Teardrops n Tiny Travel Trailers

*** never mind, I'm overcomplicating things again. Cheers ***

I wondering how thick of a torsion box I'd need to create for a bed platform. My wife and I are about 300 pounds total if we're both in the bed. (although still should be strong as a couch, for our meatier friends!) 3/4 by 1" lattice work? 2" lattice work? Since I have it, I'm thinking 1/2 plywood on edge as an option for the interior structure. I'll use 1/4 underlayment for the top and bottom of torsion box. I'm attempting to not overbuild, not overcomplicate, and keep them reasonably light. It seems torsion boxes fit the bill, right?

Background: bed platform is going to be about two feet off the floor. Queen size bed, split lengthwise down the middle so half can be stored underneath, leaving half as a couch. Supports will only be on sides and ends, nothing under the bed. (underneath is adjustable cargo space) I believe I have the supports worked out, just not how big/thick to make the torsion box so it holds up to the 6' lengthwise span.

(wasn't sure whether to post this is the general questions or in the CTC section, since that's now what this project is...)

Thanks for any thoughts! I've googled this all over the place, and can't really find what fits the bill. I can work on a sketchup design of the whole thing, but need to get some work done first...

If I'm totally missing the boat, please do tell. I can always go back to 2x4's and plywood, but I'd love to up my game a little bit.

Cheers.

Hmmm. Responding to my own post, but I might actually take a look at trimming down two hollow core doors...

MatthewWorks wrote:Hmmm. Responding to my own post, but I might actually take a look at trimming down two hollow core doors...

Or just make the size you want with 1/8" ply and a XPS foam core. 1" foam makes a very stiff panel.

rruff wrote:Or just make the size you want with 1/8" ply and a XPS foam core. 1" foam makes a very stiff panel.

I love the idea of that. I have a surplus of 1/4" (5mm-ish) underlayment on hand. Maybe 1x1 frame, 1” foam, and sheathed on both sides. You'd call it good at that?

Seems it might help decrease noise a bit too, this will be used in city camping quite a bit. (Maybe I'm fooling myself...)


Thanks, rruff.




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My guess is that would be plenty. This bed is only supported on the long ends, correct? If you can get 1.5" foam and 1x2s that might simplify your life and be even stiffer.

To get a good glue bond I've been cleaning then heavily texturing the foam with a carpet seam roller. Then trowel on a good coat of PL Premium (just cut open the large tubes) over the whole surface.

rruff wrote:My guess is that would be plenty. This bed is only supported on the long ends, correct? If you can get 1.5" foam and 1x2s that might simplify your life and be even stiffer.

To get a good glue bond I've been cleaning then heavily texturing the foam with a carpet seam roller. Then trowel on a good coat of PL Premium (just cut open the large tubes) over the whole surface.

I think I'll go for that. Looks like this is the closest I'll get to a foamie for a bit!

The local big-box store seems to have 1/2", 1" or 2" in XPS. Wondering about the white foam ( molded polystyrene?) since it's the right size and half the price... but I know it's not structural. Otherwise looks like I'll either layer it, or maybe just jump up to the 2". Slight waste of space, but still wouldn't be heavy... Then, is this just getting expensive? Man, sometimes things like this is why I don't get things done.

Thanks, rruff!

I'm not sure the EPS (the white beadboard) of equivalent compressive strength (which may not be relevant for our uses - more about under slabs that cars and trucks drive on - but why not) to XPS (blue or pink) would be anly less effective. It is stiffer generally, but you are building flat. Adhesive recommendations might change, but whatever you use it will probably dry better. Sips used in house building use EPS. I watched a house across the street being built with sips - from ground up. There is I believe an outdated belief that EPS is less resistant to moisture, but there contradictory evidence as well. Cleary a manufacturer vs manufacturer rivalry for who can discredit the others products most.

MatthewWorks wrote: Wondering about the white foam ( molded polystyrene?) since it's the right size and half the price... but I know it's not structural.

Neither is structural really, but the EPS I've seen in the stores is particularly fragile, while XPS isn't. XPS cuts and shapes easily also. The foam does need to take shear loading between the skins, so get the most substantial you can. If they have 15 and 25 psi, get 25.

Regarding the glue, I used about .12 lb/sq ft of PLP on the carpet seam rollered foam, so that will give you and idea of how many 28oz tubes you'll need.