I am looking at my mother-in-law's basement which was stubbed for a bath 20 years ago. She is now wanting to finish it out and install a bath. I am looking in the dap out (I think that is the right term) which is about 12"x14" box in the basement floor. It had a thin layer of concrete covering the bottom, which I broke out. Then I dug several inches down and still have not found a trap for the tub drain.

How likely is it that the rest of the bath was stubbed and the dap out made and poured around, but no trap installed?

How far below floor grade should the trap be located, and should it simply be in the center of the box or off to the side?

Thanks for any light you can shed on this for me. Helping ma-in-law is always a good thing.;) Thanks.

Start digging back around the dap-out and see if you can locate the drain pipe. It's unusual to rough for a tub and not include the trap but not unheard of. Let me know. Tom