How to repair delamination

Thanks folks. My issue is small at this moment. Maybe a local repair shop can deal with this before it becomes a big to-do. I'll keep you posted. Thanks again.

Composet. They offer a kit with full instructions to repair delamination.

Take a look at Composet Products, they have an easy to use kits that fixes it pretty good

Thanks for all the responses. I may start with parkmaaa's suggestion and see if it takes.

I knew an old gentleman couple of years ago who had one spot of fiberglass delamination in his motorhome. Don't know exactly which epoxy he used but know it was very thin, for he took a small-needle syringe, drilled a tiny hole in the middle of the bad area, and injected epoxy into the hole. It happened to be near enough window he could get a large C-clamp on both sides, so he clamped the area as tight as he could; never a problem since, and the area flattened out where you don't see it at all.
His problem was strictly localized, the delaminated area approx. 12 in. dia.

You could introduce thinned epoxy into the delaminated area, along with fixing the original leak location. Done properly, this would avoid any future damage.

Insurance will cover the cost IF notice IF there is an accident associated with the Delaminated area. So if for example a tree branch poked a hole over the winter and that caused the delam then it would be covered. But caulk failure is a maintenance issue

This is one of those, "lets take it apart and see what we got" ordeals . :M
Sometimes these repairs become more involved as you get into it. Water damage can travel , depending how you park it during storage periods.
Before you start, make sure you have a barn or place to do this, to keep things dry for a period of time.
It gets expensive taking up time in a dealers bay, that's the alternative. I have seen them park them outside under a tarp while they wait for parts. (happened to me under warranty,waited 6 mos. outside, covered in a tarp. A one year warranty means it takes one year to get things done. If paying cash, it would have taken six days)

The dealer said its a one piece ordeal because that's the correct way to do it. They don't 'cut n patch' seams because they can be seen, its not an original look and not professional.
The other possible reason to do a one piece repair is the water will seek a low point to settle or exit. If the delamination is up high on the trailer and you repair and patch it there, you might still have water damage in the lower portion. Delamination may later occur and he would have to charge you all that labor all over again.

If the delamination is already at a low point ?
As long as you do not mind having a seam across the front of your trailer, you can cut the filon and make the repair where you need to do it. Be prepared to do some scraping to remove the old filon and glue.
You can cut a piece of new filon to cover the repair but you have to use molding to cover the seam. Pick a spot on your trailer as best you can to hide the new seam ( at least try to make it blend as best you can )

What caused the leak ?? A roof seam, a vent cover seam or a clearance light would be my guess .
Many people remove those cheap clearance lights and replace them a better light then caulk it in using Proflex RV.
I would clean and use self leveling Dicor on the roof seams and vents. Once they are fully dry (a few days) i would cover them using Eternabond tape. Add a bead of Dicor at the ends of each length of tape to prevent premature lifting.

There are youtube videos on how to do this and many rv websites where people have done it, posted the materials they used and all the 'how-to' pics.