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sknowman · Dec 2, 2013, 12:19 PM

I'm replacing most of the floor in my single-wide on a budget of nearly $0. A friend of mine has tons of 1/2" OSB that I can take at will. So this leads to the question.

A flooring friend of mine said the 1/2" OSB was fine, but to put 2x6 cross-joists under it every couple feet, because it's not as strong as plywood. Another friend told me to double the layers of OSB to effectively make it 1" thick. Even with the cross-joists the single layer moved a little more than I'd like and I've been doing double layers of OSB.

The question is: With 2 layers of 1/2" OSB, do I still need to put in the cross-joists? It would be much easier (and cost-effective) to not have to keep buying 2x6s, but would it be enough to safely hold everything up

ma0641 · Dec 2, 2013, 03:52 PM

1/2" is not rated for floors, only walls and roofs. Glued together and nailed down should work, reverse ply.

sknowman · Dec 2, 2013, 04:13 PM

Originally Posted by ma0641

1/2" is not rated for floors, only walls and roofs. Glued together and nailed down should work, reverse ply.

I've been screwing them together to the joists with the seams overlapping. So doing it this way, I wouldn't need the extra 2x6 cross-joists? It seems like it would be strong enough with 1" of OSB I just want to be sure so I'm not redoing it in a couple months

ma0641 · Dec 2, 2013, 04:23 PM

I would have glued them too, reduces possible squeaks. Screwing them is a good idea, better than nailing. Good luck.

sknowman · Dec 2, 2013, 04:27 PM

Originally Posted by ma0641

I would have glued them too, reduces possible squeaks. Screwing them is a good idea, better than nailing. Good luck.

I'll get some glue then. But will I still need the cross joists? Or will it be strong enough just being screwed to the joists

ma0641 · Dec 2, 2013, 05:39 PM

I don't think so.

sknowman · Dec 2, 2013, 06:14 PM

Originally Posted by ma0641

I don't think so.

Cool, thanks. This cuts down a ton of time and expense that I can't afford

dannac · Dec 4, 2013, 06:06 AM

I say you need the support from the 2 x 6... and that's usually 16" O.C. for a floor.

At least put them in the high traffic area's.

sknowman · Dec 4, 2013, 03:46 PM

Originally Posted by dannac

I say you need the support from the 2 x 6... and that's usually 16" O.C. for a floor.

At least put them in the high traffic area's.

I tried out 2 layers of OSB just on the joists only (where the couch will go, no foot traffic) and it feels very sturdy. I was thinking about using the cross-joists on the walkways though, since it will end up flexing a lot over time. So I guess I need to go get more 2x6s then

And yes, they are 16" off center