Our initial design

[bigalpha]

So, that calculator shows the total in "green weight". That's going to be roughly the weight as I pick it up from Lowe's/HD?

Do you think that using 2x4's for sub-floor framing is overkill; and using 2x2's for wall framing is overkill?

[TinKicker]

Overkill is hard to judge. One man's overkill is underbuilt to another person. Best advice I could give there is to examine how other trailers are put together. It's only gonna' be right to you if it feels right to you. Otherwise you're always going to be thinking, "Man, it seems too shaky." Or, "Dang, this would have towed better if I'd gone easier on the solid oak 2x12 rafters and floor joists."

[bigalpha]

lol @ solid oak.

What the most common dimensional lumber that people use to frame the sub-floor and walls?

I'm trying to go with the popular crowd on this one

[bigalpha]

Alright, revised lumber list:

2x4 for the subfloor framing,
1/4" ply for the main floor,
2x2 for the main framing (2x4 for around the door and windows),
1/4" ply exterior skin
1/8" ply interior skin

Does this sound better? I can also use something different than 2x6's, since they'll add a ton of weight ~50#.

[Cliffmeister2000]

Alright, revised lumber list:

2x4 for the subfloor framing,
1/4" ply for the main floor,
2x2 for the main framing (2x4 for around the door and windows),
1/4" ply exterior skin
1/8" ply interior skin

Does this sound better? I can also use something different than 2x6's, since they'll add a ton of weight ~50#.

Now I'm feeling guilty for telling you it's hard to underbuild.

The one place I would not use 1/4" ply is the floor. I used 1/2", and in retrospect (because it creaks occasionally when I first get into it) I wish I'd have used 5/8". As far as the 2x6s, I've seen normal bedframes in homes that are made with 1x6 with a 1x2 lip 1 to 2 inches below the edge. The 1x2 adds strength against bowing, and the bed sits on it. Sometimes, slats sit there, and the bed sits on the slats. Plenty strong, too!

[bigalpha]

Don't feel guilty. That's the whole reason we're here to get a feel for the the 'standard' and 'correct' way to build these things.

After reading through many a'thread, I don't see a consensus that 2x2's are better or worse than 1x4's. I imagine that 2x2's would give you more wall support if you had hanging cabinets or shelves. Plus, that's a ton of insulation

I can sub the 2x6's for 1x6's. That should still provide enough stable support to function as a bench and a bed. I wonder if you can get that honeycomb stuff that inside of doors? That'd be the ultimate lightweight support .. you could fill some of the honeycombs with that expanding foam to help prevent those honeycombs from folding over.

I wonder if you could use that honeycomb stuff instead of traditional framing? That would be way cool, and "high tech".

[Cliffmeister2000]

I can sub the 2x6's for 1x6's. That should still provide enough stable support to function as a bench and a bed. I wonder if you can get that honeycomb stuff that inside of doors? That'd be the ultimate lightweight support .. you could fill some of the honeycombs with that expanding foam to help prevent those honeycombs from folding over.

I used to be in the aircraft industry, and the "honeycomb stuff" in an airframe is aluminum, while the honeycomb stuff in a door is often just cardboard or thin masonite strips in a lattice pattern. I think styrofoam insulation would have a similar effect. Those honeycombs in a door or an airframe never fold without the skin being ruptured.

I wonder if you could use that honeycomb stuff instead of traditional framing? That would be way cool, and "high tech".

The way many TDs are built, with a 1/8" skin inside and out and styrofoam insulation inside, it is very much like the skin of an aircraft. those walls are phenominally stronger than the sum of the component parts. Bonding (glueing) the styrofoam to the skin would increase vertical strength.

[bigalpha]

Do you think we'd be able to mod a hollow core door with that honeycomb interior to use as the top of the benches/bed? It'd be lightweight and pretty strong.

Maybe I could cut strips out of it and stack the strips to use for the bed supports instead of 1x6 or 2x6.

You think that we could get away with 1/8 ply for both skins along with thick styrofoam glued in the interstitial space? How well does that 1/8 ply hold up against punctures/tears/breaks?

[bigalpha]

Do you think we'd be able to mod a hollow core door with that honeycomb interior to use as the top of the benches/bed? It'd be lightweight and pretty strong.

Maybe I could cut strips out of it and stack the strips to use for the bed supports instead of 1x6 or 2x6.

You think that we could get away with 1/8 ply for both skins along with thick styrofoam glued in the interstitial space? How well does that 1/8 ply hold up against punctures/tears/breaks?

edit: use something like this for the bedframe:

[Cliffmeister2000]

I don't see why not. maybe you can buy the stuff in your picture for use in your teardrop.

I chose 1/4" for the outside skin, and 1/8" inside. I found the 1/4" easier to work with in making corners. The 1/8 would be fine if you plan to trim the corners with aluminum, or if you are a better woodworker than I am.

[bigalpha]

I wonder if that stuff could be used in lieu of traditional bracing in the walls with a large degree of success.

That'd be lightweight, and if bonded to the ply, it seems like it'd be very strong. Actually, that'd be a direct replica of those hollow core doors.

Has there been a TD build using honeycomb cardboard instead of traditional bracing?

I'll need to pitch the idea to my girlfriend.

[Cliffmeister2000]

There is probably a limit to the total surface area you can have without bracing. Even aircraft have ribs every 4 feet or so. Other than that, it should work.

[bigalpha]

would you still have to brace windows/doors traditionally? I'd imagine you would have to.

We're going to have some bracing anyways because we'll have 3 windows and one door. Do you think the roof would sag if it was all honeycomb?

[Cliffmeister2000]

I think I would brace the roof fairly traditionally. It's time others started opining, here. Many are much smarter than I am.

[TinKicker]

I had actually considered that cardboard honeycomb for my floor torsion box because of it's strength. We get in pallets of auto batteries stacked on the stuff and it doesn't compress. Unless you poke a corner of the battery into it.
If I can find enough of it I'm gonna' use it.