Announcement

Collapse
No announcement yet.

Soil Stack Vent Size Reduction

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Soil Stack Vent Size Reduction

    I purchased an old house a few years ago. Recently, while in the eave of my attic I noticed an open end of a 4" CI pipe sticking through the floor of the attic. After doing some investigation it is my main soil stack vent. I know this should be extended through the roof to get any sewer gases out of the attic. There is a powder room and (1) full bath tied into it. I have a smaller vent on the other side of the house that takes care of the laundry and kitchen.

    My questions are:

    1. Can I reduce it to 3" PVC to run through the roof? Based on its location and getting it to a good spot to penetrate the roof it would be easier to run it in 3" as opposed to 4".

    2. How far above the roof does it need to extend?
    Last edited by mcb676; 09-28-2011, 07:48 AM.

  • #2
    Re: Soil Stack Vent Size Reduction

    No you can not reduce it size. In some areas they require you to increase the size one foot below the roof. The vent needs to extend 12" above the finished roof, as long as the roof is used for weather protection, if it used for anything other than weather protection it needs to extend 7'. Here is the code I follow in Illinois.

    Section 890.1430 Vent Terminals


    a) Roof Extensions. Extensions of vent pipes through a roof shall be terminated at least 12 inches above such roof unless a roof is to be used for any purpose other than weather protection. If a roof is to be used for any purpose other than weather protection, the vent shall be extended at least seven (7) feet above the roof. (See Appendix K: Illustration D.)



    b) Flashings. Each vent terminal shall be made water-tight with the roof by proper flashing.



    c) Location of Vent Terminal. No vent terminal from a drainage system shall be directly beneath a door, window, overhang or other ventilating intake opening of the building, nor shall any such vent terminals be within 12 feet horizontally of such an opening unless it is at least two (2) feet above the top of such opening. (See Appendix K: Illustration E.)



    d) Extensions Outside Building. No soil, waste or vent pipe extension (except for vent terminals as provided in (a) and (c) above) shall be located on the outside of a wall of any building, but shall be installed inside the building. Vents located within an exterior wall or in a wall adjacent to an unheated space shall be protected from freezing.



    e) Flag poles. Vent terminals shall not be used for the purpose of supporting flag poles, television aerials, or similar purposes.
    Section 890.1440 Vent Terminal Size


    a) Vent Terminal Size. Each vent extension through the roof shall be a minimum of three (3) inches in diameter and no smaller than the vent which it terminates. Vent terminals shall not be screened.



    b) Increasers. Changes in size or diameter of vent terminals shall be made by the installation of a long increaser commencing at least one (1) foot below the roof.
    Ron Hasil Lic #058-160417
    A-Archer Sewer & Plumbing specializing in:
    Tankless Water Heaters | Drain and Sewer Cleaning
    Sump and Ejector Pumps | Backflow RPZ Testing

    Comment


    • #3
      Re: Soil Stack Vent Size Reduction

      Thanks for the response.

      Comment


      • #4
        Re: Soil Stack Vent Size Reduction

        Let's be practical. Are you pulling a permit or having this inspected?

        If so, then you need to address the requirements of your code.

        If not, then a reduction to 3" for that short distance is OK.

        Down here, 4" vents are never used anymore is single family residential,

        and 3" is getting to be pretty rare. Everything is vented on 2", now.

        Just be sure your penetration is not in a valley or ridge.

        Since venting size is based on drain fixture units, you should be fine

        according to your description of the arrangement.

        Comment


        • #5
          Re: Soil Stack Vent Size Reduction

          Originally posted by Big Jim View Post
          Let's be practical. Are you pulling a permit or having this inspected?

          If so, then you need to address the requirements of your code.

          If not, then a reduction to 3" for that short distance is OK.

          Down here, 4" vents are never used anymore is single family residential,

          and 3" is getting to be pretty rare. Everything is vented on 2", now.

          Just be sure your penetration is not in a valley or ridge.

          Since venting size is based on drain fixture units, you should be fine

          according to your description of the arrangement.
          Yea its not a problem till he gets caught, maybe not now, but when he goes to sell the phone.
          Ron Hasil Lic #058-160417
          A-Archer Sewer & Plumbing specializing in:
          Tankless Water Heaters | Drain and Sewer Cleaning
          Sump and Ejector Pumps | Backflow RPZ Testing

          Comment


          • #6
            Re: Soil Stack Vent Size Reduction

            Where were the code Nazis when he bought the house with that vent

            terminated in the attic? I'm all for compliance, but I don't think the

            O.P. is. I don't even know what his code is and he probably doesn't either.

            I just know what will work.

            Comment


            • #7
              Re: Soil Stack Vent Size Reduction

              Originally posted by Big Jim View Post
              Where were the code Nazis when he bought the house with that vent

              terminated in the attic? I'm all for compliance, but I don't think the

              O.P. is. I don't even know what his code is and he probably doesn't either.

              I just know what will work.
              Ok here is my last point. If you are going to fix it, why not fix it proper the first time?
              Ron Hasil Lic #058-160417
              A-Archer Sewer & Plumbing specializing in:
              Tankless Water Heaters | Drain and Sewer Cleaning
              Sump and Ejector Pumps | Backflow RPZ Testing

              Comment


              • #8
                Re: Soil Stack Vent Size Reduction

                Originally posted by Big Jim View Post
                Let's be practical. Are you pulling a permit or having this inspected?

                If so, then you need to address the requirements of your code.

                If not, then a reduction to 3" for that short distance is OK.

                Down here, 4" vents are never used anymore is single family residential,

                and 3" is getting to be pretty rare. Everything is vented on 2", now.

                Just be sure your penetration is not in a valley or ridge.

                Since venting size is based on drain fixture units, you should be fine

                according to your description of the arrangement.
                BULL SHIP. One hack is enough , GO 4" + drain cleaner can get a 4" cutter down stack to street !
                Last edited by toolaholic; 09-28-2011, 06:24 PM.
                I can build anything You want , if you draw a picture of it , on the back of a big enough check .

                Comment


                • #9
                  Re: Soil Stack Vent Size Reduction

                  Yes, let's be practical and do the job the right way. The code is not a suggestion
                  sigpic

                  Comment


                  • #10
                    Re: Soil Stack Vent Size Reduction

                    Big Jim, the original poster asked if it was allowed to reduce the vent stack. The answer is no it is not. When people come here to the forums with questions on how to do something, or what the right tool to use, it does them a huge disservice giving them bad information.
                    Ron Hasil Lic #058-160417
                    A-Archer Sewer & Plumbing specializing in:
                    Tankless Water Heaters | Drain and Sewer Cleaning
                    Sump and Ejector Pumps | Backflow RPZ Testing

                    Comment


                    • #11
                      Re: Soil Stack Vent Size Reduction

                      Years ago the rule was the stack vent had to be atleast as large as the sewer it served..Today , not so atleast not in IPC land.I wouldn't think reducing to 3" would harm anything. And yes you could probably reduce to 2" and be fine but I wouldn't
                      ''Beer is proof that God loves us and wants us to be happy" Benjamin Franklin

                      Comment


                      • #12
                        Re: Soil Stack Vent Size Reduction

                        For code you can not reduce a vent but if it were my home id put a 4" c/o and then reduce to three inch. Here every dwelling "new construction" must have atleast one three inch vent the amount of fixtures you can put on a four ijnch vent is huge.. but if you want to make sure ask your local inspector personaly id think it was grandfathered ?

                        Comment


                        • #13
                          Re: Soil Stack Vent Size Reduction

                          Alright, boys. Just calm down.

                          Ratz, the OP didn't ask if vent reduction was allowed, he asked if he could do it.

                          Now what does that mean? I don't know what his code is. Maybe it would be allowed

                          in his situation. Tool, the purpose of a vent stack is for drawing air, not for drain

                          cleaning. That's what clean outs are for. Granted, at times you have to snake from

                          the vent, but in the absence of a c.o. you do what you can. All I'm saying is a 3"

                          vent is more than adequate for his needs. I know the code exists for a reason, and

                          most of them are necessary, and if he hired me to do the job I would do it to his code

                          requirements, whatever they are, and charge an appropriate price. I just think he's

                          interested in what's gonna work.

                          Comment


                          • #14
                            Re: Soil Stack Vent Size Reduction

                            I can't see any big savings on reducing it. Why do it ?
                            I can build anything You want , if you draw a picture of it , on the back of a big enough check .

                            Comment


                            • #15
                              Re: Soil Stack Vent Size Reduction

                              Originally posted by toolaholic View Post
                              I can't see any big savings on reducing it. Why do it ?
                              I have no idea.

                              Where's the Master when you need him.

                              Comment

                              Working...
                              X