I damaged the rubber roof on my 2006 Pioneer with a tree limb. The repair shop said also some of the underlayment was delimnating (sp). they recommend putting new underlayment (1/4 plywood)on top of ...
Aside from the argument of whether it is a good fix or not (i don't think I would want it), this fix would add more weight to your trailer.
New roofs are expensive, though. The local mobile RV repairman just up the road from us charges a flat $400, plus $100 per linear foot of trailer. Our 26 DB would be $3,000 for a new roof.