, 2017

    Lots of people suggest bleach. Which works. If for some reason you cannot use bleach try 5% white vinegar.

  • Beth Beth on Oct 02, 2017

    I use nappy soaker, the napisan brand has the same chemicals in it as the super expensive deck cleaner product from the hardware store. Just make a WEAK mix and try it on a sample. Put it on, and using a cloth or sponge rinse off with lots of clean cool water.I did our deck ( 60 m) and our wooden outdoor furniture for about a $1 of nappy soaker. Then you must seal the wood !!I spent money and got the best sealer I could afford. Worked like a charm, and that was 3 years ago, the deck still looks brand new.

  • Ela26544792 Ela26544792 on Oct 02, 2017

    It's probably gone into the wood, looks like it anyway, if you can't get rid of it paint of it after sealing it really good.

  • Rocker chick Rocker chick on Oct 03, 2017

    I've heard & read hydrogen peroxide works best killing black mold.

  • Beth Beth on Oct 03, 2017

    Here in australia, we have powdered bleach products in the laundry aisle of the supermarket.Pre soakers for clothes ,etc, in the old days of cloth nappies ( diapers ) they would be used to soak .I used a brand called Cabot's. Water based sealer ,there is an oil based one too. We don' t have snow here but our sunshine wrecks most untreated timber so sealing is the way to go.I found out about this method by googling the chemical in Cabot's deck cleaner.

  • MaryElias Lopez MaryElias Lopez on Oct 03, 2017

    vinegar should do the trick. also bleach, but you do have to be careful it doesn't get on your clothes, etc, unlike vinegar.

  • Power wash the deck.

  • Johnavallance82 Johnavallance82 on Dec 12, 2023

    When clean - use a Wood stain and Preserver from the garden department of large store.

  • Betsy Betsy on Dec 12, 2023

    Hi Nancy: I'd use a weak solution of warm water, dish soap and bleach. Maybe a 1/4 cup of bleach to a pail of water, a squirt or two of soap and brush vigorously. Rinse and let dry. Then, seal or paint the deck. Be sure to wear rubber gloves. Here's a site that doesn't mention bleach, but I used it on my wooden steps when they had mold and it worked great; How to Kill Mold on Wood - This Old House