We are doing a hardwood installation project. So far this has involved removing carpet and particle board to get down to the 1/2" plywood subfloor. The subfloor seems to be in a good shape, so I'm happy about that. Now I've been told I need to add a layer of OSB and then the hardwood. So here are my questions:
Do I really need to add this OSB? Is it a matter of strength or just a matter of floor-height? Seems like the particle board wasn't adding much, strength-wise, and maybe adding 3/4" hardwood over 1/2" subfloor wound suffice. Since I'm doing the whole house, the floor height is not really an issue.
But assuming I do need to add the OSB, what's the best way to fasten it to the existing subfloor? I imagine I should use screws instead of nails, but do I also need to use glue?