Another vent question

[Tod B Schmidt]

I am adding a shower and toilet to an existing stack and have a basic question on the vent.

1. Is that the right place for the vent?
2. Can I take that horizontally to the main stack and join with a wye there or do I need to go to the roof?
3. If I added a kitchen sink drain to that vent for future purposes I would go 3" below the sink (wet) and 2" above (dry) right? And I assume 3 inch to the main pipe and down to 2 inch for the shower?

 

[Jeff H Young]

I am adding a shower and toilet to an existing stack and have a basic question on the vent.

1. Is that the right place for the vent?
2. Can I take that horizontally to the main stack and join with a wye there or do I need to go to the roof?
3. If I added a kitchen sink drain to that vent for future purposes I would go 3" below the sink (wet) and 2" above (dry) right? And I assume 3 inch to the main pipe and down to 2 inch for the shower?

View attachment 86341

As long as the" waste stack" carrys no waste above your vent connection its good. question on excess slope, no issue

 

[Sponsor]

 

[wwhitney]

Your drawing is hard to follow as I believe up-down on the page isn't always vertical in 3D. So maybe do an elevation and a floor plan separately.

1) If your shower is properly dry vented, it can wet vent the WC. And to dry vent the shower, you need a vertical vent take off (at most 45 degrees off plumb) that stays vertical until 6" above the shower flood rim, and which comes off the shower trap arm before the trap arm has fallen one pipe diameter (2").

2) What Jeff said, if there's nothing draining down from a story above, then your diagram is OK. If there is something draining down, you need to follow the stack separately and only recombine when you get above all the drains (and 6" above those fixture's flood rims).

3) If you add a kitchen sink, it will need it's own dry vent takeoff (at its trap elevation), it can't be wet vented by the shower. And its drain will need to join downstream of the shower and WC, as the kitchen sink drainage would interfere with the WC wet venting.

Cheers, Wayne

 

[Tod B Schmidt]

Thank you both for your answers and I apologize for the bad diagram. But all that does line up with what I was thinking.

1. The dry vent will join the shower drain before the turn down into the main stack so no worries on the 'take off before 1 pipe diameter drop'

2. No drains above so good there.

3. Will hold off on the kitchen sink and deal with all that separately. Thsi is all slab work so was thinking of future proofing it but that will be part of a bigger project in any case.