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  1. Samantha Jennings

    Samantha Jennings New Member

    Hi. I wonder if anyone could shed any light on this. We have a first floor bathroom. Everytime we drain the bath, the bathroom sink (which is about 4 feet from the bath) gurgles and quite often, the bathroom fills up with the smell of sewer gases. The bath, sink and toilet are draining fine. Dynorod have been out and say that there don't seem to be any blockages in the soil pipe.

    I have Googled it and it looks like our vent pipe may be blocked? It is a new house (six years old) and the vent pipe ends in the roof space and there is a grill at the top of the roof where the gases escape/air comes into the pipe. British Gas sent out one of their plumbers yesterday. He reckoned that he unscrewed the vent in the loft and looked in it and couldn't see an obstruction. He is going to come back with something to fit to the pipework on the bathroom sink to stop gases coming into the bathroom.

    My question is, could the grill on the roof be obstructed with spider webs maybe reducing ventilation in the vent pipe? The plumber said there was no obstruction, but I don't believe that he actually physically examined it as he didn't get into the roof space (stayed on his ladder throughout).

    Any advice would be welcome. Thanks.
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Need an anti vac trap on the basin sounds like the bath and basin are connected/ basin is teed into the bath waste
  3. Samantha Jennings

    Samantha Jennings New Member

    Hi. Thanks for the reply. I think that the British Gas Engineer is coming back to fit what I imagine must be an anti vac trap. Presumably this will stop sewer gases coming into the bathroom.

    Will there be any consequences to not actually solving the problem as to why the problem of syphoning is occurring in the first place? I am just a bit worried that British Gas are addressing the symptoms but not getting to the root of the cause of the problem.
  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    If they are connected it's just the volume of water from the bath sucking the trap out

    Anti vac trap should sort it out no problem, don't think it's a main venting issue
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  5. oz-plumber

    oz-plumber Plumber

    Has the problem just started or has it been an ongoing problem?

    If the problem has just started there is a blockage or partial blockage in one of the sewer / discharge pipes and fitting a AAV will only be a temporary fix.

    Might be time to have someone camera the drains to find the cause.

    If it's been an ongoing problem a camera down the drains will most probably find out what is causing the issue.
    It may have been installed incorrectly in the first place
  6. Samantha Jennings

    Samantha Jennings New Member

    Hi. Thank you for your replies. It is a new house (five years old) and we didn't have any problems with sewer gases in the bathroom when the bath drained to begin with. This started happening about six months ago.

    When you day that the AAV will be a temporary fix, what is likely to happen in future if the problem remains unsolved?
  7. oz-plumber

    oz-plumber Plumber

    The problem will get worse.

    Something is blocking the ventilation to the drain - that's the reason why the basin trap is be syphoned.
    Allowing air in at the basin through an AAV will probably alleviate the problem for the short term.
    I doubt it will be a long term fix.

    Either there is an obvious blockage or there is a plumbing design fault.
    If the problem has only been short term, I would assume a blockage.

    Spider webs on the vent cowl would seem an unlikely cause of this problem.

    Best pay for someone to camera the drains to see where the problem is.

    The camera should be able to pinpoint the problem and the exact location of where the problem is.
  8. king of pipes

    king of pipes Trusted Plumber GSR

    Do any family members have long hair i had a problem recently and it was caused by a build up of hair and hair treatment products blocking the pipework i had to remove the pipework and replace it , also disconnect the roof vent and check for a draught to make sure it is vented to outside cheers kop
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  9. Samantha Jennings

    Samantha Jennings New Member

    No family members have long hair! In fact, the bath isn't used a massive amount as people prefer showers. There is water in the trap of the bath though, so it isn't a case of the trap drying out through lack of use.

    If there was a blockage, wouldn't the bath, sink and toilet which all drain into one soil stack drain slowly? They all seem to drain quite rapidly.
  10. oz-plumber

    oz-plumber Plumber

    From the information you have given so far, you just have woeful plumbing installed.
    No answers seem to appease you.

    Take the recommended quick fix solutions and see how you go.

    Plenty of people have given you advice but you seem to come up with excuses as to why their reasoning doesn't suit your circumstances.

    Get the AAV fitted and let us know how you get on.
  11. Samantha Jennings

    Samantha Jennings New Member

    Oz-Plumber. I clearly don't have woeful plumbing because it used to function perfectly for the first four years we have lived here. Forgive me asking additional questions, but I want to be sure that it is money well spent before commissioning an expensive camera survey of the drains (especially since Dynorod claim they are clear from visual inspection).

    British Gas have now been and fitted a one-way valve to stop sewer gases coming out of the bathroom sink and it no longer glugs when we empty the bath. I can only assume that for now, the problem is sorted.
  12. Dan

    Dan Admin

    Try to be a bit more polite with your responses matey.
    • Like Like x 1
  13. Samantha Jennings

    Samantha Jennings New Member

    Thank you for this post. When British Gas removed a piece of Pipe to fit the anti -syphoning device, the waste pipe to the sink had a lot of slime in. I assume that this build up would have reduced the air in the pipe and led to the syphoning problem developing. Thank you again as I think I now understand why the problem has arisen!
    • Agree Agree x 1
  14. oz-plumber

    oz-plumber Plumber

    Will do.

    Re: The problem.

    Cannot see how the system worked perfectly for 4 or so years and the problem has arisen in the last 6 months.

    For 4 years the drainage system worked without an AAV, what has changed since the system was installed for it now to require an AAV ?

    I stand by my reckoning that the AAV is a 'quick fix' solution to a more serious problem.
    Time will tell.

    But by the time the same thing happens with the AAV installed, the problem will be multiple times worse.

    Lets wait and see
  15. Samantha Jennings

    Samantha Jennings New Member

    For what it's worth, I fear that you are right. I have got plumbing insurance with British Gas, but I doubt they will cover the cost of a drains survey as the new Anti Syphon Device has stopped sewer gases coming into the bathroom. I am going to price up how much it would be to get a survey done ourselves. Thanks anyway for the advice.
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