The trick is to have 2 or 3 days without rain so the product I'm about to apply to the roof has time to do it's job - kill the moss. For this application I will be spraying liquid Moss Out! on the entire roof.
Moss build-up is greatest at the edges of the shingles ... in some places it's about the diameter of a pencil or Sharpie pen but in bright sun a green sheen is seen just about everywhere. No good comes from a mossy roof.
I usually spray the roof twice annually but because I shredded my Achilles tendon, had surgery then two PRP treatments followed by months of recovery, I haven't been on the roof for awhile.
Today the moss dies.
photos by Bill Stankus