Hi All, With the upcoming kitchen remodel I need to put down new subflooring. The previous owner butchered the sub floor so I'm going to pull up the top layer of plywood and drop in a new layer of 3/4 BC ply. My question is, is BC correct for a subfloor and should the plywood but up right against the walls or should there be some space for expansion? Just so you have all the details here's what I have. The kitchen had an addition put on some time in the 80's. That spurred the kitchen I currently have. The addition added a 8'x15' bump out that wasn't there before. This caused two types of subfloor, the original in the old section which is the narrow oak hardwood on top of doug fir T&G and in the new section a layer of what looks like a BC plywood. Then the previous owner laid out an additional layer of plywood covering both the old and new section. This was the "underlayment" for the ceramic tile. No concrete board, no membrane, just plywood then thinset. Sometimes they used wire lath in certain parts of the floor but not for the entire floor. Needless to say this didn't work too well. So now that we are going to lay down brand new ceramic tile I need a new subfloor before putting down my cement board. I'm going to rip up the top layer of plywood and drop in a new fresh layer that isn't covered in globs of thinset.