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    destroyityourselfer's Avatar
    destroyityourselfer Posts: 3, Reputation: 1
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    #1

    Sep 7, 2005, 04:10 PM
    Sewage odor inside of the walls
    Hi
    Sorry if this was covered already, but I have a “mysterious” smell problem. :eek:
    We recently had our leach field replaced and tank pumped. Since then a sewage odor occurs near the downstair bathroom in the basement, but also travels up the walls into the 2nd floor bedroom and basement and even up above to the 3rd floor closet along that same wall. The problem may have existed prior to pumping, but it was surely not nearly as noticeable as it is now and not noticeable upstairs before. It gets worse at night during temperature inversions and by morning is unbearable.

    The plumbers have knocked down the walls next to the bathroom downstairs expecting to find improper venting, but so far that is not the case. We assume the tub downstairs is on a p-trap, but that would be in the cement slab so we really don’t know, but again, the odor isn’t really in the bathroom but behind the wall. The house also had improper S traps under the bathroom sinks, but replacing them didn’t help. We have no gurgaling sounds in any fixture and everything flows well.

    I think the key here is that the smell is much worse inside the walls than in the bathroom themselves and I really suspect that’s where the odor is and not from the fixture traps.

    But, how could that be? Could it be a broken main under the slab? I read on another thread that inside the wall smell could be a trap seal, but the recommended analysis doesn’t show any water flow gurgling of any kind. The plumbers now want to jackhammer the floor to see if all of the drains and vents below the slab are connected right, but that may not yield any result either and was hoping one of you might have a suggestion before they proceed with that mess.

    Thanks in advance.
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
    Eternal Plumber
     
    #2

    Sep 8, 2005, 06:29 AM
    Quote Originally Posted by destroyityourselfer
    Hi
    Sorry if this was covered already, but I have a “mysterious” smell problem. :eek:
    We recently had our leach field replaced and tank pumped. Since then a sewage odor occurs near the downstair bathroom in the basement, but also travels up the walls into the 2nd floor bedroom and basement and even up above to the 3rd floor closet along that same wall. The problem may have existed prior to pumping, but it was surely not nearly as noticeable as it is now and not noticable upstairs before. It gets worse at night during temperature inversions and by morning is unbearable.

    The plumbers have knocked down the walls next to the bathroom downstairs expecting to find improper venting, but so far that is not the case. We assume the tub downstairs is on a p-trap, but that would be in the cement slab so we really don’t know, but again, the odor isn’t really in the bathroom but behind the wall. The house also had improper S traps under the bathroom sinks, but replacing them didn’t help. We have no gurgaling sounds in any fixture and everything flows well.

    I think the key here is that the smell is much worse inside the walls than in the bathroom themselves and I really suspect that’s where the odor is and not from the fixture traps.

    But, how could that be? Could it be a broken main under the slab? I read on another thread that inside the wall smell could be a trap seal, but the recommended analysis doesn’t show any water flow gurgling of any kind. The plumbers now want to jackhammer the floor to see if all of the drains and vents below the slab are connected right, but that may not yield any result either and was hoping one of you might have a suggestion before they proceed with that mess.

    Thanks in advance.
    A smell problem's tough for us. You almost have to be on site to "snort" it down. It's not unusual for the smell to be worse in a confined area such as walls but that doesn't necessary pinpoint the problem. I fail to see how pumping the septic tank and replacing your drain field could cause a smell in your house. Since you replaced the "S" traps I assume the fixtures were vented properly. What material are the drainage pipes made of? Cast iron? Plastic? Combination of the two? Sending a Sewer Viewer,(camera) down the drainage pipes might save you the hassle and expense of jackhammering up your floor. If your drainage pipes are cast iron and are older I might have a idea. Are they? Regards, Tom
    destroyityourselfer's Avatar
    destroyityourselfer Posts: 3, Reputation: 1
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    #3

    Sep 8, 2005, 09:14 AM
    Thanks for the reply
    Hi again speedball 1

    Thanks so much for the reply. I understand why its hard to make the call without being able to see it. Let me see if I can flesh this out a bit.

    Yesterday I had the leach field guy come back because I noticed that the new D-box connection had water seeping out of it, meaning the seal was leaking. Since then, the problem lessened significantly but not completely. I guess the opening allowed much more venting through the tank and into the house when temperature inversions occurred at night and also when those drainage pipes (which are ABS, by the way) from near where the smell came from where used in the morning. Also, last night I plugged unused screw holes through the back of tub overflow drain connection behind the tub with silicon caulk thinking that was where the smell behind the wall was originating from. I also plugged the tub drain in the bathroom with a rag. This morning, that bathroom smelled almost perfect and so now I am thinking that there may have been some gas transfer through that drain too, but that is a guess. Bottom line, it is not fixed but the smell is greatly reduced and I don't have to run out of the house in the morning.

    OK, because the smell is much less now, I "pinpointed" the ongoing smell as coming from inside the now removed bedroom wall at the tub drainage area; meaning of course that the silicon plugging obviously didn't completely eliminate the gas exchange back there, but it may have helped. At that area the metal pipe from the tub overflow "T's" directly with a horizontal metal tub drain pipe directly behind and below the tub via a couple of coupling nuts and then that goes down into to a (guessing again) ABS pipe that runs horizontally under/in the slab. There is no visible P-trap for that end of the line tub drainage system, but what is below the slab, who knows. Apparently, that assumed underground connection from the tub drain (guessing again of course as it's under cement) connects with the 4" ABS main going down into the slab and out to the tank. Between the tub and main drain (the main drain is about 2 ft away from the tub drain) there is a 3" ABS pipe 1 1/2 feet away from the tub drain that goes up the 2nd floor bathroom; which we assume is the vent pipe for both the downstairs and upstairs bathtubs since no water flows through it from upstairs fixtures and because the downstairs toilet and lav also have their own 3" vent pipes.

    Here's my current best guess as to what is happening and I would greatly appreciate it if you would check my logic here:

    The leach field D-box seal breach allowed more significant venting through the septic system during temperature inversions, which unmasked a more fundamental problem of the sewer gas leak inside the house, behind the downstairs tub. If (still somewhat of an "if", but likely true) everything is vented properly, that would suggest to me that the tub has no P-trap. But, that still wouldn't explain why most of the gas smell emanates behind the tub and not in the bathroom from inside the tub. Of course, there could also be either a break or breach in the tub drain pipe or a gas leak from the connection where the metal drainage system for the tub and PVC come together, but again with no P-trap I would still assume a lot more of the gas smell would emanate from the bathroom drain and not so much behind the tub.

    So, to me that would mean it might be best to try replacing as much of the metal tub drain system first, which may or may not need cement removal. Then, if that doesn't work the only thing left to do is to dig up the cement, see what is down there P-trap-wise and while down there replace as much of that tub-to-main line piping as possible to eliminate any unseen pinhole sized breaches.

    Please let me know if this long explanation makes sense?

    Thanks much!
    :D
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
    Eternal Plumber
     
    #4

    Sep 9, 2005, 06:21 AM
    Quote Originally Posted by destroyityourselfer
    Hi again speedball 1

    Thanks so much for the reply. I understand why its hard to make the call without being able to see it. Let me see if I can flesh this out a bit.

    Yesterday I had the leach field guy come back because I noticed that the new D-box connection had water seeping out of it, meaning the seal was leaking. Since then, the problem lessened significantly but not completely. I guess the opening allowed much more venting through the tank and into the house when temperature inversions occurred at night and also when those drainage pipes (which are ABS, by the way) from near where the smell came from where used in the morning. Also, last night I plugged unused screw holes through the back of tub overflow drain connection behind the tub with silicon caulk thinking that was where the smell behind the wall was originating from. I also plugged the tub drain in the bathroom with a rag. This morning, that bathroom smelled almost perfect and so now I am thinking that there may have been some gas transfer through that drain too, but that is a guess. Bottom line, it is not fixed but the smell is greatly reduced and I don't have to run out of the house in the morning.

    OK, because the smell is much less now, I "pinpointed" the ongoing smell as coming from inside the now removed bedroom wall at the tub drainage area; meaning of course that the silicon plugging obviously didn't completely eliminate the gas exchange back there, but it may have helped. At that area the metal pipe from the tub overflow "T's" directly with a horizontal metal tub drain pipe directly behind and below the tub via a couple of coupling nuts and then that goes down into to a (guessing again) ABS pipe that runs horizontally under/in the slab. There is no visible P-trap for that end of the line tub drainage system, but what is below the slab, who knows. Apparently, that assumed underground connection from the tub drain (guessing again of course as it's under cement) connects with the 4" ABS main going down into the slab and out to the tank. Between the tub and main drain (the main drain is about 2 ft away from the tub drain) there is a 3" ABS pipe 1 1/2 feet away from the tub drain that goes up the 2nd floor bathroom; which we assume is the vent pipe for both the downstairs and upstairs bathtubs since no water flows through it from upstairs fixtures and because the downstairs toilet and lav also have their own 3" vent pipes.

    Here's my current best guess as to what is happening and I would greatly appreciate it if you would check my logic here:

    The leach field D-box seal breach allowed more significant venting through the septic system during temperature inversions, which unmasked a more fundamental problem of the sewer gas leak inside the house, behind the downstairs tub. If (still somewhat of an "if", but likely true) everything is vented properly, that would suggest to me that the tub has no P-trap. But, that still wouldn't explain why most of the gas smell emanates behind the tub and not in the bathroom from inside the tub. Of course, there could also be either a break or breach in the tub drain pipe or a gas leak from the connection where the metal drainage system for the tub and PVC come together, but again with no P-trap I would still assume a lot more of the gas smell would emanate from the bathroom drain and not so much behind the tub.

    So, to me that would mean it might be best to try replacing as much of the metal tub drain system first, which may or may not need cement removal. Then, if that doesn't work the only thing left to do is to dig up the cement, see what is down there P-trap-wise and while down there replace as much of that tub-to-main line piping as possible to eliminate any unseen pinhole sized breaches.

    Please let me know if this long explanation makes sense?

    thanks much!
    :D
    What happens out in the septic tank, manifold or filter bed should have no effect on sewer gas in your home if all the fixture trap seals were intact. This is why each fixture has its own trap seal. To isolate the fixture drain, ( and in the case of your tub, the waste and overflow),from the sewer. What you have explained puts the focus squarely on the tub trap seal, or lack thereof. It could be a crack in the bottom of the trap letting the seal leak away or a vent problem the lowers the seal level but the tub trap is where I would start. The trap could be brass or plastic depending on the material of your drainage pipes but something is surely wrong in that area and that's where I would be looking first. Regards, Tom
    destroyityourselfer's Avatar
    destroyityourselfer Posts: 3, Reputation: 1
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    #5

    Sep 15, 2005, 10:18 AM
    Yes, you are correct about that and thanks
    Hi,
    Thanks for your advice during my "crisis".
    I wanted to share with you how this worked out for your possible future recommendations.

    It turns out that the Tub in fact had a P-trap and the venting was technically correct.

    The problem was a sheared ABS vent pipe in the wall upstairs from where I thought it was.

    The pipe is made by Centaur and there is a class action law suit against them and other companies that made faulty ABS pipes between 1984 and 1989 I think.
    http://www.abspipes.com/
    Apparently it was a huge problem out here in California, and it led some townships to ban ABS all together and drainage pipe can now only be cast iron in some places.

    The interesting part is how to detect the hidden odor source. There are fuse lit smoke "candles" made just for this purpose. You can get them on the web or through a plumbing supply but I did have a difficult time finding a plumber who knew this technique. Anyone can do it, but be warned the heat can melt the ABS so do it in an outside cleanout or RV dump pipe.
    http://www.metermall.com/product%20p...%20Candles.htm

    Basically, you duct tape one of these candles to a wire coat hanger bent up to hang it inside on the lip of a clean out pipe to the tank or to the house to make sure it doesn't slip all the way down into the tank.

    You light fuse, drop it down the pipe, hang it on the edge with the coat hanger, cover the pipe with a towel and use a small vacuum cleaner with the hose attached to the blower end and you blow the smoke into the system. About 2 seconds later, smoke is billowing from your vents on the roof, and if you have a leak in the house, out of the leak too. Worked like a charm, but in some cases (large houses etc), you may have to plug the vents on the roof for maximum effect. Not a problem in my case since the vent pipe was completely sheared.

    Anyway, I hope someone else can benefit from my experience.

    Thanks again for you help.
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
    Eternal Plumber
     
    #6

    Sep 15, 2005, 10:58 AM
    Quote Originally Posted by destroyityourselfer
    Hi,
    thanks for your advice during my "crisis".
    I wanted to share with you how this worked out for your possible future recommendations.

    It turns out that the Tub in fact had a P-trap and the venting was technically correct.

    The problem was a sheared ABS vent pipe in the wall upstairs from where I thought it was.

    The pipe is made by Centaur and there is a class action law suit against them and other companies that made faulty ABS pipes between 1984 and 1989 I think.
    http://www.abspipes.com/
    Apparently it was a huge problem out here in California, and it led some townships to ban ABS all together and drainage pipe can now only be cast iron in some places.

    The interesting part is how to detect the hidden odor source. There are fuse lit smoke "candles" made just for this purpose. You can get them on the web or through a plumbing supply but I did have a difficult time finding a plumber who knew this technique. Anyone can do it, but be warned the heat can melt the ABS so do it in an outside cleanout or RV dump pipe.
    http://www.metermall.com/product%20p...%20Candles.htm

    Basically, you duct tape one of these candles to a wire coat hanger bent up to hang it inside on the lip of a clean out pipe to the tank or to the house to make sure it doesn't slip all the way down into the tank.

    You light fuse, drop it down the pipe, hang it on the edge with the coat hanger, cover the pipe with a towel and use a small vacuum cleaner with the hose attached to the blower end and you blow the smoke into the system. About 2 seconds later, smoke is billowing from your vents on the roof, and if you have a leak in the house, out of the leak too. Worked like a charm, but in some cases (large houses etc), you may have to plug the vents on the roof for maximum effect. Not a problem in my case since the vent pipe was completely sheared.

    Anyway, I hope someone else can benefit from my experience.

    Thanks again for you help.
    And thank you for the information. We stopped using ABS in the 60's in the Tampa Bay Area and went to PVC. Tom

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