Cookie cutter profile

[Forrest747]

I didn't want to hijack a thread so I thought I would start this one. Becky of oldragbaggers has a side wall profile that is all cut out. The question I have is what is the benefit if doing it that way. What is the thickness of the material and how do u skin it. Thanks.

[doug hodder]

That's a sandwich wall construction. You take a piece of thicker material, cut it out to allow for attachment points and structural integrity, then laminate a piece of thinner skin on the interior, stuff the openings with foam insulation and then skin the outer side. You get an insulated wall doing it this way and a wire-way as well. Kinda like studs in house construction, only thinner. Doug

[grant whipp]

The benefits are several:
• weight savings over solid plywood walls
• easy insulation without overly thick walls
• all the strength of a solid sheet of plywood without all of the weight
• ease of construction over stick-framing or built-up walls

Typically, a layer of paneling is glued on the inside of the wall, then the walls & cabinetry & floor are assembled, then a 1/4" layer of luan or plywood is glued over the outside (after the insulation is in place) and the outside aluminum skin is glued to that.

You can start with 1/2" plywood, or 5/8", or 3/4" ... depends on the thickness of your paneling and how you choose to skin the outside. I like 1/2" when I go with 1/4" & 1/4", but will go with 5/8" if I go 1/8" & 1/4" (keeping my walls as close to 1" as possible).

There are other methods, but it's what's been working for me for almost 25 years!

CHEERS!

Grant

[Mayne]

How thick an insulation would be used? I knw that 3/4" ply is shy of that spec, so.... would 1/2" foam insulation be used?

[Elizabeth C.]

I bought this at Home Depot last week, it is exactly the same thickness as my 3/4 ply( Note it says nominal thickness on the label).



It was under $8 for a pack of 6 sheets.

Hopes this helps!

Dr. C-Dawg

P.S. As for weight savings by using the cookie cutter method, our wall wighed 104 lbs before and only 54 lbs after cutting out the excess. Of course that also included window and door openings, so it is not entirely accurate but it is still significant.

[afreegreek]

you can get the same benefit, lower weight and room for insulation and wiring by just cutting strips of plywood or solid wood and glueing it around the perimeter, door and window openings, and attachment points.. using a full sheet and making a bunch of cutouts is a bit of a waste of wood and time.. some will argue that it is stronger but when the panel is already 10x stronger that is needed it's a bit of a stretch to split hairs that fine..

personally I'd go for thicker walls.. I have 1-1/2 inches of EPS insulation in my 18 foot trailer and can heat it with an 800 watt ceramic heater down to -10 degrees.. I usually use my propane heater because I'm on generator/ battery bank power but the ceramic heater works fine when I'm plugged into shore power.. it also leaves room to mount shallow electrical boxes for switches and plugs

[grant whipp]

How thick an insulation would be used? I knw that 3/4" ply is shy of that spec, so.... would 1/2" foam insulation be used?

I haven't had any problems getting 1/2" foam into 1/2" plywood walls (I also use it for 5/8" walls) or 3/4" foam into 3/4" walls. I typically use the Tyvek-backed white sheets from Home Depot or Lowe's

you can get the same benefit, lower weight and room for insulation and wiring by just cutting strips of plywood or solid wood and glueing it around the perimeter, door and window openings, and attachment points.. using a full sheet and making a bunch of cutouts is a bit of a waste of wood and time.. some will argue that it is stronger but when the panel is already 10x stronger that is needed it's a bit of a stretch to split hairs that fine..

personally I'd go for thicker walls.. I have 1-1/2 inches of EPS insulation in my 18 foot trailer ...

Different strokes for different folks, for sure ... ... but the original question was

what is the benefit if doing it that way? What is the thickness of the material ...?

As far as going with thicker walls, again, different strokes ...! Space is much more of a premium in a teardrop over a typical travel trailer, so even an inch-or-so of additional room in a given footprint can be a big deal (to some), and because there is so little room in a TD to begin with, it doesn't take much insulation to make a big difference (and certainly, even a little insulation is better than no insulation ... ...!).

And, as far as weight savings go, on a typical 4'x8' teardrop, I save about 100# over solid plywood construction (but, I also do my cabinetry the same way), and on a 4'x10' it's almost 150#

Don't get me wrong, I'm not saying that this method is the best one (there is NO one best way to build a teardrop!), just that it's the way I've been building 'em for 25 years, and I've found that it saves me considerable time & effort (not to mention the benefit of insulation) ... it also supplied me with some extra wood for the fireplace ... ...!

And, don't forget the standard disclaimer ... others' experiences may vary!

However you choose to build your teardrop (or tiny travel trailer), Good Luck, and as always ...

CHEERS!

Grant

[Oldragbaggers]

For me, I think it was the best method. I had both walls cut out in a weekend, (could have gotten them done in a day if I hadn't had a dozen other distractions) and I know for a fact I would have been scratching my head a lot longer than that figuring out how to do the framing. I can see how people like me, with little of this type of carpentry experience, find this method much easier.

As far as the wasted wood, 2 sheets of 3/4" cost me $88. If I wasted half of it, I can easily blow that much on dinner in a decent restaurant. I can live with it for the amount of time and head scratching it saved me. Besides, some of the pieces are large enough that they can probably be used somewhere in the cabinet framing or doors, or in other around the house projects. Not too much goes to waste around our old place.

Maybe it's a bit heavier, but that's just a different subject to split hairs on.

Grant said it best...different strokes for different folks. We all bring different levels of experience and skill, plus familiarity with different materials and differing levels of creativity to the table. And teardrops are such a wonderful outlet to bring it all together and make it uniquely your own. The way each teardrop reflects the taste and personality, skill and experience of its owner is what makes them so much fun to build and to look at.

[Lgboro]

As the king of overkill I made beams of opposing grains biscuit jointed and dowel pinned in a T . The first build I started was pine but got too heavy for my needs so I canned that one and built the same method out of cedar. Really light but is very labor intensive as each piece of cedar has to be planed but is awesome strong. I went with 1 1/2 inch blue foam insulated walls, ceiling and floor so as to allow me extended season use if needed (and as an escape pod for hurricanes and ice storms). Wood price probably tripled but that is the price for lightweight. Cedar stripped the interior and will float aluminum over the insulation when I install it to further reduce weight. About 80% complete and exactly what I envisioned to this point and to me worth the extra time and effort.

[Oldragbaggers]

lgboro: And being happy with what you got is the best reward!!

[halfdome, Danny]

Not trying to ruffle any feathers but... I like the integral strength of a solid sheet of 3/4" plywood.
The sandwich method is fine if you want to spend the extra effort and materials. The cold will find the least resistance which would be the plywood cookie cut framing.
Ever notice an insulated home in the cold? You can see the shadow of the studs.
3/4" Plywood has an R value of .94, 1" of extruded polystyrene has and R value of 5.00 so it's anyone's guess if 1/2" polystyrene is half of that value or 2.5.
Here's where I got my information
I use what's called Pacific Birch Lite that weighs 47 pounds for a 3/4" x 4' x 8' sheet. It's a 12 ply veneer core plywood.
Great stuff and I don't have to cut out holes for insulation.
I understand most heat gain and loss ( 60 - 70%) occurs in the roof which mine has 1 1/2" of the foam insulation from stem to stern. I use 1/8" ply for the ceiling and 2 sheets of 1/8" ply for the roof which equals an R value of .47 plus the 1 1/2" polystyrene at an R value of 7.5 for a total close to R-8. It's nothing like the R30 for my house and shop ceilings and R-19 for the walls.
Also we are all using single pained windows, so there goes the heat right out the window .
We are quite comfortable in our teardrop. Danny

[Oldragbaggers]

Heat gain/loss is not my biggest concern. Lance and I will not be camping in "cold weather". We are absolutely fair weather travelers. I am more concerned about condensation and sound, especially sound. Any sound dampening effects we can get from the insulation will be well worth the effort.

[halfdome, Danny]

Heat gain/loss is not my biggest concern. Lance and I will not be camping in "cold weather". We are absolutely fair weather travelers. I am more concerned about condensation and sound, especially sound. Any sound dampening effects we can get from the insulation will be well worth the effort.

My response wasn't aimed at your build in particular but the concept and the question

The question I have is what is the benefit if doing it that way.

My first build I went way over & built solid walls of 1/2" Baltic Birch plywood framed in 3/4" lumber and filled with 3/4" foam sheeting, the solid grey stuff.
I covered that with 1/4 Red oak plywood in the inside and skinned the outside with .040 aluminum.
My subsequent builds #'s 2-4 I have gone with only 3/4" plywood walls and hardly notice a difference (Jane didn't notice a change) in sound trransmission.
There is more but not enough to persuade me into insulating the walls.
Like you said before and I agree. Danny

We all bring different levels of experience and skill, plus familiarity with different materials and differing levels of creativity to the table. And teardrops are such a wonderful outlet to bring it all together and make it uniquely your own. The way each teardrop reflects the taste and personality, skill and experience of its owner is what makes them so much fun to build and to look at.

[Oldragbaggers]

Thanks Danny. I didn't feel at all like you were directing your comments at me, I just wanted to point out the other aspects of deciding to insulate or not other than temperature.

I have to admit, I went back and forth several times on whether to insulate or not and whether or not I would make the same decision again is uncertain. I just went with my gut feeling and the experiences of others. So we'll see.

[halfdome, Danny]

Thanks Danny. I didn't feel at all like you were directing your comments at me, I just wanted to point out the other aspects of deciding to insulate or not other than temperature.

I have to admit, I went back and forth several times on whether to insulate or not and whether or not I would make the same decision again is uncertain. I just went with my gut feeling and the experiences of others. So we'll see.

It will be nice and you will enjoy it like we all enjoy our teardrop builds. Danny