I am in the middle of a basement finishing project. My wife would like a kitchen type sink added, the location shares a common wall with the bathroom. It so happens to be directly behind the tub, drain end. The only access I currently have to a drain would be to the overflow of the tub (none breaking of concrete floor type access). I have full access behind the tub but the balance of the bathroom is 100% finished. My sewer is below slab so no pumping is required.

I would add a studor vent for the sink venting and a y connector in to the overflow section of pipe, this would be above the tub primary drain. Current overflow and tub drain are 1 1/2, going into a 2" dain.

I maybe able to get access below the line to the 2" but it is extremely tight and I would have to redue the tub drain assembly.

Is it acceptable (code) to connect to the overflow above the primary drain?
If not, is it acceptable to rework and connect below the primary tub drain?

Thanks

Aloha

You CANNOT connect into the tub waste above the floor...

You can connect below the tub drain PTRAP, but would need connect PAST the tub vent. This would require you to break up quite a bit of the floor... ;)

How about the bathroom sink drain... is that close by? If the bathroom sink drain is close by you could cut into that drain, but it would require that you pipe it all up so the bathroom sink AND the kitchen sink end up getting vented individually.

Let me know if the bathroom sink drain pipe is accessible for this project and if so I'll draw up the piping/vent work required, OK?

Mark

I am new to this site and having trouble uploading a sketch. When clicking on the button it asks for a URL which I am not used to.

I don't have clean access to the sink drain or vent which are both on the oppostite side of the recently finished bathroom. The only easily accessible drain is to the tub, below the primary but above the Ptrap. The bathroom tub drain, toilet and vent stack were all roughed in during the original construction years ago. The access to the tub drain is through an opening left in the concrete which I can still get to, I just can't reach the ptrap with out knocking out concrete.

Wife may need to go without the sink unless there are other options.

Your help is much apprecitated. Thanks

To upload, click... :

1. Go Advance
2. Manage Attachments
3. Browse ( select photo from your computer )
4. Upload
5. and post it with your message

Try again...

Milo

I guess I didn't see the Manage Attachment button. See the jpg attached, very rough floor plan to give perspective.

Yeah, just like I suspected... can't tie into the tub drain above the PTRAP, but remember, you can chop up the floor and connect into the tub drain (after the vent connection).

The new sink vent could connect to the vent stack (as long as no fixtures above) up in the ceiling.

Otherwise, you may want to consider installing a LAUNDRY PUMP. This requires that you can run the waste from the pump over to a large drain line. Venting would also still apply, OK?

Back to you...

Mark

Enclosed drawing shows what your connection to tub drain should look like. Have to admit, I have seen people connecting directly to the tub vent avoiding to cut into tub drain below San T. It appeared to work fine but it is against the Code. Milo

Massplumber2008: Issue is access to the vent and p-trap for tub. Both would require tearing up the newly finished bathroom. The sink add we want to do is a wife after thought.

Milo: I updated your sketch to what I could do. It was my understanding that as long as the tub drain was vented I could add the sink drain to it an use the studder vent for venting. My last connection point before concrete removal is as shown on the sketch.

If I need to bust up the concrete, my wife won't get the sink. :)

Sorry. File didn't save right, hence my Junior status. See attached.

Hi again...

Look, according to plumbing code you cannot DOUBLE TRAP any fixture which is what you are suggesting you want to do here. Adding a studor vent doesn't make it any more right... just makes it even more wrong!

Never mind then when you drain the sink some of it will probably end up flowing back into the tub... any food particles and it gets yucky fast!

Note also that Milo said he has seen people connect into the tub VENT... not above the tub drain trap... just not how it ever gets done, OK?

If you want to rig something up then you are certainly so entitled, but I can't help you with that!

Good luck with the job/wife... :)

Well that answers my question fully. Wasn't realizing the double trap issue. Not looking to compramize the final product. No sink is the answer. Thanks for everyone's input.