Removing subfloor with shell on

[KathrynOKC]

Oh my gosh what have I gotten myself into. I need to replace my floor in some areas but I thought I might as well do it all so I know what I have, but I had no idea it was best to remove the shell when doing that.

[Stupidnoob]

Now that I see what hold the shell on its pretty basic , just for me the subfloor was a beeeeeeyotch, now that its exposed its a lot easier

Removing what skins inside I can today

[riv-nut]

Excellent work!!

All the inner panels should come out by removing screws EXCEPT the ones adjacent to the door. These are riveted to the door frame (at least in mine). The best tool I've found to remove rivets is this rivet driller:
Rivet Removal Tool
This works great....they have a lot of other cool stuff at this website too. As you said it's kind of basic once you see how it goes together.

Good luck,
Lee

[Mark Lee]

I'm into replacing my rear sub floor right now on a 1989 Excella. I have the floor cut out. Now that I can see how the walls attach to the floor I'm going to pull the inside wall sheeting.I have another post and a member made a good point about needing to do this. I had hoped there was another way to go and I had a couple of ideas but they wouldn't be as strong. Also he pointed out that getting the floor into the squeezed down channel would be difficult. The more I look at it the more I can see that the stability of the wall etc is the only way to keep the seals functional. Man I hate the thought of pulling those wall panels but it looks like that is what it takes to do it right. I think I still might have to rout the sub floor down to 5/8 from 3'4 to get it into the channel. But I want the floor to be squeezed into the channel so running those screws in from the inside of the wall and tying everything tightly together looks like my best option.

[riv-nut]

Originally Posted by Mark Lee

I'm into replacing my rear sub floor right now on a 1989 Excella. Also he pointed out that getting the floor into the squeezed down channel would be difficult. I think I still might have to rout the sub floor down to 5/8 from 3'4 to get it into the channel. But I want the floor to be squeezed into the channel so running those screws in from the inside of the wall and tying everything tightly together looks like my best option.

Hi Mark, there must have been a design change in how the skin and floor attach around the edge. The floor on my '52 doesn't "squeeze into a channel" as you mention, the channel sits on top of the floor and the outer flange is what the skin/bellypan attache to. Here's a sketch of the joint. At some point they must have put the channel on edge and tried to slide the floor into the channel or something.....not sure what your connection looks like.

Lee

[Mark Lee]

Yes there are several changes from this drawing on my 89. There is a second channel that the flooring slides into. This fits between the one in your drawing and the steel frame. In my trailer there is approximately 2" of insulation squeezed between the floor and the steel frame but not in the channel [it was trimmed back]. Looks like the bolts were set with small steel reinforcing plates in the upper wall channel. The screw/bolts pass through holes in these small plates. the bolts look like they were self threading and are screwed into the frame. These bolts pass through reinforcing plates,upper channel, top of lower channel,floor wood, bottom of lower channel, into the steel frame. The bolt/screws then have a old fashioned looking square nut to tighten everything together. On your drawing it looks like there might be a nut on the bottom of the channel instead. So in mine this amounts to a sandwiched structure that is all under compression. The wall rivets are a real pain. The lower sheets were tacked into place with rivets that were covered by the higher sheets. Finally figured out that I could pull the higher wall sheets back far enough to get a small thin chisel in there and cut the rivet heads off. Took some work but now everything is exposed to work on with lower wall sheets removed. So it looks like Airstream added some support to the floor in the
spaces between the steel frames using channel support. There are some screws that sandwich these together that don't go into the frame. They just a hold the channels and floor together tightly in the spaces bridging the frame contact. Hope my explanation makes sense to you as it's a bit complex. Afraid I'm a better artist than writer.

[Mark Lee]

This has been more than a bit frustrating. You are right it's so tight getting Tyvek into the channel with the floor pan on it had to be abandoned. On the right hand side it was a running battle getting the wood in even after I cut 1/8th off the thickness. But things are going better today. A nice surprise to see how well the TEKS work. I had used a similar fastener a few years back and they didn't work anywhere as well as these do. These are size #12 from HD.The wall and floor on the right hand side is really solid. I even tried to over tighten one and couldn't get it to snap. I was really disgusted with Airstream yesterday. I can only hope that they have ended this evil and stopped all use of particle board flooring. Looks to me like the best way to get the expected quality is to buy an old trailer,tear off the pan and build it right.Today as I'm setting up to make the other half of the floor I'm thinking I'll cut 1/16 of the top and bottom of the marine plywood. It seemed like the other piece was hanging up on the bottom of the channel. I had cut 1/8 off the top only on that side with the router. I pried and banged on the edges so hard that some of the garbage particle board flaked off. Guess I'll make up some fiber glass resin and try to get it more structurally solid on and close to the edge. Well the batteries for my tools must have finished charging and I'd better get back to work.

[Mark Lee]

I almost have my rear sub floor repair finished in my 89 Excella 32'. At one point I was starting to wonder why I bought the thing but it's all looking up now. I cursed out loud and often who ever came up with the bright idea of using particle board for an Airstream's sub floor. Today I'm just mumbling under my breath. I did find a youtube video showing plywood going into a new trailer and that made me feel a little better about them.Tomorrow I may be able to start putting the inside skins back on. Yesterday was very difficult. The right half fought me every inch of the way. That should have been the easy side! I took the router and cut the edge of the marine ply down from 3/4 to 5/8. I had a pretty good template. The problem was that the ply was hanging on the bottom of the channel. Today all that I did differently was to take a sander and round off the bottom edge of the ply. That made a huge difference! I didn't even take off a full 1/8th with the router. I wanted to wrap the edges with Tyvek house wrap and let it hang down far enough to shield the insulation from any future leaks. But it's to tight and it's sharp on the edge of the channel so it would only get sliced. I do have a small square left out that goes over the sewer hose compartment. That made things easier also. I want to handle the insulation and sealing differently there anyway over that compartment. Really happy with the TEK #12 self tapping screws from H Depot. They really suck down well to the frame and seem to be much better than I expected. I used a bunch of them with fender washers [in the wall channel]. I feel a lot better about them than I thought I would. Good as it gets with the belly pan still on I think. The walls look like they are very well tied down.

[Belegedhel]

Just My two cents on the topic of whether or not to do a shell off: It took me less than an afternoon and maybe $100 in lumber and hardware to build two wooden gantry frames to lift my shell. The work it takes to unfasten the shell from the frame is the same whether you try to replace the floor with the shell on or not. If I had to do it over again, I would have left the bellypan in place except around the edges, pulled the shell, then flipped the frame over with the gantries and worked the belly pan with the frame upside down. I reinstalled the bellypan this way, and have zero regrets, it made the job so much easier.

People look at the apparatus involved with lifting the shell and get intimidated, but I believe religiously this is the way to go. It just makes everything else you do so much easier. I welded on my frame, pained it, installed the subfloor, installed the insulation underneath, and put on a new bellypan, all while flipping the frameover and over as needed.

If limited space is a concern, I have a hard time imagining less space than what I have. I had my shell sitting on one half of my driveway, and the frame occupying a small patio slab that used to be home to a patio table and chairs. Of course this is with only a 21' trailer.

See the attached pic--shell on the driveway, gantry frames being positioned to flip and rotate the frame, frame upside down for insullation installation, grey tank fitting, axle installation, and bellypan install.

[Mark Lee]

How is the trailer being supported at this point?

[Belegedhel]

In the picture above, the frame is supported by jack stands, the gantry frames are only employed during lift-and-flip operations. The shell is just sitting on the driveway, with a wooden block under each rib so that the weight is not sitting on the skin that extends below the ribs.

I used no bracing within the shell, and when it all went back together, there was no indication that the shell had changed shape. This is another benefit of lifting the shell from above, as opposed to jacking it up from below. Most pictures I see of jacked up shells employ a lot of internal bracing to provide something to jack against.

[Mark Lee]

Very nice throughout your whole setup. But what I'm not catching onto is how you lifted the shell from above. How you hooked onto it etc.

[Belegedhel]

Ah. The lifting frames go over the shell and are centered on the fore and aft roof vents. A wooden beam is run from endcap to endcap inside the trailer, and chain hoists are attached from the gantry frames, down through the vent holes, to the beam. The beam only contacts the ribs. I am told this is how the chells are lifted and manipulated at the factory as well.

[Mark Lee]

That makes sense. Mine is mostly finished. I'm happy with the strength of the floor and walls tied down onto the frame. I replaced the rear 52" of flooring with 3/4" inch marine ply. Soaked it down with Varathane especially on the edges. Mostly used #12 TEKS where I could tie into the frame. The left hand bed is the only thing not finished in the inside. The bed frame is getting beefed up to hold a RV washer/dryer UNIT. 89 Excella 32' so that puts the unit right behind the bath over the hot water heater. I'm at 9318' and it's snowing tonight. Need a few days of warm weather to get rid of temporary silicone caulk. That polyurethane is really hard to pump. Might have to get it down to a lower alt where it's warmer. Was it hard to work with for you. I used some on the inside seams and hope it was just an old tube. It was really stiff and that was with the tip of the tube cut off with a large hole. Your frame off restoration looks like the best way to go if at all possible.