[geoman1343]

I would like to add a bathtub/shower to my 1/2 bath in the basement. What can I do for a drain for the tub.

[21boat]

Short of saying connect the pipes you really need to give some distances here so everybody can figure out the venting and supplies.

Is there a P trap drain on the sink or a S trap in design? The 'trap looks like a ( P ) or an ( S ) so you know.

Where is the main sewage stack relative to that room?

Get back with more info so you get a better direction here

[speedball1]

I would like to add a bathtub/shower to my 1/2 bath in the basement. What can I do for a drain for the tub.

If your lavatory's vented you would have to take up the cement and locate the lavatory drain line. You would then cut in a wye on a combination wye and eighth bend and pipe to a 2" "P" trap and raiser at the location of the tub dap-out.. (a 12 or 14 " square hole cut in the cement). You'll need at least 60 inches of room to install the new tub. Let me know if you need more information. Regards, Tom