Every 6 months, the roof on my 2006 Jayco at our seasonal site looks like: http://i178.photobucket.com/albums/w...e/100_0353.jpg
Every 6 months (spring and fall) I manually wax the sides, front and rear of my TT. I use Meguiars RV wax and if it isn't available, I use Meguiars auto wax instead. re: http://marinerv.meguiars.com/product...ep-Cleaner-Wax
Note: Wax on, way off and its white paste dries white within the corners / inner edges. Other waxes (like Turtle wax) dries green and its green within cracks can be seen. White (of Meguiars wax) in the small cracks / corners on white TT trailer isn't seen.
For cleaning the roof, I use Protect-All RV Rubber Roof Cleaner, a bucket and sponges. re: http://www.protectall.com/rrclong.aspx
For treating our Rubber roof (every 6 months), I use Protect-All Rubber Roof Treatment. re: http://www.protectall.com/searchresu...x?CategoryID=7
If wondering, I do NOT walk on my TT's roof. I remove my shoes, slip on some thick socks, slip on some thick knee pads and "crawl" on my TT's roof. Always keeping near the edge and always ensuring 3 contact points at the same time. IMO, cleaning / treating an RV roof is like doing cleaning / treatment maintenance on a kitchen floor. For best results, I do it "on all 4s" method, adding some elbow grease and doing a "close up" visual checks at the same time. And if needed, I apply Dicor caulking after cleaning and before treatment as well. Up and Close (the old fashion way) - for best results.
Note: Some folks don't treat their RV's EDPM roof. It's their choice. For me, I see the positive results of before and after Protect-All Roof Treatment. And, I've seen for myself that Protect-All Treatment Treatment dramatically reduces (near eliminates) black streaks as well.
Hope this helps in your research....