I have a rough in for what I think is a bathtub drain in my basement. The drain is 15.5 inches from the studs. Some of the other questions I've seen on here suggest that there should be a tub box for the rough in located under a thin layer of concrete. I tried breaking out the concrete with a 4 pound sledge and it does not appear that it is a thin layer of concrete. I think I am going to have to cut the concrete to allow for the drain on the tub. Should I just cut the concrete in the dimensions to allow for the drain and then dry fit everything? Do I pour concrete once everything is fit? What are some of the other considerations I should take into account?

You must have a tu7b dap-out to hold the trap an d complete the connection. Make your cut 6" from the 2"stub up on all 4 sides. That will give you a one foot square hole. Good luck, Tom

Thanks speedball1. Im assuming that I should finish the dap-out with concrete once everything is properly fit. Is this correct?