If your RV roof is turning black, I’ll bet my hat that your problem is an old EPDM roof at the end of its life. Other possibilities include algae, mold, or air pollution, but a flaky black roof is to an RV what wrinkly elbows are to a human: signs of old age! 

Cause #1: EPDM Roof at the End of Its Life

Most RV rubber roofs are made of EPDM, a thin, flexible, plastic membrane. The membrane is actually a sandwich made of two layers: a cheaper black base, and a more expensive white-dyed top. Over time, the white top coating wears and flakes away from UV exposure, exposing the naked black underneath.

There is no “fixing” this problem. By the time your RV rubber roof has turned black, half your roof membrane is gone – literally turned to dust and carried away by the wind and rain! Your roof is almost paper-thin at this point. The black layer is not UV-stabilized; you can’t leave it alone. It will chalk and crack like mad.