# Algae stains



## Sorry Painter (May 9, 2011)

All sorts of biological crud can grow on most surfaces if the conditions are right. Some require an accumulation of dust, dirt and pollen to feed upon. Some species of green algae just need moisture from the air and sunlight to survive.


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## Roof Cleaning (Apr 23, 2008)

Sorry Painter said:


> All sorts of biological crud can grow on most surfaces if the conditions are right. Some require an accumulation of dust, dirt and pollen to feed upon. Some species of green algae just need moisture from the air and sunlight to survive.


How right you are! Here in Tampa Florida, we see Mildew grow on glass windows.
It is a self supporting organism, and as you know, it can even eat paint!
WE see tile roofs here in Tampa that were painted get dirty.
Once we clean them, you can see where the algae actually ate right into the pain on the roof tiles!


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## IowaBucks (Feb 26, 2015)

The first paragraph of your post refers to "the highly humid areas that are indicated in green on the map." Is algae causing actual structural damage to asphalt shingles an issue in a state like Iowa?


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## tccoggs (Dec 17, 2008)

I just hit my roof once a year with spray and forget and that has been successful at keeping the green and black growth off of it. I didn't have a huge issue with it, but in some shady areas, there were stains before I replaced the roof. Spray and Forget also works well on pavers. I have pavers on the north side of my house that never sees sun, so they turn green over time.

Its a little pricey for what I'm sure is just some sort of bleach, but it never killed any of my plants, so I keep using it.


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## Michael217 (Apr 23, 2011)

tccoggs said:


> I just hit my roof once a year with spray and forget and that has been successful at keeping the green and black growth off of it. I didn't have a huge issue with it, but in some shady areas, there were stains before I replaced the roof. Spray and Forget also works well on pavers. I have pavers on the north side of my house that never sees sun, so they turn green over time.
> 
> Its a little pricey for what I'm sure is just some sort of bleach, but it never killed any of my plants, so I keep using it.


What product do you spray?


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## KAP (Feb 19, 2011)

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## Coverall (Jan 19, 2017)

I'm having my local building supply bring in boxes of zinc strips for us to install at ridges. They are inexpensive and work. Can be installed for $2.50 per ft including a small profit.


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