Thanks for the quick replies guys!!
I'm talking about the roof liner, I called it the "ceiling: - maybe not the clearest description.
It seems to be made of a vinyl on the inside, some kind of cushioning (rubber foam?), then something stiff (maybe like car headliners have?).
I pushed it up, and it moved up about 1.5", then hit something solid. When I let it go and it came back down, it felt and sounded like it was sticking, maybe like tape peeling, then it would sag again. This why I think the adhesive that held it up has weakened.
Near any of the vents or lights it is very solid, the sagging is in the very center of an area about 6' long that has no lights, vents, etc.
Smart or not, I got on the roof (not all the way forward), and crawled around it some. I'm not a small guy at 255 lbs, and I could feel the aluminum skin "give" a little, then it held solidly.
I checked all the way around the coach, in all the overheads compartments, and corners, etc., and saw no signs anywhere of any water getting inside.
