5 Simple Deck Wash Recipes: General Maintenance & Mildew

Wood decks are a nice feature for the back yard but they do require a bit of TLC to keep them looking as good as possible and extend their lifespan.

SprayHere are a handful of homemade cleaners you can try including a couple for removing stains and mildew.

Some tips before getting started:

  • Use a nylon bristle brush or broom for good scrubbing power.
  • A pressure washer can be used to clean your deck if done correctly and the wood is in good shape (the pressure can cause further damage if it isn’t), keep it on the lowest setting that will clean the surface without damage (this will depend on how soft the wood is). You should be able to start safely at a 500 psi setting and work up from there. Use a fan tip setting between 40′ and 60′ tip size and spray with the grain. I found a page of expert tips for using a pressure washer here: Decks.com.
  • Check a test area first before applying detergents and chemicals to ensure that no damage or discoloration occurs. The type of wood (and the condition it’s in), the type of stain or paint can each respond differently to a treatment.
  • A simple garden hose with a spray nozzle attachment can be used if you don’t have a power washer, though you will need to put a bit more elbow grease into the job.

Quick Notes:

  • Spray deck with water first before applying wash recipe, this helps prepare the surface so the cleaner can work its magic.
  • For temperature, use quite warm but not so hot that you can’t rest your hand in it.
  • Rinse surface well when removing cleaner.
  • Remove the solution before it dries (or lightly spray with water during waiting period if it’s drying too quickly).

General Cleaner:

1 gallon water
1 cup powdered laundry detergent (no bleach)
3/4 cup oxygen bleach (optional but good to use if mildew stains are present)

  • Directions: Mix well then pour over surface. Scrub lightly with a broom or brush. Leave for 5 to 10 minutes then scrub again. Rinse. Repeat if needed.

Maintenance Spray:

Use this mix for a light jobs where no real problems or staining exists (basically just removing surface dirt and freshening up the deck).

  • 2 cups white household vinegar mixed with 1 gallon of water. Pour over surface, leave for 10 to 15 minutes then brush with a stiff broom. Rinse well.
  • You can also try: 3/4 cup oxygen bleach and 1 gallon water.
  • Or this one: 1 cup powdered laundry detergent with 1 gallon water.

Heavy Duty Mix:

  • 3 quarts of water, 1 cup oxygen bleach and 1 cup of TSP. Mix well and apply to surface, scrubbing with a stiff bristle broom. Leave for about 10 minutes before scrubbing again. Rinse well.

Fighting Mildew:

  • Try a mix of 3 quarts water, 1 cup oxygen bleach and 3/4 cup of liquid dishwasher detergent. Apply to surface, brush with a stiff broom and leave for 10 to 15 minutes. Scrub then rinse.

Stain Remover (such as Mold and Rust):

  • Mix 1 tablespoon of oxalic acid crystals (wood bleach) with 1 gallon of water. Apply to trouble spots with a brush and leave alone until discoloration has faded then rinse well with clear water.
  • Grease stains can be conquered by applying powdered laundry detergent directly onto the spot (use a brush or broom), let it set for a few minutes then rinse.

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What Readers Are Saying: 14 Comments
  1. andrew gibson says:

    All great recipes . I want to find a wood / deck cleaner that is flower and tree friendly. Maybe major flushing after the cleaning ..Thanks- Andrew with a 100 year old cedar porch

  2. Marta R. says:

    Wow! Today I used the general cleaner. I used 2 cups of Tide powder, 1-1/2 cups Oxiclean with 2 gallons of water. It was amazing. Cleaned the whole deck and also our resin table and chairs. The table and chairs sparkled afterward. And the deck looks great. A deck brush attached to a broom handle is a must! Made the job so easy. Followed given instructions to let sit 5- 10 min, scrub again and rinse.
    This will be the only cleaner I need for outdoor stuff. It also cleaned up some of my garden statues nicely. Haven’t tried it on any painted statues yet, but plan to tomorrow.

    • Carrie says:

      Warning – It’s a good thing I spot-tested first! I tried the maintenance mix using OxiClean & water… and it completely removed the finish and left wood fiber “fuzzies”! (It’s a 3-year old cedar deck with Wolman’s F&P oil-based sealer applied a year ago.) It wasn’t from being too vigorous – I used a super soft broom, and even a few places where I accidentally dripped the Oxi wound up discolored and fuzzy. Maybe the OxiClean has some other ingredient that makes it too powerful? After that, we were too afraid to use any cleaner at all. So we just sprayed it with the garden hose on full power and brushed it with the soft broom, and then rinsed it. It took off most of the dirt without removing any finish. Bottom line: I’d look for 100% oxygen bleach, not OxiClean.

  3. eileen says:

    Thks for info…what is tsp that is called for in the heavy duty cleaner?

    • karen says:

      tri sodium phosphate…..you find it in the paint area of your hardware store…it is used for prepping your walls before painting.

  4. Kathy Lockard says:

    in the heavy duty mix, what is TSP??

  5. Beverly says:

    Will the deck cleaners also work on synthetic deck products?

  6. Sue Berger says:

    Does the run off hurt the grass and flower?

  7. Joyce Wall says:

    Never heard of oxygen bleach and wood bleach., where can I purchase these items?
    I have a mobile home with plants surrounding it. I have to pressure wash it at least once a year and am concerned for the foliage I have around it. Will those items harm them?

  8. william says:

    What will remove deck stain sufficiently?

  9. paula nadels says:

    can I use your recepes safely beside our pond (with frogs and salamanders)?

  10. Russell Collins says:

    Good to see someone putting out decent info without trying to push their own “WONDERFUL PRODUCT” keep it up!

  11. Mary Howes says:

    How can I clean a cedar deck without damaging the stain?

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