This is interesting.
Our officce has a tar & sand cut shingles roof, it's about 1& 1/2 " thick with moss on the North side.
All manner of birds & the pesky local squirrel have been working through it for insects& bedding
A lot of it that has been loosened has not only blocked the cutter & down pipe, the wind has also blown a lot of the loose stuff into the decorative pond at the rear of it all , which has led to problems with the ponds water quality .
Now i know that moss likes acidic conditions for if you have small patches of moss on the lawn you sprinkle it with lawn sand which is sand mixed with powdered lime stone & it helps kill off the patch .
I wonder if some lawn sand sprinkled on the mossy roof tonight ( very very calm at present ) will help .
I'll give it a go and let you know what the result is come the middle of June & also at the middle of July .