Air admittance valve in bathroom refit

Discussion in 'Plumbers' Talk' started by Teasy, Apr 26, 2018.

  1. Teasy

    Teasy New Member

    I am completely refitting my bathroom in my 1980s home. I would like to remove the soil pipe that goes up behind the toilet, through the ceiling and out of the roof. This would create more space.
    Can i build a box behind the toilet as before but only as high as to support the cistern and then fit an AAV to the soil pipe inside the box? I would make sure the top of the box was removable for easy access.
    There is a waste pipe as shown on the picture from bath and basin then similar one downstairs from the kitchen sink.
    There is a Floplast AAV in Screwfix which i think will do the job.
    Toilet soil pipe.JPG
  2. rogerk101

    rogerk101 Well-Known Member

    That would work perfectly. I have just done the same thing, although in my case, getting rid of the vertical vent pipe enabled me to fit a full size bath into the bathroom as I was able to push it all the way into the corner once the vent pipe was gone.
  3. Pollowick

    Pollowick Well-Known Member

    You can buy a base unit for either wall or floor mount pans, the cistern sits inside that. So, specify on, say 800 wide and you can hide the cistern, waste connection and AAV.
  4. Dave does Gas

    Dave does Gas Well-Known Member

    The only thing you have to bear in mind is the AAV has to be higher than the highest flood point, usually the wash basin overflow. So provided you install it above that you should have no issues.
  5. Teasy

    Teasy New Member

    Thanks Dave/everyone.
    I will build the box height in line with the tiles that are above the basin. It will look right then, as I’m tiling right across.
  6. Dave does Gas

    Dave does Gas Well-Known Member

    Stick a few pictures up when its done please, like to see the final result.
    Teasy likes this.
  7. Isitreally

    Isitreally Well-Known Member

    No it doesn't, you can get AAVs that are ok at low level, these are very common.

    You need an A1 valve.
  8. Teasy

    Teasy New Member

    I know the one in Screwfix says you can fit below the flood line but in my case I think It will be above anyway.
  9. Peterdevon

    Peterdevon Active Member

    If you have a non mechanical septic tank you must leave the vent as it is supposed to pull air through the tank
  10. zipdip

    zipdip Member

    Yes you are fine to do that,I knocked the wall down between a loo and the bathroom to make one,the soil pipe was in the bathroom and had the bath and sink going into it and in the loo the soil which of course joined the drain under the ground was flush to the floor,I put the sink and and shower into what was the loo soil pipe using a AAV with a entry for waste water just under the valve you will have to hunt for it not many on sale and used a sink built into a cupboard with two Drawers I needed to just remove the bottom draw and cut some of the excess trim at the back so it cleared the AAV ,the loo went straight into the other soil pipe at floor level also,it has worked fine over the last year.
  11. Teasy

    Teasy New Member

    Sounds good. I like the idea of the built in unit to save that bit of space but I have already purchased the suite. But I will know for next time.

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