Unless it has been physically damaged, chances are the roof is fine. What's probably leaking is the caulking of the joints that is now eight years old. After about five years, many of the older OEM caulkings will start to deteriorate, become brittle and loose their elasticity.

When you have a roof construction that is of a different material than the trailer's frame, the expansion and contraction of the materials will vary. This places an additional stress on the caulking, with the seams moving differently at each temperature change.

If no maintenance has been previously done to the caulking, it's probably the reason for your present problems. The old caulking should be removed and replaced with a modern polyurethane product. This should ensure a leak free environment for the next eight years or so.

Your description is indicative of UV damage often found on fiberglass boats, that have been constantly exposed to the sunlight for decades. As the surfacing gell coating is broken down, it is sloughed off and eroded, exposing the underlaying glass fibers and laminating resin. As these are then in turn damaged, the layup become porous and weak.

An eight year old trailer stored inside, should certainly not be suffering this same experience. This result would likely argue, that the initial construction was poorly effected. I can't recommend your best legal advice, but if you do like the trailer, a resolution can be implemented.

The exterior fiberglass can be recovered with FRP products that will restore the surface to a better than new condition. This is a fairly common procedure, accomplished in the marine industry and can be sourced at many boat yards. The material costs are not unreasonable, but the labour can be significant, depending upon the hourly rate being charged.

Finding a person familiar with FRP repairs, that works a season job and is willing to pick up some side jobs, would be the way to go. The repairs could be effected in your yard.  It would take a day to apply the products and a day to finish them smooth. When they are recoated, you would then have a roof that would last as long as your trailer.

There is an easier and less expensive way to fix your leaking problem, if the strength of the present roof is not compromised. The application of an elastomeric coating would completely seal the roof from any leaks. If you know how to paint a wall using a roller, you can surface coat the roof as a DIY project.

You clean and slightly abrade the surface, mask off the perimiter and areas not being coated, and perform a "roller derby". A broom handle, roller and cover, a large chip brush and you're ready to go. The most difficult process is lifting the five gallon buckets onto the roof; they're heavy.

You can make your trailer serviceable again. Fiberglass repairs may cost ~$1000, the rubber coating, a quarter of that. BOL

There was a problem with the roofs in 04 &05 I think. It had some thing to do with delaminating. A friend of ours had to have there's fixed.

No idea, but I heard the same issue with Hart Trailers. Have had/have both and never a problem. They use the same roof so maybe the recall was with Hart?

There was a post on here a few years ago dealing with something like that???  Will look.

The problem with the Cimarron was very prevalent and involved the multi-layer roof basically coming into many layers. There was never a "recall" as I guess it wasn't a safety issue. There was a campaign to put a sealer over the top at one time, and I've heard of some being replaced at the factory. I know of several in the field that have had a full aluminum skin roof installed over the existing laminate roof and it works well. The warranty did not transfer to additional owners, and expired in 5 years as you say. So not much help there for most.

Hart uses something similar, but I don't believe they used the specific product that bothered Cim. I've never heard of a Hart problem.