Sewage smell in downstairs toilet and under stairs, both extensions

[Stinky]

Hi All,

I am hoping someone can offer advice on a sewage smell in my house. We moved in around 14 months ago and we have had an intermittent sewage smell for that whole time, it could be up to a few weeks with no smell but since the weather has gotten colder it seems to have gotten worse. The smell is most noticeable in the downstairs toilet but is also present under the stairs (no plumbing there, just storage). The smell also comes into the living room from where it joins the under-stairs area (the elec meter is on a panel in the living room on the other side of the under-stairs area). The house is 1930s with lots of extension work and I think both the under-stairs and downstairs toilet are outside the original footprint. Main bathroom is directly above downstairs toilet. A lot of the extension work on the house is shoddy, to be kind, and I am not sure how much plumbing was done by the guy who did the rest of the work. The kitchen sink and dishwasher seem to go into surface water (maybe?) through an old original gutter drain which is now in 'conservatory' with an air admittance valve.

As I said it is very intermittent, I have disconnected and capped (badly) the basin in the toilet with no effect. I also put some smoke in the basin pipe which came out of the external vent (I read later that smoke+plastic=bad). I opened access panel on drive and water from both bathrooms seems to flow through fine, although slow to arrive. The only thing I can think of is a cracked underground pipe venting into foundations of the extension work but could that be so intermittent?

I guess the next steps are to get a company with cameras/smoke out to take a look, I need to find someone experienced with these kinds of issues in SE London / Kent. We have a baby due in 6 weeks so really need to pull my finger out on this!

Thanks for taking the time to read and respond
Stinky

 

[JCplumb]

Have you got an open external drain near a vent brick outside?
My mums house suffers with this, the smell gets in through a vent brick and under her wooden dloorboards.
If you do have one, have a sniff of it - is it the same smell?

 

[Stinky]

Have you got an open external drain near a vent brick outside?
My mums house suffers with this, the smell gets in through a vent brick and under her wooden dloorboards.
If you do have one, have a sniff of it - is it the same smell?

Thanks for the quick response JC. The smell is in two separate locations and both are just outside the original boundary of the building but neither are against the current boundary. Also there are no uncovered drains or vent bricks that I am aware of.

Thanks
Luke

 

[REDSAW]

cover all your over flows and traps over one by one per day might help locate it?

 

[Leo21]

You haven't got a guest called Ermintrude have you?

 

[Dotty]

If you have I think we've nailed it.....

 

[kris]

I've had a similar problem in a new extension I'm doing and the cause was simply a badly blocked drain, it wasn't blocked that the customer noticed it as every flush disappeared but between the outside manhole and the shower room was loads of crap and even with the vent pipe close by it didn't stop the horrendous smell coming up through the shower top access trap when the chrome cover was off, my customers house stank with the sewage smell really bad and once we eventually cleared the drain the smell slowly disapated , good luck stinky and welcome to the forum,

 

[kris]

Or remove Ermintrude ,

 

[Stinky]

I've had a similar problem in a new extension I'm doing and the cause was simply a badly blocked drain, it wasn't blocked that the customer noticed it as every flush disappeared but between the outside manhole and the shower room was loads of crap and even with the vent pipe close by it didn't stop the horrendous smell coming up through the shower top access trap when the chrome cover was off, my customers house stank with the sewage smell really bad and once we eventually cleared the drain the smell slowly disapated , good luck stinky and welcome to the forum,

Thanks for this Kris, could a blockage also account for the smell under the stairs? There is no above ground plumbing under the stairs so no traps etc for the smell to get out of. In terms of cleaning out the drain, would you recommend pouring some kind of gel down there or is something else needed? I am not sure how I would get access other than putting something down the toilet.

Thanks