Flooring

[RichAFix]

I built some panels for a trade show a few years back, .25" luan with .75" pine sandwiched in the middle and another sheet of .25" luan. I was amazed by how light weight and strong they were. I was thinking about doing this for my floor only I would put a few supports (probably every 18" or so) with half lap joints and pink foam insulation in all the voids. All glued and stapled. I figure the fact that there will be a 6"-8" mattress on top plus the foam insulation will prevent any flex in the luan. I will also put some linoleum on the top and completely seal the bottom with that black tar goo that I hear everyone saying never dries. I like this as it gives my solid wood to screw into the end grain when I attach my sides plus it should be very light weight. Here are my concerns:
1. Is that black tar goo going to seal the luan permanently on the bottom?
2. Is this a lot of goofing around when I could just use a sheet of plywood and do the same with the goo on the bottom and add a little more weight, but wouldn't have much "end grain" to screw into?
3. Is the black tar goo even necessary if I use real .25" plywood rather than the luan (I have seen a "Camp Inn" and it looks like they just spray some kind of clear coat on plywood on the bottom)?

Thoughts? Concerns? This sitting around waiting for warm weather so I can finally weld my frame is killing me. This thing would be so much easier if I didn't stop and think about it so much.

[madjack]

I built some panels for a trade show a few years back, .25" luan with .75" pine sandwiched in the middle and another sheet of .25" luan. I was amazed by how light weight and strong they were. I was thinking about doing this for my floor only I would put a few supports (probably every 18" or so) with half lap joints and pink foam insulation in all the voids. All glued and stapled. I figure the fact that there will be a 6"-8" mattress on top plus the foam insulation will prevent any flex in the luan. I will also put some linoleum on the top and completely seal the bottom with that black tar goo that I hear everyone saying never dries. I like this as it gives my solid wood to screw into the end grain when I attach my sides plus it should be very light weight. Here are my concerns:
1. Is that black tar goo going to seal the luan permanently on the bottom?
2. Is this a lot of goofing around when I could just use a sheet of plywood and do the same with the goo on the bottom and add a little more weight, but wouldn't have much "end grain" to screw into?
3. Is the black tar goo even necessary if I use real .25" plywood rather than the luan (I have seen a "Camp Inn" and it looks like they just spray some kind of clear coat on plywood on the bottom)?

Thoughts? Concerns? This sitting around waiting for warm weather so I can finally weld my frame is killing me. This thing would be so much easier if I didn't stop and think about it so much.

RaF, we use a single sheet of 1/2ply for the floor with either epoxy or urethane to seal...most any any sealer will do, especially if all end grains which might have contact with moisture are well sealed...I believe Camp-Inn sprays with a spar urethane...after building a couple of these, I have added a sheet of blue styrofoam between the mattress and floor...oh yeah, to avoid trying to attach the sides thru plywood endgrain, we use cleats to attach wall and floor...specifically, we use 1x1/16th aluminum angle for the cleats and attach them with screws and Gorilla Glue.......
madjack

[aggie79]

As many have done, I used a similar method - 3/4" poplar framing and 1/4" baltic birch plywood skins with insulation :



But, it is a lot of work, and "upon further review", I think I would use Madjack's method for building a teardrop floor.