Why worry about it at this point? I had 10 years on my last park trailer with a rubber roof. Sat outside year around. Seldom washed it. Touched up the caulk every year. That's it. Every time you scrub it you scrub off some of the wear layer. Mine was in very good condition when I sold it and I'm sure it would go another 10 years with minimal care. Pretty doubtful you will keep your trailer for your lifetime..
2015 Chev Silverado 3500 dually D/A
2016 Cedar Creek 36CK
B&W Patriot 18K, Trail-Aire pinbox,
Level up, dual panes & all that stuff...