Before you start this step, disconnect any water tanks from the gutters so no chemicals get in to your water storage. Now apply the anti-moss spray across all the tiles on your roof. When you are spraying on a roof, always start on one side and carefully walk backwards away from where you have sprayed. That way you always walk onto a dry tile. Ensure to take extra care while walking backwards, making sure you have installed a safety rail and are wearing sturdy, non-slip shoes.