We live in a 1960's single floor concrete slab house with concrete block interior/exterior walls. We had to replace the pipes under the slab in the kitchen and currently still have the floor torn up waiting for better weather to start the floor repair process. The thought occurred to me about putting in an additional vent to help with the constant clogging/blocking issues we always had and the previous owners always fought with (plumbers always blamed it on poor venting). The sink is on an outside concrete wall and currently has a PVC Air Admittance Valve. The nearest "Aesthetically" safe area to put a roof vent in is about 10ft away across the room, and about 15ft away from the 4" main. This sink is the only item on this drain line to the 4" main. The pantry in the picture runs from floor to ceiling and there is an existing clean out we would wye off of for the vent. All plumbing from the trap to the 4" is 1.5".

Would this help or make a difference in the plumbing situation for this run? A vent from the sink area would either need to go through the counter top and a cabinet or out the concrete wall and up the back of the house, through a soffit and then roof right next to our back door.

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  • Don’t know where you are located in my area the vent needs to be within 6’ , hours is a bit far but with a air admission valve in some states this would be fine but not in my PNW location.
    – Ed Beal
    Nov 15, 2019 at 4:37
  • Skip "aesthetically safe" and punch it through the outside wall by the sink, first preference. Concrete, schmoncrete, say diamond core bits. If not doing that, since you have things ripped up anyway, upgrade the pipe size, at least.
    – Ecnerwal
    Nov 15, 2019 at 14:53

1 Answer 1


In my area, a kitchen/bath waste arm must be no more than 3ft long unless an air admittance valve is used at the fixture. If an air admittance valve is located 10 feet away it won't do anything.

  • Hello, and welcome to Home Improvement. Thanks for the answer, but it's a bit hard to understand; would you take a bit of time to flesh it out?. And, props for taking our tour before posting; few newbies do. Nov 15, 2019 at 12:48
  • @DanielGriscom Daniel, can you be specific about what is “hard to understand?” Your comment seems “general”.
    – Lee Sam
    Nov 15, 2019 at 14:20
  • @LeeSam Well, there wasn't a verb. I'll edit it to clarify. Nov 15, 2019 at 14:28
  • The air admittance valve is right under the sink. However we've always been told by plumbers over the years that a atmospheric vent is the only way to go and we will have problems until we have one installed. My question was a possible solution.
    – Dan
    Nov 15, 2019 at 18:22

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