: I am remodeling my mother's bathroom and i am making a walk in shower area for her and am ready to put the copper in. I am going to put support block behind every shower head/faucet/diverter valve and want to know does it matter how far back the threaded connection is in the wall for all these connections? I was thinking it should either be flush with the backside of the cement backer board or should it be flush with surface of the backerboard? Thanks.