The copper doesnt really work tbh. Maybe just a foot below where its placed. The copper ridge system that was sold years back was a bit of a myth in my experience. People used to put it on the ridge. But it would only really clean half a foot below it if the roof was already clean. Wouldnt really be strong enough to kill the moss that was already there. If it did was only a couple of rows of tiles as opposed to the whole roof.