(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 8 of 8

Thread: Main Vent Stack

  1. #1
    DIY Junior Member teke's Avatar
    Join Date
    Feb 2013
    Location
    Massachusetts
    Posts
    10

    Default Main Vent Stack

    I am currently working on a one level ranch and have been renovating a full bathroom and a Kitchen. The main vent stack is 3 inches (pvc) and goes through the roof. The bathroom is vented through this 3 inch vent stack . The main stack is not a straigth run, it goes up through the attic and has an elbow then runs 8 feet horizontally and then another elbow up to the pipe that exits through the roof. the entire run for the bathroom vent is 3 inch pvc (sloped back to the bathroom).

    I also would like to vent the Kitchen sink / dishwasher through the same 3 inch stack. The Kitchen sink and diswasher use a 2 inch pvc for the vent. My challange is the vent pipe for the kichen comes to the main stack from a different direction (180 degrees.)

    My question is how can I tie the kitchen sink into the 3 inch mainstack. Could I remove the elbow and use a 3 inch tee on its back feed the sink vent from one side and the bathrom vent from the other?

    Thanks in advance for your suggestions

  2. #2
    DIY Member Gordan's Avatar
    Join Date
    Feb 2013
    Location
    SE PA
    Posts
    30

    Default

    Yes, tying together branch vents is A-OK. Just don't create any traps in your vent runs where water could collect without being able to drain into some drain somewhere.

  3. #3
    DIY Junior Member teke's Avatar
    Join Date
    Feb 2013
    Location
    Massachusetts
    Posts
    10

    Default

    Thank you for the response, so there is no issue with the fitting I intend to use to tie the two vent together?

  4. #4
    In the Trades mtcummins's Avatar
    Join Date
    Jun 2010
    Location
    Pittsburgh PA
    Posts
    380

    Default

    putting a Tee on its back is almost always illegal.

    I would suggest that you Tee into the 3" above the elbow, or remove the elbow, make it an upsidedown 3x2x3 tee to pick up the old 3" vent off the bull of the tee, and then a piece of pipe down to an elbow for your 2", or a street elbow if room is tight.

    Cutting in above the elbow will be easier, if you have the room. Just hold your 3x2 tee up to the pipe, mark out where the pipes should end (you'll end up cutting out a few inches of the 3" pipe), insert tee. Much easier than cutting out the elbow.

  5. #5
    In the Trades mtcummins's Avatar
    Join Date
    Jun 2010
    Location
    Pittsburgh PA
    Posts
    380

    Default

    and if there somehow isn't room for that, can you bring the 2" into the attic, around the side, and tie it into the side of the horizontal 3" vent? tying into the vertical portion would be preferable, but if you can't, you can come in this way. just think through your air flow when positioning the tees, so that air flows from the top sweeping down into the vent pipe. It looks upside down compared to the way you put in waste tees.

  6. #6
    DIY Junior Member teke's Avatar
    Join Date
    Feb 2013
    Location
    Massachusetts
    Posts
    10

    Default

    Thank you for all of the suggestions. I do have plenty of room in the attic so space is not really an issue. I appreciate the great suggestions.

  7. #7
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,633

    Default

    Putting a tee "on its back" would almost ALWAYS create an improper vent, unless the "top" was going out through the roof.
    Licensed residential and commercial plumber

  8. #8
    DIY Junior Member teke's Avatar
    Join Date
    Feb 2013
    Location
    Massachusetts
    Posts
    10

    Default Main Stack Vent

    Quote Originally Posted by hj View Post
    Putting a tee "on its back" would almost ALWAYS create an improper vent, unless the "top" was going out through the roof.
    Hj I understand. And to your point yes the top of the tee goes directly out the roof.

Similar Threads

  1. Main stack vent horizontal offset question
    By DavidTu in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 10
    Last Post: 05-28-2010, 06:18 AM
  2. Can I vent into the main stack?
    By Louiep in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 5
    Last Post: 01-19-2010, 07:51 AM
  3. Main Stack Vent Requirements
    By seaneys in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 2
    Last Post: 12-01-2007, 07:36 PM
  4. Can I reduce the size of my main vent stack
    By cccrowe in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 10
    Last Post: 07-23-2007, 10:09 PM
  5. 2"main stack vent, big enough??
    By rheagle1 in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 03-20-2005, 06:12 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •