Plywood Only Floor? (No subframe)

[GeoDrop]

Is there a driving reason to have a subframe (presumably 2x2's) between the plywood floor and trailer frame? In the interest of shedding a couple of pounds, why not just attach the plywood directly to the trailer frame? It appears that most subframes attach to the outer perimeter and cross members anyway. The only reason that comes to mind is that the subflooring could act as cross members in some situations but I don't know how much support they would have w/o underlying steel framing.

Attachment points and thickness would be two reasons I could think of but it seems you could easily work around those issues. (Steve F's method of attaching walls).

Am I missing something?

[Ageless]

To add the 1 1/2" foam insulation

[halfdome, Danny]

I use 3/4" plywood with plam on each side for my floors. I have 4 cross members including front and back to support the plywood and mounting tabs where needed. Insulation is really not needed if you have a 4" or thicker foam mattress. It helps to put a 1/4" deep plow in your walls for the plywood floor to go into. It also helps by covering the chassis. Danny

[madjack]

I just use 1/2" ply for my floors, sitting directly on the trailer frame...walls are attached to floor with 1x1/16th Al angle used as cleats(glued&screwed)...the walls are also attached to the trailer frame and the floor just floats.....
madjack

[aggie79]

I would say it is about a wash on the strength/weight issue.

My floor is a 1 1/4" in thickness - 1/4" plywood, 3/4" 1x2 furring strip with insulation, and 1/4" plywood. This torsion box construction is very strong. It ends up weighing more than 1/2" plywood but less than 3/4" plywood.

With a torsion box floor, though, I was able to delete the steel crossmembers from the trailer frame. You could probably do the same with 3/4" plywood, but I'm not sure I would do that with 1/2" plywood.

Tom

[GeoDrop]

This is the route I'm considering. A sandwich floor construction: 1/4 ply, 1/2"-3/4" insulation?, 1/4" ply. Possibly a furring strip around the perimeter.

I would say it is about a wash on the strength/weight issue.

My floor is a 1 1/4" in thickness - 1/4" plywood, 3/4" 1x2 furring strip with insulation, and 1/4" plywood. This torsion box construction is very strong. It ends up weighing about more than 1/2" plywood but less than 3/4" plywood.

With a torsion box floor, though, I was able to delete the steel crossmembers from the trailer frame. You could probably do the same with 3/4" plywood, but I'm not sure I would do that with 1/2" plywood.

Tom

[halfdome, Danny]

The one or two cross members you plan on eliminating don't weigh that much and gives considerable strength with mounting tabs.
We're only talking of a few pounds.
A sheet of plywood is a whole lot easier than making a torsion box.
I'll choose safety over all factors.
Just my opinion, and you know how they all stink. Danny

[caseydog]

I also went with 3/4 plywood attached directly to the trailer frame. I did not save much weight, but since my walls are 4 X 8 plywood, and they sit on top of my trailer frame, the thinner floor did give me a couple inches more headroom inside.

CD

[Sawyer]

I attached my 3/4" Okoume ply directly to the trailer frame. I used pocket screws and PL adhesive to attach my sides to the floor. Super simple, 3000+ abusive miles without a hickup. Like Danny said, I don't feel like floor insulation is necessary with a good mattress. My wife and I camp all through the winter with no heater and stay plenty warm (it helps to have a dachshund who pre-warms the bed for us).

[Senior Ninja]

We used a 4X8 sheet of 3/4 plywood that I coated with three coats of varnish (both sides and especially edges) before fastening it to the frame. We screwed and glued a key around the perimeter to fit into the slot of the pre-wired and insulated walls. The walls were both glued and stapled to the key. So far so good.
Steve