Rats in cavity wall
Information, help, tips and advice on cavity walls, ceilings and lofts etc....

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Bris
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Rats in cavity wall

Post by Bris » Fri May 27, 2011 10:09 am

I have also had terrible problems with rats in my cavity wall and kitchen ceiling. It doesn't matter whst I do they always seem to come back. My house is a typical victorian mid terraced property. There is an extension at the back which is the kitchen and one bedroom built above it. This part is built over the old drain and also the new one. This seems to be the root of the problem, however they have blocked off the old drain and although the activity seemd to stop for a while they found their way back in again after a while. I've spent thousands of pounds trying to sort this out and really don't know what to do. Ive had different pest control companies in, drainage experts in, builders in, even had a guy in yesterday who put down a chilli gel which is supposed to repel them. I had my doubts about this but he told me he had treated 600 houses with it and no one had complained. Anyway last night I woke to hear a rat scratching around in a section where he and put this gel so am now very dubious about it. Poison seems to be a bit futile because as one dies another one enters. I have also had dead rats decomposing in my ceiling and it isn;t pleasant. I have lived in this house for 5 years and from what the neighbours tell me the previous owner also tried and failed to deal with the rats. I am at a loss as what to really. Any ideas would be gratefully received.

sarah w
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Re: we have your problem rats in cavity wall

Post by sarah w » Sat Jun 18, 2011 3:07 pm

[quote="avr"]We have the exact same problem and would love to know whether you resolved the problem via drains - is it over for you yet? The extension was built before our purchase of the property 6 years ago. However, it has only been a problem for the past 9 months within the house and has continued to worsen with rats now gaining access to other ceiling areas in the house. Pest control conducted a drain survey but weren't convinced that their equipment would pick up the fault - they are convinced it is from the drains. They have laid poison numerous times. We are getting pretty desperate.
Look forward to any latest news from you.[/quote]

Firstly I hope your situation has improved? I realise what a stressful time it is. Solving the drain problem in our kitchen was without doubt the best thing. A complete new drain cover was put in place. Years ago extentions were built without planning were'nt they? The original builder hadnt sealed the drain off properly ( i would love to spend a couple of hrs with him!) This did solve the problem but since we have had a couple more rats get in. My husband has since sealed the cavities from the loft and we did find a hole in the loft that led to next dr. Are you terraced? Our neighbour has since heard noises in their loft but fingers crossed we havent. Our neighbour has been in their property 2 yrs. They are the first neighbours we have had that have admitted there was a problem. They have sealed holes in their loft and brought something that gives the rats an electric shock... finially having good neighbours has helped. Its also a help to read others letters and realise we are not the only people with this problem. Poisen is not the answer because of the terrible smell. Good luck

sarah w
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Re: Rats in cavity wall

Post by sarah w » Sat Jun 18, 2011 3:21 pm

[quote="Bris"]I have also had terrible problems with rats in my cavity wall and kitchen ceiling. It doesn't matter whst I do they always seem to come back. My house is a typical victorian mid terraced property. There is an extension at the back which is the kitchen and one bedroom built above it. This part is built over the old drain and also the new one. This seems to be the root of the problem, however they have blocked off the old drain and although the activity seemd to stop for a while they found their way back in again after a while. I've spent thousands of pounds trying to sort this out and really don't know what to do. Ive had different pest control companies in, drainage experts in, builders in, even had a guy in yesterday who put down a chilli gel which is supposed to repel them. I had my doubts about this but he told me he had treated 600 houses with it and no one had complained. Anyway last night I woke to hear a rat scratching around in a section where he and put this gel so am now very dubious about it. Poison seems to be a bit futile because as one dies another one enters. I have also had dead rats decomposing in my ceiling and it isn;t pleasant. I have lived in this house for 5 years and from what the neighbours tell me the previous owner also tried and failed to deal with the rats. I am at a loss as what to really. Any ideas would be gratefully received.[/quote]

From our experience i would also say it was your drains that is problem. Are you able to get the floor up to view the drains? I wonder if your neighbours have a problem? At the time some of the neighbours didnt want to admit there was a problem. Seal the tops of your cavities from the loft, and any holes in the loft. Im sure you have probably done all this...I realise what a horrible situation this is. good luck

hmas
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Re: Rats in cavity wall

Post by hmas » Sun Oct 02, 2011 10:05 am

As a Professional Home maintenance advisor and faced with a rat problem in the air space of a flat roof extension.I did make so many wrong assumptions (i need to go back to school) however it may help some one to know the outcome.I carried out a full detailed investigation of the structure and eaves both on this property and next door as it is a terrace approx 1820s and could not find any access way for them to get in.The final outcome was when i realised that we had employed a flat roof company some 7 years previous to re-felt the roof and by removing the vent on the soil stack found that they had cut off the top 18" of the foul pipe, re-boarded the roof and re-felted and then remembered that they needed to re-fit the top back on and guestimated the position of the lower half of the stack so that the top 18" was not in line by some 2.5" and as such the rats came up the soil stack and through the overlap.And that i now know that rats climb vertical 100mm pipes by pushing their back to one side of the pipe and strenching their legs out climb quite easily and they reverse this going down as i have watched this happen using a 9mm flexible pipe camera.The main question is who would assume that the foul pipe was not in one piece ?

steveconti
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Re:

Post by steveconti » Mon Jan 23, 2012 12:30 pm

ok some of you know im sueing the builder who built my house but ive a new problem now..lol
Ok monday had the council out to bait cos we had something going in and out of the cavity wall between us and next door, the council guy confirmed it was a rat ( or more then one) getting in via next doors water/sewage drain cos he found rat droppings, so he baited the main drain and a smaller on in the road and will be back in a week, thought ok rat be dead in a few days. guy next door isnt interested even though its in his walls, behind his cupboards and under his stairs, but its driving me nuts and i dont want it getting into the house or biting my power cables behind the power point where it seems to like scratching. So any ideas guys???
rep for any ideas im getting to the point i dont want to open the doors unless i have something heavy and big in my hand..lol cant bait anywhere outside the drain as i have a little boy and there are a million cats that just LOVE my garden

steveconti
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Re: Rats in cavity wall

Post by steveconti » Fri Feb 03, 2012 7:16 am

The first step in rat pest control is to understand your foe; simply putting down a rat killer or rat poison is unlikely to solve your problem. Rat pest control can be a very straightforward procedure as long as you fully understand the behavioural traits of the rats. We receive far too many emails from people who have used a rat killer poison only to discover that they subsequently end up with a rotting corpse under their floor boards. By reading the following we hope you will become a mini expert on rats. This section has been written for us by Ed Allen who is regarded as one of the worlds experts on rat pest control.

Ratatouille
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Re: Rats in cavity wall

Post by Ratatouille » Tue Sep 02, 2014 2:17 pm

Hi there, I have a similar problem with rats getting into the loft of my extensions and would like to read the article mentioned in the previous post, should there be a link?

Cheers!

Simon

testing2
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Re: Rats in cavity wall

Post by testing2 » Fri Oct 31, 2014 12:48 pm

This is a device I have found that might do the trick:

Sonic Mouse and Rat Repeller: https://www.diydoctor.org.uk/DIY-superst ... eller.html

Does anyone know if they actually work?

Ratatouille
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Re: Rats in cavity wall

Post by Ratatouille » Sat Nov 01, 2014 1:25 pm

I've used similar devices which sadly don't seem to have had any effect.

JohnDee
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Re: Rats in cavity wall

Post by JohnDee » Tue Feb 01, 2022 7:58 pm

bornlivelife wrote:This is my first post and have a really difficult problem Im hoping someone might have some ideas how to help.

Have a full width single storey flat room extension on back of a semi, and there are rats in the roof. Poison put down kills them off for 2 weeks, then they return ao need permanent fix.

Have sealed all cavity walls in extension at head height and this barred them from the roof but they were still in walls. Found a loose brick below damp course in main house where it joins extension, pulled it out and found a lot of gaps between bricks where a gas pipe had been put in, so put loads of concrete in below damp course and sealed it. This barred the rats from walls.

2 weeks later they are back in roof of extension, but previous work is still perfect, ie they must have another route into the extension roof, between ceiling and flat roof. There are no external gaps in roof and the walls are all perfect above ground level. There are no holes in garden

Putting posion in drains kills the rats for 2 weeks so there is some connection between drains and flat roof

Conclusion: I think the rats are in main house (built 1959) back wall cavity which the extension (built 1991) is joined to. I think somehow the drains are connected to this cavity possibly from previous kitchen sink drain. Think they are getting into flat roof extension through hole for electric supply into roof

Questions

1. Can i seal the main house cavity wall with anything that rats will not penetrate?
2. Do i still need the air in this cavity wall, as it is not internal since extension was built?
3. Would a smoke pellet in cavity wall show me where the holes are?
4. What can I do !!


Hi
I will try to answer your questions
1. ​Yes you can seal it, it is the only way. Use mesh and wirewool etc
2. I dont think you need the air in the cavity wall, but it doesnt mean you have to seal it up with the concrete.
3. You coul try but I dont know if its going to help.
4.Contact local pest control, use the inspection cameras

blusu
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Re: Rats in cavity wall

Post by blusu » Wed Feb 02, 2022 6:31 am

Sorry, can only save you money by telling you what doesn't work! Have rats in the loft which enter via cavity wall. Have 3 of those sonic things on all the time, (2 different makes) mains operated not cheap ones. and 6 battery operated lights, which switch on when something moves. The rats obviously thought I had set up a disco. The first really cold night there was a real party going on there, kept me awake, so checked the internet said they don't like onions. So at 3 am in the morning I chopped some onions in half and threw them at them. It has been quiet since (a few weeks now) but I won't hold my breath perhaps they are just being quiet! It also said they don't like daffodil bulbs so have planted loads in the garden, sounds doubtful to me but I will try most things. I would not advise poison the stench for months as you cannot find them is terrible and bluebottles get everywhere never again. Have also put peppermint oil tablets in the vents, and meshed around the inside of vents. I only get rats in cold / very wet weather as no food in the loft, beware candles and soap are food to rats! All is quiet so far but fully expect to find them eating onions quietly!

Ratatouille
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Re: Rats in cavity wall

Post by Ratatouille » Wed Feb 02, 2022 9:20 am

I seem to have been successful in stopping them getting in to one of my lofts by filling the tops of the cavity walls with galvanised wire mesh, covered in concrete with broken glass mixed into it, but they still seem to be getting into my smaller loft, where I have done the same thing, so that must still have a gap somewhere. I'll have to do more investigating.

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