Look on the brite side. If you have delam then you know you have a leak. If you have the old style corrugated aluminum siding and have a leak, well you may not know it until you have dry rot. Delam is mainly cosmetic. It can be caused by a bad glue. More than likely it's from a leak. You won't have the bigger dry rot problems with an aluminum framed trailer with delam.
In either case it's not good. Delam can be a major $$$$ repair or as simply as a small fiberglass repair depending on how big the delam area is.
Not too many Rv'ers can repair delam.
On the other hand fixing dry rot and replacing aluminum exterior panels would be easier.
I think you take your chances either way. Keeping up religiously on maintenance is the key.
