Black stains on roof!

[compman69]

I went up on the roof to check everything before I leave for the keys after I got my RV back from the dealer getting warranty repairs done and found the roof black as rubber.
I tried using Dawn dish soap and also a car wash and it barely took any of it off.
I have the fiberglass roof but I didn't want to use too strong of a chemical like bleach.
If I put Dawn on it when it is wet and scrub it with a scrub brush on hands and knees it comes up. But there's got to be an easier way! I would love some suggestions! And what can I use to prevent this from happening again.

[Hugeez]

Good question. Following

[rsdata]

I use this on outdoor furniture. I recently used it on my Shamrock roof also.
Pretty effective, but might need a little scrubbing also for heavier deposits.

Bleach-Free, No Scrub Mold & Mildew, Moss & Algae Cleaner | Wet & Forget

[BandJCarm]

Let me ask. Did it look anything like this picture?

If so, a certain batch of Dometic A/C units leaked oil onto the roof and ruined the roof. My dealer and Dometic worked together (somehow?) to get a new a/c and a new roof. But it has to be a certain batch of A/C units, not just any one of them, as I understand.

I also had some 'normal' black streaks on roof and sides, but "black streak remover" took it out of sides. I did not try it on the roof, as the dealer got involved with the A/C issue before I could.

[compman69]

No it is a slick mildew like substance. It's imbedded in the grain is the Fiberglass

[Iggy]

Originally Posted by compman69

No it is a slick mildew like substance. It's imbedded in the grain is the Fiberglass

I suspect it is because you are in a high humidity area and things grow any were the water/moistures stays.
In Arizona we don't have those problems. Our roof catch on fire here.

[Wolverine 1945]

Remember what ever you use on your roof is going to run down the sides of your unit !!!