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Discuss AAV on Soil Pipe within a room in the Plumbing Forum area at

  1. Stants

    Stants Member

    Hi Im looking to use an Aav to terminate a soil Pipe within a Wall Ive read up and spoken to Manufacturers ( Polypipe ) and they say as long as it has Vent / Grill over it for air flow its ok I know the requirements regarding its height etc it will however be in a habitable room ( Bedroom ) and although they don't advise it they don't say you cant do it,. its for a Loft conversion im just wondering if any of you Guys and Girls have done it in a loft conversion and Building control had excepted it, the alternative is to exit it up through the roof just trying to avoid potential failings after time
  2. oz-plumber

    oz-plumber Plumber

    If you take the vent up through the roof then you can leave the vent open to atmosphere and there should be ho failings over time.
    • Like Like x 1
  3. Stants

    Stants Member

    hi the failing I was on about was going through the roof around where the pipe exits the roof if theres no hole there in the first place 0 chance of leaks that's why im considering the Aav
  4. snowhead

    snowhead Plumber

    The risk of the AAV failing is greater than the roof flashing failing, if done correctly.
    Although a failed AAV would be easier to fix.
    • Like Like x 1
  5. Stants

    Stants Member

    That's what I was thinking changing the Aav,s a simple process plus I'm going to the trouble of concealing the soil pipe ( purely aesthetics) my existing Soil pipe is an old cast iron which I've away hated looks crap

  6. Stants

    Stants Member

    The main thing I was after in my initial post was " would building control allow it " ( Conseald ) if not only option would be through the roof
  7. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    You also do not quite understand the pipes function.

    The pipe not only lets air in (to stop it collapsing) but it also needs to vent foul gasses to atmosphere. That's the point of 1m above local opening window. If you remove the ability to vent as designed then it WILL still vent. However it will do so directly into your bathroom. Not only a potential health hazard, but worst of all a never ending moaning from the significant other...
    The very minimum to vent should be 2" and make sure yiu have no 90 deg bends, 45 degs max.
    • Like Like x 2
  8. Stants

    Stants Member

    Well unless I've read it wrong
    hi have I read it wrong then ? You can't use an Aav in this instance then . I did speak to Poly Pipe technical they seemed ok ????
  9. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    There is no such thing cant, of course you can. You can do what you like. However, whether you should, whether its the correctbthing to do is where Im coming from.

    By giving you chapter and verse you know potential consequences and choices. Therefore, you take complete responsibility for your actions.

    Have fun.
    • Like Like x 1
  10. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Stants , of course you can use an AAV , just make sure you can get it if it fails , they do , but are generally very reliable , buy a McAlpine one not a chinese ebay one .
    You mention building control , so they obviously know about it , so they should be happy with an AAV .
    • Like Like x 1
    • Agree Agree x 1
  11. Ric2013

    Ric2013 Plumber

    Well, it really depends on the circumstances, for example whether the drain is vented elsewhere, and whether it is prone to surcharging. A drain does need a vent open to atmosphere and there are guidelines as to how many OPEN vents (as opposed to stacks that are only partially vented by AAVs) there should be and where they should be.

    FWIW, I'll give an example. My neighbour was told by the BCO that he would be allowed to use an AAV if my soil stack (connected to the same drain) was open to atmosphere, but not if my soil stack was terminated in an AAV.

    What Yorkshire is suggesting is, however, best practice and how they used to do it in the old days, but there are also good technical reasons for not wanting to run a pipe through the loft that would make even a Luddite such as myself agree that AAVs are sometimes a good solution.
    • Like Like x 1
  12. hammers4spanner

    hammers4spanner Plumber GSR

    AAV has become an item that has basically been abused for a long time. No wonder their is so many problems with drainage now .
    Your in the loft and won't take it through the roof which is the best practice .
    • Agree Agree x 3
    • Like Like x 1
  13. Stants

    Stants Member

    Hi Dave I see what your saying " if it aint broke don't fix it "
  14. dan_the_plumber

    dan_the_plumber GSR

    Soil stack won’t vent into room. That’s the point of AAV. They do need to be installed above the spill over level of the highest appliance though. This usually means above the top of the upstairs basin.
    For this reason the soil pipe would normally be taken up into the attic and have AAV installed there.
    It would be accessible and saves having to go up through roof.
  15. hammers4spanner

    hammers4spanner Plumber GSR

    Sorry disagree had a few fail over the years . Smells tracking back whipped off n changed job done
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