We have just completed an expansion of our great room from 14 x 16 to 23 x 24 and are going to install 4" wide by 3/4 thick plank flooring. I know from the previous thread and other literature that you should be installing the floor perpendicular to the joists. The problem is the joists of the expansion run opposite to the joists of the original room. The subfloor is 3/4 t&g. If we add 1/2 on top of this for rigidity it will put us out of whack with our current adjacent tiled rooms. Is blocking between the joists a remedy (if so, what is the minimum size and spacing that we can get away with). If this is not really an issue let me know that also.
You're in luck! It's pretty common today to install 3/4" flooring directly over 3/4" plywood. In fact, NOFMA (Nat. Oak Flooring Manufac. Assoc) approves it. See www.norfma.org . The only things you have to be careful of are:
1. Joist spacing needs to be on 16" centers.
2. Tighten up your nailing pattern on your flooring. 6" spacing max.
Hope this helps!
Wood Floor Guy
Last edited by AtlanticWBConst.; 08-20-2009 at 02:53 PM.
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