Plumbing basement 3/4 bath

[WiLucas]

I’m working on a basement bath installation and am a little stumped on how to run the drain lines and if I can vent the whole bath to an AAV under the sink.

I’ve 2 options mocked up, but am open to more - I’ve not yet cut the concrete. Hoping it would be okay to cross over the WC drain to avoid cutting through extra blocking for the shower walls.

 

[James Henry]

You can't cross over the drains like that if your planning on wet venting the bathroom through the lavatory.

 

[Sponsor]

 

[James Henry]

The consensus on this forum is to install it like this.

 

[WiLucas]

The consensus on this forum is to install it like this.

That makes sense (a lot more concrete to remove) and if it allows the AAV to under the sink to vent it all I can’t argue. Standard elbows for the bends under the sink or should I sweep them?

 

[James Henry]

Make sure you use 2" for the lavatory drain.

 

[James Henry]

Use sweeps and combination wye and 1/8th bends.

 

[Reach4]

You can't cross over the drains like that if your planning on wet venting the bathroom through the lavatory.

Do you think everybody would agree that this would be prohibited? It would work great.

 

[James Henry]

Do you think everybody would agree that this would be prohibited? It would work great.

Are we back to the" No vertical offsets" argument again?

 

[Reach4]

Are we back to the" No vertical offsets" argument again?

Relates to that discussion, yes.

 

[James Henry]

Relates to that discussion, yes.

heavens to Betsy.

 

[James Henry]

Lol.

 

[WiLucas]

Are we back to the" No vertical offsets" argument again?

It looks likes the space behind the bathroom is to remain unfinished indefinitely. So, would this one work if I used a sanitary T above the other T (instead of the elbow) and placed the AAV on top. Then ran an inch and half line from that T to the sink (a horizontal long sweep for the sink)?

 

[wwhitney]

Do you think everybody would agree that this would be prohibited? It would work great.

Wisconsin seems to have its own plumbing code, which by my reading clearly prohibits the arrangement shown:

https://docs.legis.wisconsin.gov/co...dings_and_environment/380_387/382/iii/31/13/b

That section on horizontal wet venting speaks of the lavatory and the shower/bathtub have a "common horizontal drain" and says the toilet(s) may connect to the "common horizontal drain".

That raises the question of whether that common horizontal drain could be pitched, say, 22.5 degrees, so that the shower trap arm could cross over the toilet fixture drain and both connect to the common horizontal drain.

Cheers, Wayne

 

[WiLucas]

Just finished the inspection. If you’re curious I went with the wye on its back and the AAV above it. The inspector was surprised I didn’t run 2in to the sink and put the AAV under it. Apparently in Wisconsin an offset wet vent is okay.