We are renovating an apartment and trying to install a 3/4'' solid hardwood floor in the living room. We pulled out the existing carpet along with a 5/8''particle board underlayment. Under that we found 15/32'' plywood subfloor (not tongue-and-groove) over joists and we are trying to determine the best way to proceed from here.
Based on bits and pieces I've collected from online forums, it's my understanding that we have to install additional plywood underlayment as the current subfloor is too thin. We will also try to put extra screws in the subfloor as it is currently creaking.
My questions are:
- What thickness plywood should we use for the underlayment - 5/8'', 3/4'' ?
- Should the plywood be tongue-and-groove ?
- How do we lay the underlayment over the subfloor - parallel, perpendicular?
- How to fasten it - screws/nails AND glue?
One more thing to note is that the hardwood floor will transition to tiles at the end of this room as it enters the hallway so that might have some significance for the choice of the underlayment thickness.