Soil Pipe Smell

[Victoria Hodgson]

We've recently moved into an older property and are in the process of addressing several botch jobs around the house. There's a 'drain' smell coming from the internal wall that houses the soil pipe running from the upstairs bathroom downstairs. We have it checked with CCTV for cracks and leaks and it seems to be OK, so I wondered if it was a venting issue? Any idea

 

[Bahco]

Does the top of this pipe terminate outside thru the roof as it should
If as you say work has been bodged check the ground has been filled in properly where the pipe enters underground.

 

[kevplumb]

cast or plastic ?

 

[Victoria Hodgson]

Thanks Bacho. No, It doesn't terminate through the roof. It look's as if it travels from the upstairs bathroom, horizontally and then vertically downstairs through a boxed in internal wall and outsiide. The soil pipe from the downstairs toilet also joins it just before it goes outside.

 

[Victoria Hodgson]

Plastic.

 

[Bahco]

Is your toilet plumbed into a stub stack with a small valve on top.
Check the connection from the toilet to the soil pipe. You say it goes along hjorizontally but there should be a branch teed off with a valve on top.
This valve could be allowing air out instead of allowing air in and would need replacing if this was the case.

 

[brumylad]

do any sinks, basins, showers or baths run to the stack ?

your waste plumbing might be suffering from trap seal loss.

Also Get the soil pipe pressure tested, this will check all the joins are air tight.

Post some pictures.

 

[Victoria Hodgson]

Hi there, I can see the downstairs sink goes into the soil pipe and the trap seems to be in order so suggesting that thats not where the smell is. There is no vent whatsoever would this cause a problem, its all very hard to see as its boxed in fro the upstairs toilet then goes horizontally under the floor then vertically and then boxed in also downstairs where it meets the other toilet which joins the soil pipe. I have unboxed it all downstairs and the smell really incrteased but i couldnt find any wet or dampness sauggesting a leak but there still could be a hairline crack somewhere I guess, you suggested a pressure test,, I havent heard of this??? who would do it a plumber? Also do you know if you are meant to have some sort of vent??? The soil pipe isnt on an outside wall anymore as the house has a single story extension and I have noticed most house have a big pipe going up high toletting the smells out we haent got this should we have, most things have been bodged in this house so I wouldnt be surprised if the job isnt up to standard. Many thanks for your time . Victoria

 

[brumylad]

the soil stack should be vented somewhere or at least have an air admittance valve.

I would get a plumber to give a quote for the necessary remedial work for an answer.

 

[Victoria Hodgson]

Shall get a plumber in to do that thanks for the advice at least I know what to ask them to quote for now. Marry Xmas

 

[DforDave]

I thought he was married already.

 

[Victoria Hodgson]

Can anyone tell me where an air admittance valve would be fitted on a soil pipe as I have no idea where to start looking as it seems the bad smell could be because this isnt working or there is no venting.

 

[DforDave]

This may help--->

http://www.diydoctor.org.uk/projects/air_admittance_valves.htm

 

[Victoria Hodgson]

Many thanks I now understand the working of this and know what to look for, if there isnt one fitted I shall get one installed hopefully this should solve the bad smell problem.