Please help: post-reno sewer smell

Discussion in 'Toilets and Sinks' started by fussen, Sep 2, 2013.

  1. Sep 2, 2013 #1

    fussen

    fussen

    fussen

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    Your expertise and experience valued. I'm a layman with a big problem I can't solve!

    We are at the top of a sewer/vent stack on the 30th floor of a tower.

    We replaced 15 year old high flow toilets during a total reno of 2 baths. Into both baths, we put the same two-piece, 1.28 gpf single-flush floor-mounted Duravit Stark 3 comfort height toilet

    http://www.plumbingforums.com/photo/post-reno-sewer-gas-smell-pics-323.html

    In one bath, no problems. In the other bath we have an intermittent sewer gas smell.

    • This work was done by certified plumbers, with City permits and inspected and passed inspection.
    • We did not move any existing drains, simply reno'd around & put new fixtures on existing ones.

    In the problem bath
    • there is a shower drain: no smell.
    • there is a sink drain: no smell.
    • there is no smell in the wall-hung vanity (which is on the same wall as the sewer vent and smelly toilet) which our contractor tells us is open to the wall interior behind a cosmetic board.
    • The shower is now large and extends over top of a former bathtub drain that has been sealed. That drain never smelled before reno and is now capped, siliconed and the space around it filled with rubber firestop per code. It is now under a fully tiled shower base.


    • Plumber returned, lifted toilet, showed us he'd used a wax ring with black funnel. He added a second wax ring (no funnel) and re-set toilet.
    • Note: when the toilet was off the air from the drain was blowing VERY hard into the bathroom. The building's plumbing system maintenance rep who came on-site at one point said that's entirely possible and normal at the top of a stack like this. (any comment? is it?) Other times we've had the drain exposed the air pressure has seemed neutral.
    • After plumber re-set toilet, now with 2 rings, intermittent smell continued. Although not every time, often smells after we finish showering. We turn on the bathroom fan before we shower & by the time we get out (10 minutes?) later it is smelling. It is also noticeable at times when we have our suite windows open and there is a wind.
    • Building manager advised sewer gas smells have been experienced in other suites with negative in-suite pressure -- which ours has. They claim cutting the bottom off the suite door (to the hallway) has resolved it for others; we've done that and it has not resolved.
    • We used painters tape to seal off the joins between toilet tank top & lid; between toilet tank bottom and toilet base; closed lid and sealed it to base. Did not resolve.
    • Building plumbing system maintenance company advised vent was clear at the roof. We were also told that other suites would be reporting problems if the vent was plugged.
    • We removed the toilet and with a plastic bag and tape, covered over the sewer drain and surrounding tile (attached pic). There was no smell during that time but it could have been that conditions just weren't right (assuming negative pressure is related).

    http://www.plumbingforums.com/photo/post-reno-sewer-gas-smell-pics-325.html

    Only guess from plumber, building maintenance manager, etc. was that negative pressure was too great for volume of water in the low-flow toilet; that sewer gas must be bubbling through the P-trap. They advised us to get a larger-flow toilet. However,

    • we have never witnessed bubbling in the toilet bowl.
    • there is no smell in the toilet bowl -- when we encounter the smell before it's spread far, it smells fresh in the bowl when the air around the toilet doesn't.
    • I understand that the idea is more water in the bowl would provide more pressure against sewer gas bubbling through. However, I also understand now that more water in the tank doesn't necessarily mean more water in the bowl, and toilet specs don't seem to include water volume retained in the bowl (only water surface area which is not necessarily a measure of volume depending on bowl shapes).

    Instead of replacing the toilet with a larger flow one immediately, we replaced it with the same model to rule out a faulty toilet.


    • Recently walked in as it started to smell (weather had changed, wind was blowing & our suite windows were open).
    • There was no smell in the toilet bowl but it was quite strong around the tank. I sealed the top of the tank with a plastic bag and tape, then set the lid on it.
    • Smell recurred the next day.
    • I removed the bag from the tank and there was no smell in the tank. But, it was very evident it was strongest behind the toilet, between the tank and the wall.
    • The back of this toilet base is completely open (see attached pic) so the large open space will allow full opportunity for gas escaping the drain/seal to escape the base. Because space is so tight, we'd never be able to get a silicone seal around the back side of the base.

    http://www.plumbingforums.com/photo/post-reno-sewer-gas-smell-pics-324.html

    Other suggested causes:

    • Sealed bathtub drain causing problems with venting. But, how could this be when there was no smell before and that drain wouldn't have served as a vent as it had a P-trap.
    • Vent in wall is cracked or had a screw put in it during reno. But, assuming contractor is correct that back of vanity is open to the plumbing (not sealed with drywall), unlikely since there's no smell in the vanity.

    I'm leaning toward both wax ring installations being faulty.

    I don't know if it's that, if I need to start cutting into walls, or requesting our building maintenance people investigate anything else... :confused:

    Any input very welcomed. Thank you.
     
    Last edited: Sep 2, 2013
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  2. Sep 2, 2013 #2

    IFIXH20

    IFIXH20

    IFIXH20

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    The closet flange should mount on top of the finish floor not flush with the finish floor. I can't see the photo clear enough but the closet flange don't seem to be sealed with the drain. What is connecting the brass closet flange to what appears to be a cast iron drain? Usually lead is attach to the drain and flange. I think you problem is at the toilet flange/drain.
     
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  3. Sep 2, 2013 #3

    johnjh2o

    johnjh2o

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    IFIXH20 hit the nail on the head. They placed a brass flange over the top of the cast iron flange. Your sewer smell is caused because there is no seal between the two flanges. There are much better ways to replace closet flanges. We have had good results with this product. It fits inside the cast iron and sealed with a gasket that is tightened with bolts that are part of the flange. Jut be sure that the flange is also fastened to the floor.
    http://www.oatey.com/products/drains-and-closet-flanges/closet-flanges/replacement-closet-flange
     
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  4. Sep 2, 2013 #4

    fussen

    fussen

    fussen

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    Thanks so much IFIXH20 and johnjh2o! To have both of you respond with the same concern is very helpful, so thanks for contributing.

    I may have questions, but will investigate this with the contractor/plumber this week.

    Truly, thank you again!!
     
    Last edited: Sep 2, 2013
  5. Sep 2, 2013 #5

    fussen

    fussen

    fussen

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    Hi again,

    I'm less confident in the assessments now that I've removed the toilet (could just be I don't know the parts & expected install). Also measured the pipe diameter: 3".

    Here are some new pics. Comments appreciated!

    a) How big a deal is it that the brass flange is flush with the floor?

    b) There is a rubber/plastic piece, not just brass on cast iron.

    http://www.plumbingforums.com/photo/toilet-underside-333.html

    *Note: the wax is somewhat deformed because the toilet wasn't lifted straight off.
    http://www.plumbingforums.com/photo/wax-after-toilet-removal-326.html

    http://www.plumbingforums.com/photo/wax-before-removal-327.html

    http://www.plumbingforums.com/photo/seam-at-next-pipe-join-334.html

    http://www.plumbingforums.com/photo/removing-2-wax-rings-328.html

    http://www.plumbingforums.com/photo/layers---brass-at-top-a-329.html

    http://www.plumbingforums.com/photo/layers---brass-at-top-b-330.html

    http://www.plumbingforums.com/photo/layers---brass-at-top-c-331.html

    http://www.plumbingforums.com/photo/rubberplastic-piece-332.html

    Thank you!!
     
    Last edited: Sep 3, 2013
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  6. Jan 18, 2014 #6

    fussen

    fussen

    fussen

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    Hello everyone,

    Our plumbers visited yet again and we shared the information provided in these posts. They disagreed with the suggestions, saying the suggested product was for a 'completely different purpose'. Instead, they caulked all over and around the top of the closet flange. It worked, at least for 99.5% of the time. And with that we're sufficiently satisfied.

    Thanks to everyone who took the time to comment and share your expertise. It was very appreciated!
     
  7. Jan 18, 2014 #7

    Caduceus

    Caduceus

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    Thanks for following up with us. Though I didn't participate in advice on the thread, I would have to add that by caulking all over and around the top of the closet flange the plumber has confirmed what IFIX and John had suggested was the problem. Hope you stay trouble free and stop by the forum again.
     
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  8. Jan 18, 2014 #8

    IFIXH20

    IFIXH20

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    I think your plumber did you a disservice. I think they should have removed the brass flange, Then cut the ABS flange out with a inside pipe cutter and install a long closet flange with the flange setting on the finish floor. (In the first set of photos the drain looks like cast iron instead of ABS. My mistake)
     
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  9. Jan 19, 2014 #9

    fussen

    fussen

    fussen

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    @Caduceus and IFIXH2O thank you for your follow up comments. I'll be relying on all of this input heavily if I need to address it again, with the same or different plumbers.

    My delay in posting, in part, was fear of the smell returning. It did feel like a 'bandaid' fix though I'd resorted to effective as the minimum criteria and that seems to have been nearly met. In many months now we've smelled gas only once.

    It's frustrating as I'd prefer it to be done right, but with your additional comments perhaps the next time we need to lift the toilet we'll have a chance to get it right.

    Thank you for generously sharing your time and expertise. I wish I could host you in Canada and hire you for the job!
     
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  10. Feb 4, 2014 #10

    fussen

    fussen

    fussen

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    Well everyone, fingers crossed.

    When the smell returned (no surprise given the stop-gap 'add caulking on top of the flange' strategy) we switched plumbers. As we had with our first plumbers we shared everything that had been said on this forum first. As soon as they lifted the toilet they confirmed that they agreed with these assessments and that the problem was the flange setting.

    They've replaced the brass flange (in both baths -- we didn't want to risk it!) with a very similar product to the one recommended here (they referred to it as a Twist & Set). Pic attached.

    Thank you all so much for your time & support. I can't tell you how appreciated it has been.

    photo (6).jpg
     
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  11. Feb 11, 2014 #11

    Caduceus

    Caduceus

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    Let's hope this does it. Please follow up with us and tell us if the problem is solved.



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