I glued my panels in place with an automotive headliner spray. I pulled the overhead vents and created as much room as I could to spray into a cavity and used some plywood and a material load handling ratchet bar to keep pressure on the ceiling for overnight. I also used some construction glue around the ceiling vent holes while I had the pressure on it. When I released the pressure the next day i was pleased with the results.
I have a 2000 Newmar Mountain Aire.
2000 Newmar Mountain Aire 4093
Rotax 912 powered parachute
Loving DW, DS& soon to be DIL, DD
GS Owners web site