SMELL FROM FOSS !!!

[Colandhelinfrance]

Hi, we have just had part of our house near Ruffec renovated, including putting work right, done by the French plumber who installed our foss.

The renovation included re-laying the soil pipe from the loo's under a concrete floor and into our field where the foss is situated. The work looks first class, but with one problem. A horrible smell from the foss,which comes and goes. We managed to trace one source of the smell to a waste pipe, which was installed for our washing machine (in a separate utility room) we filled the waste pipe up with water (creating a water seal in the u bend) and this stopped the pong from there.

There is still a smell coming and going, the only other place I can see it could come from is the sink waste pipe (yet to have a sink attached) the builder has told us that this is where it IS coming from. He then taped it up until we have the sink fitted, but the smell is still there. He insists that once the u bend is fitted and filled with water the smell will go.

I am not convinced at all, as there should now not be any smell with the pipe taped up.

Any suggestions please.

[Dave]

Hi, we had smells from our fosse and it was caused by the flushing of the loo, whenever it was flushed it caused a vacuum on nearby waste pipes from the bath and sink that siphoned the water out of the trap thereby allowing the smell from the fosse to enter the bathroom, i cured it with some 'anti syphon' wastes bought from the UK, since then i have seen in a friends bathroom a waste pipe from the sink with a vertical 'T' that had a small valve at the top, this does the same job as my 'anti syphon' wastes from the UK. of course if you have NO live waste pipes yet this is not the cause, did he install a breather pipe before the fosse, ours is discreetly hidden on the outside end of the house to a height of around 3 metres, knowing this forum I am sure that someone with more knowledge than myself will give you some advice, i wish you good luck with solving your 'smelly' problem.

best regards

Dave

[Colandhelinfrance]

Thanks Dave,

We are using the foss, but the smell is only downstairs in what will be the kitchen, we have a vent pipe outside, this is about three feet above out guttering. The kitchen is completely plasterboarded except the hold where the waste and water pipes for the sink come in. This is quite a large hole, and if you put your hand there you can feel a draft, but I can not smell anything at this hole, or indeed around the taped up sink waste pipe.

Regards     Colin

[Punch]

First thing to perhaps trying is elimnate the kitchen sink pipe by fitting a tempoary trap and filling it with water. You could just make one up with some 40mm bends.

If the smell persists after this, it could be that your plumber hasn't glued one or more of the joints (perhapsbehind the large hole in the plasterboard?)We had this recently in a bedroom where a customer was complaining about a smell. It turned out that a boxed in horozontally run soil pipe, had not been solvent glued and the smell was permeating from one of the joints.

As Dave has mentioned it could be caused by siphoning, but dpends on how he (your plumber)has run his pipes.

Like all these problems it is very difficult to diagnose a problem without seeing the installation.

regqards,

Paul

 

[Gyn_Paul]

Hi, I realise it's probably not easy if the place has been plasterboarded, but would it be possible for you to break into the plumbing at the place furthest/ highest from the fosse and add another air valve? this would allow air into the system to balance the vacuum effect of the flushing loo. But only if it is sucking...

The problem might be that the air is being pushed out of one of the traps as the loo flushes.

I totally agree with Punch vis. the taped-up pipe: strip off the tape and put a U-bend on it temporarily - a thin strip of masking tape will normally make it gas-tight without recourse to welding it in place. Fill it with water and then shine a torch down it and observe the movement of the level as the loo is flushed. if it bubbles you've found your problem. Often it can be cured by fitting deep traps (greater head of water to move before the gas can escape round the U-bend), but really troublesome ones may need intervention at the fosse.

paul

[Weedon]

I think that an earlier poster has suggested this but if I read it incorrectly have a look to see if the installer has fitted a vent pipe and if not, fit one between the last waste pipe and the fosse.  For some reason it is not always done by installers, as was pointed out to me when I had a french artisan at my place looking at my own installation, when he was surprised that I had installed one.

In the "dormant" stage there will be gas present in your pipes backing up from the fosse and then when you flush, the gas has to escape through the line of least resistance and if it is a sink waste or washing machine waste or other some such pipe, there is your smell.

weedon

 

[Colandhelinfrance]

Thank you weedon, we do have a vent pipe. I have a trap on the washing machine waste & no smell comes from there. But as far as the sink waste is concerned, there is no trap on it yet, but the pipe is taped up.