Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss Air inlet, toilet, basin, shower . LEVELS .Any issues with setup? in the Bathrooms, Showers and Wetrooms area at

  1. P B

    P B Member

    New second floor shower and toilet with basin.
    Don't want vented pipe outside as it will look ugly and is close to a window so am putting air inlet valve internally in a cupboard by toilet.
    Air inlet above toilet bowl level. Then down to toilet waste height with elbow and horizontal part of pipe.
    Toilet waste tees into the pipe next. Pipe runs along under basin and will pick up waste using a strap boss.
    Then pipe turns at 90 to go trough outside wall and then drops 2m before long horizontal to original soil pipe location 4m away.
    Shower waste will possibly drop 2m internally through lower room and join soil on its horizontal to original soil stack.

    Assumptions -
    Shower will overflow before sink or toilet.
    Air inlet will never overflow as water will never back up this far.
    Shower shouldn't have waste backing up unless there is a blockage much further down this setup.
    Sink and shower should never get vacuume from toilet flushing due to 110 pipe size...

    Any thing I am missing or any for seen problems with this. It is a selfbuilt loft conversion with building control notice.

  2. P B

    P B Member

    Looking as if we are through the wall from outside, here is the units mock up minus connecting pipe and basin/waste. Left in pic is basin unit then toilet then air inlet.

  3. oz-plumber

    oz-plumber Plumber

    I doubt you will need a vent if the soil pipe is going into a vented stack, with the distances you mentioned.

    In answer to your question: Are you missing something?
    Answer: Yes
    • Like Like x 1
  4. P B

    P B Member

    Hi oz-plumber. Existing stack removed as would be lower than new second floor toilet.
    Apart from the pipes in pictures.. .. Am i missing anything in the theory and proposed setup?

  5. oz-plumber

    oz-plumber Plumber

    Are you proposing to vent the new stack and your existing plumbing from an AAV installed in a void in your bathroom?

    If so, I would highly recommend that you should avoid this setup and vent an open vent to atmosphere.
    • Agree Agree x 2
  6. Harvest Fields

    Harvest Fields S. Mod Trusted Plumber GSR Top Contributor!!

    Vent it through the roof and box in the rest of the stack
  7. Maryplumb

    Maryplumb Plumber GSR

    if you have a building control notice have you not submitted drawings to building control? They usually want to see an isometric of the drainage
  8. chris watkins

    chris watkins Plumber

    Is the stack the head of the run?
    If so it must (part H) be vented.
    It doesn't have to be a 110mm vent.
Similar Threads - inlet toilet basin Forum Date
Soil pipe inlet too high for toilet pan Plumbing Forum Feb 23, 2019
Connecting 15mm toilet inlet to 15mm isolation valve Plumbing Forum Feb 22, 2019