Moss generally develops in the shaded areas that are slow to dry up after rain. If you want to remove it, it is recommended that you simply pressure wash the surface after applying a solution of 20% dish soap and 80% water to the surface. It is important to remember to not use the pressure washer on high power or too close to the surface when rinsing, or you risk damaging the surface. Always keep the nozzle at a 30° angle, 12’’ away from the surface and use the fanned nozzle setting.