Floor construction method

[quack24]

Hi guys I'm sure this was asked or discussed before but I can't find it
I'm building a 5x10 on a 4x8 hf trailer my plans for the floor is to lay down the blue styrofoam and then bolt two sheets of Baltic 5x5 to the trailer does anyone see anything wrong with this? Should I paint the plywood first? I'm really open to ideas

[quack24]

Another thing my teardrop will be airstream inspired I plan on using aluminum angle for the frame and riveting on aluminum sheet metal I plan on rolling the aluminum angle with a harbor freight metal roller and getting an angle iron die from a website swag off road does anyone know if it is possible to roll aluminum angle to a one foot radius? Or maybe I should make the frame from steel?

[KCStudly]

Rolling any shape "the hard way" (vertical leg on plane) is never as easy as in the flat. It will depend on the thickness and leg size of your material, as well as the alloy and state of hardness/annealing. Testing is in order. I hope your HF rig is up for it.

On your first question, do you mean to put the foam directly over the top of the trailer frame and then cap that with ply; or do you mean that you will bolt the ply to the trailer frame and have the insulation infill the spaces between the trailer frame members? The later has been done with no bottom skin; the former is not advised.

I would not sandwich the foam between the wood and steel without some other hard surface (another layer of ply or strips underneath), otherwise the foam could crush and deteriorate over time leaving your fasteners loose.

[quack24]

The guy who makes the dies for the angle iron says it can be done but I want to see if anyone did it before
And about the foam that is what I was planning on doing sandwiching it between the trailer and the plywood I was thinking if I can do it like that I won't have to waterproof the plywood

[quack24]

The thickness of the aluminum I was planning on using was 1/8 or 3/16 by 1 1/4 it's going to be 6061 t6 from online metals dot com and yes I was planning on rolling it the hard way

[quack24]

What do you mean when you say "strips underneath"

[Talia62]

What do you mean when you say "strips underneath"

He's talking about a framework of wood, so that the insulation doesn't get crushed between the metal trailer frame and the weight of your teardrop structure. If you lay a full sheet of insulation directly on the metal trailer frame, then place your plywood flooring on top of that, then you have all that weight pinching the insulation and crushing it thinner. Go through some of the build threads and see how most people are making their insulated floors and you'll see what he means.

[KCStudly]

I guess it is feasible, but you would have to look at the total weight of the finished cabin vs. the surface area of the trailer frame vs. the load bearing capacity of the specific foam you intend to use. Then you would also want to analyze any lack of uniformity of your loading (i.e. say the galley is especially heavy, you would want to look at the local effect of weight/surface area/capacity).

If the surface area of the trailer was insufficient or marginal, you could, in theory use strips of lumber or ply that are wider than the trailer frame to extend the hard surface over a bigger area of foam.

But why? IMO, for longevity, the foam needs some protection against physical damage, water infiltration, mold, etc. Frankly, the foam is pretty fragile. You could do the PMF thing on the bottom, but I doubt it would cost any less than a sheet of underlay ply, and would be at least as involved to do.

[quack24]

Ok here's the revised floor plan cut out strips of 3/4 plywood and lay them down along the frame of the trailer (or maybe I should use pvc trim instead ) and then put ice shield on the bottom of the Baltic birch panels bolt (for water protection) than bolt the birch down to the trailer than infill the bottom with foam

[quack24]

Any ideas or reasons this won't work are greatly appreciated

[KCStudly]

Just the weight and cost issues. For the price and weight of a bunch of 3/4 ply slats you could easily cover the whole thing with 5mm underlayment.

[quack24]

I was sort of trying to not make a sandwich floor not sure why

[quack24]

I was also leaning towards pic trim or something rot resistant
Does anyone have any experience with the grace ice shield I remember seeing a couple people saying they use it just can't remember who it would be nice to hear some feedback from them about how well it hold up

[KCStudly]

I think 2bits used something like that on his little TD and had it all sag back off again in the Texas heat; the adhesive backing did not stick well.