Moss, lichen and algae can grow on any hard surface where there is enough moisture and color. Even though they are not harmful to the surface, they are unsightly and can cause a slipping hazard on wooden decks. Moss and lichens can be cleaned off with oxygen bleach along with a good scrubbing but if the surface also requires the removal of old, peeling paint, the best method to accept both tasks at the same time is by using a pressure washer.
Rent or buy a pressure washer. Read instructions carefully if you’ve got no prior experience working with the equipment.
Put on eye protection. A pressure washer uses a lot more pressure than a garden hose and can lead to serious bodily injury.
Put the widest nozzle which can be found on the pressure washer and place it on a low setting, roughly 1,000 to 1,200 psi.
Hold the nozzle approximately 10 to 12 inches in the wooden surface. Use a back and forth sweeping motion to spray down the surface and keep the nozzle in motion in any way times once the pressure washer is functioning.
Gradually raise the pressure if necessary. Avoid letting the spray to linger in any 1 area, especially if the wooden surface is old and weathered. The force out of a pressure washer is strong enough to dent milder wood.
Use an oscillating tool with a sanding accessory to get rid of any small areas of paint remaining on the surface.