I am getting ready to install solid ¾” wood on a floating plywood subfloor over concrete. My plan was to cut the sheets of ¾” CDX plywood in 2x8’ pieces and float them in a brick pattern over a moister barrier at a 45 degree angle. 4x8’ sheets of CDX plywood are going for $20/piece. The price has gone up since I first priced out my project a few months ago at $12/piece. I am able to get 7/16” 4x8’ OSB sheets at $6/piece. Would it be ok to screw two sheets of the OSB board together and float them over the concrete with a moister barrier?


Thanks for your help!
Luke

A floating subfloor is typically made up of (2) sheets of 1/2" PLYWOOD screwed together. I do not know how well OSB would work. It seems to me it would work, but I cannot say if it would be as good.

Read this article by NOFMA. It answers all your questions regarding plywood, OSB and going over concrete.

http://www.nofma.org/Portals/0/Publicat ... 010_04.pdf

You can use single layer, but make sure it is ¾" The reason you cut the 4x8 panels into planks and then staggering them, running them the opposite direction your going to lay the wood, is so long joints in the subfloor are not running with the flooring. Just like if your going over existing wood flooring, you go across it in the opposite direction.

You can also use full single panels, but run them on a 45º in the room, unless your planning a 45º installation for the finished wood.

Use ¾" and 1½ fasteners so you don't blow through the OSB and puncture your moisture barrier.