Correct way to connect soil pipe

Discussion in 'Plumbers' Talk' started by Rick999, Mar 17, 2019.

  1. Rick999

    Rick999 New Member

    I’m hoping someone may be able to point me in the right direction when it comes to connecting a new toilet to the existing soil stack. Hopefully, to avoid any future problems and potentially smelly repair jobs!

    I am putting a new toilet upstairs at the opposite side of the house to the current one, but want to go into the same soil stack. In order to avoid the two pipes meeting at the same point and to avoid some other pipes I need to drop one branch down by about 300mm.

    Can I do this using a 125deg bend or would this be bad practice? Am I better going down vertical then across? I’ve attached a diagram which hopefully explains a bit better (apologies for the terrible drawing!)


    Any advice would be greatly appreciated!
  2. spirits are real 2016

    spirits are real 2016 Well-Known Member

    picture won't load.
  3. Rick999

    Rick999 New Member

    Hopefully you can see the photo this time

    Attached Files:

  4. KIAB

    KIAB Well-Known Member

    I think it would be easier to use a double branch,difficult without seeing it first hand, got any photo's of outside pipe work arrangment.

  5. Heat

    Heat Well-Known Member

    Or use two 110mm junctions, one above the other.
  6. Rick999

    Rick999 New Member

    That’s what I plan to do, but I still need to drop where it comes out of the wall to avoid some other pipe work. Would you do this vertically? Or could you use a 125deg bend?
  7. Heat

    Heat Well-Known Member

    135 degree bend
  8. Rick999

    Rick999 New Member

    Thank for the correction I mean 135 deg bend.
    Heat likes this.
  9. Heat

    Heat Well-Known Member

    Yes, wasn’t trying to correct you, but just saying that is what you use.
    Just the 90 degree bend through wall, turned at 45 degree angle to meet a 135 degree bend.
    Distance between those bends (or none) will depend on what level ‘horizontal’ run will be needed.
    Obviously it will need a slight fall
  10. Rick999

    Rick999 New Member

    Thanks, was just a bit worried that the slope would be too much (greater than 1/40) and may cause issues like blockages?
  11. Heat

    Heat Well-Known Member

    I meant keep the horizontal run with a slight fall of 1/40.
    Turn the 90 degree bend coming through wall outside to the 45 degree angle to immediately meet the 135 degree bend and then run the rest just ‘horizontal’ at 1/40 over to the soil stack
  12. ecoplumbing

    ecoplumbing Active Member

    Fall doesn't have to be 1 in 40. That just applies to underground drainage. As long as the horizontal fall is between 18mm - 90mm per meter you'll be fine.
    Heat likes this.
  13. Heat

    Heat Well-Known Member

    2.5 degrees of fall
  14. Rick999

    Rick999 New Member

    That will be fine on the long section. It was the short say is at 45degrees or so...thought that may cause an issue, and I thought I may be better off going vertically down for 300mm then across with about 1/80 slope?
  15. Heat

    Heat Well-Known Member

    No, just go 45 degrees on short section.
    To use two of 90 degree bends fairly close together is more likely to cause blockages, (although not against regs).
    I think it also looks better to have a 135 degree bend. Much neater and clearly looks better flow

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