Smell in the bathroom

[ZakUK]

Not sure if im posting in the correct forum, but gonna try here:

Im at my wits' end with this:
Basically i have a funny smell in the bathroom appearing on and off throughout the day. There are no leaks, no blockages and it is felt strongest under the bath. Had it first time at the beginning of november last year, then went away and came back like a week ago.
It appears at random, then goes away. Had a plumber in to change the sink and bath waste and while he was there, the smell came. He had a look under the bath, checked the pipes, traps and said he has absolutely no idea.
Anyone ever came across anything like that or have some suggestions ?

Thx
P.S. had extension built and completed in december 2023, if it can be related.

 

[Wayners]

Check electrics.
Switches if arching can smell of fish or just unpleasant a bit. It's the plastic melting

 

[ZakUK]

Check electrics.
Switches if arching can smell of fish or just unpleasant a bit. It's the plastic melting

Underneath the bath ?
Its defo not melting plastic smell under there.
P.S. Ill add to my original post that extension was built downstairs, bathroom was untouched upstairs

 

[Elsa TLC]

My mate called me with the same problem on a 1st floor flat he was renting out.

I took the bath panel off to inspect. It was cleaner than Singapore under the bath.
The soil pipe however wasn't fire proofed from the flat below.

I suggested that the neighbour maybe dead and that's the smell.

I was right. The neighbour had been dead for sometime.

 

[Wayners]

I'd get the foam gun out under bath and block holes.
Check neighbour just incase

 

[Elsa TLC]

I'd get the foam gun out under bath and block holes.
Check neighbour just incase

That's the community spirit.

 

[ZakUK]

I'd get the foam gun out under bath and block holes.
Check neighbour just incase

Thats my plan so far, but i thought ill check here to find maybe other solutions.

 

[ZakUK]

My mate called me with the same problem on a 1st floor flat he was renting out.

I took the bath panel off to inspect. It was cleaner than Singapore under the bath.
The soil pipe however wasn't fire proofed from the flat below.

I suggested that the neighbour maybe dead and that's the smell.

I was right. The neighbour had been dead for sometime.

Forgot to mention that i live in a semi. So hopefully nobody hid dad body in my living room

 

[Jurassicspark]

Could be the AAV.

 

[ZakUK]

Could be the AAV

Another detail: before extension was built, bathroom's water was running into a hole in the patio (sorry dont know terminology) and you could see that water going from pipe into the hole. Now, bathrooms pipe is connected directly into big black waste pipe (where toilet waste goes).
Would AAV issue cause smell under the bath or coming from the waste hole in the bath ?

Thx

 

[Elsa TLC]

Forgot to mention that i live in a semi. So hopefully nobody hid dad body in my living room

The house i was in today get Rats. Dead rats can also be smelly

 

[Jurassicspark]

Would AAV issue cause smell under the bath or coming from the waste hole in the bath ?

If the AAV is sticking, you'll smell an unpleasant smell coming from the drain in the bath.

Do you ever hear a gurgling noise?

 

[ZakUK]

If the AAV is sticking, you'll smell an unpleasant smell coming from the drain in the bath.

Do you ever hear a gurgling noise?

Drain in the bath nor sink has no smell. The smell comes from under the bath
I hear noise of water running quickly down the pipe, dont know if thats the gurgling noise you talk about.
The grey pipe u see in the photos goes outside through the wall and connects straight to the big waste pipe (if this info helps).

 

[Elsa TLC]

Drain in the bath nor sink has no smell. The smell comes from under the bath
I hear noise of water running quickly down the pipe, dont know if thats the gurgling noise you talk about.
The grey pipe u see in the photos goes outside through the wall and connects straight to the big waste pipe (if this info helps).

The shallow trap could be being pulled.

 

[ZakUK]

The shallow trap could be being pulled.

But, there is no smell coming from the bath drain whatsoever. It accumulates under the bath and then spreads into the bathroom.
P.S. no smell today since morning.