We are rebuilding a 1973 GMC. One of the damaged areas was the ceiling due to various roof leaks over the last years that it sat unused. We searched for weeks before locating the ultimate replacement material: fiberglass! This is a description of what we used and how we did the job; we write this in hopes it can give ideas or almost step by step instructions for others who may need ceiling panel replacment also.
We found thin 1/16 4x8 sheets of colored & slightly textured (very similar texture to the original wax-backed cardboard originally used) fiberglass in the plumbing department of our local building supply store. This material is meant for tub enclosures. Also there were all the various joint and end caps.
For complete ceiling replacement, front to back, 4 sheets are required.
We began with what we considered the hardest to replace, the section over the kitchen area. In retrospect, it appears one can start with any section.
To replace the kitchen section, we removed the refrigerator (2 screws each side) and unscrewed its cabinet from the ceiling (2 long screws just behind the top black perforated vent sheet metal above the refrig). We of course removed the kitchen cabinet (2-3 screws along the back into the side wall and 2-3 at the front up into the ceiling). This gives a totally clear run for the new piece. We pulled the old broken ceiling piece out, and used it as a template over the new 4x8 sheet. We placed the new fiberglass good face down, then the old piece face down on top of it, and we marked around the edges. We found that 73 1/4 was the correct width (side to side of coach), and 44 long. Then we cut out for the refrig vent, not bothering with the piece behind it over the refrig cabinet. Ie., we did not cut out a rectangular hole in the middle of the material, we just cut 2 sides of the rectangle and left the back part off no needed inside the refrig cabinet. Make sure you do not make the back (toward the rear of the coach) too long there are wires in there, about 2 back from the fiberglass ceiling panel with the hall light, that you do not want to push against. Feeding the new ceiling over the refrig cabinet took some doing had to use a wide thin putty knife to help guide it over corners and under roof aluminum angle brackets. But it did slide in. The panel fits 1 over the fiberglass ceiling piece previously mentioned, and stops 5 from the center air conditioner back opening. Although it hangs down at this point in time, it will stay up when the next piece is put in .
Next we put a full 48 long by same 73 1/4 wide piece in the center. Only holes to trace here from the old piece were the mounts for the bunk beds and 14.5 x 14.5 hole for the air conditioner. We found it best also after trying to put it up to cut small 3/8 x Ύ notches in the front edge corners to give clearance to the wires that cross the side mounting rails at those points. Thank goodness for the old piece so we could just trace the other locations! It went up without a hitch.
Last front piece was the section right behind the drivers area. This too traced nicely from the old to new fiberglass material. Again, 2 bunk mounts, 14.5 x 14.5 vent hole, and 2 small (about 1.5 diam) holes for the side ceiling lite fixtures. It too went up nicely.
We did same with rear ceiling piece. Removed old piece, traced onto new, and it went right up (cabinets and air conditioner trim removed of course).
It looks beautiful. Better than new. We believe this fiberglass material will be very durable for wear. Hope this helps someone else!