Wet Vent question for slab foundation

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Dylan B, May 2, 2021 at 8:36 PM.

  1. Dylan B

    Dylan B New Member

    Joined:
    Sunday
    Location:
    Phoenix
    Two questions. If I’m using 3” for toilet run and 3” vent run, what is the longest run trap to vent for that toilet?

    2nd question. Can a lavatory 2.5” run into the 3” toilet run before it connects to wet vent?

    I have tried to outline this in the diagram.
    Appreciate all the help, this has me stumped. Open to all suggestions.


    And yes. I’m replacing the existing pipe and 45 as clearly they are broken and that is why I’ve decided to build an additional bathroom

    B33CB7B5-566B-46D1-A4F8-21AD5C026AB9.jpeg F9B8A877-1D4A-4A5F-8A8D-A0E9F8B3C982.jpeg
     
  2. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    Toilets trap arms in the UPC code are limited to 72" from its vent.. other codes may vary.

    UPC (except in washington state) also wants the toilet to be the most down stream fixture in a horizontal wet vented system.

    What type of pipe is that under the slab? It looks like concrete to me.
     
  3. Sponsor

    Sponsor Paid Advertisement

     
  4. Dylan B

    Dylan B New Member

    Joined:
    Sunday
    Location:
    Phoenix

    Even if it’s a horizontal wet vent it has to be the last fixture?

    yes, it is cast iron to concrete. I plan on cutting before the clean out cast iron and after the 45 (concrete) and replacing with pvc with Fernco fittings.
    I just cannot figure out how to horizontal vent with the direction of the flow and it tying into the main line 3.5 feet below ground.

    suggestions?
     

    Attached Files:

  5. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
  6. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    Reading that IPC section, the toilet does Not have to be the most downstream fixture. Your drawing would work for that given the limits of trap arms in the code that Reach4 provided.

    Im certain that concrete pipe is not approved for burial under a building. Someone likely enclosed a porch there.. I see it occasionally here and have to remove all of the concrete pipe from the envelope of the house if we find it.
     
  7. Dylan B

    Dylan B New Member

    Joined:
    Sunday
    Location:
    Phoenix

    But can the lavatory connect to the toilet run before it connects to wet vent?

    Do you have any code that says I would
    Have to dig up concrete if it’s existing structure? Technically, the concrete portion of the pipe is under a concrete patio that is not enclosed.

    the wall for the new bathroom would technically be on top of the pvc and the pvc/concrete fernco would be outside that wall and under a non enclosed porch. It does have a roof overhang but it is not enclosed.

    If you see from the picture, the previous owner had build a storage room over the broken plumbing and I just am trying to convert that storage room to bathroom ( the concrete portion of the pipe is outside of the “storage room” but under the concrete patio slab
     
  8. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I am not clear on what you are asking.

    The lavatory needs to be vented with a real vent or an AAV.
    That upsized drain pipe from the lavatory can then wet-vent the toilet .
     
  9. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    Your drawing shows the sink with the vertical dry vent being the most upstream fixture. Downstream the toilet connects and downstream of that the shower connects. Seems fine to me. You're allowed to have one fixture tie in upstream of that dry vented fixture.

    Concrete is not an approved material for burial within the envelope of a building. Never has been approved for that and can never be grandfathered in. If its outside then thats where a gray area begins.. but you can argue that if it comes up. Again, I don't know the specifics of your
     
Similar Threads: Vent question
Forum Title Date
Plumbing Forum, Professional & DIY Advice Wet venting questions Apr 25, 2021
Plumbing Forum, Professional & DIY Advice Venting question - 2nd floor bathroom Apr 17, 2021
Plumbing Forum, Professional & DIY Advice Another venting question Apr 13, 2021
Plumbing Forum, Professional & DIY Advice Adding a 2nd floor bathroom - venting and drain questions (see diagram) Apr 12, 2021
Plumbing Forum, Professional & DIY Advice Venting Question for Bathroom on slab Apr 8, 2021

Share This Page