I have a 4 inch thick concrete floor in a third floor condominium that was poured over plywood for fire protection. There is some movement in the building and the concrete has cracked. I want to install a hardwood floor and need to put plywood down as a subfloor. My question is what is the best adhesive to use, and if I use a good adhesive such as liquid nail, do I still need to disturb the concrete floor with nails or screws? If so, should I use nails or do I need screws? How close together should these be, i.e. every how many inches? I am concerned that putting too many nails or screws could disturb the concrete floor and create more cracks. Any information would be appreciated.

Building subfloor over concrete