My 5'er had a failure of the Alpha EPDM roof this past December after 5 1/2 years service. The membrane had an alligator skin look where condensation from my 2 a/c's was dripping on it. Alpha Systems said he was "normal aging" and not to worry about it. It may have been normal aging, but moisture was leaking through it. Fortunately I caught it so the only damage was to the luan material right under the roof membrane.
My solution was RV Flex Armor. Problem solved and no more rubber roof or caulking to worry about.
Ed
KM4STL
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch, Progressive Industries EMS-PT50C, TST Systems 507 TPMS
2010 Jayco Designer 35RLTS,Cummins/Onan RV QG 5500 EVAP
Fulltime since 2010