Need Some Info on Sub-Flooring
 

I'm building a camp 7' off the ground and my floor joists are 2' apart and made of 4" metal cees.
My question is whats the best wood to use for the subfloor.

3/4" treated plywood- I like this but know the sheets will leave a crack after drying. I don't want cracks through the floor. $30 a sheet

23/32" untreated plywood- i will put one coat of water sealer on this.
$19 a sheet

23/32" tounge and groove OSB- I like the looks of this but don't know how strong it is compared to the plywood. $14 dollars a sheet

Geaux Pox. :)

got a buddy that works at roy o' martin that osb suppose to be stronger than plywood

neither . 3/4 wil sag for sure on a 2' center. the houses we frame the subfloor is 1 1/8 thick its called spandex it expensive but worth it also there is a new product if you are looking to sheet were walls and roof that require no tyvek of roof felt this company also makes a decking with a 1 yr no sand gaurentee which meens that from the day you lay this stuff the seams will not swell in the weather due to the house not being "blacked in" call me if you have any questions 225 610 4212

Thanks,
Do you know anything about the stuff they carry at Lowes now.
Its 23/32" OSB T/G. You think it will suffer from edge swelling?
My floor joists are 2' centers but each joist is 4" wide which makes for a little more coverage. The walls and floor will be 26 ga metal sheets.

i would not use the osb if your underside of the dwelling is going to be exposed. if you do i would seal the sheets with a heavy duty exterior primer pre-installation. once yer sub floor rots yer kinda screwed. you could put a 1/2'' treated ply and then go over that with a t&g osb . it will take more time but make sure you glue your sub floor down and nail it with ring shank galv. nails and deck screw the perimeter hit the "butt joints with screws 4-6" o.c. squeaky floors suck

Pox,
Thanks for the info.
I did alittle research myself and GP says Plywood is 10% stronger than OSB and has a better water resistance, and they sell both.

3/4" Plywood or OSB can be used but for strength it is better to double layer it. Layer in different directions. As pox side exposed side needs to be sealed.