Cleaning stained asphalt shingles

[saw_dust]

There are companys in Florida/Georgia etc. that apply chemicals to remove the stains on asphalt shingles,and rinse the fungi off with a garden hose,has anyone on this forum had any experience with cleaning asphalt shingles?These stains are caused by an airborne spore that survives in high humidity areas and feeds off of the asphalt in the shingles I have read about some of these chemicals...Shingle Shield/American Roof Brite/Shingle Care to name a few...care to comment please ?

 

[beenthere]

If the stains are from a fungi (growing) then a simple mixture using chlorine bleach should do the job. Another way is to put a galvanized (or copper) strip at the peak (ridge) of the roof. The residue from the metal will keep the roof clean (normally). Look for barns that have galvanized cupalo's or vents, and you will likely see a clean streak immediately below them on the roofing.

 

[saw_dust]

I have read about the zinc strips and I have read that the chlorine damages the shingles....but could be a sales pitch to get you to buy the so called Shingle cleaning chemicals...