Toilet troubles - No soil stack vent

Discussion in 'Plumbers' Talk' started by DIY123, Sep 16, 2020.

  1. DIY123

    DIY123 New Member

    Hi guys,
    We’ve been having trouble with our upstairs toilets not flushing properly/getting blocked/slow to drain.
    The toilet has been augered and is clear, drains have all been inspected and the soil stack is clear. Which led me to believe it was a vent issue. At this point I discovered that there’s no vent for the soil stack neither outside, nor into the loft!
    My question is, is there a way to improve the venting without needing to rip out the walls to get to the stack? Is there somewhere else in the system that we can add a vent?
    thanks!
     
  2. just pumps

    just pumps Screwfix Select

    Where does the soil stack end then if neither in the loft nor outside?
     
  3. DIY123

    DIY123 New Member

    I suspect it just terminates in the wall, hard to tell without ripping the wall out though.
     
  4. just pumps

    just pumps Screwfix Select

    You might have to.
     
    The Teach likes this.
  5. Kas228

    Kas228 Active Member

    Is this something that has recently started being a problem, has it ever been ok?
    How long you been in the property etc.
     
  6. AnotherTopJob

    AnotherTopJob Active Member

    There's probably an air admittance valve somewhere, they're often boxed in a corner but ideally should be accessible.
     
    Alwaysworking likes this.
  7. DIY123

    DIY123 New Member

    It’s been an issue for around 6 months,have been in the property for 3 years. Toilet clogs regularly but never used to. We’ve had a camera survey all the way up the stack and no issues. Just lots of limescale buildup which has been cleared since.
     
  8. DIY123

    DIY123 New Member

    That was my hope, but nothing accessible/visible. I’ve spoken to a friendly plumber who suggested he might be able to fit a ‘dergo’ in the bathroom and box it in. But that it’s not really the done thing.
     
  9. The Teach

    The Teach Screwfix Select

    Where exactly does it clog ? its important to know plus there are other important ideas which need airing.

    When it comes to wc's what has changed since the property was built,info helps

    maybe the wc pan operation is not that good,what manufacture is the wc pan.

    do you have a downstairs toilet on the same soil pipe.does it clog up ?

    Some properties dont a have their own vent pipe but rely on venting by neighbouring properties or other arrangement,it could be mentioned in the property deeds but they can be incomplete or defective.

    have a dig around :D
     
  10. Kas228

    Kas228 Active Member

    AAVs are normally 3 feet or so above the highest loo. Mine is in the eaves of a chalet style house. If it was ok before then it may be stuck, any panels around screws or masticked?
     
  11. jonathanc

    jonathanc Screwfix Select

    what has changed in the last 6 months? and exactly what has been blocking up. could be as simple as someone who is normally out at work taking a dump at home because of lockdown and they are in the habit of using tons of bog paper...
     
  12. DIY123

    DIY123 New Member

    Ok so here’s some more detail. Upstairs en-suite and family bathroom back onto the same wall, toilet waste pipes both meet in that wall but are boxed in, presumably with a t connector and then down the soil stack meeting the downstairs loo before exiting to ground. Downstairs loo has never had an issue and is still fine. The upstairs family bathroom loo is ancient and has never flushed properly, just swirls the waste. En-suite bathroom has always been fine up until about 6 months ago when it started blocking about once a month, but cleared when plunged. That toilet has been augered and it’s fully clear. We had someone out recently to inspect the drains and the stack. They stuck a camera up and cleared loads of limescale out of the drain, but otherwise the stack is completely clear. Upstairs en-suite loo is still blocking intermittently, and shower/ sink are slow to drain leading me to believe that the issue is one of venting. But unless there’s an AAV hidden in the wall on the top of the stack. I’m lost as to what could be causing the issue.
     
  13. jonathanc

    jonathanc Screwfix Select

    can you look down on the plumbing from the loft to see if there is an AAV?

    if its venting issue can you hear the traps gurgling when a toilet is flushed?
     
  14. robgul

    robgul Active Member

    Interesting - we have a similar flushing issue with one loo - but I put that down to not enough water in the cistern . . . I've taken out the baffles that restricted the water level and it's a it better - however a friend who is a bathroom/kitchen designer has suggested that make of china is not the best design, it's Villeroy & Boch and probably design over function for flushing flow.

    BUT we have another issue in the same bathroom that we get a smell of drains coming back through the shower waste .... the pan and shower both go into the same soil pipe (although I don't know where as it's all boxed/tiled in) I am guessing that flushing the loo is "pulling" on the waste trap for the shower and then letting air back in? There doesn't appear to be a soil vent anywhere in the loft or through the roof.

    I've put some of BARRY SCOTT'S Cillit Bang stuff down the shower waste to see if there's a blockage or constriction - no real difference.

    Not sure what to do from here?
     
  15. AnotherTopJob

    AnotherTopJob Active Member

    Part of the problem with recent/new builds or tilers with no plumbing knowledge is they tend to box pipes in with no thought of maintenance. If there is likely to be an issue, it's probably a few years down the line and not their problem.

    If access is an issue then an inspection camera may be very useful and they are relatively cheap now. DIY123, you mentioned using one inside the pipe but they are also great inside walls and only need a 10mm hole or less.
     
  16. robgul

    robgul Active Member

    Tell me about it - we have two boxed in cisterns. One has an "inspection panel" about 20cm square - and the other after a bit of prising off of glued on mouldings has some visible screws (with the Pozi heads clogged with glue) for a panel that may or may not come out.
     
  17. DIY123

    DIY123 New Member

    This was a good suggestion thanks, after more investigation and digging around with an inspection camera I’ve managed to track down what looks like an AAV boxed in next to the sink in the en-suite bathroom. To get to it would mean pulling apart the en-suite and removing the sink etc. which leads me to my next question. Assuming the valve has failed and is the cause of the issue. Would fitting a new AAV elsewhere in the system fix the problem? We’re having a new bathroom put in which is next to the en-suite so now would be the opportune time.
     
  18. AnotherTopJob

    AnotherTopJob Active Member

    I suppose you could add another AAV if it shares the same soil pipe.
    However it would mean boxing in a corner of the new bathroom, something which wouldn't be necessary if the existing one is satisfactory.
     
  19. robgul

    robgul Active Member

    I'm clutching at straws here . . . . after some testing I'm certain that the ground floor cloakroom WC is pulling the shower waste in the en-suite that's immediately above it on the first floor - run the shower, its trap fills - flush the cloakroom WC half a dozen times and it starts to smell, and gets worse (it's difficult to see if the shower trap water level is lower as it's the type that's very shallow with a sort of loose "cup" full of water that sits in it)

    There is no visible venting of the soil stack.

    I've been reading up about AAVs and wonder whether it's feasible to fit one adjacent to the cloakroom WC - the waste goes into the pipe at floor level (in a flexible pipe)

    - this may be nuts but: would fitting a boss as high as I can on the soil pipe (about 60 cm above the entering waste from the WC) - then with a stubby bit of tube and an elbow fit an AAV (parallel to the soil pipe) ???? The WC and shower upstairs are going to drain past it but presumably gravity will mean it just drops down the pipe. Would that let the downstairs WC flush wihout pulling the shower waste?
     
  20. rogerk101

    rogerk101 Screwfix Select

    That would sort out the emptying shower trap issue ... and maybe other issues too, but you should use a Y coupling rather than a T coupling, as this will avoid any slow and steady buildup of waste in the coupling.
     

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