About 10 years ago I was turned on to a product by an RV repair service near Ft. Wilderness (Disney World) for sealing some seems on the fiberglass roof of my Travel Supreme Select 45'. Now that was a LOT of roof!!! Anyway, the product worked so well I bought a second gallon to keep as a spare. I just opened the second can after sitting 10 years. After stirring it was perfect! I then did the entire roof perimeter seam of my Lexi 255 GTS. And touched some of the factory coated area's... We have owned RV's of some sort for nearly 40 years. If RV's have a weak link, it is usually roof seams.
The product:PLAS-T-COTE-: CLEANEDŽ Alkyd Fibered Roof Coating
Plas-T-Cote Roof Coatings - Roof Coating Manufacturer - Roof Sealants by Elixir Industries
I hope some of you find this helpful.
2006 Lexi 255 GTS