Roof Buckling

BrucePerens · 08-09-2017, 07:02 PM

I removed my roof vents to find a really distressing buckle in the roof, which is the cause of leaks I've had in that area. It extends under the air conditioner and both of the center roof vents. It looks like it existed when I purchased my (salvage) 3023. It is a divot in the roof at one point, and a delamination of the aluminum from the foam with a bump in another, and a difference in height where the center seam is.

I have not been on the roof of this Trailmanor until today, and of course I put down a board to distribute my weight, but I have no idea what previous owners have done.

This is going to be annoying to repair. I'm going to have to fill the bump with silicone at the same time I put caulk under the window and screw it down. I'll have to build up the divot with butul rubber and attempt to achieve a relatively level area of rubber before screwing down the vent.

**B_and_D** · 08-09-2017, 07:48 PM

Sadness...I wouldn't want to deal with that, but it probably can be fixed...

Shane826 · 08-09-2017, 07:49 PM

For the love of everything holy, don't use silicone. It doesn't stick over time because of how much the trailer shakes and bounces and vibrates going down the road, and it's extremely difficult to clean off and start over when it fails.

Maybe take the paint off down to bare metal and use some sort of JB Weld to build it up, then you can grind and sand it to shape? Disclaimer: I don't know if JB Weld sticks to aluminum, but there has to be some similar product that does. Someone mentioned using 3M 5200 as a body filler...

BrucePerens · 08-11-2017, 11:17 PM

Actually, the roof vents had already been caulked with silicone, I suspect in the factory. And it stayed around for 14 years. Someone later re-caulked over the silicone with another rubbery material, possibly because of the leaks which were not caused by the caulk failing but by the roof buckling. The silicone wasn't difficult to remove.

So, here goes another two days work on the Trailmanor that I didn't plan to do. Having done the kitchen sink plumbing and the floor, which were both two-day projects, I'm hoping I don't have another big repair for a while and that the upcoming AC service and roof sealing doesn't come with more surprises.

After removing the old roof vents, I bought a box of Fiberon 1.25" x 1.25" x 35.5" solid composite lumber balusters for deck construction, and built new frames for the roof vents out of them using a miter box to do 45 degree corners. These are much more water-resistant than wood, and have a 25-year guarantee when used for their intended purpose. Trex 2x4s are also available, but more difficult to find and very pricey. I screwed the frame pieces together with 4-inch deck screws at the mitered corners for stability and to make the corners tight enough that water shouldn't intrude there.

The frames that came with the trailer were a plastic lumber and were much thinner and just stapled together. These were held down by the vent, not screwed into place at all.

I glued one of the frames down, filling voids, and then screwed it down, counter-sinking the screw holes so that I had a flat surface on top of the frame for the vent to attach to. Then I broke my caulking gun, so the second frame went on with silicone I had in a squeeze tube. We'll see which does better.

The buckling dent and bump are just about a half-inch height difference so it wasn't difficult to fill, and the bump got glue inside of it.

I still don't understand how this buckling happened, but it is at the weakest points of the shell where three holes are cut in the shell close together, one of them for the heavy air conditioner and the other two for roof vents. I really wish that Trailmanor had built a frame that spanned all three openings and added some structural rigidity there, because there is obviously a structural weakness in that area.

I bought two new roof vents. One is a conventional Ventline one, and the other is a fancy Maxxfan 5100k, which can be left open and running in the rain and has a reversible fan with a thermostat. There's enough room for that on the front vent opening, not the back one. I don't know if the Maxxfan will add much on top of the Fantastic Vent on a hot, dry day, I mostly bought it to have something I could leave open and not worry about rain, and it's nice for the thermostat to turn the fan off as the night cools off. I think their more expensive model might even close the vent automatically, which would be better if you have your heat set to come on at night.

The Maxxfan can be locked open while the RV is moving, it's specified to take that, but as it's sitting on top of the rear shell when the Trailmanor is closed, it would not be much use. It will be nice to keep the vent open the rest of the time, though, and not worry about the rain.

Oops, Maxxfan needs more than the 1.25" high frame to keep from hitting the top of the rear shell when the front shell is closed. Its opening knob projects down too far. I will either reuse the original plastic frame that came with the Trailmanor, on top of my new frame, or build a second 1.25" frame to put on top of the first. I have enough composite left to do that.

I put butyl rubber on top of the frame and screwed the Ventline vent into the frame. I'll do the same with the Maxxfan tomorrow once I resolve the height issue. It's easy to remove a vent from the butyl without damaging it, and it seals well enough that I don't think I'll need caulk there.

I'm not sealing the roof until after my August trip, but I think I'll remove the degrading center strip and seal the center, edges, and around the AC and vents with Eternabond. I'll have to service the AC before that, to see what shape its gasket is in, etc.

Shane826 · 08-12-2017, 06:47 AM

Were the vents caulked (bead around the edge of the seam then tooled smooth) with silicone, or were they sealed (bead of silicone smooshed between the vent and roof)? Sealing with silicone works, caulking usually doesn't. Glad your silicone came off easily. I haven't had the same experience with the gobs of silicone on my TM.

HoMiPa · 08-12-2017, 01:39 PM

Quote:

Originally Posted by BrucePerens

I still don't understand how this buckling happened, but it is at the weakest points of the shell where three holes are cut in the shell close together, one of them for the heavy air conditioner and the other two for roof vents.

Where did your TM come from, originally? Depending on that, I would be willing to bet it was caused by snow load. It certainly what caused mine.