We cleaned this roof a couple of weeks ago in South Gulf Cove. A large development that falls within Port Charlotte, Florida It's right down the street from me, I am in Gulf Cove.
This was originally a 10 minute video, I cut it to 2 minutes. The 10 minute version is on YouTube. If you want to see just how much black algae discoloration there was, you should watch the 1st 10 seconds. It has some close ups.
33981,33947,33946,33953,33987,33993,33948,34224,34 223,33952,33954,34293,34287,34288,34286,34291,3427 5,34292,33985 I have been licensed and insured in Charlotte and Sarasota County since 1989.
Most homeowners are unaware, that the roofing manufacturers specify exact cleaning methods and chemicals, that may be used on their products, without voiding their warranties. They all say "DO NOT PRESSURE WASH"
Seeing as how the roofing manufacturers not only make the product, but also stand behind it with a warranty, common sense dictates we listen to them.
"We" being you the homeowner and myself and others, who are in the business of cleaning roofs as contractors.
Here in Florida, stains that appear on a roof are the living algae organism ( Gloeocapsa Magma algae ) that not only looks filthy and ugly, it will gradually reduce the roofs' lifespan, costing you unnecessary money, many years earlier than necessary.
An infected roof not only reduces your homes lifespan, but it's curb-appeal = it's property value.
Shingled Roofs, Barrel and Flat tiles are all affected by this algae. In the case of tile, the greatest problems are cosmetic, besides ugly, algae can eat away at the glazing on your tile. If it is painted tile, then the algae will eat the paint and get under the paints surface, making it peel. Pressure Cleaning glazed tile can remove the glazing even faster, or blast the paint off like it's snowing out!