Durgo smell Drainage and wastage systems and plumbing help, advice and answers

[80Sprint]

My new downstairs shower room/toilet builds up a drain smell overnight or if left unused for some time. The flow to the main drain was just about the minimum the inspector would allow but it all seems to flush ok. The shower and the sink are also tapped into the vertical pipe that was left cut off by the builders as i was going to final fit the room. The pipe has a Durgo valve fitted on the top and is boxed in but not sealed. The tee for the shower and sink are below the Durgo.

Could the smell be coming from the shower/sink and does the fitment above sound right. Should i expect to get the smell from the Durgo ? I know you can use these inside but surely the air will smell and it has to escape in the room. I could cut into the wall and vent externally ( don't know why the builder didn't do this anyway ) but i don't want to damage the wall and redecorate.

There is an external soil stack on the opposite side of the house and the drainage meets at the front of the house and out to the road. Could i do away with the Durgo and cap it ?

[stokedan1]

My new downstairs shower room/toilet builds up a drain smell overnight or if left unused for some time. The flow to the main drain was just about the minimum the inspector would allow but it all seems to flush ok. The shower and the sink are also tapped into the vertical pipe that was left cut off by the builders as i was going to final fit the room. The pipe has a Durgo valve fitted on the top and is boxed in but not sealed. The tee for the shower and sink are below the Durgo.

Could the smell be coming from the shower/sink and does the fitment above sound right. Should i expect to get the smell from the Durgo ? I know you can use these inside but surely the air will smell and it has to escape in the room. I could cut into the wall and vent externally ( don't know why the builder didn't do this anyway ) but i don't want to damage the wall and redecorate.

There is an external soil stack on the opposite side of the house and the drainage meets at the front of the house and out to the road. Could i do away with the Durgo and cap it ?

i think external stacks need planning so maybe this is why the builder kept it internal, dont cap the durgo ( air admittance valve ) this will siphon your toilet and traps. check all traps have seal check connections to soil pipe and durgo is fitted correctly

[BigRod-BidefordDevon]

You do not say where the the shower room is in the house, if it is at the front of the building the Local Authority may have insisted in the Stack Pipe being internal for cosmetic reasons.

I would check the Durgo valve as it may be defective/sticking. Under normal operation air/odours should not egress as the valve is designed to only allow air to enter the pipe.

Do not cap the pipe, if air wasn't able to enter above the moving water, a vacuum could be created causing the water to stop flowing. This causes the level of water in the pan to rise as though the drainage system is blocked. Therefore, the valve allows air to equalize inside the pipe allowing water to flow freely.

If the waste pipe connection is close to the toilet pan connection!! every time the pan is flushed water may be drawn out of the shower or basin traps. Central heating and strong sunshine can also cause evaporation of water in the traps. Once the water seal is broken by the the level dropping noxous gases can escape from the traps.

Unfortunately, the best indication of where the nasty smell is coming from is to get your nose as close as possible to the possible offending fittings.

If the Durgo is at fault you would be best off replacing it, not cheap, best to go to DIY superstores rather than builders merchants.

If it is the traps of shower or basin just ensure they are topped last thing at night by tipping a cup of water down them.