Do I have to have a vent stack for a basement sink?
I bought a house that had a roughed in bathroom in the basement with what I thought was a bad layout...a toilet already installed then drains on the floor (capped) and a drain/vent a few feed to the left of the toilet. The top drain on the right is a 2" stub that appears to be for a shower/tub, the bottom drain is a clean out for this set and it appears the water from the bathroom above it goes through the same clean out.
I have decided to just do a half because every full bathroom layout in this area doesn't look good. Problem is if I go with the drain/vent then the room will be pretty huge for a half bath. The only option I can see is to use the top right drain and push out the wall slightly for it so a base cabinet will cover the drain. Will this work without proper venting? I'm assuming the floor drain is already trapped (which I will verify) but if it is and I use this drain do trap the sink also? I guess I could have a vent go through the back wall, up and over and meet the existing vent if I had to but I wasn't sure if I needed to for this.