Supervising the experts - backer board install
We paid plumbers to repipe the house in copper and are redoing the tub surround at the same time so the walls are down to the pipes and studs. I decided to pay the 'experts' to put up the backerboard for me before we tile and now wonder how much work I have ahead of me. (The experts being the plumber's wall guy.)
The wall board guy came yesterday and had no backerboard. He returned today with backerboard but started installing it without any vapor barrier. When I told him to stop he said, no, the vapor barrier goes over the cement board. uh. no. I called his boss and he was told to stop work. So tomorrow, it seems, he will return to put up a vapor barrier.
Since I AM now the expert and he's just the muscle, please help me confirm *I* understand the right way he should do the job.
I've got a 3 walls needing backerboard, from tub ledge to ceiling. Fixtures are on one short wall (shower over tub), no cutouts for soap/shelves. My understanding is that he should wrap tarpaper horizontally around the 3 walls starting from the bottom, overlapping the tub, then overlapping each layer by at least three inches working up to ceiling. (tarpaper should NOT be hung vertically, right?) 3mm+ plastic sheeting could also be used?
He left the "hardibacker 500" here so I see that it is .42" thick. One wall from stud surface to tub lip is .25", the other two walls have a .5" gap (fixture and long walls). Those .5" gaps need to be shimmed, yes? or is there some other work around to get the job done and this joker outta my home?! Or should I just run out to Lowes and get some .25" thick strips to quickly shim it tonight?? Then the backer board will sit on the lip of the tub all the way around? or should the backerboard overlap and all 3 walls need to be shimmed?