If you have a rubber roof you should wash the roof a minimum of twice a year. I use an RV roof cleaner and protector product either made by Camco or Dicor for the roof. To name two products on the market. They also make products that clean and protects the awning. You can buy these products almost anywhere such as Walmart, auto parts stores and camping dealers plus the Dreaded Camping World.
2016 34RL CC; 2008 Ram Mega Cab 2500HD, 6.7L, 68RFE 6 speed, 4X4, Smarty S67, TDR 135K+miles