Floor Thickness

[denverd0n]

Discussions about lightweight construction seem to be pretty popular recently, so here's a question for you all. How thick does the floor that you kneel/lay on need to be?

I'm thinking sandwich construction with 1x2 framing (sideways, so, 3/4" thick), a piece of 1/4" plywood for the bottom (facing the street), and then what for the top? Is 1/2" going to be solid enough that my 200 lbs. fat butt won't make it sag? Or should I go with 3/4"? My guess is that 5/8" would be about perfect, but that doesn't seem to be very readily available around here (at least, not at the local Home Depot).

[toypusher]

The Cubby plans from Kuffle Creek use 1/2" plywood on a 2x2 frame. The frame is mostly to fasten the sides to and something more substantial to put bolts turi into the frame. There are lots of Cubbys out there and I have not heard of one that the floor gave out.

Hope this helps.

Kerry

[asianflava]

I have a sandwich floor, made from 1X2 sticks and 1/8" birch ply (both sides) and rigid insulation. It was all epoxied together and secured to both walls, it lays on top of a 2X4 on both ends. The span across the 2X4s is over 7feet, just with the side screws it is able to support my weight (I'm well over 200lbs) with no problem. When the frame is made, there will be an addidional crossmember to stiffen the floor even more.

[David Beckett]

I used half inch plywood on a 2x3 frame with 2 foot centers. Very solid with no sagging.

[Guest]

I'm not too concerned about weight.
My plan calls for 3/4" plywood anchored to the steel frame of the trailer.
I'm somewhat surprised that many of you guys are placing a wood frame in between the steel trailer frame and your plywood floor. I can understand that approach for like what Rocky did in a lightweight situation, but if you are using 1/2" plywood, why not just bump up the plywood thickness and nix the wood framing? Am I missing something here, or are you guys using that space for underfloor storage?
Any other plywood on steel decks out there, or am I just an odd duck?

[Kevin A]

I'm not too concerned about weight.
My plan calls for 3/4" plywood anchored to the steel frame of the trailer.
I'm somewhat surprised that many of you guys are placing a wood frame in between the steel trailer frame and your plywood floor. I can understand that approach for like what Rocky did in a lightweight situation, but if you are using 1/2" plywood, why not just bump up the plywood thickness and nix the wood framing? Am I missing something here, or are you guys using that space for underfloor storage?
Any other plywood on steel decks out there, or am I just an odd duck?

Dean,

That's one of the changes I made on my Thims when I set out to rebuild it. The original trailer had a wood framed plywood deck on top of the steel trailer frame, by eliminating the wood frame under the plywood I was able to gain 3-4 inches of head room inside the trailer by lowering the plywood floor directly onto the new frame without changing the overall height of the trailer. I used self drilling screws to attach the 3/4" plywood to the frame. The original wood framed deck was necessary to add strength to the original steel frame, my new frame being better built allowed me to eliminate the wood framing under the floor. I have several photos in my album that show a comparison of the old and new frames/decks.

[Syekick]

I would think that those who mount the plywood directly to the steel frame, without building a sandwich, are also mounting the sidewalls directly to the steel frame. Those who build a flooring sandwich could mount to either the steel frame or the floor sandwich.

The only advantage to the sandwich flooring I can think of is the ability to add insulation or a dropped floor.

[toypusher]

I'm not too concerned about weight.
My plan calls for 3/4" plywood anchored to the steel frame of the trailer.
I'm somewhat surprised that many of you guys are placing a wood frame in between the steel trailer frame and your plywood floor. I can understand that approach for like what Rocky did in a lightweight situation, but if you are using 1/2" plywood, why not just bump up the plywood thickness and nix the wood framing? Am I missing something here, or are you guys using that space for underfloor storage?
Any other plywood on steel decks out there, or am I just an odd duck?

The frame is not for extra strength at all. It is used to fasten the sides to and to allow space for insulation and under floor storage. It also allows more space for the onboard water tank in the Cubby. 1/2" plywood should still be plenty strong for the floor. If, however, your crossmembers on your trailer are 3 or 4 feet apart, you may want to use thicker plywood.

Kerry

[JunkMan]

Any other plywood on steel decks out there, or am I just an odd duck?

I am mounting my floor directly to the frame and plan to use 1/2 plywood. I am using sandwich type walls with insulation, but they will also bolt or screw directly to the frame (overlapping and hiding the sides of the frame). I plan to add rigid foam insulation between the frame rails. Although the frame will cause some thermal transfer, I don't think it will be much, and the mattress will add to the insulation on the bottom of the trailer.

[Keith]

Hi Dean,

We used aluminum for our floor. We picked it up near you. My dad used to drive truck for Louisiana Pacific. He used to make a lot of trips to their press board mill in Arcata. He had seen large sheets of aluminum when he was in there and asked about them. They are from the machine that the sheets are pressed on. They replace them occassionaly and sell the sheets to a metal recycler. We were able to get them from there. They are 59" wide and I think up to 30' long and about 1/4" thick. They work out great for a 5' wide trailer.

Keith.

[shil]

I use 5/8 T&G plywood screwed and bolted right to the steel frame. No worries, it seems to be holding up just fine. Almost time to take the tear out of hibernation! We'll soon see how well it survived its first winter.

[IraRat]

This might seem like a weird consideration, especially since you can't really do much walking in a TD anyway, but...

Isn't there going to be totally different feel to the floor by placing the sheet directly on the trailer frame? That 2 by 2 framing also provides a kind of cushioning/flex to the floor, I would think.

[denverd0n]

I have a sandwich floor, made from 1X2 sticks and 1/8" birch ply (both sides) and rigid insulation.

1/8"!!??!! Wow! I'm amazed that a floor that thin can support a person, even if it is sandwich construction. I guess I won't have to worry at all about using 1/2". Now you've got me wondering if I can get away with 1/4" on both sides.

My overall philosophy on the whole teardrop can be summed up as, "as strong as it needs to be, as light as it can be."

[An Ol Timer]

The word sandwiched here can be used in two different ways. In one way the two pieces of plywood and a piece of insulation are just stacked together like a sandwich. If they are glued together, then that is a whole different meaning. If glued securely they will form a girder with the plywood panels becoming the upper and lower surfaces and the insulation being the web much like a steel girder. As long as the web holds the two surfaces in their proper planes one will be in tension and the other in compression when you try to bend the girder. What I'm trying to say is that a lot of strength can be achieved in a floor or wall if all layers are securely fastened to each other. This would help in making much lighter, but stonger walls and floors.

[toypusher]

Does anyone out there know the best adhesive to glue plywood and rigid foam insulation together?