Moss typically grows in lightly or heavily shaded areas that receive periods of sun. They can survive through the heat and cold and take a long time to grow. Moss can hold in moisture and cause damage to wood surfaces like outbuildings and decks. If you have an old deck with accumulated moss, follow these basic steps to safely remove it.
Step 1 - Sweep
Remove all debris from the deck such as leaves and dirt. Sweep over areas with moss as well. This can help get rid of some of the bigger accumulations of moss. Larger chunks may come off with the light pressure of the broom alone.
Step 2 - Wash the Deck
Attach your garden sprayer nozzle to your garden hose. This will give you more control where you are spraying, as well as more power to do the job. Spray down your entire deck making sure to get in between all the cracks, and into the corners. You can also use a pressure washer for this task but be sure to use a low setting to avoid damaging the wood on the deck.
Step 3 - Apply Soap and Water
Mix water with dishwasher detergent. A cup of dish soap per one gallon water should be a safe bet. You can use a regular dish detergent, but it will create a lot of foam and is more difficult to rinse off. Apply water and detergent mixture to entire deck and allow it to soak but not dry completely.
Step 4 - Sweep Deck
Moving the push broom along concentrate on areas heavily affected with moss growth. The soap and water along with the motion from the broom should help to loosen and remove moss. For those tougher areas get down on your hands and knees with your scrub brush for a more focused removal. Make sure to get down into the cracks on your deck as the moss is most likely growing from these.
Step 5 - Rinse Deck
Once again take out your garden hose and sprayer to thoroughly rinse deck off. Make sure you remove all of the detergent and continue rinsing until you no longer see bubbles.
Step 6 - Clean Up
Pick up all moss debris and properly dispose of into a garbage can.
If you still have moss that was not removed in the cleaning process then you may want to look into purchasing a moss killer. If you keep your deck clean and dry with regular maintenance you should not have to deal with moss on such a regular basis.
Reminder: It is not recommended to power wash your deck as this can peel off paint you have applied or damage the wood itself.