Two big problems with attaching to RV ceilings. One is the material is so thin, screws are not getting much grip. Tape is often just hanging onto the surface they put on for appearance and pull that first layer off.
I might think it needs "special" attention!
One way might be to use some form of short expanding fastener. One might due for that corner?
Depends on how you want to deal with this! A first thought if trial and error is okay, is to try a short plastic anchor first as they are less damage to ceiling if they fail!
A short anchor and short screw, may get it done to hold a good long time.
But a bit more sure to work the first time but also harder to redo is a molly bolt of really small short size.
If not familiar with them, they are kind of the standard for work on sheet rock, etc. that tends to crumble and not hold. Small and short is needed to avoid going to far and creating damage on the outside to leak!
Make a hole just large enough to fit the molly in, screw the "bolt" down to expand the molly inside the wall. avoid going to far and "feel" when it gets fully expanded and STOP before stripping the threads. Back the bolt out and add the strip for final.
These work okay in foam as the fingers on the molly just press into the foam without much trouble. Kind of tricky if not used to mollies as it take a bit of "feel" for how far to go before stripping them!
But once done right, they expand about 3/4 inch wide inside and hold really well.
RV ceilings are not really nice to work!!
