I'm getting ready to install about 700 sf of 3/4 oak prefinished. The bulk of the floor will be installed over either 3/4 osb or 3/4 plywood all which meet subfloor specs.

One 12' X 12' area is currently 3/4 X 2,1/4 oak over 3/4 diagonal pine subfloor.

If installed a a right angle to the existing floor and avoiding the cracks when nailing is this a suitable subfloor?

I am new to the site and have learned quite a bit just reading through the forums but didn't find this in my search.

Thanks

I'm not sure what the professional opinion is going to be on this, but here in upstate NY we have a very old housing stock....with most of the houses coming up after WWI or WWII...and it was very common for old houses to be built with absolutely no subfloor and instead just oak 3/4th flooring that spanned the joists (I have this in my house on the 2nd floor). I have talked to a few installers and each said this is common and then do install over it-just run perpendicular or at an angle and try not to hit the gaps...ive seen a bunch of houses done this way and it seems solid.

You may install over an existing hardwood floor that is well attached. Re-nail any loose areas and run the new flooring at right angles or at a 45 degree angle. Do not run parallel to old flooring. Read pg. # 7

http://www.nofma.org/Portals/0/Publicat ... Floors.pdf