Wall thickness considerations

[redg8r]

Well into my r&d, I'm hitting a hurdle when deciding on wall thickness so thought I'd ask the seasoned vets here.

If you were doing a fresh build, what thickness would you shoot for? Is there a sort of "Industry standard" such as there is for traditional housing and mobile homes?

I'll be using a sheet press to laminate my panels in a torsion box style, but after much research, I'm clueless on how to accommodate for weatherstrip, seals, window trim rings, door latches & such.

What would you do? Thanks in advance for the insight.

[bc toys]

well you got at least 1/2 ply on out side and 1 1/2 studs then 1/4 inside wall 2 1/4 yep that my math you can get window trim and rv door latches are for 2 1/4 also you just got to cut them in good luck

[Lgboro]

Almost every thing on my tear had to be fitted or customized to fit. You should be able to work around most any situation and find a good solution.

[redg8r]

Sorry, guess I could've listed my materials....

1/8" (.125) FRP outer skin
_________________________
?" extruded foam sheet and hardwood stringers
_________________________
1/4" (.25) Birch ply interior

I'm looking to glue these up in a hydraulic press creating a preformed rigid wall.
I just don't want to make the panels so thin that finding hardware becomes an issue.

[KCStudly]

Decorative trim rings, or "rosettes" can be made to space out the inside where you use hardware that is thicker than your wall.

Some people have gone as thin as a single layer of 1/2 inch ply (15/32 inch) and others have built battleships.

TPCE is getting 5mm inside, 1-1/2 thick foam with minimal framing, and canvas/paint outer skin, so my overall thickness will be about 1-3/4 inch. Many people feel that the 1-1/2 thick insulation in the side walls is way overkill from an insulation point of view, but because my foamie is a hybrid with traditional galley, I wanted to have the beef in the galley wing walls.

Good luck with your planning and build; remember to include lots of pics. We love the

[NathanL]

I went with 1/2" MDO on the outside because I already had it in bulk quantities and in 4'x10' sizes so I could make a single piece longer than 8'. Then I used 3/4" studs to create a space for 3/4" foamboard insulation and 1/4" paneling on the inside. That also meant I could use two pieces of 3/8" MDO - one on the inside and one on the outside and 3/4" boards to space them for the door and come up with the same thickness as the wall.

[Oldragbaggers]

I did a sandwich wall that is 3/4 inch ply frame with insulation and 1/8" skin inside and outside, covered in fiberglass cloth and epoxy resin. So my wall thickness is 1" and that's fine. But if I were starting over tomorrow I would go with a solid 3/4" uninsulated plywood wall.

[danlott]

I did a sandwich wall that is 3/4 inch ply frame with insulation and 1/8" skin inside and outside, covered in fiberglass cloth and epoxy resin. So my wall thickness is 1" and that's fine. But if I were starting over tomorrow I would go with a solid 3/4" uninsulated plywood wall.

I went with 1/4 plywood on inside and outside with 3/4" framing and insulation on the inside. I to would only go with solid 3/4" plywood next time.

Dan

[redg8r]

Thanks so much everyone!

Interesting to see a couple posts recommending a solid 3/4 core if you could do it over again....
Just curious as to why you would go solid in lieu of insulation??

[NathanL]

The drawback to a solid wall with no insulation in it is that sometimes it can get that beating on a drum sound inside if it rains heavy or wind blows or combo of both. I put insulation in mine the 2nd time mostly for sound deadening than for hot/cold weather.

[danlott]

There is a big debate about insulating walls. I do not think that there is much benefit to doing it. Plus it adds a lot of time to your build.

Dan

[Oldragbaggers]

Thanks so much everyone!

Interesting to see a couple posts recommending a solid 3/4 core if you could do it over again....
Just curious as to why you would go solid in lieu of insulation??

I would go with solid walls if I had it to do over for a number of reasons. The first two reasons are in a tie for first place on the list. The first is cost. You buy two perfectly good sheets of 3/4" ply. If you're building solid walls, you're done spending money on the materials for the walls. If you're building a composite wall, you then cut away a large portion of that plywood and you go back out and buy insulation, skinning plywood and glues. In my case, because I used marine ply for the skins, the final cost for my composite walls was about 4x what the solid walls would have cost. The additional time it adds to your build cannot be understated, it's substantial. That's the second reason. In addition, if I had solid walls I could attach things were I wanted, and would have the option of changing my mind about the placement of things later into the build. with the insulated walls you need to have it all figured out ahead of time, you cannot change it later once you've committed to where you're leaving solid wood to attach things. And you have to have a reliable way to mark out where those solid areas are for reference because you won't be able to see them anymore once your skins are on. If you don't mark them accurately you run the risk if drilling into foam instead of solid wood and end up with unwanted holes you need to fill.

Plus a lot of things for teardrops come in 3/4" widths standard, like trim rings for the factory doors (I paid $20 each extra to get 1" trim rings, more additional cost) and other kinds of trim, galley wall cap trim comes to mind.

It boils down to simpler, faster and less expensive. I know there are advantages to the insulated walls. That's why I built them in the first place and I am sure I will appreciate those advantages while camping, but they came at a very high price.

[DMcCam]

There are many, many teardrops with 3/4" solid walls; probably most. It's a simpler less costly way to go.

We went with the same sandwich wall design as Becky, 1/8" Baltic birch ply inside, skeletonized then insulated 3/4" signboard, 1/8" Baltic birch ply outside then .040 aluminum. We wanted to make the walls as light as possible yet add some sound deadening and insulation. We also wanted to hide the electrical in the walls. My best guess is that we saved about 80 lbs instead of just the 3/4" signboard.

Becky is certainly right about the costs too (4X seems about right to me too), everything is custom fit which takes both time and money. I don't know yet if your gain that much over the solid wall to justify the effort but I do know that it added about 4X the time investment in construction as well.

I'd like to hear from someone who started with the solid 3/4" walls then made another teardrop with the sandwich type. They could really shed some light on the pros and cons for sure.

Cheers,

Dave

[hankyknot]

What a great thread that I'm so glad I found. I have been planning, maybe wrongly it seems, to build my walls and insulate them in very much the same way traditional stick built houses are made, only on a much smaller scale.

Now though I'm thinking maybe I would do best just to build single skin walls and maybe find a way to "hang" an insulative layer on them once they are up. Perhaps something as simple as a quilted removable wall lining for winter use? I have attended yurt building classes and slept in a yurt that simply had blankets hung on the walls and small woodstove in them and not even noticed the 10" of snow that fell overnight until the door was opened.

Maybe simple is the best way to go, especially for the first one. Nothing says it has to be forever right and I can always unbuild it if it doesn't work.

[danlott]

What a great thread that I'm so glad I found. I have been planning, maybe wrongly it seems, to build my walls and insulate them in very much the same way traditional stick built houses are made, only on a much smaller scale.

Now though I'm thinking maybe I would do best just to build single skin walls and maybe find a way to "hang" an insulative layer on them once they are up. Perhaps something as simple as a quilted removable wall lining for winter use? I have attended yurt building classes and slept in a yurt that simply had blankets hung on the walls and small woodstove in them and not even noticed the 10" of snow that fell overnight until the door was opened.

Maybe simple is the best way to go, especially for the first one. Nothing says it has to be forever right and I can always unbuild it if it doesn't work.

If I build another trailer I will use 3/4" plywood and use carpet hull liner on the inside. This will add a little insulation and sound deadening. This will also help with condensation.

Here are a few pictures of some fellow members builds that used the hull liner.





Here is a discussion on using hull liner.

http://www.tnttt.com/viewtopic.php?f=2&t=49873