wall construction -- hollow or solid?

[dpjeansonne]

I once saw a build with hollow insulated walls but can't find it again. Can you point me to a build with walls constructed of 3/4" plywood with cutouts for rigid insulation?

If insulation is not a requirement, would you still hollow out for reducing weight or just go with solid walls? I think I will still want a 1/8" skin on one or both sides.

[tony.latham]

Can't quite help you. I'm in the final stages of my build –I used Steve Fredrick's system following his Teardrop Shop Manual. GLAD I DID. Anyway, my walls are 1/4" plywood inside and out, with 3/4" framework inside for bulkhead hardpoints, furring strips, door jams, and a ledge to hold the ceiling on. In a sense, it's much like those that have built with a 3/4" plywood that's hollowed out. But to answer your question, the walls are solid. Where there is no wood, there is pink 3/4" foam. It really stiffens up the wall panel. 1/8" ply is a bit on the fragile side but not when it's back by rigid foam. My ceiling is sandwiched 1/8" ply with 1" foam and it's nice and stiff too.

TL

[RandyG]

A 3/4" whole piece of ply is very heavy, it just makes sense to have cutouts if you plan on having both sides skinned. Any way to shed a couple of lbs here and there will really add up in the end.

[KCStudly]

Becky's (Oldragbaggers) "Sagwagon".

Dave McCam's masterpiece "The Atma Travelear" used CNC router cut skeleton wall cores.

[KCStudly]

Aggie79's/Tom's Silver Beatle, a fan favorite here on the board.

[grant whipp]

I once saw a build with hollow insulated walls but can't find it again. Can you point me to a build with walls constructed of 3/4" plywood with cutouts for rigid insulation?

If insulation is not a requirement, would you still hollow out for reducing weight or just go with solid walls? I think I will still want a 1/8" skin on one or both sides.

I'm a huge advocate & pioneer (in recent times, anyway ... ...) of the "hollow insulated walls made from plywood core" build technique. Weight savings are substantial, and the insulative value gained is decent enough, even if you don't put insulation in (any dead air space has an insulative value). However, may I suggest that you start with a 1/2" core plywood with 1/8" on the inside and 1/4" on the outside (especially if you plan to skin the trailer with aluminum)? I think you'll find that the end result will be more than strong enough, light enough, moldings for around the doors and galley walls will be easier to find, and you won't loose that little extra bit of interior width.

If I can be of any help with advice or otherwise, please don't hesitate to ask. Good Luck on your build, and as always ...

CHEERS!

[Jdw2717]

I went with 1/4" outside with 3/4" solid pine for the "frame" and then 1/4" inside and put the white foam board in between. I wish I had taken a picture but it had vertical 3" x 3/4" boards for "flat studs" that would hold the cabinet faces and doors. The edges all have about 2" or so of wood to screw in the 1.5" x 1.5" braces between walls for the roof and ceiling. This gave me 1.5" of insulation in the roof between 1/8" layers inside and out.

I used solid wood over plywood because I was worried that if water found its way in, it would delaminate the plywood and lose most of its strength. I am not sure that it would really matter but that is the way I pictured it. Either way is good, just go with what you feel is the easiest/best way for you and seal it up properly. Good luck.

[dpjeansonne]

Thanks for all the responses. That is what I was looking for.

[grantstew8]

My walls are 1/4" with about 3/4" frame. I've been thinking about the insulation and am seriously considering heavy duty bubble wrap.

I may just use eps polystyrene if I can't find a convenient source. Considering I'm upgrading from a tent this will be sheer luxury.

[Kody]

I have changed my wall design build. I was going to use 1/2" ply as the wall but have now decided to use a frame of 3/4" x 3" timber and cover the surfaces with 1/8" ply. I decided to go this way as there is no-one I can rely on 100% to be here to help me and my wife. This design will be lighter than using 1/2" ply and we can both manage the frame/wall when I/we erect it. I will be placing foam in between the 3" framing and this will certainly stiffen the wall up. It will also be much easier to instal the door hinges and locks. I need to join 2 sheets of ply together and by joining on a 2 1/2" wide x 3/4" battan it will make it so much easier and stronger.The weight of the new design will also be much easier on my lousey back and this was a big arm twist to build the new design. Getting old is painful, especially when it comes in a rush from an injury.

Kody

[KCStudly]

I decided to go this way as there is no-one I can rely on 100% to be here to help me and my wife.

I found this to be somewhat of an "ah ha" moment with regard to my decision to do a foamie hybrid. I was able to lift and place my walls by myself without much effort.

I did have help setting the first wall, but it was just happenstance, not a necessity.