My fix for roof sag

[ByronDillard]

I noticed significant sagging in the roof of the front shell of our 2015 2720 after a 2 week trip in 2023. The front shell was sagging under the air conditioner, and this was most obvious when the front shell was up, and the rear shell was down during set up and take down. The sag was worse on the door side because of the vent mounted between the air conditioner and the side, which leaves very little roof to hold everything up.

Apparently the sag was caused by some relatively minor water leaking around the air conditioner and previously around the vent. I sealed up the vent several years ago with eternabond and that seemed to solve leak around the vent. We would occasionally get some water dripping from around the vet, but it apparently was coming from the air conditioner area and flowing through the roof over into the vent area. I finally went crazy with the eternabond and used about a roll and a half to seal everything on the front shell very tightly, especially around the air conditioner. We haven’t noticed any leaking since then.

I had a read the post about raising the roof with an external frame and considered doing that myself. However, I contacted the factory and got a quote for replacing the front roof (approximately $4,500) or rebuilding the whole front top shell (approximately $7,000). I was planning to bite the bullet and make an appointment with the factory for a rebuild this year, but I was not able to get them to schedule me due to their factory move. It seems that the sag was getting a little worse with each trip we made, so I decided I needed to go the roof frame route. I am documenting my thought process and approach in this post for future reference.

I am fairly handy around the house, but I do not have any serious metal fabrication or welding capabilities so my solution needed to be something that could be implemented with off the shelf supplies from Lowe’s or Home Depot.

I bought 4, 10 foot long, 12 gauge steel, strut channels from Lowe’s. I bought 1/2” bolts, cone nuts that slide into the channels, nylon cap nuts, etc, to put everything together.

I cut one strut in half and laid a 5 foot piece along the top of the wall on each side of the shell. I cut a strip of half-inch rubber padding to go between the strut and the top of the camper to spread the load as evenly as possible, and minimize the chance of slipping. I did not secure the side rails to the camper. They are held in place by the cross rails and the thru bolts that are pulling the roof up, so the entire assembly cannot slide once it’s put together.

I cut two struts, the width of the top shell, to set on top of the struts that run along each side. The air conditioner on my camper extends slightly beyond the back edge of the front shell. I needed to position the side rails so that they also extended off of the back edge of the front shell far enough to allow me to put the cross rail in place behind the back edge of the air conditioner.

I needed to be able to pull up on the roof on both sides of the air conditioner, especially on the vent side, so I cut a strut to run between the front and back cross rail.

To pull up on the roof, I bought eight, 3/8 x 8“ carriage bolts to run up from the inside of the shell through the holes in the struts. I bought a couple of pieces of steel that were 3” wide and 1/8” thick and cut 4, 18 inch pieces to go against the ceiling on the inside to spread the pull from the carriage bolts across the aluminum ceiling. I managed to cut round ends on the pieces with an angle grinder so that I didn’t have any sharp corners. I used a long drillbit to drill down from the outside through the holes in the struts through the roof so that I had the holes in the correct positions. After the holes were drilled in the ceiling, I transferred the exact measurements to my steel plates for the inside so that I knew exactly where the holes were needed. I drilled holes, then manually filed them out into squares to secure the bottoms of the carriage bolts.

I ran the bolts up through the plate through the shell roof. On the outside, I put a layer of double sided Eternabond under a fender washer to seal directly to the roof of the shell. I put another piece of regular Eternabond over the top of the fender washer then secured that with spacers and a nylon locking nut to hold the fender washer firmly against the roof of the shell with the sandwiched Eternabond layers. Finally, I put a washer and another nylon locking nut on the bolt on the top of the cross rails so that I could pull the roof up. I went around and tightened the carriage bolts gradually to get the lift I needed in each spot. I was able to restore a nice crown to the roof. I raised the back edge of the roof on the sides of the air conditioner by about 2 inches from where it was before I started.

This rack does add some weight to the roof and it is noticeable when lifting the front shell. My front shell was always a little difficult for one person to lift, but I can still do it by myself with this new rack installed. I estimate that this rack weighs about 70 pounds. All of the weight is applied directly on top of the side walls directly above the lift arms so it should all transfer down to the frame without any problems.

I painted the inside to match the ceiling and the outside to match the silver roof. The entire assembly is low profile so it is not too noticeable when you look at the camper. It basically looks like a bike rack at first glance.