Sulphur smell in bedroom of basement flat when upstairs use their Saniflow

[andy_b]

We recently bought a one bed basement flat in a 3 storey 1900's building (one flat on each floor), and discovered when moving in that the flat directly upstairs from us have a Saniflow system fitted in their bathroom, which is at the other side of the building to our bedroom.

The odd thing is we get a sulphurous/eggy smell in our bedroom whenever they run their Saniflow, and it's worse when it hasn't been run for a while (eg their first shower of the morning). When the other flats in the building use their bathrooms or we use ours there is no smell. Nobody else has a Saniflow though. Upstairs had two plumbers round who both said that their Saniflow works correctly and isn't blocked.

Outside the building in our garden there is a drain cover over the sewer pipe, which runs in front of our bedroom window. The eggy smell was there too. We had this checked out and pressure cleaned, but no change, and we had a CCTV survey done, which checked from the outside drain cover to the bottom of the soil pipe below our bedroom cupboard. They also did a smoke test and everything showed that there was no leak in the pipes.

Through a process of elimination, we know that the smell comes from the drain outside and we know it leaks inside through the bedroom window. The problem is how can we stop it? The drain cover is slightly loose, would a new cover help?

When upstairs Saniflow is running we get a lot of water related noises. At first there's a noise that's almost like banging and that is followed by a sloshing noise as the bursts of water enter the soil stack in our bedroom cupboard. The soil stack pipe is plastic.

And finally, after the Saniflow has run there is a dripping noise that can be heard for about 30 mins after, which can only be heard at the other side of the flat, near to where the Saniflow is. We don't hear this in our bedroom.

If anyone can shed some light on this I'd be really grateful!

 

[rpm]

Hi and welcome to the forum Andy,
Eggy type smells tells me the Saniflo needs a service even if it is fully working but unless it has been vented to the stack the smell would normally be in the room where the Sani is.
The average cost of a full service is around £60 - 100 plus parts if required depending where in the country you are but to try and trace the source of the smell try this to clean the Sani and all pipes both to and from it.

Switch the power to the Sani off
Pour hot water and a strong smelling thin runnie (runny?) disinfectant (not bleech) down every basin & shower trap untill you hear a gurgling sound as the air comes back, then add more to the toilet pan until the water level in the pan is 2" higher than normal and leave for just under an hour. Then when the power is restored to the Sani can you now smell the disinfectant in your flat?

Your neighbour may need to do this up to 4 times in a month to clean the Sani depending on how old and dirty it is inside and please come back to tell us the results.
Good luck

 

[andy_b]

Thanks rpm.

I'm not a plumber but I believe the Saniflo is vented to the stack. Would there be an AAV in their bathroom if it wasn't venting to the stack? Or is it missing this and that's causing the noises?

They did have it serviced around 6 weeks ago after we first complained, and the engineer told them about the solution they need to run through it. I think he did it when he was there and they have done it themselves a couple of times since. I didn't know it could be needed once a week though. Unfortunately it didn't stop the smell. We weren't in our flat at the time they had it serviced so I don't know if we would have been able to smell the disinfectant in our flat. I'd guess we would as all smells seem to come from the drain outside.

 

[rpm]

Having re read your post I would think the loose fitting drain cover isn`t helping but don`t understand how the smell is getting through the window if it is shut. The banging noise could be air in the water pipe causing "water hammer" or the pipe isn`t secured with clips and the sloshing noise is the Sani discharging in to the stack, can you box this pipe in and use soundproofing? But I can`t help with the final dripping noise without being there.

 

[andy_b]

Thanks again rpm.

The smell comes through the window because it's an old property with single glazed sash windows. If I hold my hand around the window frame I can feel a draft coming in.

The banging noise only seems to happen when their Saniflo is first turned on, it doesn't continue if they leave it running for 5 mins for example. Would that be water hammer then? If so how do we fix that? I don't think it would be loose pipes as the pipe runs through the joists (at right angles to the joist) so would secure it in place?

I think you're right that the sloshing noise is the Saniflo discharging into the stack. The pipe is boxed in but it's been done poorly, so we were planning to get this done with some rockwool and see what difference that makes.

The dripping noise is a mystery..

 

[rpm]

There may or may not be an AAV fitted depending on how and when the stack was installed for the whole property and others here are better informed than me on that subject but if there is one then it was not fitted for the Saniflo as they either vent to the room or to the outside and venting to the stack is not a great idea as there is no non-return valve on the exhaust.
Water hammer is caused by air being in the cold water supply pipe, the cold water pipe not being securely fixed and banging against wood or walls or the ball valve in the toilet cistern needs attention. If it doesn`t happen when a cold water tap is turned on but only when the cistern is flushed I would say it is the ball valve.
I`m puzzled when you say "If they leave it turned on for 5mins" because a Sani shouldn`t run for longer that 15 - 20 seconds and if the engineer used the offical Saniflo cleaner / descaler then A) you wouldn`t be able to smell it and B) it doesn`t work very well which is why I say disinfectant.
I`m leaning towards a general smelly drain and loose window rather than the Sani now.

 

[Centralheatking]

I am frankly quite worried - things like basemant flat and smelling bad things - set all my alarm bells ringing - do you have co and other sensors fitted ? - I am sure it is ok but i needed to let you know my concerns Centralheatking let us know more please

We recently bought a one bed basement flat in a 3 storey 1900's building (one flat on each floor), and discovered when moving in that the flat directly upstairs from us have a Saniflow system fitted in their bathroom, which is at the other side of the building to our bedroom.

The odd thing is we get a sulphurous/eggy smell in our bedroom whenever they run their Saniflow, and it's worse when it hasn't been run for a while (eg their first shower of the morning). When the other flats in the building use their bathrooms or we use ours there is no smell. Nobody else has a Saniflow though. Upstairs had two plumbers round who both said that their Saniflow works correctly and isn't blocked.

Outside the building in our garden there is a drain cover over the sewer pipe, which runs in front of our bedroom window. The eggy smell was there too. We had this checked out and pressure cleaned, but no change, and we had a CCTV survey done, which checked from the outside drain cover to the bottom of the soil pipe below our bedroom cupboard. They also did a smoke test and everything showed that there was no leak in the pipes.

Through a process of elimination, we know that the smell comes from the drain outside and we know it leaks inside through the bedroom window. The problem is how can we stop it? The drain cover is slightly loose, would a new cover help?

When upstairs Saniflow is running we get a lot of water related noises. At first there's a noise that's almost like banging and that is followed by a sloshing noise as the bursts of water enter the soil stack in our bedroom cupboard. The soil stack pipe is plastic.

And finally, after the Saniflow has run there is a dripping noise that can be heard for about 30 mins after, which can only be heard at the other side of the flat, near to where the Saniflow is. We don't hear this in our bedroom.

If anyone can shed some light on this I'd be really grateful!

 

[rpm]

Good point CHK, got so into the sani side of things it never entered my head.

 

[andy_b]

There may or may not be an AAV fitted depending on how and when the stack was installed for the whole property and others here are better informed than me on that subject but if there is one then it was not fitted for the Saniflo as they either vent to the room or to the outside and venting to the stack is not a great idea as there is no non-return valve on the exhaust.

The building was converted in 1980. I imagine its vented up through the roof but I don't know. I'm not certain but it seems that when it rains outside we can hear the sound of water running down the soil pipe in our bedroom cupboard. I'm not sure if the Saniflo is vented, if it wasn't would that be the cause of the noises?

Water hammer is caused by air being in the cold water supply pipe, the cold water pipe not being securely fixed and banging against wood or walls or the ball valve in the toilet cistern needs attention. If it doesn`t happen when a cold water tap is turned on but only when the cistern is flushed I would say it is the ball valve. I`m puzzled when you say "If they leave it turned on for 5mins" because a Sani shouldn`t run for longer that 15 - 20 seconds.

They have their Saniflo connected to their whole bathroom, which is a shower, toilet and sink, sorry I wasn't too clear on that. If they have a shower then the Saniflo will run in bursts every 7 seconds and shoot the water down into the soil pipe. The banging noise (almost sounds like thunder) only happens right at the start of the Saniflo being run, so it would maybe happen twice right at the start of them having a 5 minute shower for example. The noise happens whenever the Saniflo first comes on.

if the engineer used the offical Saniflo cleaner / descaler then A) you wouldn`t be able to smell it and B) it doesn`t work very well which is why I say disinfectant.

Ahh I see, I'll ask them to put some disinfectant through it then.

I`m leaning towards a general smelly drain and loose window rather than the Sani now.

I'm thinking its that too. The smell definitely creeps in from outside. The drain is the inspection point for the soil waste, and right after it is a gully followed by an air vent for the rest of the pipe I assume. I've put a pic up below. Our bedroom window is just behind where I was standing. The sewer main carries on some distance to the left down a pathway and into the street. Around 100 metres I'd say.

 

[andy_b]

I am frankly quite worried - things like basemant flat and smelling bad things - set all my alarm bells ringing - do you have co and other sensors fitted ? - I am sure it is ok but i needed to let you know my concerns Centralheatking let us know more please

Good point, we do have a carbon dioxide sensor in the lounge, I'll move it into the bedroom and see if it goes off. Upstairs had their boiler checked out after we raised the smell issue with them and their boiler is ok. Ours is brand new (the previous owners fitted it before they sold).

 

[andy_b]

Duplicate post

 

[andy_b]

There is a water gully after the drain, could the faster flowing bursts of water coming from the Saniflo be disturbing the water in the gully enough for it to let smells through? We're considering fitting a sealed drain cover to try and stop the smell but don't want to waste our money if it won't solve anything! Or is there a fault in the waste pipe going from their bathroom and the Saniflo pushes the smells down into the drain?

 

[Barry98]

andy which posts dont you think are been seen ?

 

[andy_b]

Duplicate post

 

[andy_b]

Thanks for your help so far guys. Sorry for duplicate posts, nothing was showing up when I posted yesterday.

This morning I went outside while upstairs had their shower running to see if I could work out where the smell comes from. It seemed to be coming from the gully, or at least it was most noticeable there, rather than the inspection cover next to it. Over the weekend when upstairs have a shower in daylight I'll try and get a better idea for what's going on.

Edit: I noticed yesterday that I could smell the same smell in the street a couple of houses down and at a time when nobody else in our building was in. I'd not noticed it anywhere else before.