Existing Drain smells and big mice problem!

[chris101]

Last year we had a new side extension built where existing drains use to lie.

Since the next extension that has been foul smells on and off since the completion and mice have appeared within the extension many a times, to a point that we are hearing them every day in the walls and I have even spotted a few.

The mice are only heard and have been seem in the new extension area.
Speaking to the plumbers/builders who did the job, it seems the old drains which they built the extension over were not removed but plastic was put into them and then covered with soil.

Is this a correct practice and how can we make sure this is definitely the cause of the smells and mice?

The builders are coming some point next week to break a few kitchen tiles to find/identify the old drains and if the issue, seal them up.

 

[Hugh Jaleak]

Are you sure its mice? Drains are usually the domain of rats, and unfortunately if redundant drains are not sealed off correctly, this is what happens.... If you've a smell and a vermin problem, then that suggests to me the old drains were not blocked off properly. Plastic and soil are not enough, pipes should be plugged with concrete at the downstream end!

A smoke test will identify any breaks/breaches in the drains, I would insist the builders carry one out before leaving this time for your peace of mind if nothing else. Rats, once they've found a convenient point to enter/exit will come and go at their leisure, to collect food. They never come alone either.....

It may be worth asking if the local Council have a 'Rat man', if it is rats they need to be exterminated and disposed of correctly.

 

[chris101]

Pretty sure they are mice as they are too tiny to be rats unless the rats are in the walls and mice come out from time to time...

 

[NotAgainFFS]

I was told by our env health guy that a rat can squeeze itself through a hole the size of a pencil.

We had one in the kitchen once - My Mrs screamed like she'd been stabbed when the beast stared her out from the top of the fridge freezer.

It took me and the bloke 48 hours to trap and despatch "Rowena," who'd got in through the space between a 15mm radiator tail and the concrete floor.

 

[chris101]

The builders came over today and took out 2 tiles in the utility section (above where the old drains were).

There is a stale smell around there although not strong which is the same smell from behind the washing machine, under the downstairs shower and celar.

The strong smells haven't come out for a few days now so will have to wait for a moment of the smells to return to then check the hole to see if its as strong there.
The strong smells are normally eggy/sulpher which is different to this stale smell at present.

My wife thinks it could be when had been raining that the smells gets worse and since its been warmer/drier in the last few days, it may of made a difference?

 

[Hugh Jaleak]

Eggy smells are often associated with Hydrogen Sulphide, often found in drains and toxic in too high a concentration. This could suggest there may well be a problem with a broken or leaking drain nearby or even under the building....

Assuming you paid within the original cost for drainage work to be carried out correctly, then I would now insist your builder carries out a smoke test to identify any breaks,leaks or other problems in the drains and then completes any remedial work to repair broken/seal up redundant drains as required.

There is probably some reasoning behind your wife's thinking, older systems of drainage are 'combined' whereby waste water and rainwater discharge into the same system. During periods of rain the sewers are running at a higher capacity, therefore air (and gases) in the system would be displaced, and need to escape.

 

[Charnwood]

a rat can squeeze itself through a hole the size of a pencil.

Codswallop! That's akin to saying we humans could squeeze through a 3" soil coupler.

 

[chris101]

This morning we woke up with a very stale smell in the kitchen/diner which lingered throughout the ground floor.
The smell was very strong from behind the washing machine and the area where the 2 tiles have been lifted (definitely more stronger putting nose between worktop and washing machine).

This smell thought was stale but not eggy like other occasions.

I called the builder but he only came an hour later and by then the smells had weakened and we had the washing machine on as well so the smell between worktop/washing machine was of washing smells.

The builder said he is pretty sure its not the old drain as according to him and a few people he has asked, the fact we have lifted up 2 tiles there should be a consistent strong smell from the old drains which there isn't.
There is a stale smell when you put your nose down into the whole but no where strong to stink the whole room...

Although his conclusion is that he believes it is nothing to do with the old drain and rather the bathroom sink, shower or toilet, is there anything I can advise him to do to make sure or does he have a valid point with regards to the old drain system?

 

[Hugh Jaleak]

I would still insist a smoke test is done, and if any leaks/breaches are found, the issues are rectified. As per my previous post, drains are the domain of rats, and a redundant drain makes a ideal home. They will find a way out, making their own if necessary, to come to the surface in search of food.

I would strongly recommend that the matter is investigated and any remedial work required is done before any further issues are found. I rather suspect the builder is trying to fob you off, (obviously any further works would be at his expense), but you clearly have concerns or you wouldn't be asking!

 

[chris101]

Any companies you can recommend who can do these tests?
I rather pay and get this done independently rather than having the house dug up again in sections...

 

[CombustionGuy]

Rats can't get through a hole the size of a pencil I keep rats they need room for there head just like cats do so your looking at a hole about 1 inch. I would say drain could be a issue but just a quick question does your washing machine waste do into a sink trap or a washing machine trap ( hockey stick) long white pipe with trap on the bottom ? Have you cracked the traps in the morning to see if they have any water left in them? As it
Might be sucking the traps out. Was the old drain a vent for the foul drain?

 

[chris101]

The washing machine has a trap of its own but the pipe of the sink runs through the dish washer as well and the meets at the washing machine main pipe then into the big pipe that runs into the manhole.

How do I 'crack' the traps to check if there is water in them?

I doubt its just the traps as I can smell the same smell under the floor boards from the 2 tiles that have been lifted...

The old redundant drain went above the roof, so not sure it vented into the air?

 

[Hugh Jaleak]

Depends where you are, Andy (Hertsdrainage2010) covers North London I think, he might be able to help or point you towards someone who can.

 

[chris101]

I was going to perform a bung test however the builders paid for a CCTV drains survey to be completed.

The moment the surveyors entered the property they could smell the stench from the drains area and without even looking further they said you have a rats problem.
They checked under the open hole in the utilities section that the builders created and found rat droppings!...

They then went to the manhole and looked through the pipes and found 2 exits that had been blocked with only plastic...
This could be potentially where they are entering from.

I explained about the eggy smell as well and the surveyor said that is dangerous as if the smell get very strong and the area wasn't well ventilated, in the rarest of occasions it could turn into an explosion!!

They have advised to get the builders back and find the old redundant drain and make sure its capped off which means digging more of the suspended floor to find out.

Having said this, they were able to find and identify a gap in the floor that goes into the cellar.
Could it even be the rats are entering from the cellar rather than the drains?