Bathroom drain venting advice - old house

[TGrump]

Hi all,
Recently bought a house and will be DIY-ing a bathroom remodel. The plumbing seems interesting and I have little experience in this area.

The sink is an s trap with no vent.

Here's what we got:

What I think is the shower vent runs a little over 8 feet to tie in with an AAV at the kitchen sink.

Here is a crude sketch of overhead view

The vent from the toilet:

I plan to move the sink to the opposite wall and upgrade it to a p trap with a dedicated vent through the walls.
Any comments, concerns, advice?
What is going on with the AAV under the kitchen sink?

Thanks for your time.

 

[Reach4]

What is going on with the AAV under the kitchen sink?

Kitchen sink is fine, but it cannot supply a wet vent for the shower.

 

[Sponsor]

 

[TGrump]

Kitchen sink is fine, but it cannot supply a wet vent for the shower.

So if I'm understanding you correctly, the shower venting is inadequate?

If I were to link a shower vent to a new bathroom sink vent, would that vent properly?

 

[Reach4]

So if I'm understanding you correctly, the shower venting is inadequate?

It is not acceptably vented per code.

If I were to link a shower vent to a new bathroom sink vent, would that vent properly?

Probably. The shower +lavatory drainage would need to combine before joining kitchen waste.

 

[TGrump]

Probably. The shower +lavatory drainage would need to combine before joining kitchen waste.

This will be difficult to achieve. Can you tell me why this is the case?

Thanks for your responses

 

[Reach4]

This will be difficult to achieve. Can you tell me why this is the case?

You mean like "that's the UPC rule for wet venting"? Is that the answer you wanted? Or do you care to know why that's the rule in UPC code, which applies where you are? Or were you wanting to know the chapter and section of the code?

Let me give you a Google search that can turn up info for you (paste with the quotes):
"wet vent" "bathroom group" "upc"

You can merge drainage in any order if you want to dry-vent each trap separately.

 

[Jeff H Young]

I guess its up to you . Id tear it all out and start over. I wouldnr have an s trap exposed vent and a kichen sink hook up like that unless I couldnt afford to do it right, and if you are on a super tight budget I get it dont mean to offend. but for a few hundred bucks it could be right. Otherwise just connect the pipes the shower will find its way down the pipe. youll be fine.

 

[TGrump]

You mean like "that's the UPC rule for wet venting"? Is that the answer you wanted? Or do you care to know why that's the rule in UPC code, which applies where you are? Or were you wanting to know the chapter and section of the code?

Yes. Well, I guess I don't need to know the chapter and section of code. Thanks for the info.

You can merge drainage in any order if you want to dry-vent each trap separately.

Can I dry-vent (1.5" PVC) the bathroom sink and shower separately into a common attic vent stack? The drain is 2" if that matters.

 

[TGrump]

I guess its up to you . Id tear it all out and start over. I wouldnr have an s trap exposed vent and a kichen sink hook up like that unless I couldnt afford to do it right, and if you are on a super tight budget I get it dont mean to offend. but for a few hundred bucks it could be right. Otherwise just connect the pipes the shower will find its way down the pipe. youll be fine.

No offense taken, thanks for your input.
My new plan is to switch S trap to a P trap with a dry vent, dry vent the shower, and bring the toilet vent into the wall. Then have them all merge into a vent stack.
I know that this wouldn't change much for the kitchen drain...

Does that sound reasonable?

 

[Reach4]

Can I dry-vent (1.5" PVC) the bathroom sink and shower separately into a common attic vent stack? The drain is 2" if that matters.

Wet venting the shower with a lavatory is actually easier, I think, because a dry vent needs to be vertical (with 45 degrees still considered vertical) or at least with some special considerations. I am muddy on that. If you bring the shower drainage over to the wall where the vent pipe is, that always works for a dry vent. The wet vent can actually be horizontal.

I am not sure if 1.5 inch shower vents are OK in UPC. I would think so.