Black Steaks on Side of CT

[jmayaa]

I spent most of a weekend last fall washing and waxing my CT. It looked great when finished.
I noticed the other day it has those danged black streaks running down the sides again.
Is this some kind of residue off of the roof?
I'm pretty sure it has a galvanized steel roof on it,
Would coating it with a "roof" type coating stop this run off?
What would be a good type of coating to apply?
Many Thanks,
Jeff

[hankaye]

jmayaa, Howdy;

The same thing happens with the White EPDM (Rubber), RV roofs as well.
Dust, dirt, pollution, bird crap can and will all be contributors
to the dreaded black stripes... Give it a good wash and lots of rinse water...
there are things much worse to worry about ... or not.

hank

[RWH]

I have the same problem. The streaks are coming from the galvalum roofing. My plan is to paint the roof with white fibered paint meant for mobile homes and metal roofing. It's best to do this fairly quickly before the galvalum oxidizes which may prevent the paint from adhering properly. I was also advised to do this when I bought the trailer at the dealer.

[smokepole50]

I ran across a product called Dunn E-Z from Muncie, Indiana. A simple spray and wipe. The black streaks come right off. It seems to work on my aluminum 5x10 and my steel 6x14 equally well. It even works on my vinyl siding at home. Saves a lot of back breaking work. Not a salesman for them either! The stuff is a little pricey. It was over $20 a quart but you mix it in different ratios for different cleaning chores. Worth it to me. At my age streaking is out of the question...