Rats are back again. Out of ideas.

Afternoon all.

We had a rear extension built in Autumn 2014. We discovered we had a problem with rats. We killed them with poison. They came back. We killed them again with poison. They came back again.

A long story short(ish), they have been getting under the house and then coming up either through the new cavity wall or behind the oven, up through pipe runs etc. I've blocked all these off over the last 3½ (barring the small hole in the cavity wall behind the oven which is the last to do) but know prevention is better than cure. I don't want rats living under my house.

We paid for cctv drainage investigation in 2015 on the advise of my last plea-for-help to sort this problem (see link above). They found nothing. We've checked and rechecked the state of all external walls at ground level (front and back as live in a terrace). There are no holes, only air bricks. On the rear 5 air bricks, on the front 3 air bricks - an older design but still secure.

We'd already decided it must be the sewers so last year when they returned we asked Thames Water to come out and have a look. Our rear extension was built on top of the old inspection manhole but another was put in the garden. They discovered the old inspection pit was badly damaged. Cue floor up, old manhole cover up and a full repair. The gaps in the side of the manhole were big enough to allow a rat to squeeze through, presumably under the concrete floor for the new extension and in to the main part of the house where it is a suspended wood floor. This was July. Result. No more rats.

Until this month. There must have been a little poison left down there following my last cull last year as the cat did its usual pacing around the kitchen floor for a week and then the unmistakable smell of rotting rat coming up through the floor. I took up the corner of the living room floor again this week for the umpteenth time to put more poison down and when I had checked it the next day again it had been nibbled.

I am totally out of ideas with how to resolve this. TW are reluctant to come out again as they say they've solved it and repaired the manhole. They also checked right up and down the sewer in to neighbouring properties at the time and found everything to be secure.

I've had the council out before who told me I didn't have rats (despite seeing two in my house over the last 4 years) and am unsure where to go from here. I want the problem solved as I have three very young children and rats are not the most hygienic house visitors we have.

I live in a terrace and none of my neighbours have this problem. I don't believe them to be coming along the terrace or anything like that - there are solid brick walls between us all which must be supported down to foundation level surely?

So, has anyone ever paid for any of the 'survey' options from the likes of Rentokil etc?
Are they worth it/did they solve the problem/guarantee?
My only crumbs of hope are that last year when we had a loft conversion put on our house that maybe the extra weight has caused some sort of sewer problem/damage (this is since TW came) and somehow this has caused a crack and they can get in again somewhere. Otherwise I don't know what to suggest...

Added a couple of pics of the sewers. Not really sure it helps but hey...

Have you heard them in the cavity wall at all?.

They can come up the gutter downpipes and into the loft/ cavity wall.

Plus they leave a trail of scent that the rest follow iirc.

I'd never have a suspended floor for that reason alone (something living in it!).

We had them in the loft and it was a real ballache to get rid.

Keithmac said:

Have you heard them in the cavity wall at all?.

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Yes (I realise I meant between the plasterboard walls where the new toilet was built during the extension - there is access from below the floor)That was just before we thought we'd eradicated them for good last year.

Keithmac said:

They can come up the gutter downpipes and into the loft/ cavity wall.

Click to expand...

They're not doing this here. They're definitely coming in from below somewhere.

Keithmac said:

I'd never have a suspended floor for that reason alone (something living in it!).

Click to expand...

Likewise. If it was avoidable I wouldn't either!!
How did you get rid in the end? They certainly seem to follow each other. It's like there is one rat that goes out on a discovery mission and then all the others follow. We kill them, then a few months later another little discoverer rat...

I need an expert of somekind. I can put the poison down but I need someone to think like a rat for me haha!

A friend had rats , were getting in thru the loft , climbed external waste pipes to roof level and then into loft , she thought she had pidgeons nesting in the loft till I pointed out that the tiny babies had four legs not two.

bongos said:

Yes (I realise I meant between the plasterboard walls where the new toilet was built during the extension - there is access from below the floor)That was just before we thought we'd eradicated them for good last year.


They're not doing this here. They're definitely coming in from below somewhere.


Likewise. If it was avoidable I wouldn't either!!
How did you get rid in the end? They certainly seem to follow each other. It's like there is one rat that goes out on a discovery mission and then all the others follow. We kill them, then a few months later another little discoverer rat...

I need an expert of somekind. I can put the poison down but I need someone to think like a rat for me haha!

Click to expand...

Baiting and traps sorted it for us, next door is a Council house and they managed to get the Pest Control out who baited the drains as well.

Neighbour mentioned he'd fitted some metal gauze onto the downpipes as well a while back.

I left the light on in the loft as well and this seemed to be a deterrent for sone reason?.

Get a few proper traps down, if they're scouting about you may be able to nip it in the bud.

Keithmac said:

Baiting and traps sorted it for us, next door is a Council house and they managed to get the Pest Control out who baited the drains as well. Get a few proper traps down, if they're scouting about you may be able to nip it in the bud.

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This is the problem. I've recently been able to nip it in the bud as they've been culled as soon as they appear but i'm trying to find prevention rather than cure. It's a ballache ripping the laminate up every few months just to get in one corner of the house and put the poison down. If I could find how they were getting in then I might be able to feel like i'm doing something!

I'm no drain expert, but the entry into the inspection chamber from upstairs looks like it's angled against the flow and kinda just thrown in.

Could you install an IR IP camera under the floor with pan and tilt to see where they are coming in?

They might chew it though!

Hi

Your story sounds very familiar. Over a year ago we had a very similar problem which went on for 5 months before we finally solved it. We had a new extension built 4 years ago at the back of the house (7m x 5m – big enough) which involved new sewer pipe connections, build of a new sewer chamber and blocking up of old sewer connection. Extension floor (concrete raft) was built over sewer pipe, and builder did a great job and all was well. However, 3 years later we started hearing noises under the suspended floor of the older part of the house, and on investigation it was clear we had rats. We laid poison and blocked up with steel wool and concrete/expanding foam where we *thought* they were getting access to the house (under a section of new decking) and thought we’d solved it. Couple of weeks later they were back. More lifting of sections of suspended floor in older part of the house, laying of traps, use of motion sensor cameras – all of which told us there were 3 or 4 down there at any one time. More theories as to how they were getting access, more lifting of sections of floor, more rat traps and poison etc. We’d have a period of 2-3 weeks of quiet (and awful smell from decomposing poisoned rats) and then they’d be back. We’d employed a domestic pest company by the way, but all they could do was identify what they thought were potential access points, and lay more poison and/or traps. Again a couple of weeks quiet, then they’d come back. Incidentally, we caught very few in rat traps – they seem to be extremely smart and wary of them!

In desperation one day we rang Rentokil, and spoke to one of their surveyors. After telling him the story he said it was pointless getting them (Rentokil) out (as they’d just do the same – lay traps and poison), but he recommended we get a CCTV survey of the main sewage line done, and gave me a name and number of an expert. Needless to say I got in touch immediately and they came out and surveyed the main sewer (which was now under the concrete extension). The video footage identified the problem – there were 2 sets of excavated debris at 2 separate points, where the old sewage connections from our house joined the sewer pipe. The guy said this debris was from the rats excavating the infill to gain access to the house. Bear in mind these old connections had been blocked up 4 years ago at the time the extension was built – I’m assuming by pouring concrete down from our end. The surveyor said this often happens – rats at a later date can start exploring and then excavating these. The debris in the pipe was evidence of this. Solution was 2 in-pipe fibre glass re-linings and he was 100% adamant that was where they were accessing the house, and equally adamant that if we re-lined the problem would be solved. I liked his certainty, so they came back a week later, did the work (expensive – ouch!) and the problem was solved. That was over a year ago and we haven’t had a problem since.

Moral of the story – you can’t keep poisoning them as they’ll keep coming back once there’s a way in. If you can’t see the way in get a CCTV survey of the sewer pipe – if we’d done this earlier we’d have saved months of stress, annoyance and disturbance (opening up sections of floor etc.). I'm happy to say the problem is solved, but it was an awful 5 months and I wouldn’t wish it on anyone.

Hope this helps

Henrik

bongos said:

Afternoon all.

We had a rear extension built in Autumn 2014. We discovered we had a problem with rats. We killed them with poison. They came back. We killed them again with poison. They came back again.

A long story short(ish), they have been getting under the house and then coming up either through the new cavity wall or behind the oven, up through pipe runs etc. I've blocked all these off over the last 3½ (barring the small hole in the cavity wall behind the oven which is the last to do) but know prevention is better than cure. I don't want rats living under my house.

We paid for cctv drainage investigation in 2015 on the advise of my last plea-for-help to sort this problem (see link above). They found nothing. We've checked and rechecked the state of all external walls at ground level (front and back as live in a terrace). There are no holes, only air bricks. On the rear 5 air bricks, on the front 3 air bricks - an older design but still secure.

We'd already decided it must be the sewers so last year when they returned we asked Thames Water to come out and have a look. Our rear extension was built on top of the old inspection manhole but another was put in the garden. They discovered the old inspection pit was badly damaged. Cue floor up, old manhole cover up and a full repair. The gaps in the side of the manhole were big enough to allow a rat to squeeze through, presumably under the concrete floor for the new extension and in to the main part of the house where it is a suspended wood floor. This was July. Result. No more rats.

Until this month. There must have been a little poison left down there following my last cull last year as the cat did its usual pacing around the kitchen floor for a week and then the unmistakable smell of rotting rat coming up through the floor. I took up the corner of the living room floor again this week for the umpteenth time to put more poison down and when I had checked it the next day again it had been nibbled.

I am totally out of ideas with how to resolve this. TW are reluctant to come out again as they say they've solved it and repaired the manhole. They also checked right up and down the sewer in to neighbouring properties at the time and found everything to be secure.

I've had the council out before who told me I didn't have rats (despite seeing two in my house over the last 4 years) and am unsure where to go from here. I want the problem solved as I have three very young children and rats are not the most hygienic house visitors we have.

I live in a terrace and none of my neighbours have this problem. I don't believe them to be coming along the terrace or anything like that - there are solid brick walls between us all which must be supported down to foundation level surely?

So, has anyone ever paid for any of the 'survey' options from the likes of Rentokil etc?
Are they worth it/did they solve the problem/guarantee?
My only crumbs of hope are that last year when we had a loft conversion put on our house that maybe the extra weight has caused some sort of sewer problem/damage (this is since TW came) and somehow this has caused a crack and they can get in again somewhere. Otherwise I don't know what to suggest...

Click to expand...

I saw a program not to long ago, rats in London and South East have developed an immunity to the poison. These have been labelled super rats. I cant unfortunately remember how they managed to rid them of the problem.

Hi

bongos said:

Afternoon all.

We had a rear extension built in Autumn 2014. We discovered we had a problem with rats. We killed them with poison. They came back. We killed them again with poison. They came back again.

A long story short(ish), they have been getting under the house and then coming up either through the new cavity wall or behind the oven, up through pipe runs etc. I've blocked all these off over the last 3½ (barring the small hole in the cavity wall behind the oven which is the last to do) but know prevention is better than cure. I don't want rats living under my house.

We paid for cctv drainage investigation in 2015 on the advise of my last plea-for-help to sort this problem (see link above). They found nothing. We've checked and rechecked the state of all external walls at ground level (front and back as live in a terrace). There are no holes, only air bricks. On the rear 5 air bricks, on the front 3 air bricks - an older design but still secure.

We'd already decided it must be the sewers so last year when they returned we asked Thames Water to come out and have a look. Our rear extension was built on top of the old inspection manhole but another was put in the garden. They discovered the old inspection pit was badly damaged. Cue floor up, old manhole cover up and a full repair. The gaps in the side of the manhole were big enough to allow a rat to squeeze through, presumably under the concrete floor for the new extension and in to the main part of the house where it is a suspended wood floor. This was July. Result. No more rats.

Until this month. There must have been a little poison left down there following my last cull last year as the cat did its usual pacing around the kitchen floor for a week and then the unmistakable smell of rotting rat coming up through the floor. I took up the corner of the living room floor again this week for the umpteenth time to put more poison down and when I had checked it the next day again it had been nibbled.

I am totally out of ideas with how to resolve this. TW are reluctant to come out again as they say they've solved it and repaired the manhole. They also checked right up and down the sewer in to neighbouring properties at the time and found everything to be secure.

I've had the council out before who told me I didn't have rats (despite seeing two in my house over the last 4 years) and am unsure where to go from here. I want the problem solved as I have three very young children and rats are not the most hygienic house visitors we have.

I live in a terrace and none of my neighbours have this problem. I don't believe them to be coming along the terrace or anything like that - there are solid brick walls between us all which must be supported down to foundation level surely?

So, has anyone ever paid for any of the 'survey' options from the likes of Rentokil etc?
Are they worth it/did they solve the problem/guarantee?
My only crumbs of hope are that last year when we had a loft conversion put on our house that maybe the extra weight has caused some sort of sewer problem/damage (this is since TW came) and somehow this has caused a crack and they can get in again somewhere. Otherwise I don't know what to suggest...

Click to expand...

Hi

I appreciate this is a few years old, however did you get to the bottom of the issue? We also have had a recurring problem for around a year.

Sewer rats leave black marks along the skirting boards. Rats don't like running across rooms, they would rather run along the perimeter, thereby leaving them open to attack from one side only.

A few years ago, a regular customer in Chiswick had a persistent rat problem. The local council pest control eventually refused to put down more poison on the basis that the poisoned grain may in fact be attracting more rats. The customer ended up paying about £10K to have the footings back filled with concrete.

Difficult to comment on your problem without you providing more info.

Move.

Mottie said:

Move.

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My customer did consider moving, then she sat down and crunched the numbers. Her home was worth about a million at the time, she factored in moving costs, stamp duty, decorating costs and so on.

Ten grand to backfill made sense.

Get professionals in, decent company will guarantee results and have more expertise in locating nest etc.