Hi all,
I'm trying to track down an intermittent sewer/drain smell in my house and would appreciate some advice.
The house is the middle property in a terrace of three houses, built around 15 years ago (UK).
The symptoms:
- Occasionally we get a sewer/drain smell downstairs, mainly noticeable in the living room.
- The smell seems omnidirectional – we can't pinpoint a specific source.
- It often happens when we flush the toilet or run the shower, but sometimes it occurs when we haven't used any plumbing ourselves.
- We never smell it upstairs in the bathroom.
What I've checked so far:
- The upstairs soil stack appears to be boxed in behind the bathroom wall near the toilet.
- In the loft above that area I cannot see any 110mm soil pipe or air admittance valve (AAV).
- There is no soil vent pipe exiting our side of the roof.
- However, on the roof ridge on the neighbouring property, there is a terminal that looks like a vent pipe (photo attached).
I also read somewhere that newer builds sometimes share soil stacks or vent stacks between neighbouring properties, so I'm wondering if that might be the case here.
My questions:
1. Does the item in the photo look like a soil vent terminal for a drainage stack?
2. In terrace houses like this, is it possible that multiple properties share the same soil stack vent, with the vent exiting through one of the neighbouring roofs?
3. If that is the case, could pressure changes when either house uses plumbing cause smells to escape somewhere in my branch pipework?
I originally thought this might be caused by a failed AAV, but since I can't find one in the loft I'm wondering if the system vents externally via a neighbouring property instead.
Any thoughts on whether this setup is typical, and where I should investigate next, would be much appreciated.
Thanks!
I'm trying to track down an intermittent sewer/drain smell in my house and would appreciate some advice.
The house is the middle property in a terrace of three houses, built around 15 years ago (UK).
The symptoms:
- Occasionally we get a sewer/drain smell downstairs, mainly noticeable in the living room.
- The smell seems omnidirectional – we can't pinpoint a specific source.
- It often happens when we flush the toilet or run the shower, but sometimes it occurs when we haven't used any plumbing ourselves.
- We never smell it upstairs in the bathroom.
What I've checked so far:
- The upstairs soil stack appears to be boxed in behind the bathroom wall near the toilet.
- In the loft above that area I cannot see any 110mm soil pipe or air admittance valve (AAV).
- There is no soil vent pipe exiting our side of the roof.
- However, on the roof ridge on the neighbouring property, there is a terminal that looks like a vent pipe (photo attached).
I also read somewhere that newer builds sometimes share soil stacks or vent stacks between neighbouring properties, so I'm wondering if that might be the case here.
My questions:
1. Does the item in the photo look like a soil vent terminal for a drainage stack?
2. In terrace houses like this, is it possible that multiple properties share the same soil stack vent, with the vent exiting through one of the neighbouring roofs?
3. If that is the case, could pressure changes when either house uses plumbing cause smells to escape somewhere in my branch pipework?
I originally thought this might be caused by a failed AAV, but since I can't find one in the loft I'm wondering if the system vents externally via a neighbouring property instead.
Any thoughts on whether this setup is typical, and where I should investigate next, would be much appreciated.
Thanks!
