Hi. I was looking for additional info regarding framing a basement with a subfloor. I have installed 1in rigid foam board in the entire basement including the walls and floor, taped every seam and spray foamed the perimeter for expansion to ensure a vapor/thermal barrier and hopefully a warm and dry basement. I then installed 3/4 in t&g plywood on top and secured it with tapcon screws predrilling holes using a hammer drill. I did it this way so that all the framing and drywall would be above the vapor barrier and would stay dry.
I plan to build the walls on the ground and stand them up. My question is what is the best way to secure the base framed wall plate to the subfloor. Screws or nails work best? Also should it go into the subfloor only, or should it also penetrate the concrete. A friend of mine framed his basement directly on the concrete without any vapor/moisture barrier on the ground and used the 22shot nailer to secure his framed walls to the ground. Should I use that even though the subfloor has already been secured to the concrete with tapcon concrete screws? Or will regular screws or nails work best and how long should the screws/nails be or how far should they penetrate the concrete?