I just tore out a ton of particle board subfloor that was previously used for carpeting. The entire house has decking (2x6 planks) running on a 45 degree angle over joists with 3/8" plywood over the decking, with the exception of a few rooms where I tore out the particle board so just decking there. I'm trying to figure out how to attach more 3/8" plywood to the decking where I tore out the particle board. We are installing t n g hardwood eventually.
Should I try to drive decking screws through plywood into the joists, or can I just glue and screw into the decking?
Does the plywood need to be oriented perpendicular to the joists, even with the decking under already? Or should I orient the plywood so that it will run perpendicular to the hardwood we will install (so, parallel to the joists..)
Should I take the time to level the plywood subfloor over the decking, or should I just wait until installing the actual hardwood tongue and groove to worry about leveling (or "flattening, as I suppose it will be)?