[markley]

Hi all..I have done an extensive search and just can't find an answer to what I am after. Hopefully I will be able to explain this clearly. Anyway, I am in the planning phase of finishing off my basement..just trying to get an overall layout. A question that I have is how to vent the half bath. As far as I can tell there is a "rough in" for a half bath. There is a capped 4 inch pvc pipe (toilet drain?) extending about 10 inches above the concrete floor, and a capped 2 inch pvc pipe (sink drain?) as well. Also, the main waste drain (3 inch?) from the above floors comes down about 4 ft from stubs and goes into the concrete floor. All that I can guess is that the roughed in drains connect with the main waste pipe somewhere beneath the concrete and then out to the septic. The concern that I have is that there is not a vent pipe that goes from the basement up to the roof?? Is this somehow vented using the main waste pipe (which is vented at a few points on the floors above)? There is another half bath just above the proposed basement bathroom which is vented (2 inch pipe) to the roof. I will post a few pics shortly.
Thanks in advance for any comment/suggestions!

 

[markley]

Attached are a few pics.

 

[VIPlumber]

It's common (I do it often), and hopefully common sense, that if they plumbed in for a 1/2 bath that they would have vented it as well. My guess would be that they would have tied in before your 2" sink drain to the nearest wood frame wall (maybe up through the cinderblock? possibly but doubtful). Then they would have hooked it up to a vent on a higher floor. That's why you don't see a roof penetration for this one.

My suggestion would be to have someone come out with a drain camera to confirm. Then you'll have your answer.

 

[markley]

Thanks for the reply! The kitchen sink is almost above the basement bathroom, and has its own 2 inch vent that goes to the roof. I guess its possible that the basement bath is tied into this one (as you said through the cinder block), but I really do doubt it. I am also redoing the 1/2 bath that is above this one as well. Would I be able to run a vent (essentially extending the 2 inch above where the sink would tie in) up through the ceiling and tie into the vent for the bathroom above? If this is possible, would that also be venting the toilet (guessing that the 2 inch sink drain ties into the 3 inch toilet drain under the concrete, then out to the main waste line to the septic)?

 

[TheEplumber]

If you run the sink vent up and connect to the upper bathroom you should be venting the toilet at the same time.
Have you pulled the insulation down in the ceiling joist to look for a capped pipe?

 

[markley]

No I have not pulled the insulation yet to look for a capped pipe. Hopefully it is there and I won't have to tie into the vent above.
Thanks