OSB on subfloor (maybe not what you think!)

[jrhode]

Let me start out saying by saying that I've read all the posts on OSB vs. Plywood, and I don't really want to start WW III. Or is it WW IV? :D

Here's my situation. My subfloor in my new home is 3/4' plywood, nailed and glued. (I know, screwed would have been better...) I will be installing radiant floor on top of that subfloor in a "sandwich" type install. To do that, I will cut 3/4" plywood or osb into strips 8" wide, leave a gap between them, into which will go aluminum plates with an omega shaped groove. The pex tubing goes into the groove. On top of that will go my flooring, which will be 80-100 year old barn siding, 8" to 12" wide, planed to 5/8" thick.

Here's my question: Does the osb have the same fastener holding ability as the plywood? (to nail the flooring into)

Also, what grade of either should I get? I've already got my subfloor, this stuff would basically just be acting as filler/leveler between the pex tubing.

Thanks for any help.

[Rich]

I would say the OSB has similar holding capacity as plywood with nails - and not as great with screws. Plywood grade wouldn't really matter much - but would imagine B-B would work - CDX might get you by but it has so many voids that I wouldn't use it.

[Tom R]

Generally speaking, - - your fastener length should be a minimum of 3 times the thickness of the material you're fastening, - - which puts you at 2" fasteners, - - which goes through your 'spacers', - - and into your existing sub-floor about another 5/8".

Actually, I probably go with 2 1/4" ring-shank nails and glue, - - unless you're trying to achieve a 'cut-nail' look.

[jrhode]

Thanks for the replies.

Tom, talking about nailing & fasteners, are you talking about nailing through the t&g or face nailing?

[Tom R]

Actually, both, - - and either way would require a minimum 2" length nail. I would use 2" through the tongues and 2 1/4" for the face nails.

[Cole]

Awhh come on guys, I want to get it going again.

Tom, I am really disappointed in you. :lol:

[Tom R]

Cole, - - I swear I was just getting ready to post before you said that, - - I was about to say you guys should be puttin' me in for some kinda' award or something, - - do you know how hard it is to 'hold back' sometimes, - - OSB?, - - even as a 'spacer'?, - - man, - - the things I'm willin' to put up with sometimes. When I say 'award' I mean like a little black fancy-assed sports car or something, - - you know the kind I mean!! :lol:

[Cole]

:lol: :lol: :lol:

[JCA]

Ummm... OSB is better than plywood, atleast for floors anyway I think. I say this with no real knowledge of lumber though. I say this because....if you lay a 3/4" sheet of OSB on a flat surface, beside a sheet of 3/4" plywood and leave them for say a week, the plywood will roll up, and the OSB will stay flat. Therefore on a floor the plywood will pull away and squeak worse than OSB. And.. it's just as strong if not stronger I think, plus it dosen't fall apart anymore. Also, when plywood first came out everyone said it was crap, then they loved plywood when OSB came out because it was something new to dislike.