How to Clean a Slippery Wooden Deck

In our recent decking questions and answers blog post, we lightly touched on the problem of green and slippery decking, which can be a health hazard and unsightly. So today we’re going to delve deeper into this problem and come up with the best solutions to for slippery deck prevention and cleaning. We also detail how much it will cost you to carry out any of these tasks.

Further Reading:
Compare Decks, Pergolas and Gazebos
Difference Between Decks and Patios
Difference Between Decks and Porches

We’ve discussed this issue slippy decking with deck finish experts as well as homeowners who have put these solutions to work, and here are the top suggestions for stopping and treating slippery decks.

wet deck

Keep your Deck Clear of Debris to Prevent Algae

Algae is the top cause of a slippery deck, and the key is to prevent it from growing. Debris such as leaves, twigs and dirt holds moisture against the deck, creating the right environment for algae to get a foothold. Use a stiff broom, and remove debris before it gets wet, when possible. Hosing off the deck on a sunny day when it will dry quickly is a good part of regular maintenance too.

  • Stiff push broom: $8 to $20
  • 25-foot hose: $10 to $24
  • Spray nozzle: $5 to $12

Remove Algae and Mold with a Detergent and Oxygen Bleach Solution

Spring and fall are common times to find unwanted growth on your decking. Let’s start with a cheap fix for small patches of algae, mold or mildew, a solution of:

  • 1 cup ammonia-free, powdered laundry detergent
  • 1 quart of oxygen bleach (not chlorine bleach)
  • 2 to 3 gallons of water

If your deck is very small or very large, adjust the amount of solution you mix, using the same proportions. Mix the solution in a bucket, and apply it with a mop or a pump sprayer. Allow it to sit for 15 to 30 minutes before scrubbing the area with your stiff broom. Finally, thoroughly rinse the area with a hose. You’ll want to seal the deck after cleaning in order to protect the wood from further damage. Premixed oxygen bleach cleaning powders for mixing are also available.

NOTE: Avoid chlorine bleach. It might bleach clothing, stain wood siding and harm plants and animals.

  • Powdered Laundry Detergent: $5 to $15
  • Ammonia: $2 to $5
  • Oxygen bleach: $3 to $6
  • Oxygen bleach cleaning powder in various sizes: $4 to $20
  • Mop: $6 to $10
  • Pump Sprayer: $12 to $35
  • Stiff Broom: $8 to $20
  • 25-foot hose: $10 to $24
  • Spray nozzle: $5 to $12
  • Deck sealer or stain & sealer: $22 to $40 per gallon
  • Roller with handle, pad and tray: $12 to 40

Pressure Wash the Deck in Extreme Cases

This solution to a slippery deck should be chosen with caution. Using a power washer on the deck can cause damage to its surface which can lead to it deteriorating or rotting more quickly. However, it is an effective “last resort” solution when the deck has large areas affected by algae, mold or mildew. Set the pressure to no more than 1,300 PSI to prevent or limit the damage. Follow guidelines in the owner’s manual for best results. A pressure-washed deck should be allowed to thoroughly dry and then sealed with a high-quality product. For this reason, it makes sense to wait to power wash it until several days of sunny, dry weather are in the forecast.

• Pressure Washer: $75 to $300 and up
• Pressure Washer Rental: $35 to $50 per day
• Deck sealer or stain & sealer: $22 to $40 per gallon
• Roller with handle, pad and tray: $12 to 40

Apply Anti-Slip Coating

There are products formulated for decks that seal the wood and help to prevent slipping. Most are formulated with sand or aggregate suspended in the sealer to give the surface some grit. These coatings are applied like deck stain, though are sometimes somewhat thicker and more difficult to work with.

• Anti-Slip Coating: $75 to $125 per gallon
• Roller with handle, pad and tray: $12 to $40

Spread Sand onto the Deck While Sealer is Wet

A cheaper method of making your deck surface gritty and therefore less slippery is to sprinkle sand onto the wet sealer where it will remain embedded once the sealer dries. Load coarse sand into a handheld broadcast spreader. Next, apply deck stain or sealer to an area two to three feet deep—only as deep as you can comfortably reach with the spreader—and 12 to 20 feet wide. While the material is still tacky, cover it with a light to moderate application of sand.

The sand that falls onto areas not yet wet can be pushed onto the wet area with a broom or brushed off the deck. This method provides six to 24 months of good wear, depending on how much you use the deck. Sand that has been loosened with foot traffic should be brushed off the deck periodically to prevent it from scratching the deck’s sealer and surface, thereby rendering the decking susceptible to moisture.

  • Roller with Handle, pad and Tray: $12 to $40
  • Handheld broadcast spreader: $10 to $35
  • Coarse Sand: $5 to $15 per bag

Use Anti-Slip Strips, Inserts, Tape, Inserts or Mats Where Needed

There are several different products you can apply to your deck to help prevent slipping. Durable, anti-skid strips can be attached in strategic locations to provide secure footing. They’re excellent for stairs, and are typically attached with fasteners such as screws. One issue to note is that they are somewhat raised, so might present a trip danger while protecting from slips. While hard to find, slip-resistant inserts can be very useful on decks that have space between the decking boards. The inserts fit into the gaps and can be secured in place. Most are coated with a durable, coarse surface that offers excellent traction.

Traction tape is a cheaper solution, though the materials isn’t as durable as strips or inserts. The tape is widely used on stairs, landings and other locations where slips are likely. Most anti-slip tape has a peel-off backing, so it is easy to cut to size and install.

Anti-slip mats are very useful on decks wherever slips are likely including next to hot tubs, outsider doors and on landings. Most are made of rubber or a similar synthetic material with a diamond or other texture surface. These mats should be picked up when the deck is not in use, because while preventing slips, they will hold moisture against the deck that will eventually lead to mold growth and rot.

  • Anti-slip strips: $8 to $25
  • Anti-slip inserts: $2 to $4 per linear foot
  • Anti-slip tape: Less than $1 per linear foot
  • Anti-slip mats: $3 to $10 per square foot


Jamie Sandford - Owner and Lead Editor at RenoCompareJamie Sandford is the Chief Editor at RenoCompare (find out more). Jamie has been involved in construction for over 30 years. Straight out of college, Jamie worked with construction crews for the television, film and theatre industries for over 12 years. In his thirties, he turned his attention to DIY decorating and construction, working on many house renovations and remodels. During this time he started to specialize in home flooring and in 2013 he launched the Home Flooring Pros website. Two years later he launched RenoCompare.

“I’ve seen interior design, remodeling, and construction from both sides of the street, contractors on one side and homeowners on the other. My aim is to close the gap between the professionals and the consumers and make it easier for both sides to work smoothly and effectively side by side. At RenoCompare we want to save you time and money by giving you the information you need as simply and as quickly as possible!”

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