What is involved in taking a toilet out of a commercial building and replacing it with a toilet? There are currently four back to back toilets (2x2) and I want to remove one of the sink and the associated toilet and put in a shower. I'm going to use an on-demand water heater and am only concerned about not having the toilets backup into the shower.

B

Any time there's a clog or a partial blockage the discharge will back up out of the lowest point, as a rule a floor drain or a shower. That's a given! You will have to break up the floor, cap off the toilet and use the two inch sink drain and vent for your new shower. Cut a wye or a combination wye and eighth bend to the sink drain and run a trap and raiser to the desired location. You may then install the shower base and enclosure of your choice or build your own custom built tile shower. You may cap off the sanitary tee that picked up the sink and turn it sideways in the wall to hide it. Good luck, Tom