I have started my first hardwood floor installation. After removing the carpet, I discovered a layer of particle board, which is on top of the plywood subfloor attached to the joists. I plan on nailing in a hardwood floor.

My question is: Can I install OSB board as the new underlayment directly on top of the particle board, or should I demo the entire particle board layer first?

I don't want cut unnecessary corners, but I'd rather not take the time/effort to demo the particle board, plus I would need to double the OSB layer to be level with the adjacent room.

Thoughts?

Thanks!

NOTE: I corrected myself - I'm talking about underlayment, not subfloor.

As long as you have the height to add another layer it won't be a problem. You want to make sure the fasteners for the OSb are long enough to go through everything and hopefully into the joists if possible.

Not understanding why you would have to double up on the OSB? Why not tear out the PB and do it right with some nice plywood? OSB isin't that great. If for some reason that PB gets wet your gonna have a huge mess on your hands.

I love a PB sandwich but in this case.........

The second layer would be raise the floor up to be level with the existing adjacent room. If I can keep the PB and add OSB (or plywood) on top then I can even it up in one step.

Do you recommend plywood instead OSB?

I prefere PH (peanut butter and honey). Add a sliced banana now and then.

Then whats on top in the ajacent room?

http://www.youtube.com/watch?v=s8MDNFaGfT4

The adjacent room is ceramic tile, which is on top of plywood (on top of particle board on top of plywood subfloor).

At SOME point I will be demoing that tile floor and want the plywood underlayment to be level with the underlayment in the new floor I am starting now. That will be part of a project next year.

If your already planning on demoing the tile, then I would rip up the pb and plan on doing the same when you do the tile a couple of inches of headroom makes a big difference. And yes plywood is preferred over osb

You mean there's no cement board under that tile? Just set right to the plywood?

That's right - no cement board. Tile, plywood, particle board, plywood.

I thank I have been convinced to take it all down the plywood subfloor.

Remove the particle board. OSB or plywood is a suitable sub-floor for nailing down hardwood flooring, but not particle board.