Back to back bathroom drains and vent setup

[jeffesonm]

Renovating back to back bathrooms. Was hoping to keep the 1950s cast iron as the outside looked good but got a clean out off and inside looks not great.

Does this look okay? Line to kitchen has its own 2” vent.

 

[Breplum]

Would not meet UPC code because the WCs and shower would each need their own vent.
Any run in excess of 5' needs a cleanout if on the first floor.

 

[Sponsor]

 

[jeffesonm]

Thanks. I am in NC so on IPC.

I was reading this thread and found this link: https://wabo.memberclicks.net/assets/pdfs/Plumbing_Venting_Brochure_2018.pdf

Based off the diagram (attached) it seems like I can have these all drain consecutively into one 3" line which I turn up and vent out the roof? With the lavs coming in at the stack?

 

[wwhitney]

The layout works for the IPC. The right hand lav can wet vent the tub and two WCs; the left hand lav just wet vents the shower. So it is important that the kitchen tie in downstream of any wet venting.

For the tub and shower drains, they are limited to one pipe diameter of fall before joining their respective lav drains to be wet vented. This is to prevent siphoning of the traps.

Cheers, Wayne

 

[jeffesonm]

Thanks Wayne.

Here is what I hope to be the final layout.

One of the two lavs on the left is actually a bar sink upstairs on the wall adjoining one of the bathrooms. From what I read it the wet venting has to include only bathroom group fixtures so moved shower drain over to main line instead of wc arm.

 

[wwhitney]

Here is what I hope to be the final layout.

That looks fine. Note the tub trap arm extends from the tub trap outlet to that vertical wye where it joins the lav drain as it turns horizontal. It's a little odd that your tub trap arm increases in size, but fine, particularly as long as the drain center line falls no more than one pipe diameter based on the trap size.

One of the two lavs on the left is actually a bar sink upstairs on the wall adjoining one of the bathrooms. From what I read it the wet venting has to include only bathroom group fixtures so moved shower drain over to main line instead of wc arm.

That is correct that wet venting has to include only bathroom group fixtures. So your options are to move the shower as you did, or to put the bar sink on a separate vertical drain (with separate vertical vent, although the vents can combine within the wall at any elevation at least 6" above both sink flood rims). Then the bar sink drain could join the kitchen sink drain, but that bar/kitchen drain would need to be kept separate from the lav drain until after the shower drain joins the lav.

Either way is fine, just wanted to throw out another option.

Cheers, Wayne

 

[jeffesonm]

Thanks, really appreciate the info… time to glue it up!