zinc or copper roof strip to stop algae?

[imported_noel]

I've come across a couple of things hat lead me to believe that a strip of copper will help reduse roof algae. I read the same for zinc or galv. I was wondering if anyone had any tales to tell about either the copper or zinc.? Does one last longer than the other? Does it work at all?
Thanks

[Wgoodrich]

I think what you are talking of may be zinc oxide or copper sulfate being used as an herbicide. Have heard of this used but not sure of results.

A new roof or herbicide application recommended by your neabyby ag store would probably provide more positive results in my opinion.

May have other opinions though.

Wg

[thiggy]

Having a galvanized strip of sheetmetal such as flashing running the length of the roof near the peak will help discourage the formation of algae on the shingles. The rainwater washing over the galvanized strip leaches small amounts of zinc out which runs across the shingles below. You can often notice this by looking at a roof which has galvanized thimbles through which vent stacks pass. The shingles below the thimbles generally are without algae and mildew.