I have a 2005 Chaparral 5th Wheel that I purchased used from a dealer. I never had an occasion to check the roof until I wanted to check the caulking and found a large soft spot behind the AC. I purchased insurance through Good Sam and discovered that this soft spot is not a covered expense. I was lucky that no damage occurred inside (drought in Calif). I went online and checked out diy videos. I removed the rails on each side (15'), removed the AC (Leaking gasket), and also removed a rear roof vent. I peeled the roof rubber back to just above the AC inlet and replaced 2 4' X 8' panels that were damaged by leak. I had my son help me to re glue the roof and pull the rubber back down. I replaced the gasket under the AC. This took me approx 3 weeks to complete the repair. I can only imagine what the Dealer would have charged. I am guessing around 6 thousand dollars because the dealer would have replaced the entire EDPM rubber membrane. I am an old, Gray Fat guy with lots of time. Also I was very pissed off that insurance didn't cover the repair. My cost was $400. If I buy another used RV, I will check out the roof before purchase. Good luck with your repair!