: I'm remodeling my master bath and I had a plumber rough plumb the drain. After he was finished, I learned that I really should add another 1/2" of plywood on top of the existing 5/8" tongue and groove for added stability, before I put in my custom shower pan. There is play in the existing drain and piping, in that when I pull up on the drain I can create space for 1/2" to 3/4" additional plywood height. My concern is that by pulling the drain and piping higher, the attendant strain/pressure caused by the increased height may cause a loosening of the connection between the drain and the pipe. Is this a legitimate concern?
I would suggest having the plumber return to extend the pipe to the desired height. You're taking a big chance by lifting the pipe higher, it could and probably will cause a leak because of the additional stress being placed on the joints under the floor.