How to Clean a Wood Deck: Step by Step Guide

Cleaning a wood deck the right way comes down to three things: the right cleaner, low pressure, and a brightener to finish. I have been restoring decks since 1993, and when a stain fails early, the cause is almost always the prep, not the stain. This guide covers the exact process I use, from choosing between a cleaner and a stripper to the 48 hour dry time before you stain.

In this guide:

1. Deck Cleaner or Stain Stripper: Which Do You Need?
2. Tools and Materials for Cleaning a Wood Deck
3. How to Clean a Wood Deck in 9 Steps
4. Using a Stain Stripper Instead
5. Pressure Washing a Deck Without Damaging the Wood
6. How to Clean a Deck Without a Pressure Washer
7. Cleaning Mold, Mildew, Algae, and Gray Wood
8. Cleaning New Deck Wood Before Staining
9. Deck Cleaning FAQ

Deck Cleaner or Stain Stripper: Which Do You Need?

Cleaning a wood deck starts with one decision: a deck cleaner or a stain stripper. A cleaner removes dirt, gray oxidized fibers, mildew, and an old stain that has worn away evenly. A stripper removes stain that is still on the wood, which you need when the old finish is peeling, blotchy, or a different brand from the one you plan to use next.

I suggest using the same brand of cleaner and stain when the manufacturer makes both, because the products are designed to work together. On my own jobs, I use Restore A Deck for prep under almost every stain brand. If you want to compare the cleaners on the market, I test every major brand side by side in my deck cleaning reviews on DeckStainHelp.

Tools and Materials for Cleaning a Wood Deck

Cleaning a wood deck takes only a few tools, and most homeowners already own half of them. Have everything on hand before you mix the cleaner, because the cleaner should never dry on the wood while you look for a brush.

• Deck cleaner or stain stripper plus a wood brightener. A kit gives you both in matched amounts.
• Pump sprayer for applying the cleaner and brightener. A Chapin Clean and Stain Sprayer handles both and resists chemical damage.
• Stiff scrub brush on a pole, such as a deck scrub brush, for working the cleaner into the grain.
• Pressure washer with a 25 or 40 degree fan tip, or a garden hose with a strong nozzle if you scrub by hand.
• Plastic sheeting and a garden hose to protect plants and nearby surfaces.
• Rubber gloves and eye protection.

How to Clean a Wood Deck in 9 Steps

Cleaning a wood deck follows the same nine steps whether the wood is pressure treated pine, cedar, or redwood. Plan on most of a day for an average deck, plus two dry days before staining.

1. Clear the deck. Move all furniture, grills, and planters at least 20 feet away. Sweep leaves and debris off the surface and out of the gaps between boards so the cleaner reaches the wood.
2. Protect plants and nearby surfaces. Soak plants and grass around the deck with water, then cover them with plastic sheeting. Keep the plastic off plants on hot days so they do not overheat, and rinse them again when you finish.
3. Mix the cleaner. Follow the manufacturer’s ratio exactly and mix in your pump sprayer. A cleaner mixed too weak leaves gray wood behind, and one mixed too strong is harder on the wood and the plants.
4. Wet the wood and apply the cleaner. Lightly wet the deck, then saturate a section of about 200 to 300 square feet. On railings and other vertical surfaces, start at the bottom and work up to avoid streaking.
5. Let it dwell and scrub. Leave the cleaner on for about 10 to 15 minutes and keep it wet the whole time, adding more if it starts to dry. Scrub the wood with a stiff brush, moving with the grain.
6. Pressure wash or rinse. Rinse the section with a fan tip held about 12 inches from the wood, moving with the grain at low pressure. If you do not have a pressure washer, scrub harder and rinse with a hose.
7. Repeat and rinse everything. Work through the deck one section at a time. When you finish, rinse all decking, railings, the side of the house, and any plants to remove loosened dirt and cleaner.
8. Apply the brightener while the wood is still wet. The brightener neutralizes the cleaner, restores the wood’s natural pH, and brings back the wood’s color. Let it dwell as the label directs, then give the deck a light rinse.
9. Let the deck dry for 48 hours. Wood needs to be fully dry before staining, so wait two dry days and push the start date back if it rains. Stain applied to wet wood will not absorb properly.

Using a Stain Stripper Instead

Cleaning a wood deck with a stain stripper follows the same steps, with three differences. First, the stripper replaces the cleaner, so you do not need both. Second, strippers need a longer dwell time, and heavy or solid coatings may take a second application. Third, the brightener step is not optional after a stripper, because strippers leave the wood darker and with a high pH.

For stubborn coatings, I add the Restore A Deck Booster and Thickening Gel additives. The Booster increases stripping strength, and the Gel keeps the stripper from running off vertical surfaces like railings and balusters.

Pressure Washing a Deck Without Damaging the Wood

Pressure washing a deck is where most DIY cleaning jobs go wrong. Never pressure wash a deck with water alone. Without a cleaner, you need high pressure to remove dirt, and high pressure tears the wood fibers, leaving the surface fuzzy and splintered. With a cleaner doing the work, the pressure only needs to rinse.

• Pressure: 500 to 800 PSI for cedar, redwood, and other soft woods, and up to about 1,200 PSI for pressure treated pine.
• Tip: Use a 25 or 40 degree fan tip. Never use the red zero degree tip on wood.
• Distance: Hold the tip about 12 inches from the surface and test in an inconspicuous spot first.
• Direction: Move with the grain in long, even strokes. Stopping in one place leaves marks that show through the stain.

How to Clean a Deck Without a Pressure Washer

Cleaning a wood deck without a pressure washer works well for dirt, gray wood, and light mildew. Apply the cleaner the same way, let it dwell, and scrub every board with a stiff brush on a pole, working with the grain. Rinse thoroughly with a garden hose and a strong nozzle, then apply the brightener.

Hand scrubbing takes more effort, and it is less effective at removing old stain with a stripper. If you are stripping a failed finish, a pressure washer at low pressure gets far better results.

Cleaning Mold, Mildew, Algae, and Gray Wood

Cleaning a wood deck with mold, mildew, or green algae calls for the same process, with more attention in shaded areas. These growths hold moisture against the wood, so scrub shaded sections and areas near trees a second time if the first pass leaves dark spots.

Gray wood is not dirt. It is the top layer of wood fibers broken down by UV exposure, and a good cleaner plus a brightener removes it and brings back the wood’s natural color. If mildew returns quickly between cleanings, RAD Guard Mildew Cleaner and Preventer slows regrowth on shaded decks.

Avoid chlorine bleach. It kills surface mildew, but it breaks down the wood fibers, leaves the wood looking washed out, and is hard on surrounding plants. Oxygen based deck cleaners are safer for the wood and do a better job.

Cleaning New Deck Wood Before Staining

Cleaning new deck wood is just as important as cleaning an old deck. New smooth lumber has mill glaze, a compressed surface from the milling process that keeps stain from absorbing evenly. I let new smooth wood weather for 3 to 4 months, then clean and brighten it to open the surface before staining. Rough sawn wood can be cleaned and stained right away.

Deck Cleaning FAQ

Can I clean my deck with just a pressure washer and water?

No. Water alone needs high pressure to remove dirt and gray fibers, and that pressure damages the wood. A deck cleaner loosens the dirt chemically, so you can rinse at low pressure and keep the surface smooth.

Do I need to clean a new deck before staining it?

Yes. New wood has mill glaze and dirt from construction that block stain absorption. Clean and brighten new wood before the first coat, including new railings.

Is deck prep different for oil based and water based stains?

No. The cleaning and brightening steps are the same for both. The type of stain matters more than the base when it comes to prep.

Do I need a deck cleaner if I use a stain stripper?

No. A stain stripper cleans the wood while it removes the old stain. You still need a brightener afterward.

Can I use bleach to clean my deck?

I do not recommend it. Chlorine bleach breaks down wood fibers, discolors the wood, and harms plants. Use an oxygen based deck cleaner instead.

How long after cleaning a deck can I stain it?

Wait 48 hours of dry weather after cleaning and brightening. If it rains, start the 48 hours again once the wood dries.

Have a question about cleaning your deck? Ask in the comments below. I answer most questions within a day.

Scott Paul Wood, Deck, Paver Concrete Sealing Pro Owner

The Sealer Store is operated by OPW LLC and owned by Scott Paul, an exterior restoration contractor working since 1993 with more than 10,000 decks restored. He opened his first storefront in Rochester Hills in 1996 and has been selling these products online since 2002. We are the largest online dealer in the country for several of the brands we carry, and we are not a manufacturer. Scott also publishes independent reviews at DeckStainHelp.com and ConcreteSealerReview.com, where the products sold here are compared against competing brands.

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