I have this sunken tub I plan on removing, filling with some gravel and sand and then tie in some rebar to existing slab and fill the top with cement. My plan is to have a 36”x48” shower on the left and build a Japanese soaker tub on the right which will be 27”x48”x 27” deep. Both will be enclosed behind glass. My question is how can I run the plumbing for the shower and tub drains without encasing them in cement? I live in area with a lot of movement and I’m afraid the pipes may move and crack.