unbearable stench - what have I done wrong

[Tin Soldier]

New build large extension - completely separate drain/waste from old system until it meets well outside to go into septic tank

 

Kitchen and bathroom have been  plumbed in for months and months

Kitchen has 1 waste will trap, thus no smell

 

Bathroom has three waste points

 

1. toilet is plumbed in to

2. sink is almost plumbed in to

3. SVP leading to an AAV in the loft

 

the sink has a 40mm pipe solvent welded to a reducer in a 110mm pipe, it comes upwards and out of the wall and is bunged at the end with an airtight bung. it was awaiting the wife painting the upcycled vanity unit (still bloody waiting)

 

It was set up this way for months, no smell

I put up a false wall, no smell

I tiled the false wall, no smell

 

months pass.

 

unbearable stench seemingly coming from false wall.

 

My thinking was one of the kids had slammed into the 40mm waste pipe broken the solvent weld, thus a small amount of gas is leaking.

Last night, I punched a large hole through the wall, cut the waste pipe to sink, and replace it brand new, this morning I woke to a godawful smell again

 

any ideas how/why this has started months after installation?

 

my plan for tonight is to go up to loft and check on AAV, but I doubt that's it

 

Edited October 24, 2019 by Tin Soldier

[Jeremy Harris]

Are all the traps full of water?

 

We have to remember to run the tap in the bath in the second bathroom once a month or so (we don't use it) otherwise the MVHR extract in there pulls in smells from the treatment plant when the trap dries out.

[Tin Soldier]

theres only two traps in the bathoom, one is the shower, which has plenty and I've run litres into, the other is the toilet, which is fully functional

 

Like I said the sink waste doesnt have a trap, but an airtight bung

 

in the kitchen, theres the kitchen waste trap which again is full 

[Ferdinand]

What sort of awful smell is it - poo awful smell, stagnant drains awful smell, dead rat in the wall smell etc?

 

Can you learn anything from the timings eg after someone has done a number 2, or had a bath or something?

 

Are there any external factors that may affect? eg drain work next door?

 

My first thought is if there is something coming back up one leg from another leg. Had that when we had just done my upstairs bathroom last month - because a bath running away puts more water through than a shower water was coming back up the drain of the downstairs shower and bringing gunge up into the shower tray through the drain. It also brought smells.

 

The solution was a one way valve in the waste pipe of the downstairs shower to stop backwash. We put similar in when we added the pipework for a bath upstairs as it was all done in the very personal style of the previous selfbuilder and his belt needed some braces.

 

And as JSH says - check traps.

 

Ferdinand

Edited October 24, 2019 by Ferdinand

[Onoff]

Our upstairs ensuite; the cistern overflow exits into the shower & basin waste pipe (I didn't do it). Sometimes a waft comes back up that way.

 

My wall drain in the new downstairs bathroom has a hair trap. Both women here have hair like Cousin It. If I don't regularly (yes me) remove the face plate and clear the hair trap it starts backing up across the wet room corner. Happened recently but the hair trap was clear. The odd hair that had got through had built up on top the drain grille outside. (No holes in the grille for the pipe shoe as yet).

[SteamyTea]

Occasionally, a neighbour, about 100 metres from me, blocks the main sewer. This causes a back up to the 6th house where I am.

The smell is very noticeable inside my house.

So do you have had neighbours that are causing the problem. If so, report it to the water company, they fine the bend blocking culprits.

Failing that, I find it is a hummus supper.

Edited October 24, 2019 by SteamyTea

[Tin Soldier]

interesting

 

so another question is

 

If all the traps are full, and the pipes sealed how does the smell get out?

does it force its way passed the seals in the soil pipe or?

[joe90]

Faulty AAV?

[Tin Soldier]

fingers crossed

[epsilonGreedy]

7 hours ago, JSHarris said:

Are all the traps full of water?

 

We have to remember to run the tap in the bath in the second bathroom once a month or so (we don't use it) otherwise the MVHR extract in there pulls in smells from the treatment plant when the trap dries out.

 

 

That is an interesting one, noted.

[Mr Punter]

I am pleased to note you blamed the kids first.  Well done, that is what they are there for.

 

Blocked drain below ground can cause issues. Lift a cover and have a look.

[Tin Soldier]

Hmmm replaced aav with a spare

 

Question is should I be able to notice the diaphragm withing it moving at all when toilets are flushed

[Nickfromwales]

1 hour ago, Tin Soldier said:

Hmmm replaced aav with a spare

 

Question is should I be able to notice the diaphragm withing it moving at all when toilets are flushed

You should hear it open tbh as the gurgle sound of the water flowing is open to atmosphere at the AAV when it functions. 
Can you block off the AAV temporarily to start a process of elimination? 

 

Last job like this ( same symptoms ) was a big juicy dead ? that got jammed in the battens behind the wallboards. 

The thing was dripping out of its own back end when I found it. Yuk. Smell is very similar but also distinctively rat, not crap, is easily identifiable to those who’s nose knows. ?

[Onoff]

8 minutes ago, Nickfromwales said:

Smell is very similar but also distinctively rat, not crap, is easily identifiable to those who’s nose knows. ?

 

I'd describe the smell when they die and rot as somewhat "meaty"...

 

@Tin Soldier, noticed any more flies than usual, always a sign. 

[ProDave]

The correct diagnosis would be to to do the normal air pressure test on the pipes to see if anything is leaking.

[Nickfromwales]

1 hour ago, ProDave said:

The correct diagnosis would be to to do the normal air pressure test on the pipes to see if anything is leaking.

He has a point  

[Onoff]

2 hours ago, ProDave said:

The correct diagnosis would be to to do the normal air pressure test on the pipes to see if anything is leaking.

 

Daft question but how do you physically  test for leaks at joints when testing if the pressure is dropping, logic says soapy water at the joints? 

[Tin Soldier]

I can't test the svp behind the false wall without a lot of destruction  ?

 

I just can't understand how everythings Been fine for months and this week it starts stinking 

[Onoff]

2 minutes ago, Tin Soldier said:

I can't test the svp behind the false wall without a lot of destruction  ?

 

I just can't understand how everythings Been fine for months and this week it starts stinking 

 

What smell is it? Poo, rat, 10 Rillington Place type decomposition? ...

 

 

[Tin Soldier]

Poo

[JFDIY]

Is there any means of positive pressure getting out, i.e is there an open stack on the system anywhere? 

 

Could be when another user on the system flushes it pushes a slug of foul air through one of your traps, you might just have the smallest trap depth in that room.

 

 

[ProDave]

Okay another possibility

 

You have a dead mouse in the wall.  Don't under estimate how much stench a rotting mouse corpse can make as it decomposes until you have smelled it.  It might be nothing to do with the pipes at all?

[recoveringbuilder]

I feel for you! We had this in our last house. It wasn’t happening for the first couple of years then all of a sudden it started happening. We would have it for a few days then it would disappear for months only to return again, we tried everything, new aav, put an outside stack in , tested pipes, resealed  all the pipes at the toilet pan , nothing worked, one plumber we spoke to said the under floor heating was causing it drying out the shower trap but we never did get to the bottom of it. 

[SteamyTea]

Can you flush gallons of water down everything, talking a tonne or two, not a bucket.

See if it goes away, or backs up.

Maybe with some bleach to act as a marker smell.

Edited October 26, 2019 by SteamyTea

[Tin Soldier]

Well  I got to the bottom of it

 

There was very little water going through the inspection chamber I basically did as above and ran gallons and gallons of water down every outlet at the same time, very little making its way out

 

5 mins later I heard something slowly moving down the pipe outside like a rat crawling down it, until... 

 

Well you don't want to know what it looked like, Needless to say it was massive, it was brown and it stunk.. It spewed our of the inspection chamber base  broke up and was followed by a torrent of water

 

Diagnosis

 

Baby wipes, bits of plaster, bits of plastic all probably places there whilst pipes were open and kids could get to them

 

I am smell free!