Main stack with a 30deg diagonal jog

[akita]

I'm not sure about the connection to the main stack that currently has a short run of 30deg from level. This stack serves an upstairs toilet and sink, and I'm unsure if this short jog needs to be ripped out and made 45deg from level or steeper to work as the vent for the nearby WC.

What do you all think?

 

[hj]

It makes no difference what its slope is, it will NEVER be a vent for the toilet unless you do a major revision of the piping.

 

[Sponsor]

 

[akita]

The pipe is all dry fit at this point.

I'm all ears. Any advice?

 

[Jadnashua]

General rules:
- once a pipe becomes a drain, it cannot be used as a vent beneath it
- you can only 'wet vent' things on the same floor of the same bathroom group

You are trying to create a vent using a drain from above. The generally accepted way to do that is to run a new line vertically above where that main stack changes from a drain to a vent, and connect the vent from below there. The rules generally require that connection to be at least 6" higher than the highest drain on that line, or at least 42" above the floor level of those drains (higher is okay).

If your locale allows the use of an AAV, you could use that to vent the lower fixtures, but it's best to have an atmospheric vent, as those don't degrade and need to be replaced eventually.

 

[hj]

Your WC line is dropping BEFORE it reaches the pipe you want to use as a vent. That CANNOT be done.

 

[akita]

Is this an ok option to vent the problem WC?

 

[Jadnashua]

I don't think the vent can go horizontal until it gets higher. Any angle 45-degrees or higher is considered vertical, and the vent line must come off of the drain line within certain distances (depends on the pipe diameter) before it turns down (the elbow under the toilet doesn't count as down). YOu could take the vent off after that pipe you're trying to get under with it, then turn it down. You can go horizontal quite a ways with a 3 or 4" pipe before the vent.

 

[akita]

This is going to be tough.

I think I have enough room to get a new 1.5" dry vent to run at >45deg through the space between the tub apron and basin into the nearby wall. (Immediately above that sanitary tee shown in the pic is the tub running perpendicular to the joists).

Aside from the ugly tightness, would that satisfy the venting requirement for the problem WC?

 

[Jadnashua]

I think so, but I'm not a plumber. Hopefully one of them will confirm or correct.

 

[Highlander]

The tub doesn’t appear to be vented either...

 

[akita]

Yup, that's true. It's getting a 1.5" one up to the attic. Will take a new picture after I rework it.

 

[akita]

Routing iteration number 2 shown in attachments. Is this ok? Any advice?

 

[akita]

I cleaned up some of the drainage angles and added clean-outs. I'm hoping to glue this weekend.

(Having no toilet, shower, or kitchen sink is kind of a drag!)

Any last critiques?

 

[Jadnashua]

It doesn't look like the tub trap is vented...the vent must come off of the trap arm...i.e., after the trap but before it goes down to the main drain line.

 

[akita]

Would it be proper if the tub p trap went right into the vertical 2inch vent? If yes, would that be a tie in with a sanitary tee?