Well.. what would you like to know and I'll try to un-vague it for you.
Through the roof is a synthetic liquid rubber. It sticks like tar (to everything) but according to the manufacturer.. wont shrink, crack, etc.. and has a lifetime warranty. I talked to a few locals who used it to seal up roof seams on horse trailers, etc.. before using it on the bus.
So far.. this stuff has worked great. It bonds extremely well (tried to remove some of it from an area around a window... not happening unless you use a wire wheel on a grinder or lots of patience with a razor blade). It solved my issues but its not all I'm using. I'm reinstalling the gutters and moldings using the proper butyl tape (which should seal out water on it's own). It can be applied vertically as long as it isn't applied too heavy.
Keep in mind what ever you end up using needs to have some give or it will end up cracking/leaking again as the bus moves. These bodies flex and give quite a bit so a seam glued together with something that sets up firm will either crack back open in short order... or cause another area of the fiberglass to crack. They are assembled in panels to allow for movement without causing damage... so a bit of flexibility is required. DONT use silicone or anything of the like... it wont stick and will fail.
Are the seams in an area that use a molding to cover them or are they lapped exterior skin seams? Have any pictures of the problem areas?
