Teardrops n Tiny Travel Trailers

Posted: **Fri Nov 04, 2016 7:56 am**

My searching for this doesn't get results even thought I'd wager it was here. Using sandwich construction for walls (1/4-3/4-1/4) and after a woody look with a kind of frame and panel quality, it occurred to me to frame the roof on top of the walls, rather than inside or between. Anchor down through 1 x 2 into the top of wall. Even wondered if I could pre-assemble the ceiling (head liner?) and kind of lay it on all together. Ends of the roof spars would then be covered buy 1x trim or "frame". Some of the foamies seem to do this - lay the roof foam across the top of the wall. This could be a terrible idea too

Posted: **Fri Nov 04, 2016 8:31 am**

I did kind of what you are suggesting for my foamie hybrid build. If I were doing a more traditional sandwich build like yours, I would use the Steve Fredrick's method: leave or cut a rabbet on the inside top; set the ceiling down inside (perhaps with the spars already glued on, like I did), back fill between the spars with mini rib like rim boards; skin it; and then do whatever trim frame you want for your woody look on the outside.

You may also want to search for Woodbutcher's posts about his Slow Mobile build (I don't think he did an actual build thread but posted some construction pics here and there). That is a beautiful woody with external stick frame built by a master craftsman.

Posted: **Fri Nov 04, 2016 4:38 pm**

It's a little more work, but I temporarily framed my roof in place, removed the framing, installed the interior 1/8" plywood and hull liner, and then re-installed the roof.

Posted: **Sat Nov 05, 2016 10:06 am**

I use the Fredrick's "inside out" method. A lip is left on the wall that is the depth of the ceiling/spars/roof.

The ceiling is joined and three coats of poly applied. The blue tape is to keep the surface clean of poly so the glue has a bare-wood surface.

It's set onto the walls on a bead of glue and attached with a pneumatic 1/4" crown stapler.

Spars (and ceiling blocking) are added. (each rib gets a bead of glue and held from the inside with crown staples.)

It's an easy process. Steve Fredrick's Teardrop building Shop manual goes into great detail with this. I highly recommend it. :thumbsup:

Tony

Posted: **Sat Nov 05, 2016 10:07 am**

Here's how I do mine with a 1/4" deep rabbet going the full length of the walls.
I glue and staple the prefinished 1/8" Baltic Birch plywood to the edge of the rabbet, bulkheads, cabinet face frames and dividers.
Then it just a simple matter of gluing and screwing the spars to the outside of the walls.
I also put glue on the areas where the spars contact the ceiling and use padded prop sticks from the inside until the glue dries.
Then I attach filler blocks between the spars and use a top bearing bit to shape to them to the wall profile.

This method is very similar to building a cabinet or piece of furniture with two finished ends, something I've done so many times as a cabinetmaker.
To hide the back (ceiling and spars in a teardrop) you make a rabbet on the inside of the ends to receive the back.
A teardrop is something like building a cabinet face down.

Danny

Set up for routing ceiling rabbet.
The extra large router base helps keep the rabbet a consistent depth.

Posted: **Sat Nov 05, 2016 12:48 pm**

This is very useful and instructive, and some ideas are appealing, but still wonder why not set roof on top of walls. What appeals to me is the hatch which, with the frieze or apron or whatever that's called - the top "frame" piece of the frame and panel look, attached to the hatch, will provide a really good weather seal as it laps over the wall. Ghcoe's foamie hatch does this

I could be way off base and it may be a terrible idea, but seemed easy. After seeing halfdome's pictures, I wonder if setting ply on top of walls and then spars on top of that is even better. And then I'm thinking I have a lot of narrow t&g cedar, and wouldn't that make an interesting ceiling. Laminate foam, ply, and final roofing on top of that. But please, dissuade me if you think I'm off base.

Posted: **Sat Nov 05, 2016 1:35 pm**

I wonder if setting ply on top of walls and then spars on top of that is even better.

And then how would you cover this structure above the walls?

T

Posted: **Sat Nov 05, 2016 4:30 pm**

Trim - like 1 x 4 (I am thinking I'll rip 1/8" or so strips and laminate the curve). The frame part of the frame and rail exterior. Its that same frame piece I want to be attached to hatch and hang over outside of walls at hatch portion. I'd probably have the outer or top ply of roof sandwich over hang the frame piece, and use a conventional roof edge trim.

Posted: **Sat Nov 05, 2016 4:46 pm**

QueticoBill wrote:I could be way off base and it may be a terrible idea, but seemed easy. After seeing halfdome's pictures, I wonder if setting ply on top of walls and then spars on top of that is even better. And then I'm thinking I have a lot of narrow t&g cedar, and wouldn't that make an interesting ceiling. Laminate foam, ply, and final roofing on top of that. But please, dissuade me if you think I'm off base.

Many canned ham trailers were constructed in the method that you describe. The roof inner plywood was stapled to the wall framing, then full length soars were added, and narrow-width, thin plywood strips were added between the spars to build up the profile to the height of the spars.

The only disadvantage that I see to this method is that the butt joint of the roof structure to the sidewall structure does not provide much racking resistance. One of the more "conventional" roof framing methods, where the roof structure is essentially joined in a rabbet joint - to the sidewall framing and sidewalk skin that extends above the framing - should provide much greater racking resistance.

Sent from my iPhone using Tapatalk

Posted: **Sat Nov 05, 2016 6:50 pm**

Thank you. It does however seem the plywood is what would add strength. I think any arrangement of spar attachment would provide little "racking" resistance. With the the inner or headliner layer glued to the tops of the walls, it should be pretty rigid.

Posted: **Sat Nov 05, 2016 8:10 pm**

With the ceiling and the roof layer of plywood along with the spars between the walls you create a sandwich that's quite strong.
Personally I put two layers of 1/8" Baltic Birch plywood on the roof, glued in opposite directions to seal the first layers joints and to give me a roof strong enough that I can stand on it.
I think it's well worth the extra cost and effort and can't impact fuel mileage much at all.

Recently a friends Teardrop was hit and run, the video shows it flipping on it's roof, which appears to have held up quite well considering the impact, a sign of good building practices on his part.
He's a member of this forum and I'll let him tell the story when & if the time comes.

Danny

Posted: **Sun Nov 06, 2016 7:10 am**

I think it's stronger to use what Tony & Danny did. Much easier as well, since the ceiling panel can be pre-finished prior to installation. That's what we did & it makes for a simple & strong structure.

Here's the rabbet joint being cut into the edge of the sides, edge guide & straight cut bit with a router

Headliner on the bench

In place & working, pre-finished with raw canvas

A view from outside, looking at the front of the skin after the ribs start going in place.

I think this is a good system to use for assembly & strength

Posted: **Sun Nov 06, 2016 9:29 am**

If I were not putting a "frame" on the sides, I'm sure I'd go with the rabbet, but with the frame piece, it's simply a deeper and "off set" rabbet, with deeper seat and equal or thicker edge. I can still pre-finish ceiling.

I need to pull out my grad school structures class notes and see if I can make the stressed skin roof panel work with 1x on the flat. Albeit, loss of insulation. I'm leaning toward 1/4" ply. I'm not even sure if there are published engineering data for 1/8" ply.

Posted: **Sun Nov 06, 2016 9:31 am**

PS: I really appreciate the discussion. I know you are only sharing lessons from your hard earned experiences. Thank you.

Posted: **Sun Nov 06, 2016 12:05 pm**

QueticoBill wrote:If I were not putting a "frame" on the sides, I'm sure I'd go with the rabbet, but with the frame piece, it's simply a deeper and "off set" rabbet, with deeper seat and equal or thicker edge. I can still pre-finish ceiling.

I need to pull out my grad school structures class notes and see if I can make the stressed skin roof panel work with 1x on the flat. Albeit, loss of insulation. I'm leaning toward 1/4" ply. I'm not even sure if there are published engineering data for 1/8" ply.

QueticoBill wrote:PS: I really appreciate the discussion. I know you are only sharing lessons from your hard earned experiences. Thank you.

From the quotes above, It seems to me you prefer theory over practical knowledge, so my suggestion would be to search Anjib posts as I believe he's a structural engineer with a wealth of knowledge.
You may come to the same conclusions as us with "hard earned experiences" have.
Good luck with your build.

Danny

Teardrops n Tiny Travel Trailers

Roof framing on top of walls

Roof framing on top of walls

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