Leaks from the belly band, or more accurately the steel plates embedded in the fibreglass, is fairly common on
Trillium trailers. Search the term "belly band" and you will see what I mean. The steel plates start to rust, then they expand and cause the fibreglass around them to crack and leak.
Typically the plates are ground out and the fibreglass repaired after.
While I don't have any
leaks yet, I can see bulges on the inside of my 4500. I am going to take the belly band off my trailer grind out the offending plates, and then fibreglass over the seam. I plan to
paint over the repair, and the rest of the trailer for that matter. No belly band.
This is a fairly popular option.