Decks play host to a wide range of outdoor activities during the warmer months. A season’s worth of alfresco cooking, dining, and entertaining can easily dirty the surface with spots from grill grease, food or drink spills, soot from the firepit, and more. And because these spaces are exposed to the elements, they can naturally gather stains from dirt, leaves, tree sap, rusty furniture, and other grime throughout the year.
Deck stains can be difficult to remove, but with the right cleaning method and supplies, you can get your outdoor space looking as good as new. Keep in mind that the best deck stain remover will depend on the type of stain. Use the instructions below to learn how to clean a deck to restore your space for outdoor living.
How to Clean a Wood Deck
Plan to clean stains on decks as soon as possible to prevent the mark from setting into the wood permanently. In general, it’s best to avoid using harsh chemicals to clean your wood deck. Chlorine bleach, for example, breaks down the wood fibers and can result in permanent damage to your deck or harm to the surrounding environment.
To maintain your wood deck’s good looks, reapply sealer or stain about every one to two years. Use these cleaning methods to tackle some of the most common deck stains.
How to Clean Barbecue Stains
If your last backyard barbecue got messy, remove grease spots or saucy spills using a household dish detergent.
Step 1: Scrub the Stain. Mix dish detergent designed to cut through grease, such as Dawn Ultra Liquid Dish Soap with hot water. Using a stiff-bristled brush scrub the area.
Step 2: Rinse the Area. Use a dampened sponge to mop up the loosened grease. Rinse the area with a garden hose before it dries.
How to Clean Candle Wax
Clean up candle wax following these steps.
Step 1: Scrape Away Wax. To clear away wax drips from outdoor candles, first carefully scrape away as much residue as possible using a plastic card, putty knife, or similar tool that will not gouge the wood.
Step 2: Warm the Wax. Cover the area with plain paper (such as a brown paper bag) and use an iron set on low to gently warm the wax. The residue should lift away on the paper. Repeat until the wax is gone, replacing the paper as needed.
Alternatively, you can clean candle wax off a wood deck using mineral spirits. Saturate a rag and set it on the dried wax until it absorbs the residue, rubbing lightly if necessary.
How to Clean Green Algae or Moss
Spurred on by damp, dark conditions, algae and moss growth creates a slippery deck surface and can lead to wood rot or other permanent damage. These stains are difficult to remove and usually reappear once the roots are formed in the wood, so it’s important to treat them right away.
Step 1: Mix Bleach Solution. Remove green algae or moss stains on wood decks using an oxygen bleach solution. Mix together 1 cup oxygen bleach, 1/2 cup borax, and 2 Tbsp. dish detergent in 1 gallon water.
Step 2: Scrub and Rinse. Scrub the stained areas with a brush dipped into the solution, then wait about 15 minutes before rinsing with a hose.
How to Clean Leaf Stains
When leaves accumulate on decks or porches, they can start to decompose and leave behind dark marks or silhouettes. You can avoid these stains by regularly clearing away leaves from your deck as they begin to fall.
Step 1: Scrub the Area. To remove leaf stains on wood decks, scrub the area with a solution of dish detergent and warm water.
Step 2: Let Sit, Scrub, and Rinse. Let the cleaning solution soak in for about 15 minutes before scrubbing again and rinsing with a hose.
For stubborn stains, try scrubbing with a solution of one cup oxygen bleach to one gallon of water, repeating as necessary until the stains disappear.
How to Clean Mold and Mildew
Mildew or mold is a common problem for decks in shady or damp areas, but regular cleaning can help keep it at bay. Some deck cleaners contain acids or chlorine, which can harm plants; check the label before using the product.
Step 1: Clean the Surface and Let Sit. Clean the surface with a commercial deck cleaner/brightener. If it is not in liquid form, mix the powder concentrate with the recommended amount of water and apply with a garden sprayer, brush, or roller. Let sit for a few minutes.
Step 2: Brush and Rinse. Brush briskly with a stiff brush or broom. Rinse with a garden hose.
How to Clean Rust on Your Deck
Rusty outdoor furniture can leave red-brown rings or marks on your deck.
Step 1: Spray Deck and Wipe. To remove rust stains, spray a 50-50 solution of water and distilled white vinegar on the stain and let sit for about 10 minutes before wiping clean with a cloth.
For stubborn stains, try using an oxalic acid cleaner following the manufacturer’s instructions.
How to Clean Tannin Stains
Tannins are naturally occurring compounds found in many trees and plants. They can sometimes cause dark stains to appear on wood decks after rain draws tannins to the surface.
Step 1: Use Deck Cleaner. Remove the black streaks of tannin-rich woods with a specially formulated deck cleaner for tannin stains, following the manufacturer’s instructions.
How to Clean Tree Sap on Your Deck
Tree sap can harden on the surface of your deck, creating stains that are difficult to remove.
Step 1: Soften the Sap. To soften the sticky residue, apply Murphy Oil Soap directly on the stain.
Step 2: Scrub and Rinse. Let sit for about 15 minutes, then scrub with a brush and rinse.
How to Clean a Composite Deck
Composite decking is an engineered product that blends wood fibers with inorganic materials like plastic and bonding agents. Because it’s not lumber, composite decking requires very little maintenance. The material never needs to be stained, sanded, or sealed. Composite decking is fade-resistant, stain-resistant, and moisture-resistant, which means there’s no mold, mildew, or rot.
The real benefit of a composite deck is that it doesn’t require much maintenance. All you need to do to clean composite decking is dab soapy water on the deck with a cloth. If there are any stains, you can use a toothbrush for a deeper clean. Avoid harsh chemicals and power washing when cleaning a composite deck. Simply sweep your deck with a soft-bristled brush.
How Often to Clean a Deck
A lot of things will affect how often you clean and maintain a deck. If you’re prone to spill or make messes, you should prioritize these isolated, small clean-ups as the messes are made.
Do you need a full deck refresh? That depends on a lot of other factors. If you live in the suburbs or an urban area with fewer trees, you will need to clean less frequently. If you live under the canopy of trees, your deck will pick up dirt, leaves, bird droppings, and all the natural debris that comes from living with nature, and you’ll want to tend to it more often.
The material of your decking boards makes a big difference, too. Composite decking boards will need less maintenance than wood decking. Other factors that affect your deck include your climate and how much natural light or shade falls on your deck. Deck maintenance should be added to your list of regular “home work.”
