You'll physically remove the moss using a stiff-bristled brush, which can be a large project if you have a big roof covered with moss. You'll need a few hours (or days) and some patience for this ...

This gives the moss remover time to soak in and do its work. If not, hold off. Climb onto your roof with your harness to ...

Not all roof cleaners can cover the same amount of square footage ... But whenever you notice discoloration, moss, mold, or mildew, it’s a good idea to give your roof a spray.