Frame question - ceiling under skin

[jaarnold100]

I'm currently renovating a 3124 that I received fully dismantled (all interior taken apart). I've finished re-wiring and would like to re-hang the cabinet over the full size bed. Problem is I have no idea what type of frame is in the ceiling to support this cabinet mount. I can see the 5 holes that were originally holding the cabinet up but a brief test indicates there is no framing in that section of the ceiling (Tap a bit through hole, it goes through insulation directly to outer skin - about 2"). So, I'm unclear what is supposed to hold this cabinet in place. Can someone provide help on how this cabinet is typically mounted/held up (as it's not a typical wall mount.
Thanks for the help,
Jeff

[Shane826]

Well, the simple answer is there is no framing in the roof except the outer edges of the roof panel. On some years there was a frame inside the roof cutouts for the vents and A/C but not all years had that. The roof is 1” thick.

As for how the cabinet is installed, if it ever stops raining I’ll pop open a TM and try to get a look.

[Larryjb]

I believe the sides of the shell do have some wood framing where things like the hold-down clamps are mounted, and the cabinets are mounted.

I can't be absolutely sure, but I don't think you could mount any cabinet just anywhere on the walls of the shell. You will likely have to find where the wood support.

When I had to repair a hold down clamp, I used a #10 screw instead of the old #8 and I could feel it bite into something behind the skin of the shell. I realized at that time that there was more than just Styrofoam behind the skin in those places.

[Shane826]

This is a wall before that aluminum skin as vacuum bonded to it. No framing in the walls except around the perimeter. Look close over to the right, you’re seeing the wood on the open end of the wall for the bag seal and then another wall stacked behind it. That’s not a wall stud.

[jaarnold100]

Thanks for the replies. A bit more clarification: I'm specifically looking for info on the long cabinet that sits over the bed (full trailer length). It has 5 screw holes in the top cabinet frame member which would have gone into the ceiling (5 matching holes on the ceiling). There were also 3 screw holes in the bottom edge that would have attached to the rear trailer wall.

Question is, this is a pretty flimsy way of mounting something of that weight - a handful of #8 screws into nothing more than the 1/16" (or 1/8") aluminum skin. For the wall cabinets, I expect the vertical tension is really what's holding it and you bank on the screw not tearing (in a downward direction) into the aluminum panel. So, for the long upper cab over the bed, is the weight simply being held by the 3 screws into the wall and the 5 ceiling screws are simply keeping it from tipping away from the wall?

Sorry, that's about the best description I can provide. Happy to provide more pics if that helps.

Thanks again.

[Larryjb]

Shane, I'm not saying that you are wrong, but I still say there must be something more than just the Styrofoam and skin for the wall hanging cabinet to secure to. Otherwise the hanging cabinet would eventually pull the skin away from the foam. I'm not sure how they do it, but there must be some reinforcement of some type.

It is possible that, before the skin is glued on, a small section of Styrofoam near the top is cut out and a piece of wood fitted into it, just before the skin is vacuum bonded. It is also possible we are looking at the door side which might not have a cabinet.

[Bill]

Let me take a stab here. At one point, I had to remove the exterior molding that covers the join between the sidewalls and the front wall of my TM. Once the molding was off, I could see the construction of the sidewall and front wall, as well as the way they were attached to each other.

There was no wood anywhere that I could see. As I recall, the front wall was framed with 5 pieces of aluminum channel - across the top, across the bottom, up and down the two sides (these pieces were notched and bent to form the curve in the front wall), plus one full-width cross piece behind the bend above the front window.

Each sidewall had a bent vertical piece at its front edge - I believe also notched and bent, to conform to the curve in the front wall. The joins were rather crude - the wall panels were simply overlapped and through-bolted at the overlap.

A couple thoughts. First, there is plenty of aluminum framing in that area. When you poked a drill bit into one of the suspected mounting holes, and it went straight through with no resistance, perhaps you were poking it through the existing hole in the aluminum channel, a hole that was intended to accept a relatively big lag bolt. The drill bit would encounter no resistance as you pushed it through, and would feel like it was simply passing through the foam, all the way to the outer skin. But the threads of a lag screw would bite into the aluminum.

Second, in my TMs, if I opened the cabinet doors, I could see that the interior skin at the bend in the front wall was not fastened down in any way. It was simply bent to conform to the curve, but then left hanging. Sloppy build, I always thought. By any chance, is that skin also loose in your TM? If so, you could pull it out a bit and see what is behind it. Or is build quality has improved and the inside skin skin pieces have been fastened down in some way, perhaps you could unfasten them and see what is behind them.

Finally, if the situation continues, you might consider removing that external molding at the curve, to get some idea of how the front and side walls are framed.

What year is your 3124? The transition from wood wall framing to aluminum framing happened gradually, in the 2001-2003 time frame.

Bill

[Shane826]

That loose skin piece is just cosmetic. It just covers up where they had to notch the flat wall to allow it to curve down the front. The actual wall behind it has aluminum skin bonded to the foam core, but it’s kinda ugly how they made the bend. So they just stick that piece in there so the back of the cabinet looks “finished”.

[Bill]

Shane -

Are you saying that there is no aluminum channel running across the front wall behind the bend? That's not what I recall, but I'll admit it has been a while. But I'm pretty sure of the presence of aluminum channel, framing the sides of the front wall and the sidewall. I'm not about to pull the trim to confirm, though. It was a real PITA to get it re-shaped and re-glued to those pieces of aluminum channel, and then bonded and caulked to the skins.

Bill

[Shane826]

I don’t think here are any cross-pieces where the roof curves down to become the front wall. Yeah there is aluminum along the outer edges the whole way, like you said it’s sectioned to allow the bend.