Hello Im updating a 1973 home. My local city uses 2012 residential building codes. Im building some new interior walls. Im using non PT 2x4's for bottom plates. I walked thru a new home construction this afternoon, and I noticed all the walls, interior and exterior have PT bottom plates. Is this code per the code book, or are these builders just going over and beyond the code. Also all the wall bottom plates in this 1973 home are NON PT. Just trying to understand the codes. Thanks for any knowledge on this subject.

Long story short I've gotten tons of different answers and am wondering if there's a flooring pro that can give me the right answer. Long story short toilet leaked, ripped up tile and 1/2'' plywood. I have 3/4'' subfloor planks. I cut new 1/2'' plywood and some said nail it, some said screw it. And to reduce future squeeking liquid nails subfloor. So i glued then screwed, and am now wondering which is right ring shank/screw shank nails, or the 1-1/4'' screws I used? Now I'm reading only the nails or staples should have been used. If not is it too late to use new fastners close to the ones I already used then remove all the screws and fill the holes, or am I fine? I'm putting schluter ditra and tile over it. Thanks.