The original roof had failed a long time ago. It consisted of a sandwich of plywood, extruded polystyrene foam, and thin steel sheet for the ceiling. This sandwich fit into slots in the aluminum side rails. The actual roof covering was vinyl glued down to the plywood. The plywood had delaminated due to being moist, and was so wet I could wring water out in some areas. I found a thread a while back on popup portal detailing a roof rebuild on a Bethany of similar vintage. I decided to model my rebuild after this one. I wanted to post a link but I couldn't find the thread again.
The previous owner used steel square tube to make rafters that prevented the roof from sagging down. They are heavy and look bad, and I knew they had to go. Since the only structural element in the original roof was the rigid foam, it would be very easy to damage the roof by setting something on it or something, and creating leaks that lead to further damage. I purchased 5 pieces of 1"X2" Aluminum rectangular tubing that would be a part of the new roof 'sandwich'. They are light, stiff, and strong, making them good for this application. Another thing I had to consider was wiring for the lights. I decided to use raceway for the wiring, so if there are ever problems I can easily access the wires. I also purchased a new roof vent with a fan in it to hopefully help keep the camper from becoming a sauna during the summer.
Original roof sandwich demo. You can see the water damage. The glue in the plywood had disintegrated and the layers of veneer peeled off like paper.
Inside the camper as purchased. You can see the steel 'rafter' and light gauge steel panel used for the ceiling.
Another problem I ran into was finding 1/8" plywood. In order to fit the sandwich into the channel on the side rails, I was limited to a thickness of 1-3/16". This meant I needed very thin material to make the inside ceiling, and 1/8" plywood for what would become the backer board on the roof. I was able to find plastic wall paneling that I could use for the new ceiling, but just couldn't find 1/8" lauan plywood. I was cleaning up a pile of material from the original roof that had become exposed after the snowmelt and found the answer. The original material was that fake wood paneling stuff that was popular in the 70's. A trip to the local Menards and I had all the material I needed for the roof, minus the waterproofing.
I finally had some decent weather, so I covered the camper trailer with a tarp and parked it outside so I could begin working on the roof. I used a CAD program to lay out the different components and experiment with spacings of the aluminum pieces. Once I had a design I liked, I cut all the plywood and foam and dry fit everything. I used some extra aluminum to reinforce the opening for the roof vent.
Dry fitting the components of the roof sandwich together. The aluminum rafters are light and strong, and will be hidden once the roof is completed.
Everything dry fit together correctly, so it was time to glue it together. I decided to use gorilla glue, due to the good things I've heard about it. It requires a bit more care than other glues, but it provides a strong, waterproof bond. Something important to note is that the glue expands as it cures. You need to clamp or weight down whatever you're gluing together. I definitely wasn't prepared for that. I had my family scrounging up anything heavy they could find. We had all kinds of stuff from the garage, laundry soap, paint, anything to hold the foam down on the plywood. It still raised up a little bit at the plywood seams but not enough to cause problems. If I ever use this stuff again, I'll definitely be prepared with enough stuff to keep things flat.
Lots of junk to hold the foam down on the plywood while the glue cures.
After the glue was done curing I took the weight off and glued on the plastic panels that would be the ceiling inside the camper. I used white wall panels I found at Menards that were thin enough. I glued them down with FRP panel adhesive as recommended by the manufacturer of the panels. I also left a gap between each panel. I have concerns about how well the glue holds on to these panels, as well as thermal expansion. When I ran my heater to warm up the garage to work the next day, the panels started to warp and bubble up. For anyone else attempting this I would recommend finding a different material. I'll have to find a way to deal with this later.
Plastic ceiling panels glued down.
I let the glue cure for the plastic panels overnight and put the rails on the next day. It was difficult at first to get the slot on the rail lined up with the edge of the roof sandwich. I ended up just starting at one end by shoving the rail on, and tapping it on the rest of the way with a mallet, being careful not to catch and kink the plastic panel or plywood. All in all, fairly quick and easy.
The roof is put together and squared up. It's kind of hard to see, but there is a spot on the lower part of the center panel that is warped from thermal expansion.
With the roof together and squared up, I was almost ready to install it on the trailer. There were some design issues with the way the lifting system attached to the roof, so I had to take care of that first. I'll get into that in the next post. Thanks for reading!
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