I had a quick discussion off line with Tim Morrissey, looking for advice and know how on the ceiling repair. His videos are excellent, and this the most relevant one for what I wanted to do:
I already have new headliner from the wonderful folks at ATC. The nice thing about this headliner (same as original) is that it is wide enough that there isn't a seam down the middle. I was very curious to know about stuff Tim didn't cover in his video, because his roof lifters and canvas were in really bad shape so he wasn't fussy about how it all came apart. I wanted to know how to actually remove the roof without causing any damage. I was thinking of this sequence:
1) Build supporting mechanism to hold the roof up
2) unscrew bottom of lifting panels (not sure how to hold the springs so they don't unwind)
3) remove trim screws around outside of roof
4) remove trim
5) peel off the roof from the frame without damaging the sideliner
6) peel off the thermal pack header
7) remove existing headliner
8) lift roof off of camper
9) drill out all the rivets holding the lifter panels to the ceiling
10) remove existing insulation (partially done already)
11 remove/enhance stock wiring (I hate the frame grounding mechanism that the factory uses)
12) replace insulation, tape/seal it to create full vapor barrier
13) Install new headliner
14) reinstall thermal pack header
15) reinstall roof - sealing sideliner to roof
16) reinstall lifter panels to roof
17) reinstall trim & screws
I was also wondering about glues/sealants in use that I have to replace when reinstalling, and how to remove the existing glue/sealants on disassembly without damaging anything.
Finally, I wondered about all those darn rivets they use to install the roof lifters into the roof. They use screws at the bottom and rivets on top. Why?
After chatting with Tim, we both agreed that since my sideliner, lifters and roof were in good shape, it made no sense to remove the roof to replace just the headliner.
So I cut out the remaining headliner, leaving just 1/8" or so along the edges. The aluminum tape I used stuck well to the aluminum tubing and the bits of headliner that remained behind. There are just 4 small sections of the original headliner left, one in each of the four corners of the roof. When I get close ups, you will see why. It has to to with how I plan to attach the new headliner without taking off the lifter panels.
The rigid insulation was cut snug using my table saw. I left 1/2" of the rockwool that was up there between the roof and the rigid stuff, so the total R value should be around 7 or so. (1" or Rockwool, plus the R-5 of the 1" thick rigid stuff).
One odd bit. Each of the N/S tubes is bent as shown below. Possibly to decrease the height of the roof to allow it to slope downwards at the ends for better water flow.