How To Remove Mildew From Wood Deck?

Helen Skeates
Helen Skeates
22 min read

Mold can be found on any sort of wood floor, no matter how well-maintained it is. Your decking boards can be saved from utter inoperabilities if you discover how to remove mildew from wood.

There is no need to worry if the mildews have already reached the wood pores or if they are only beginning to grow on the surface of the wood. Your deck can be saved from rot and decay with a little elbow grease, the right cleaning supplies, and a little bit of time.

Fortunately, removing persistent mildew from your wood deck can be as simple as following a few simple steps. To keep the wood from decaying, consider a non-chemical treatment.

Let us help you with mildew housecleaning. We’ll also give you some pointers on how to preserve your wood deck free of mildew growth so that you can relax on it guilt-free.

Why Does My Wood Floor Grow Mildew?

You may have a general knowledge of how mildews grow on wood, but you may not know how to prevent it. However, this is to be expected for a wood floor with a high density that is exposed to sunlight on a regular basis.

Wood Deck Cleaning | Fence Cleaning | Wood Restoration Washing Clean

If you have a wood deck, mold and mildew are going to be right at home. Mold can grow on your decking board if there is any water left.

Debris such as leaves, twigs, and other small objects left on the floor can feed the fungus that causes mildew to grow. Some mildew-causing fungus pose a serious threat to human health.

Fungi, known as wood-eaters, can appear in a greenish-black color. Wood floors can be infected by a fungus known as Stachybotrys chartarum.

Wood-eating fungi can be seen in a greenish-black coloration. Stachybotrys chartarum is the scientific name for this type of wood-destroying fungus.

What Is The Difference Between Mold, Moss and Algae?

Dead organic debris is a food source for mold and mildew. Your wood deck’s fibers can also be a source of food for them as they decompose and spread.

In terms of health risks, mold is the more serious. Mold often appears as a slimy, fuzzy growth on the surface of your deck. Mildew grows on surfaces and is usually dry and powdery unless it’s wet.

Moss and Algae, on the other hand, are plants that rely on sunlight and water to sustain themselves. Even while they don’t disintegrate your wood deck boards like fungus do, they can still cause long-term harm to hardwood deck boards and rails over the long term.

Having mold, mildew, moss, and algae growing on your deck can make it look drab. A DIY deck cleanser and some elbow grease will do the trick. Afterward, we’ll go through some preventative techniques to keep your deck from becoming a breeding ground for fungi.

Cleaning Instructions

Depending on whether you’re dealing with fungi (mold or mildew) or a plant growth on your deck (wood or composite), your cleaning solutions will differ slightly (moss or algae).

How to Clean Mold from Wood Deck

To remove mold from painted or stained lumber:

  1. If possible, keep the area dry. If gloves or goggles are required, use them.
  2. Using a vacuum, brush or shop vacuum, remove any remaining dirt or debris from the area and dispose of it as soon as possible.
  3. You may make your own wood deck cleanser solution by combining 1 tablespoon of Dawn® or Joy® dishwashing detergent with 1/4 gallon of warm tap water in a clean bucket.
  4. Remove mold from your deck surface by scrubbing it with a soft bristles brush or an old toothbrush.
  5. Use a clean, dry rag to clean the area.
  6. Spray the afflicted area with an undiluted vinegar solution in a spray bottle.
  7. Wait an hour, then use a clean rag to dry the surface again.

To remove mold from raw, untreated lumber:

  1. If possible, keep the area dry. If gloves or goggles are required, use them.
  2. Using a vacuum, brush or shop vacuum, remove any remaining dirt or debris from the area and dispose of it as soon as possible.
  3. In a clean bucket, combine 2 fluid ounces of dishwashing detergent (such as Dawn® or Joy®), 500 ml of bleach (about 1/10th of a US gallon), and 1/4 gallon of warm tap water. Mix well.
  4. Wash the affected area with a hard-bristled brush or scrub-sponge until the mold is gone.
  5. It’s time to let it breathe.
  6. Make sure that you use fine-grit sandpaper to get rid of any mold or discoloration that may still be present.

How to Clean Mold from Composite Decking:

  1. If possible, keep the area dry. If gloves or goggles are required, use them.
  2. Pour 1/4 gallon of warm tap water over 1 spoonful of dishwashing detergent (such as Dawn® or Joy®).
  3. Scrub the moldy area with a soft-bristled brush or an old toothbrush.
  4. Use a clean, dry rag to clean the area. To avoid damaging your composite decking, avoid using a pressure washer.
  5. Spray the afflicted area with an undiluted vinegar solution in a spray bottle.
  6. Wait an hour, then use a clean rag to dry the surface again.

How to Remove Moss and Algae from Wood Deck

Wood that has been stained, painted, or untreated can be cleaned of moss and algae by following these steps:

  1. In a clean bucket, combine one gallon of warm tap water and three-quarters of a cup of chlorine bleach for a homemade deck cleaner solution.
  2. If the moss or green algae on your deck is really bad, you can boost the cleaning power of your solution by adding an additional 13 cup of ammonia-free laundry detergent powder.
  3. Allow the solution to rest on your deck for about 20 minutes before rinsing it off.
  4. Make use of a scrub brush or shop broom to remove moss and green algae from the surface of the decking boards.
  5. To remove the solution and any moss residue, use a garden hose or running tap water to wash the wood. Use a fanning nozzle on your power washer to avoid damaging your paint, stain, or wood.
  6. Allow the air to dry out the area entirely.

How to remove moss and algae from composite decking:

  1. In a clean bucket, combine one gallon of warm tap water and three-quarters of a cup of chlorine bleach for a homemade deck cleaner solution.
  2. If the moss or green algae on your deck is really bad, you can boost the cleaning power of your solution by adding an additional 13 cup of ammonia-free laundry detergent powder.
  3. Allow the solution to rest on your deck for about 20 minutes before rinsing it off.
  4. Scrub the deck board’s surface using a stiff-bristled scrub brush or shop broom to remove moss and algae..
  5. Remove the cleaning solution and any moss residue by rinsing the surface with a garden hose or tap water. To avoid damaging your composite decking, avoid using a pressure washer.
  6. Allow the air to dry out the area entirely.

Other Deck Cleaning Products

Mold, moss, and green algae can all be removed from wood with a deck cleaner and brightener, such as the DeckWise Wood Deck Cleaner and Brightener, which we highly suggest. This powerful cleanser is on hand and ready to use, protecting your outdoor space from mold and algae growth and restoring it to its former glory.

Help! My Patio Deck is Turning Green!

Preventing Green Mold, Moss And Green Algae Growth

Preventing the growth of mold, moss, mildew, and algae on your deck will save you both time and money in the long run. Keep undesirable deck growths at bay with a few simple tips:

  • Deck finishes cover over your deck planks to keep moisture out. Apply a deck stain or sealer. For fungus and plants, which thrive in moist conditions, this is a huge obstacle.
  • You should keep your outdoor deck clean since fungi like mold and mildew feed on organic matter. If you have leaves, pine needles, or other debris on it, these deck pests have a feast waiting for them. Keeping your deck clear of debris is a great way to keep fungal spores at bay.
  • Choose composite deck boards because of their protective shells, which prevent water from seeping into your boards. Fungi and other deck growths can be kept at bay more easily with composite decking than wood.

Removing Mildew From Wooden Deck

To get the job done right, you must meticulously follow each step.

Step #1. Preparing tools and protective gears

Protecting yourself against mold and chemicals is a must before beginning the eradication process. When cleaning the mildew, make sure to use protective gear such as rubber gloves, goggles, and a protective suit and shoes.

Check for a bucket, spray bottle, scrub, and water hose, depending on your remedy of choice.

You’ll want to make sure there are no plants near the cleaning area during pre-cleaning processes. Do not let them near your delicate plants because the chemicals they use can harm them.

Also, wipe away any dirt from the deck surface before attempting to remove the mildew with a scrubbing brush. All corners must be thoroughly cleaned of pollen, twigs, and leaves.

Step #2. Choosing a cleaning recipe

In this step, you’ll have to pick a fighter—a clean solution. For your convenience, we’ve provided step-by-step instructions and recipes for all of our cleaners.

  • Solution: 2 gallons of warm water, 2 gallons of oxygen bleach, a quarter cup dishwashing soap, and a cup of Borax are all you need to prepare the solution.
  • In order to make the solution, combine an adequate amount of white vinegar in a spray bottle with water.
  • A gallon of water and a third of a cup of liquid detergent will get the job done.
  • The recipe calls for a gallon of warm water and a cup of baking soda.
  • Prepare a gallon of water with a cup of trisodium phosphate (TSP).

Commercial deck cleaners with mildewcide qualities are another option to these homemade cleaners. Just use them with caution.

Step #3. Applying cleaning solution

The cleanser can be poured onto the molded area and distributed. The sprayer can also be used to target the damaged areas of the deck.

Wait five to ten minutes before using the solution. If you’re using white vinegar, let it dry for an hour before using it.

Step #4. Scrubbing or wiping the mildewed area

Remove all mildew by scrubbing after the cleanser has dried. Avoid harming the wood finish by using a hard but soft-bristled brush.

Wipe the deck clean of mold stains before applying the vinegar solute.

Step #5. Rinsing and drying wood deck

Using the water hose, rinse away the residual cleaners and water from the wood deck after erasing the mildew stains

Roll up your awnings if there are any to let the sun dry the surface. To expedite the drying process, use a dehumidifier.

Mildew Prevention On Wood Deck

You don’t realize how quickly mold can rot wood if you don’t give it enough attention. To help you out, here’s a helpful post on how long it takes mold to ruin wood.

The best way to keep mildews away from your wood deck is to make it an unattractive location for them to live. Here are a few ideas:

  • Keep the deck dry by ensuring that it is exposed to sunlight on a daily basis and that there is no water accumulating on top of the surface of the deck.
  • Sweep away pollen, leaves, and other debris from the deck on a daily basis.
  • Apply a quick-drying water sealant with herbicide characteristics.

Get Rid of Green Mold from a Wood Deck

Our simple ways for eradicating green mold from your deck might help you decide whether or not to replace your hardwood deck with a mold-resistant composite deck. Wood decking can be cleaned with just a few simple substances, the correct equipment, and some elbow work.

The first time you seal a deck, make sure it is absolutely clean. Clean the surface well before applying any stain or sealant.

Homemade Deck Mold Remover

In order to clean the entire surface of your wooden deck, you can use a homemade mold remover. This easy-to-prepare solution for removing mold from decks and railings is not only effective, but also economical.

Simple Wooden Deck Cleaner

  • 3 liters of piping hot water
  • Laundry detergent: 1 quart of water
  • Bucket
  • Scrubbing brush

Clean the deck with a broom to get rid of any loose dirt and debris. The furnishings in the areas that will be cleaned should be moved out of the way. Using a scrub brush and a pail of water and detergent, remove the green mold off the deck. Rinse the deck with a garden hose after the mold has been removed.

Removing Mildew from Wooden Deck

It is a mixture of hydrogen peroxide and natural soda crystals that is used in a wide variety of household cleaning solutions. The mildew on a wooden deck can be easily removed with this natural alternative to chlorine bleach.

Green Mold Stain Remover

  • Water that’s been warmed
  • Oxygen bleach in powder form
  • Bucket
  • Scrubbing brush

To prepare this DIY mold and mildew cleaner, simply combine enough water and oxygen bleach to form a paste in a bucket or plastic container. Apply the mixture with a scrub brush straight to the green mold stain and let it sit for about 20 minutes before removing.

The brush can be used to remove the loose mold. Use a yard hose to thoroughly clean the area. You might try a different mold removal approach if any of the discoloration remains after the first treatment.

How to Minimize and Prevent Mold Growth on Decks –

How to Remove Green Mold from a Wooden Deck with Oxygen Bleach

Many individuals have been cleaning their decks and eradicating mold with chlorine bleach for many years. The wood fibers can be damaged, even though this method is effective at killing fungi. Oxygen bleach is a safer mold cleaning alternative than chlorine bleach. Oxygen bleach, Borax, and soap are used to eradicate mold from this homemade deck cleanser.

Oxygen Bleach Deck Cleaner

  • Warm water in 2 gallons
  • 2 cups of oxygen bleach in powder form
  • Liquid dishwashing detergent: 1/4 cup
  • Powdered Borax: 1 cup
  • Bucket
  • Scrubbing brush

Before you begin this process, remove any dirt or debris from the deck. In a bucket, mix together the water, bleach, soap, and Borax until the mixture is completely dissolved. You can use a brush to dip into the bucket of bleach solution and splash the liquid onto the wood to apply it.

Scrub the deck from one end to the other, starting at the farthest side. If the brush becomes too dry, re-wet it. Rinse the entire deck with a garden hose after 15 minutes of sitting in the solution. If you’d like, you can use a deck brightener solution afterward.

Removing Green Mold from a Deck with Vinegar

Deck mold and mildew can be removed with white vinegar. Mold may be killed at the source with this acidic liquid, which dissolves oily residue and filth.

DIY Vinegar Deck Cleaning Solution

  • Vinegar that’s been diluted with water
  • Water
  • a spray bottle
  • Scrubbing brush

Before commencing the cleaning process, sweep the deck to eliminate any loose dirt. To get started, fill a spray bottle halfway with water and white vinegar.

Depending on the extent of the green mold infestation, you can either spray the entire deck or just the problematic sections. Brush away the green mold with a scrub brush or stiff-bristled broom. Rinse the deck off with a garden hose to complete the job.

To remove mold from walls with vinegar or any other location afflicted by the fungus, both indoors and outdoors, use this simple mixture. Mold spores can be effectively destroyed and eradicated with vinegar.

How to Eliminate Green Mold from a Deck with Baking Soda

Baking soda can be used as a natural alternative to harsh chemicals in cleaning products. To loosen and eliminate green mold, you can use this soluble powder as a light scouring agent.

Baking Soda Deck Cleaning

  • 1 liter of hot water
  • 1 pound of baking soda
  • Bucket
  • Scrubbing brush

Once the decking has been swept clean, proceed to the next step. Use a scrub brush to scrub moldy spots with the mixture of warm water and baking soda. Lastly, use a garden hose to wipe the deck surface.

Cleaning Green Mold Off a Deck with Trisodium Phosphate

Inorganic compound TSP, or trisodium phosphate, reacts with water to form an alkaline solution. Green mold may be removed from wood with this cleaning chemical, which is highly effective.

Trisodium Phosphate Deck Cleaning

  • 1 liter of water
  • 1 cup phosphate trihydrate
  • Bucket
  • Brush with stiff bristles
  • Gloves for protection

Sweep the deck thoroughly to get rid of any leftover debris. Protect surrounding plants from the cleaning solution by covering them with a plastic tarp.

Mix the TSP and water together in a bucket, then scrub the decks with a stiff-bristled brush after putting on some gloves. Pay special attention to areas with green mold as you scrub in that direction. When you’re finished, use a garden hose to thoroughly wet the deck.

How to Remove Green Mold from a Deck with a Pressure Washer

When it comes to cleaning your deck’s wood, a power or pressure washer is an excellent choice. In order to avoid damaging the wood’s surface, you should be aware of a few things. Pressure washer detergent is needed for this procedure.

Pressure Washing a Wood Deck as a Deck Cleaner

  • Deck scrubbing service
  • Scrubbing brush
  • Washer with a lot of power

Many home improvement stores, like Home Depot, rent power washers for a day, if you don’t already have one. To begin, take everything off the deck and brush off any debris. To use the pressure washer, follow the manufacturer’s directions and add the deck cleaner to it.

Turn on the washer from the furthest corner of the deck. Sweeping the cleaner across your deck boards should be done while utilizing the cleaner’s soap pouring nozzle. Unless you have a very tiny deck, cleaning it without a power washer can be very time-consuming.

Scrub the moldy areas and corners with a cleaning solution and a scrub brush. This is the best approach to remove black mold from the outdoors using this method. The use of a power washer for the removal of black mold indoors is rarely practical.

Switch to the washer’s widest nozzle. When sweeping the deck, keep the nozzle two feet from the surface and go in the direction of the wood grain.

Make sure to rinse the deck thoroughly with clean water to complete the cleaning process. If you haven’t already done so, you may want to seal your wood deck after power washing it.

If you notice green mold forming in the shady regions of your wood deck, don’t worry; it’s easy to remove if you apply the appropriate cleaning technique. Using one of our cleaner solutions to clean your wood deck on a regular basis can also help prevent mold from re-appearing. To remove mold from vinyl siding, you may wish to use the same techniques that work for removing mold from wood.

We hope you found this guide to removing green mold from a wood deck helpful, and we’d appreciate it if you shared it with your friends and family on Facebook and Pinterest.


It’s a good thing that the methods for removing mildew from a wood deck don’t involve a lot of effort. They’re simple to follow and won’t cost you a lot of money, too!

Keep in mind that if the mildew infection worsens, you may have to entirely remove your wood deck and replace it, this time with the assistance of professionals.

Helen Skeates

Helen Skeates

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