Your shingled roof came with a zinc or copper particle as part them. That powdered zinc / copper will slowly leach itself out and stop algae infestations on the roofing. That usually lasts about 7 years. After about 7 years, you will see some graying coloration, often in streaks, but not always.
Then soon it will turn black with a tough algae known as Gloeocapsa magma. Once it starts infesting your roof and eating away at the limestone filler in the shingles, you will find quite a bit of your
Venice Florida homeowners questions answered about roof cleaning!
I have owned a pressure Cleaning business here in Charlotte and Southern Sarasota County Florida since 1989. Chuck Bergman Pressure Cleaning. 941-698-1959
A+ rated with Better Business Bureau - http://www.bbb.org/w...tte-fl-90024694
Please watch this Video about my company:
I pressure cleaned Venice FL roofs for many years. In time, it came about that the roofing manufacturers started saying "Do Not Pressure Wa