Moss is sometimes desirable in a garden or yard because it adds texture and character, however, it is often unwanted on a deck. It becomes slippery when wet and often hides the natural look of wood. Depending on the type of moss growth on your deck, its thickness and the type of wooden deck you own, there are different techniques and practices to safely remove it. Moss removal maintains the look of your wood deck and enhances its visual appeal. It also will create a safer environment for your family.
Herbicides and Moss Treatments - A moss treatment will remove moss from a deck by killing the fungus. Most treatments use a herbicide to accomplish this task. For many homeowners that is all that will be needed to remove the moss. The treatment is simply applied to the deck surface using a spray gun. Be careful to follow the mixing instructions on the product documentation and use only enough to treat the square footage affected by the moss. After use, thoroughly clean and wash the deck as instructed. In addition, herbicides may harm untreated wood decks. If your deck is unstained, or you have a well, consider an alternate method of treatment.
Non-herbicidal Procedure - For others concerned about adding chemicals to the environment and potentially to their groundwater, other options are more suitable. Moss can be removed using a plastic scraper, the kind used to apply drywall joint compound. Slide the scraper over the affected area, gouging and lifting the moss up and off of the wood deck. Holding the scraper flat and flush against the wood deck, push forward in short choppy motions until the moss comes up and free from the deck. This prevents harm to the deck and provides the fastest means of removing the moss. Use a stiff outdoor brush to push the moss from the deck. Then rinse and clean the deck surface with a softer brush, being careful not to damage the exterior stain or wood.
Power Washing - A power washer is another option for removing moss from a wooden deck. In most cases, this will be the best option, however, care should be taken when using one of these tools. Power washers are powerful and can damage a wood deck by removing layers of stain and sealant. To reduce damage, hold the power washer at a sharp angle to the deck and move it side to side slowly until the moss is removed. Never point the washer directly down at the deck. To clean in between the deck boards, move the washer along the length of the gaps so the water stream passes along the edges of the boards. Inspect the deck finish for signs of stripping, and then rinse the deck with a hose after the moss is removed.
Prevention - To prevent moss from returning, apply a moss treatment to the wooden deck. This is applied with a roller. Closely match the application instructions on your product. Another option is to apply another layer of sealant or stain after the moss is removed. This can reduce moss growth in some cases. In addition, remove items that cause shadows on the deck where moss grows, like barbecues and tables. Trim back overhanging tree limbs and plant growth and clean the deck frequently with a hose and spray nozzle.