Which is stronger

[asmith555]

For a slate tile floor over floor joists.

Which is a stronger floor:
1. 2X10's on 12" centers
2. doubled up 2X10's on 16" centers
3. 2X12's on 16" centers

[montytx]

They are all fine. I do old houses with 2x6 16oc and we simply put down plywood over the subfloor then hardi. No problems.

[handyman923]

Of those three options, 2-2x10 @ 16" oc will produce the most stiff floor. 2x12 @ 16" oc is about 10% less stiff. Hope that helps.

Dave