Smell coming from behind the toilet

pieroabcd

Hi,
my bathroom at the ground floor has had a terrible month.
For more than one year I've never had problems, and suddenly in mid August I've started to experience a constant smell of sewer.
I've asked to clean the drains and inspect inside (all "clean").
I've replaced the air admittance valve at the top of vent system.
I've had a plumber to replace the syphon under the sink with a p-trap (that made the largest difference, like night and day).
After al those operations the smell has decreased by a lot (I'd say that it's 75% less intense than before), but there's still a strong constant whiff that comes from behind the toilet.
In the pictures you can see the spaces in quesiton, that I've tried to cover with some sponge foam.

The plumber will give a look but I'd like to have some advice. What should we look at?
The pipe connecting the bowl to the drain is flexible/corrugated. Should I have it replaced by a rigid one?
Can the wax ring have any role in this? 
Abundant water is constantly present at the bottom of the bowl.

If we can't identify the problem is it ok to seal completely those spaces (with what)? or can the closure have bad consequences?

Thanks.

pieroabcd

My worst fear is that the drain pipe itself is holed with very little space to operate to replace it..

victor2

Sealing it more permanently isn't going to achieve a lot - assuming tha\t is where the smell is originating.. The odour will still come up around the cistern. I would think the only way to tackle it would be to pull the toilet out, which is obviously quite a bit of work. Those flexible pipes are designed to last and it's hard to see how it could have got damaged, unless it was badly installed, but then it would have been a problem from the beginning.

pieroabcd

I also don't understand how all of a sudden 2 components started to have these smell problems.

Lorian

Is it a flat?

Is the water draining from the bowl quickly when flushed - not rising up towards the rim?

would have thought the pan connector needs pushing home properly.

No other plumbing happened recently? 

pieroabcd

Lorian said:

Is it a flat?

Is the water draining from the bowl quickly when flushed - not rising up towards the rim?

would have thought the pan connector needs pushing home properly.

No other plumbing happened recently? 

It's flat. 
The water is flushing quickly, not rising.
No other plumbing in this home. I don't know about the others. 

pieroabcd

Also, nobody uses this toilet, if not rarely, and not sitting on it. It doesn't even remotely wobble, it's well firm. 

pieroabcd

As expected the cause of the smell was a big hole in the drain pipe, that was at the top. 
It had been covered by some tape. 

I don't know who is worse: if who installed such an abomination or the previous owner that didn't oversee them.

victor2

pieroabcd said:

As expected the cause of the smell was a big hole in the drain pipe, that was at the top. 
It had been covered by some tape. 

I don't know who is worse: if who installed such an abomination or the previous owner that didn't oversee them.

Glad you've got it sorted. Clearly a bodged install, probably hidden away from the owner before they saw it.

Vortigern

Looks like there had been a strap boss to connect another waste pipe into the soil pipe. 

Where does that other waste go now?

pieroabcd

This pipe connects to the flexible  attachment to the toilet on one end  and on the other end  to the main pipe that goes to the sewer using a big gummy extension.