Terms - Stick Frame, Skeleton Wall, SIP

[Watercamper]

Hi!

This is my first post (other than my introduction) and I would like to begin our conversation with some help with the td terminology.

Is the following correct?

A skeleton frame starts with a sheet of plywood. Sections of various sizes and shapes are then removed from the plywood. Typically, these voids are filled with foam and then this composite is sheathed on both sides (using an adhesive) with plywood.

What is the td definition of a SIP - Structural Insulated Panel? Can you give me the location of a photo or photos of a build using SIPS's.

Lastly, I can't find photos or a real definition of a stick frame or stick wall? Can someone point me in the right direction?

Thanks!

[atahoekid]

Welcome to the forum. A stick frame or stick wall is built much like houses. You have a frame built with dimensional lumber skinned with plywood on one side or both. A SIP is what some members of the foamie crowd are doing. Essentially you take a core material (foam) and skin it on both sides. For Foamies, the choices have been ply, canvas, fiberglass or some combination. Take a look at some of the Foamie builds and you'll get an idea. It might be more correct to call this sandwich or composite panel construction. Anyway take a look. It might be a method for you. It was for me.

[mezmo]

Hi Watercamper,

Welcome to the forum !

Your definition for a 'skeleton frame' is close enough. It's also
referred to as a "cookie cutter" by some, analogized to what
remains of the cookie dough after you've removed the cut-out
cookies from it.

The TD version of a SIP is just the SIP on a smaller scale. A foam
core with skins of 1/8inch -1/4inch plywood or aluminum or FRP
or such. [Various combos of such are possible.] Check ot the
Foamie section for a couple threads on that. Member Linuxmanxxx
has the most actual posting info on them. Here's one:
viewtopic.php?t=50769&p=940644 . Just
use the Google Search on the header to look for more.

The "stick frame" is analogous to the ususal wooden house
framing, just on a smaller scale. It's also referred to as the
"sandwich method" by some. TDs and TTTs just use smaller
dimension 'studding/framing', generally nomial "1x" materials
such as 1x1, 1x2, 1x3 etc. Some also use the nominal "2x"size
materials too. Just remember that the larger sized pieces add
up fast in weight. This framing is then covered with sheet goods,
usually plywoods, aluminum sheeting, FRP etc., again various
combos of them are used - personal preference. If all the
components are glued together they become 'unitized' and the
whole structure is much stronger.

Also, be aware of the admonition to build it closer to an
airplane versus building a house or a "tank". It is extremely easy
to "overbuild". It's all just considering all factors and coming up
with the right combination to suit your needs and the dynamic
requirements that a vehicle such as a TD or TTT needs. Just by
looking through the various build journals you will get a sense
of what approaches may be best for you.

Cheers,
Norm/mezmo

[Nobody]

Your definitions are pretty close . My TD frame is 'stick built' but instead of building the frame & then adding the inner/outer sheathing, I cut my inner skin(s) from 1/4" oak plywood (using a cardboard template), glued the frame to the skins, & once the walls were in place on the floor, I added the foam insulation & then the outer ply (luan) skins. Aluminum outer skins was the last thing added other than the doors & fixtures...

[Oldragbaggers]

I like the way you did that Harvey!!

[rowerwet]

I way over built the sidewalls, two sheets of 1/4" and 1x2" lumber...
"stick built" is the easiest way to make super strong insulated walls, fully glue all joints for strength, and you end up with an "I" beam for every stick with the inner and outer skin. I way over built my sidewalls, two sheets of 1/4" and 1x2" lumber... should have just made them with 1/4" ply and 1" foam, then fabric skin.
I'm not sure about the difference in cost between that many feet of lumber and glue compared to just cutting holes in a sheet of plywood. Both methods take careful figuring to get the frame where you want your galley walls, doors, windows, and storage bulkheads.
Also make sure you draw the internal framework on the outside of both panels so you can find them after you close the wall up.

[grantstew8]

SIP is a composite panel, thin outer skins glued to a core normally eps. The strength comes from the glue sticking the three bits together. If the glue failed the strength is lost.
There is loads of info on http://sipsindustries.com.au

If you go down the stick build route consider building the inner skin first....

[Watercamper]

I way over built the sidewalls, two sheets of 1/4" and 1x2" lumber...
"stick built" is the easiest way to make super strong insulated walls, fully glue all joints for strength, and you end up with an "I" beam for every stick with the inner and outer skin. I way over built my sidewalls, two sheets of 1/4" and 1x2" lumber... should have just made them with 1/4" ply and 1" foam, then fabric skin.

Thanks Harvey! This is what I thought Stick Frame meant but I wanted to be sure. And I really like your assembly. In my mind, I had planned an outer, curved frame assembled with pocket screws and glue and trimmed with a router using a hardboard template (sound familiar ). And then I wanted to simply add "studs" where needed and any other pieces where screws would be needed (darn - sure looks like your assembly - you beat me to it!).

Now, I'd like to comment on your comment above. I've only been looking over the construction methods of a td build for a couple of days but the one thing that I kept seeing was the feeling that things were overbuilt (I r an engineer). Your comment and my perusal of the foamie builds seem to support this idea. That said, I don't wish to have a fabric skin - I'm a woodworker! So - my initial idea was 1/8" interior and exterior skins over 3/4" x 1.5" framing. Instead, using your comment above, what do you think of 1/8" interior and exterior skins over 3/4" foam (instead of 1 1/2") with 3/4" framing pieces in the necessary locations? This should be a rather strong wall but a bit flimsy until the roof spars are connected and everything is assembled. Thoughts? Anyone?

[wagondude]

That plan should work out just fine. In the Foamie section, pay particular attention to the build thread for the Poet Creek Express. Although KC plans to skin with canvas, the outer skin could just as easily be done with plywood. Of most interest to you will be his method of placing hard points for fasteners. The thread is long, but very detailed.

[Watercamper]

... Poet Creek Express. Although KC plans to skin with canvas, the outer skin could just as easily be done with plywood. Of most interest to you will be his method of placing hard points for fasteners. The thread is long, but very detailed.

Thanks! I found his info this morning but when I saw the length and number of photos, I pm'd him with my questions about his build. I may just have to spend some time going through all of his info.

[DMcCam]

Hi Watercamper, We did the skeletonized wall system of two 1/8" Baltic birch plywood sandwiching a 3/4" 'skeleton'. It makes a very strong wall but not as light as stick framing. You can check it out on my build thread if you're interested.

All the Best,

Dave

[rowerwet]

I way over built the sidewalls, two sheets of 1/4" and 1x2" lumber...
"stick built" is the easiest way to make super strong insulated walls, fully glue all joints for strength, and you end up with an "I" beam for every stick with the inner and outer skin. I way over built my sidewalls, two sheets of 1/4" and 1x2" lumber... should have just made them with 1/4" ply and 1" foam, then fabric skin.

Thanks Harvey! This is what I thought Stick Frame meant but I wanted to be sure. And I really like your assembly. In my mind, I had planned an outer, curved frame assembled with pocket screws and glue and trimmed with a router using a hardboard template (sound familiar ). And then I wanted to simply add "studs" where needed and any other pieces where screws would be needed (darn - sure looks like your assembly - you beat me to it!).

Now, I'd like to comment on your comment above. I've only been looking over the construction methods of a td build for a couple of days but the one thing that I kept seeing was the feeling that things were overbuilt (I r an engineer). Your comment and my perusal of the foamie builds seem to support this idea. That said, I don't wish to have a fabric skin - I'm a woodworker! So - my initial idea was 1/8" interior and exterior skins over 3/4" x 1.5" framing. Instead, using your comment above, what do you think of 1/8" interior and exterior skins over 3/4" foam (instead of 1 1/2") with 3/4" framing pieces in the necessary locations? This should be a rather strong wall but a bit flimsy until the roof spars are connected and everything is assembled. Thoughts? Anyone?

If you go that route, I would look into vacuum bagging each lamination (sidewall) to make sure the glue to foam bond is best. I would make each side wall as a 4x8 (or whatever size you want for the sidewalls) then after the inner and outer skins were bonded, cut the profile you want.
But, just to echo what GPW (godfather of the foamlings) would say, "why do you want any wood?"

[bobhenry]

When I built chubby I did mine inside out from Harvey's method. I built the 5/8 plywood profile from 3 vertically oriented sheets and joined them using a 1x3 as the joining member. It was foam filled and all the electrical was in this 3/4" void. It was a pain adding the inner 1/4 luan inner sheeting and face glueing the 1/4 luan outer final face. I would never recommend it a a method.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I house framed the barn just like any mini barn I had ever built I simply cut down the size of the members on the table saw and extensively used let in wind bracing for wind shear strength. It is a rock no wiggle no jiggle. Having a full 2" void made electrical work much easier and added a great insulation factor when filled with blue ridged foam.











While this method is not readily endorsed by the purists it was extremely quick and very construction friendly it was 30 days start to finish working 4 weekends only.

[Oldragbaggers]

I did what Grant Whipp calls a cookie cutter wall. I don't find it reduced the weight all that drastically by the time the inner and outer skins were on, but I am so happy to have the insulation. At first I didn't think the insulation made a big difference until I camped in the fall last year. In the morning I found there was condensation on the areas of the wall where there was no insulation (literally dripping!!) like the solid areas around the door and the areas that had insulation was dry as a bone. I will never again doubt whether insulation is a good thing. Unless you only camp only in the desert.

[DMcCam]

I will never again doubt whether insulation is a good thing. Unless you only camp only in the desert.

We agree Becky, we found that our wall insulation keeps the cabin cooler in the warmer climates too; bonus!

All the Best,

Dave