Green stains on a deck are likely caused from mildew, mould or algae. These green stains are a common result of the deck's constant exposure to weather elements. It is important to clean deck stains to keep the wood in good condition and preserve the overall appearance of the deck. Target the green stains on the deck or clean the entire deck at once with this cleaning method. By following the proper steps, you can successfully remove green stains from a deck and renew its appearance.
Remove any items that are sitting on the deck. Remove furniture, grills or other items that may interfere with the cleaning process. Sweep the deck with a broom to remove dirt and debris.
Mix a solution of oxygen bleach and warm water in a large bucket. Oxygen bleach is an eco-friendly cleaner that will not damage the wood or harm the surrounding landscape. Typically, you should use between 118 and 177ml of oxygen bleach per gallon of water. The exact measurement of oxygen bleach varies depending on the concentration of the active ingredient in the final product. The active ingredient in oxygen bleach is sodium percarbonate. The more sodium percarbonate in the product, the higher the concentration. Refer to the package label for specific mixing instructions. Let the oxygen bleach mixture rest for about 5 minutes prior to cleaning.
Pour a liberal amount of the cleaning solution directly onto the deck, working one section at a time. The oxygen bleach mixture will begin to foam as it is applied to the wood. Allow the oxygen bleach mixture to soak on the deck for 10 to 15 minutes for maximum cleaning benefit.
Scrub the deck with a scrub brush. Use a long-stemmed scrub brush for large decks to cover more area at once. The oxygen bleach works on its own so only a light scrubbing is necessary.
Pour some of the oxygen bleach mixture into a pump-style garden sprayer to clean the deck rails as well. Spray the handles generously with the mixture and let it soak for 10 to 15 minutes. Scrub the rails with a toilet brush or one of similar size to remove stains.
Rinse the cleaning solution from the deck and rails using a garden hose.
Clean the entire deck with oxygen bleach rather than just targeting the stains. This will give the deck an even appearance.
Protect your eyes and clothing and follow manufacturer's directions when using cleaning products.