I agree oil or gasI'm no roof expert so once again I find myself here at the institute.
What am I looking at here? This is a 1995 ish roof that I am sure has never been cleaned. These spots will not come out with 10% SH sprayed right on it.
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To dark to get a photo now but I can try to better explain. That is one of the worst spots at the very top of the roof. In other areas on the slope of the roof it was in streaks and lighter. Mold was the worst around these areas. For the most part the roof is now clean except for some faint streaks and these dark areas at the very top.More prevalent on the N side. Now since I posted I was reading around the web and found something called Artillery Fungus. Anyone heard of this? Could it be?
Thanks for all the help.
PL
Thanks Guys. Interesting thought on the tar leaching up. Can that happen? Honestly when I was looking at it I was thinking this is tar but the granules still seemed to be there. It wont budge.
Anything bad about using a low pressure 40º on the roof at a good distance just to rinse? I so often hear about how bad it is to use a pressure washer on a roof but honestly the 40º has about as much pressure as a hose but a nice pattern.