Plywood Wall Framing

[Frog]

I've looked at lots of construction photos and it seems that most people use something like a 1/2" outer solid core plywood with 1"X interior framing which is filled with insulation then a thin interior plywood skin.

Does anyone create the exterior profile of 1/2" plywood then create an inner frame by laying out a 3/4" plywood profile on top of that then remove most of the 3/4" plywood buy cutting it into a one piece plywood frame? It seems like it would work well and strengthen the outer wall, especially if its made of two 5" X 5" 1/2" sheets. The inner frame would still be a nominal 3/4", the same thickness as dimensional 1'X material, and although possibly only a few pounds heavier would be more stable and less likely to expand and contract or warp than solid wood? It seems that it would go faster than all the cutting and assemply needed with a wood frame.

If it's not done, I'm sure there are good reasons. Just curious.

Thanks in advance for the responses.

[bobhenry]

Flat stock such as plywood and osb does not hold screws as well as solid wood. Should you need to prove this to yourself screw a couple 1" screws into both and get out a claw hammer and pull them. If you will look in my album you will see I used 1/2 osb as sub siding standing vertical and cleated the sheets with 1 x 4 's this 3/4" void gives room for 1/2 deep electrical boxes and 3/4 foam insulation. I do agree that if I had cut a grid of 3/4 osb or plywood it may have been more ridged but lighter I doubt and as to more effecient I totally disagree.

[aggie79]

Does anyone create the exterior profile of 1/2" plywood then create an inner frame by laying out a 3/4" plywood profile on top of that then remove most of the 3/4" plywood buy cutting it into a one piece plywood frame?

That's the method I'm using - 3/4" mdo plywood for framing. Here's a pic of the ply being cut.

This is the way Grant Whipp constructs his teardrops. I posted this question to his forum some time ago:
http://www.forum.teardrops.net/simpleforum_pro.cgi?fid=02&topic_id=1222953610

You really don't need a 1/2" outer ply skin. I plan on using 1/8" baltic birch on the exterior followed by .040 aluminum.

[Frog]

Bobhenry:

Thanks for the answer, particularly about the holding power of solid wood.

I'm curious as to why you went with OSB for the deck and walls vs solid core plywood. I always though the plywood would be stronger and lighter than OSB.

[Frog]

aggie79:

When referring to 1/2" exterior I was mostly referring to those that were not skinned with somethin else. However, the extra rigidity of the 1/2" 5'X5' would help. Depending on chassis and tow vehicle, the extra weight may not mean a lot.

[Nitetimes]

I screwed both sheets together and cut them out at the same time. Lots quicker than framing. No problem holding fasteners. I used 1/4" oak ply on the outside and 1/4" birch on the inside, I definitely think 1/8" on the inside at least would be fine but it's what was available when I built it.
I also found after the fact that I really could have cut out more of the 3/4" and lightened it up a bit.

http://teardroptrailers.us/TDbuild/slides/b019.html

[Frog]

Nice build job. I'm sure a few pounds more or less for the Ranger doesn't make much of a difference.

[xrover]

I screwed both sheets together and cut them out at the same time. Lots quicker than framing. No problem holding fasteners. I used 1/4" oak ply on the outside and 1/4" birch on the inside, I definitely think 1/8" on the inside at least would be fine but it's what was available when I built it.
I also found after the fact that I really could have cut out more of the 3/4" and lightened it up a bit.

http://teardroptrailers.us/TDbuild/slides/b019.html

That is a wicked curve on your hatch!
Well done.

[bbarry]

I've looked at lots of construction photos and it seems that most people use something like a 1/2" outer solid core plywood with 1"X interior framing which is filled with insulation then a thin interior plywood skin.

Does anyone create the exterior profile of 1/2" plywood then create an inner frame by laying out a 3/4" plywood profile on top of that then remove most of the 3/4" plywood buy cutting it into a one piece plywood frame? It seems like it would work well and strengthen the outer wall, especially if its made of two 5" X 5" 1/2" sheets. The inner frame would still be a nominal 3/4", the same thickness as dimensional 1'X material, and although possibly only a few pounds heavier would be more stable and less likely to expand and contract or warp than solid wood? It seems that it would go faster than all the cutting and assemply needed with a wood frame.

If it's not done, I'm sure there are good reasons. Just curious.

Thanks in advance for the responses.

I considered both building up a frame and cutting it from a single sheet (okay several joined sheets) of plywood. In the end, I cut it out as it was less time consuming and probably a bit stronger.



You definitely don't need 1/2" for your skins though! It's just extra weight and expense. I am going with 1/8" skins on outside and inside for a total wall thickness of 1". Many folks, such as Nitetimes, used 1/4" for the outside (if not the inside). This give some added impact resistance. After seeing the 1/8" ply really firm up when epoxied to the frame, I'm happy with my choice.

[Frog]

bbarry:

Will you use anything to cover the 1/8" outer skin such as aluminum?

[bobhenry]

Bobhenry:

Thanks for the answer, particularly about the holding power of solid wood.

I'm curious as to why you went with OSB for the deck and walls vs solid core plywood. I always though the plywood would be stronger and lighter than OSB.

It was left over from re decking my roof and I had it on hand. In retrospect it may become a mistake 4 more years down the road. My entire build was made out of scrap and crap. I have $$980 in the completed trailer and much of that can be recouped and reincorporated into a later build. Chubby was a lab experiment to see if I could make a comfortable full size tear. If I only had know how well he was going to turn out and how much my wife has grown to like camping I would have taken Mike's motto to heart." Use the best materials you can..."

[aggie79]

I also found after the fact that I really could have cut out more of the 3/4" and lightened it up a bit.

I agree. #2 will be lighter.

[bbarry]

bbarry:

Will you use anything to cover the 1/8" outer skin such as aluminum?

Yes, planning on an aluminum skin over the exterior ply skin.