I found this spotted roof today - It is only on one slope of the roof. Has anyone seen this before and is it worth noting in the report? If so, what would you suggest I call this? It was taken with 4k, so I can zoom in and send a photo if you need a closer look.
Thank you for the expertise and advise in advance.
(not sure if this image uploaded or not; it is my first time uploading to this forum)
Does it happen to be on the north side?
Lichen, It grows on the north side or in the shade of a tree with minimal sun and is damaging to the shingles, But can be cleaned if you remove it before it gets too out of control.
Water marks on your lens… 
Yes, it is on the north side.
LOL> Good one Larry.
Thank you Scott. I will do my research and provide valuable feedback in the report. I appreciate you.
I suspect what Scott said.
The north side gets the least amount of sunlight & can cause an environment for it to grow.
I have seen the moss a few times. This is my first time seeing Lichen. Thanks again for the valuable brainpower guys! You guys rock.
Woven 3 tab shingle valley.
I cannot argue with that ryoung7. HAAA
lack of sun as noted by others likely
Morning, Charles.
Hope this posts finds you well.
Arguably not but I will move on to what’s important.
Vulnerable area. Woven shingle valleys.
As well, lichen are composed of 2 parts, algae and fungus, half of the lichens duet. Long Copper strip on the peak will remove the lichen over time. Likely tree branches above the roof.
Lichen alright. Some on my shed again under those trees.
Yep Lichen. This can happen to homes that are on a non paves road. A little bit of dust gets kicked up and lands on a shady spot of the roof and that is all that is needed to get them started. If you spray the area with a product called “Wet and Forget” or another “Spray and Forget” it will go away without damaging to the roof.
My understanding is that it’s minimally damaging at most, and most of the damage is created by removing it. I hadn’t heard about the products Craig mentioned.
Yes, thank you. My comment was a chuckle for Randy.
Maybe that stuff works better than what I used; 
but this product worked to kill the moss and the lichen on the roof of my shed, but did not remove it from the shingles. I had to go up with my low pressure washer (1,200 psi) and clean it off.
What I found is the lichen had already damaged the shingle.
You can tell in a few places where the granules are missing where the lichen was.
This is what it looked like before I cleaned it.
Ok, you know that the shingle companies put additives in the better shingles to prevent moss and lichens from growing? Well here in my area of Michigan that is not good enough, especially om a lot of the longer life roofing. After a while the roof out in the country start to look like this 
The good roofers here add a Zinc Strip to the first or second run of shingles. this is from ZincShield ® https://www.zincshield.com/ 
it just peeks out from under the edge of the bottom. Over the years as rain washes over the zinc strip it dissolves some of the zinc and deposits it on the shingles below as it goes down the roof. I have a 60 yeas roof from Decra, stone-coated steel roofing. https://www.decra.com/metal-roofing-products/shingle-xd Not cheap but worth it. The only thing is that I live on a dirt road. So I get some streaking on it. I have yet to figurer out how to add a zinc strip to it, so every so often I put some "Spray and Forget or Wet and Forget in a hose end sprayer and wet my roof down. That about all it takes.
The pictures were from the Zinc Shield site, check them out at- https://www.zincshield.com/
looks great! thanks for the info.
