Sagging slide out ceiling in fifth wheel

[Raven]

Last year, water had seeped into floor edges in slide out. The right sided slide wall had separated from the rail. It was a fairly easy fix. Now we discover 3 areas in the ceiling slide where there is noticeable sagging. One area is damp to touch. Because our fifth wheel is stationary, we are unable to take the unit to a repair Centre. We will be inspecting the roof of the slide this week & are hoping that we can get some guidance on what to look for. Any ideas will be greatly appreciated.