A few questions building on a mesh floor utility trailer.

[Chello]

I have an 5x8 utility trailer from craigslist. It had a wood floor with mesh underneath, so to save weight I removed the wood and am in the process of removing the railings and tailgate. I am planning on a sandwich floor with 2" foam walls/ceiling and I have to questions that I could use some clarification on.

1. After looking at a lot of builds a lot of people are building on top of wooden framing type platforms. I will be building between the fenders and have metal structure everywhere. My plan is to use 1/4" ply with a 1"x4" perimeter, 1" foam in the void, and topped with 1/4" ply for the floor, bolted down to the trailer cross members. I am not planning on having any other structural wood inside the sandwiched foam except for around the perimeter. Will this be solid enough? From what i can tell it should be.

2. When it comes to skinning, i'm set on using PMF inside and out for rigidity. My question is concerning the outside walls and the metal frame of the trailer. Since the body will be sitting inside the "L" of the trailer rails, how should i handle the skinning? In my mind i have 2 options. 1.) Skin wall down and around the floor and then set the whole foamie inside the trailer and bolt it down. Or 2.) Bolt body onto the trailer and skin the wall down and round the outside of the trailer metal and around the underside. I'm leaning toward option number 1, and also considering some sort of caulk between the trailer and camper wall. Any thoughts?

Thanks in advance, and i'm looking forward to sharing my build in the future.

[GPW]

Hi Chello , would it be thinkable to just make the cabin to pop on and off the trailer , your floor secured with a few bolts ... that would make access easier and allow for easy covering ... You are going to leave the mesh on the floor eh ?

[Chello]

Hi Chello , would it be thinkable to just make the cabin to pop on and off the trailer , your floor secured with a few bolts ... that would make access easier and allow for easy covering ... You are going to leave the mesh on the floor eh ?

I am leaving the mesh floor, thinking it will help water drain out from under the floor if i decide to make the removable cabin.

[KCStudly]

I would not try to wrap the steel. Invariably you will have a bump or "chink" there that the canvas won't be in "intimate contact" with; and the ability to glue to it and not have adhesion issues with different expansion rates just seems too sketchy to me.

If you do decided to go with a removable slide-in, I would consider adding hard wood rub rail skids to the underside after wrapping the canvas under the floor (perhaps adjacent to both sides and one more down the middle... you might even want to hold the cabin wall back a little narrower than the inside dimension of the 'L' to allow the rub rails to stick out to the sides a little, keeping the cabin clear of the fenders and whatnot when sliding in and out). Oiled oak would be good; consider these rails as wearing surfaces and don't worry too much about sealing them (other than the face that attaches to the canvas and any fastener holes where they attach). Size the rub rails so that they keep the cabin proper up out of the 'L' shaped side rails of your trailer; that way you don't have much concern for rot. This space between the 'L' and skid will collect debris and moisture which the oiled oak will do okay with, and can be replaced later if it starts to rot. If you are doing a slide-in you won't want to be adding caulk here anyway.

If you end up doing a permanent install, I would still wrap the canvas under the cabin before installing on the trailer. Then stuff the gap area with some of that foam rod batting/crack filler (like this, comes in different sizes) before caulking over it with a non-silicone/paintable exterior grade caulk. Trowel the caulk up into a wedge so that water sheds off of it. That way if you ever have a problem or need to restore the caulk, it would be much easier to cut thru and remove, and you won't waste so much caulk; plus the foam backer allows the caulk to flex more than if it was a solid wad of caulk.

[Chello]

You echoed my concerns with wrapping over the steel. I'm leaning toward a permanent install and appreciate the suggestions on the filler foam.