Smell from Soil stack

[marc_ely]

We moved into a 22yr old house about 6months ago. Since moving in we've noticed various nasty smells in the bathroom, cloakroom, utility and ensuite. They come and go and are not always in all places at once. They mostly occur after a hot dry spell, followed by rain, but not always.

Tonight the smell was very bad in the bathroom while I was bathing the kids. It appeared to come from the toilet, and the waste pipe next to it. This goes into a boxing and then goes downstairs to the cloakroom, and then down to the main sewer. There is a similar setup in the ensuite, which again has the waste pipe going into boxing and downstairs again, to the utility this time.

I have checked in the loft space and the soil pipes do not continue upwards into this space. There appears to be no ventilation of the soil pipes, unless this is inside the boxing, which has no access panels I can look through.

The bathroom tonight had water in the traps on the bath and the sink, and it still smelled, so I don't think the smell is coming from the overflows due to dried out traps. I am also reminded by the boss that the toilet has been recently cleaned!

I can't see any leaks around the soil pipes themselves, so I am a bit confused as to where the smell is actually coming from? Does anyone have any idea? And how do I go about fixing this problem? Some sort of vent pipe?

Thanks for reading. Marc

[Dave Baker]

Probably a bad joint buried somewhere inside the boxing - but then you knew that already.

[Tim Downie]

We had a mystery smell like this about our house for a while until we realised that the drains were backing up. A partial blockage meant that pipes that should have been empty after flushing had toilet "residue" lying in them after use.

It wouldn't do any harm to lift any inspection covers that you have and check that things are flowing freely. I must admit, I'd be surprised if your soil stack wasn't vented somewhere.

Tim

[Roger]

The message from marc_ely contains these words:

If the top of the soil stack is open to the atmosphere then you are bound to get smells in the house if the open end is boxed in rather than outside the house. However your house should not have been built like that.

The chances are that the interior soil stack terminates in an air admittance valve which could have failed. Seems to me that you have no option but to dismantle the boxing in in the vicinity of the top of the pipe.

Another possibility is that one of the waste pipes has become partially detached from the soil pipe and no long makes an airtight joint but again you need to remove the cladding to see what is what.

[Frank Erskine]

That reminds me - I have a brand new AAV stashed in the loft (ISTR). I bought it years ago as part of a bathroom revamp, but changed the plans. The idea was to do away with the internal soil stack above bath level, having difficulty getting a short enough bath to accomodate both. Letting the end of the new bath into a studding wall a little bit at the other end solved the problem.

[Rod]

Hepworths produce a product called HepVO - which is a sort of trap. The documentation for this (linked below) shows, on page 4, 10 different ways in which conventional traps can fail, thus allowing foul air into the building. I am not trying to get you to change traps - but it does have nice little pictures/explanations and is readily accessible.

[Tim Lamb]

In message , marc_ely writes

Following major building works here, some 15 years ago, we had

*offensive effluvia* coinciding with spells of dry/wet weather.

Invariably foul water had backed up in the drains and was readily cleared by rodding. The pong would subside after a week or two.

I am reasonably sure that the builders accidentally lost something like a half brick which is gradually being shifted through the system towards the sewage receptor (about 50m to go).

Fiddling with air admittance valves had no useful effect. After several repeats, it percolated through to my brain that there must be a leak such that backed up sewage could find its way under the house.

Sure enough, where a new connection had been made in the existing system, the new plastic shoe was not fully sealed to the old benching. With the new discharge above the existing this only became a problem when the system backed up!

On the wet/dry link, my theory is that our pipe work is *geographically* uphill from the house. Clearly the drain has a fall but the trench back filled with free draining shingle, may actually be collecting subsurface water and directing it back under the house.

Luckily, the inspection pit was large enough for even a portly farmer to fix. No smells since but the real test will be how to recognise a back up without the accompanying pong:-)

regards

[John]

OP mentions the toilet had been recently cleaned! Is this enough? I ensure enough Domestos (not cheap smelly stuff) is put into the trap at night several time a week.

I thought it was permissible for several properties to omit a vent pipe - as long as something like one every 5th house has one. Can anyone correct this?

[Dave Plowman (News)]

I had this which turned out to be a failed toilet pan outlet seal. Didn't leak but allowed fumes to escape. They came up from the drains rather than being produced locally - so worse on a hot day. Of course any leak on the stack might do this. I'm afraid you'll have to unbox things and inspect. It will be the last bit you look at...

[Mark]

We had one like that (I can't be sure it was exactly the same) and it did not work (it let smells through) so was replaced with a conventional trap.

[Ian_m]

A friend had a similar problem where the toilet cistern overflow had been incorrectly been plumbed directly into the soil pipe (via a bodged mess of silicone), this was venting the soil stack into the cistern. Was only a problem at certain times when there was positive pressure in the stack.

Fixed by routing the overflow through an external wall as per normal and sealing teh stack hole.

Stopped the smell.

[Hugo Nebula]

On Thu, 3 Jul 2008 09:34:55 +0100, a particular chimpanzee, "John" randomly hit the keyboard and produced:

Or even confirm it. Provided all stacks are fitted with air-admittance valves, then a drain can have up to five stacks without an open vent. More than this, and up to x stacks, and there must be at least one open vent. There must be at least one open vent for every y stacks above x.

'x' and 'y' being numbers ICBA to look up.

[[e-mail]]

Smell from our stench pipe

[Fredxx]

Before replying to an 13 year old post from a broken website, please read and digest this:

Don't you think it might have been fixed by now?

[Harry Bloomfield Esq]

It's a fruitcake website, where many of the posters are fruitcakes - what do you expect?

[John Rumm]

I would rather not, but thanks for the offer.

[Brian Gaff (Sofa]

Actually I'm not sure why they are allowed to connect to the main backbone of Usenet. Their software is the main problem and of course when stuff is displayed there, the year is often missing from the date, though I can see it in text. Also because they do not quote without some convoluted messy interface the whole context is gone. The cynic in me might suggest that this is deliberate to get outsiders onto their web interface and get advertised to. Considering for years Google has had a less than perfect but workable web interface to the Usenet I'm surprised its still going at all. Brian

[Andrew]

On the plus side, the OP doesn't have Covid