I only have one 4" drain roughed in in my basement which i am guessing is for the toilet. I want to install a stand up shower or tub, whichever is easier. I do not not want to cut up the concrete as i will be doing this myself. Can I just build a small platform to set the tub or shower pan on and run the plumbing underneath and "T" into the main 4" PVC pipe that is about 3' away? I figured I could put the shower/tub drain pipe at a slight angle for the water to flow out. Please let me know if this would be feasible or if anyone has any other ideas. Thanks a lot!