Beltzington
Platinum Member
RVs are primarily designed to be road safe and worthy. I'm sure corners are cut on the cheaper models but the roof leaks are inherent when using a rubber membrane as roofing material. Ask any facility manager of a large flat roof building how many leaks they have had to repair and they would laugh and say "you mean today?" If you look at the trailers called "park" models which are designed less for tow-ability and more for long term exposure many use more traditional roofing materials.