We are about to roof a newly constructed barn. I have noticed on an older building we have that no moss grows below skylights that have metal flashing but grows heavily elsewhere. I was wondering if anyone inserts a row of metal under the top row of shingles the whole length of the roof to prevent moss growth. It seems like a good idea to me. If I did it does anyone have any experience with doing so? If so what type of metal. I think the flashing around the skylights was just galvanized metal. Thanks for your help. Lynne

You are 100% correct about the flashing preventing moss. It isn't galvanized that does it, its copper flashing with copper nails.

We are about to roof a newly constructed barn. I have noticed on an older building we have that no moss grows below skylights that have metal flashing but grows heavily elsewhere. I was wondering if anyone inserts a row of metal under the top row of shingles the whole length of the roof to prevent moss growth. It seems like a good idea to me. If I did it does anyone have any experience with doing so? If so what type of metal. I think the flashing around the skylights was just galvanized metal. Thansk for your help. Lynne
PS. The copper flashing leaches copper sulphite which killls moss.

It might have been a zinc flashing which looks a bit like galavnized from the ground. Copper and/or zinc are the way to go, both work. I've sent you two private messages with web sites and more info.