My daughter and son-in-law have a house built in 1949. It has lath and plaster walls. They want to install a shower in their tub and tile the stall. One of the three walls is an exterior wall. Do we strip the:confused: walls back to studs and then use backerboard and seal it or should we install green board behind the cement board? How do you demo just the stall without damaging the rest of the plaster? Or should we just demo the entire room and start fresh?