Do main stacks have to be vertical?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by arfeller, Oct 20, 2020.

  1. arfeller

    arfeller Member

    Joined:
    Aug 25, 2007
    Location:
    Port Angeles, WA
    Major remodel. Basically demo'd half the house and rebuilt. Poured a new concrete footing and relocated the bathroom and kitchen. Way more then I first intended. Isn't it always?? But... I messed up and did not allow for a channel through the foundation for the sanitary sewer line.

    The sanitary line basically comes right up to the foundation footing with its invert being about the same elevation as the bottom of foundation footing. I would like to bring it up over the footing, through the wood foundation wall and under the house. Keep it horizontal and then tie in the drain lines. I have attached my attempt to draw it out and also a picture of the outside line. There is a little bit of offset I tried to correct with slight twist of the fittings.

    I plan to mound up dirt around this to make sure it has protection.

    I know I need CO outside the house also, just have not installed until I can confirm I can do this.

    Washington state.

    plumbingn drawing.gif main.JPG
     
  2. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Nothing wrong with jogging the building sewer as shown in your picture.

    Cheers, Wayne
     
  3. Sponsor

    Sponsor Paid Advertisement

     
  4. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I think you are asking what the maximum slope for your house sewer line is. Right?

    What do you propose -- 1 inch per foot, or what?
     
  5. arfeller

    arfeller Member

    Joined:
    Aug 25, 2007
    Location:
    Port Angeles, WA
    Thank you for looking at my question and taking time to respond. The normal layouts and alignments I see all have the stack coming in horizontal and then going vertical with the lines inside the house coming into a vertical stack. I was planning on keeping my stack horizontal and coming into the side of it under the house. I should be able to maintain a ~1/8" tp 1/4" per foot slope on the Horizontal after this jog you see in the picture.

    After I bring the main line in over the top of the footing I really don't have the elevation to take it vertical and tie in the inside sanitary... At least I don't think I do. side profile.gif
     
  6. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Not a problem from a performance point of view.

    With 1/8 inch per foot, my understanding is that UPC requires local signoff/permisson with 4 inch, and does not allow with 3 inch. Check your local inspector. So if you need 1/8 inch per foot, use 4 inch, and check the local inspectors first.

    With IPC code (not relevant to you), I think 1/8 inch per foot is OK, even with as small as 3 inch. and no special permission. I only bring that up because it is functional, but is not allowed in your area.
     
    arfeller likes this.
  7. arfeller

    arfeller Member

    Joined:
    Aug 25, 2007
    Location:
    Port Angeles, WA
    I have enough room to do 1/4". Thank you for bringing that to my attention!
     
  8. wwhitney

    wwhitney Well-Known Member

    Joined:
    Mar 17, 2019
    Location:
    Berkeley, CA
    Some terminology from your plumbing code (UPC):

    A Stack is a "vertical main" DWV line extending one or more stories

    The Building Drain (almost always horizontal) is the lowest level of drains that exit the building, up to the point 2 feet from the exterior of the wall.

    The Building Sewer (almost always horizontal) is the exterior drain pipe after the end of the Building Drain

    In your drawing, what is the vent you show just to the right of the WC? You need to vent the WC fixture drain before it combines with any other drains. [Except that it can combine with a shower, tub or lavatory if wet venting the WC.]

    Cheers, Wayne
     
  9. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    plumbing drawing.gif The plan view of your plumbing drawing looks good but needs a minor tweak. Branch a line off for the kitchen from the branch leading to the laundry rather than from the toilet.. Each fixture has its own vent which is missing on the side view, but its there in the plan view. Are you omitting a sink in the bathroom on purpose? You could horizontally wet vent the bathroom too to save a bunch of time and materials . Got a blueprint of the layout that you could post a pic? or draw your walls on your plumbing drawing?
     
    Last edited: Oct 21, 2020
  10. arfeller

    arfeller Member

    Joined:
    Aug 25, 2007
    Location:
    Port Angeles, WA
    Ah... Yeah. I see what you are saying about the vent for WC. That change will be easy. Thank you. Layout for walls attached. Also included a sketch that shows the venting configuration. Ignore the drain section as it was an early drawing and did not have the drain lay out correct.

    Thank you all for the review and help!

    house.gif bathroom iso.gif
     
    Tuttles Revenge likes this.
Similar Threads: main stacks
Forum Title Date
Plumbing Forum, Professional & DIY Advice Vent stacks and main Sep 30, 2005
Plumbing Forum, Professional & DIY Advice Underground water main Today at 1:07 AM
Plumbing Forum, Professional & DIY Advice Need Advice Galvanized Pipe Main Entrance Oct 24, 2020
Plumbing Forum, Professional & DIY Advice Is this steep slope ok on the main drain line? Oct 14, 2020
Plumbing Forum, Professional & DIY Advice Digital Water Main Monitoring Valve Oct 1, 2020

Share This Page