roof support?

[Greg Barrick]

I am in the planning stage of building a 6-1/2' wide x 10' or 12' x 4' tall teardrop. I just picked up an old 6-1/2' x 12' camper frame. I am planning on trying to build quite light and basic, just large with a front bed cross-wise. My question is: what will I need to keep the roof from sagging being 6-1/2' wide???

[Lgboro]

I built a 4 wide but built out of all cedar wood for light weight. All my framing was done in a T with opposing grains biscuit joined and dowel pinned. The result was a really really strong frame. Had I known how strong it would turn out I would have used 1/2 inch instead of 3/4 strips.

[terryjones1]

My trailer is 78" wide (6'-6").
I used 1" x 3/4" pine roof spars, placed 9" or so apart, sandwiched between top & bottom 1/4" plywood.
My roof doesn't sag.
I think you would do fine with 1-1/2" x 3/4" spars.

[Woodbutcher]

I use 1" X 1 1/2" spars. with 6 1/2 ft I would beef them up to maybe 1 1/2 X 1 1/2" in the roof with 12" centers or less.

[48Rob]

I chose 3/4" x 2" (actual size) for my trailer.


The trailer is 7' wide. I used Oak for extra strength, around 12"-14" on center, with two layers of 1/8" plywood each glued and nailed separately.
I can walk on the roof, carefully, at just under 200#

Rob

[glenpinpat]

I used 1.5"x1.5"(2x2) on ours spaced at 9"apart. I also used 2x4 to support the hatch and 2x4 along the front of the trailer just before the bend starts. Our trailer is also 6'6".

[Greg Barrick]

Thank you for your input. You make it sound too easy! By the way, I hope my new td turns out half as beautiful as yours!

[Oldragbaggers]

Rob, the inside of your Cabin Car sure is purty!!

[48Rob]

Becky,

Thanks, I like purty things...

Greg, each individual roof support, unless it is massive, is not able to support very much on its own, especially in the center of the span.
However, when you have several minimal supports a short distance apart, and all connected together with the exterior roof, and sometimes an interior ceiling, it becomes very strong and rigid.
There are span tables available to help size the supports, but they are designed for homes/buildings that must consider different types of loads, and so are not a lot of help.
The TD community, with thousands built, is a pretty good indicator of what works.
The average size seems to be between a 1x2 and a 2x2.
While size is important, it is more critical to choose a strong species without defects.
A Pine 2x2 full of knots is far weaker than a straight grained 1x2 piece of Poplar...
Spacing, or centers also is a determining factor.
Placing the supports 24" on center may leave you with a weak roof, but moving the supports to 12" centers may allow you to entertain your friends on the roof with no, or very little deflection.

Rob.

[Martiangod]

I went overkill.on my 6.5 wide, 2x4,s tapered. 14"center tapered out to 2" at the sides, did mine for snow load. Skinned in 3/8" ply. 14 to 18" centers, i can jump up and dow on it with little or no deflection.4 feet of snow should be no trou le as long as the walls stay standing: )

[Oldragbaggers]

Holy heck Slow, you pulling that thing with a Peterbilt? It must weigh a ton!!

[LDK]

I chose 3/4" x 2" (actual size) for my trailer.


The trailer is 7' wide. I used Oak for extra strength, around 12"-14" on center, with two layers of 1/8" plywood each glued and nailed separately.
I can walk on the roof, carefully, at just under 200#

Rob

The cabin car is a beauty Rob. I love that interior and I love the look of those exposed roof spars.