Stick Frame Construction Strength

[clarkbre]

I'm starting to design a box for a camp trailer I'm building and need some tips. I'm going a different route than a teardrop but much of the same construction will apply to my design. I have a 4x8 Redtrailers.com trailer that I've modified to 4x6. My plan is to make a 48"x72"x22" box that will hold all my camping gear and mount a large cartop tent ontop of the box. That's where my questions start.

In building the box, I know that I will have to seal it as best as possible to keep all my gear dry while on the road. That shouldn't be too hard. But, with the cartop tent mounted on top, plus two campers, I am looking at about 500 pounds on top of the box.

My plan is to build a frame using 1x2's and cover it in 1/2" plywood. With the proper frame design and the plywood, will this be strong enough or should I bump up to thicker framing or plywood?

Any suggestions would be great.

[Ageless]

I'm disassembling a 68 trailer that used 3/16 ply (interior) and 1x2. Except for the damage from dryrot, this lasted 41 years.

Does this answer the ?

[asianflava]

I used 1x2's and skinned it with 1/8th inch ply on both sides.

[Steve_Cox]

Clarkbre
In thinking about this box with the weight on top, It will have to have doors to access your gear. How about a bulkhead down the middle of the box with access doors on both sides. You might want to skin the inside with 1/4" to help create a torsion box. I've seen some of that type camper with a galley on one side and the gear storage on the other. Got any pictures of what you are shooting for design wise? I found this pic of a box with the top that opens.

[aggie79]

My floor is made from 1x2s laid "flat", 16" o.c. with 1/4" ply top and bottom. It spans 56". There is some slight deflection but it is not noticeable. You may want to consider using 1x2s on edge, with the crowns up if they have a crown.

[clarkbre]

Below is what I have for an idea. I also attached a picture of my modified trailer frame. I like the ideas of using 1x2’s and plywood. It sounds like with the proper design, the 1x2’s and ½” ply should be more than adequate. I was planning on bolting the floor of the box to the trailer, laying 1x2’s flat on the floor, putting in vertical supports 16” OC, and then building the top rim and stringers on end. Once the ½” ply is on top of that there should be very little flex on the top of the box.

I do like the idea of a bulkhead as well. I think that would really stiffen things up.