Mouse in loft (video)

[Radian]

Every Winter we get at least one unwelcome house guest in the loft. This year is no exception.?

 

The night before last, the little bu99er climbed on top of my DIY seesaw bottle trap locking it down with him on the outside. Look how he frantically wants to get inside to munch the peanut in there! How ironic.

 

So yesterday I made an arch out of a cardboard box to stop him climbing on top. At 3AM he got the bottle half way down by gingerly leaning into the opening, but it wasn't until later that he lost all will power and got completely inside. BINGO!

Next stop, the back of Sainsbury's car park two miles away ?

 

In the past we've released them closer to home (across a busy road) but on more than one occasion the same mouse has got back in the loft the following day so now we take them for a longer ride. Pure coincidence there's a nearby Owl sanctuary between us and the supermarket.? Ahem. At least we give 'em a sporting chance.

 

But enough of that. I want some ideas how to stop? getting in. I think I know where as there's a very obvious entry point into the soffit box. This seems inevitable because it's where the eaves meets a perpendicular roof at a valley something like this:

 

 

 

The cross section sketch shows the mouse entrance at the gap between the timber fascia and adjacent roof. The gap is necessary as water cascades down the GRP valley and down to the lower gutter. Looking at this junction from the inside of the loft I can see daylight here.

 

The obvious solution is to spray foam the gap from inside the soffit box but this will bridge the fascia to the valley gutter and rot it out. The eaves have plastic vent trays all the way along the bottom of the first row of slates but stop at the gap no doubt for the same reason. Seems like a stupid design.

[ProDave]

Best of luck but I doubt you will stop them.  A cold roof has to be ventilated, and a mouse can get through a hole that a biro pen will fit through, i,e, through the holes in a standard air brick or soffit vent.  I used to deal with them with poison no messing and no return.

 

This is why I am such a fan of an airtight warm roof design, the buggers have not got in this house yet.

[Radian]

Yeah. I sure wish it was a warm roof. However, I think the vents have small enough gaps: smaller than fly size. I've checked all round the other soffits and all are well caulked. Just the two valleys seem to stand between me and peace and quiet.

 

Unless it's up the cavity walls ?

[tonyshouse]

Oil of peppermint well puts them off

[Iceverge]

1 hour ago, ProDave said:

I used to deal with them with poison no messing and no return.

 

They might go and die somewhere inaccessible and decay with a nasty smell. 

 

Also the poison can be passed up the food chain and do lots of damage to birds of prey that are quite helpful keeping rodents at bay. 

 

Simple traps or a cat maybe. 

[Roundtuit]

1 hour ago, Radian said:

 Unless it's up the cavity walls ?

  

Looks like a field/wood mouse. I'm sure it could scale the wall and get in as you suspect, but my money would be on it getting in nearer ground level and going up the cavity.

[Radian]

9 hours ago, tonyshouse said:

Oil of peppermint well puts them off

 

Yes I'm already using that to deny the half of the loft that I've already cleared of cluster flies (yes, we've got all the usual pests)

 

9 hours ago, Iceverge said:

 

They might go and die somewhere inaccessible and decay with a nasty smell. 

 

Also the poison can be passed up the food chain and do lots of damage to birds of prey that are quite helpful keeping rodents at bay. 

 

Simple traps or a cat maybe. 

 

And that's why we use the see-saw bottle trap made out of a juice bottle, coat hanger, rare earth magnet and wood scraps. It's extremely effective except for when the mouse gets on top and pushes it closed like it did this time and in a previous year: 

 

 

 

9 hours ago, Roundtuit said:

  

Looks like a field/wood mouse. I'm sure it could scale the wall and get in as you suspect, but my money would be on it getting in nearer ground level and going up the cavity.

 

It would seem more likely to get in at ground level but I've gone all round checking for gaps and there are none. The telescopic vents have grilles that are too small for rodents to get in. Oh, wait a minute - there might be a way in through the gas meter box - I remember it was full of snails last time I looked. They must have got in around the pipe or something and once inside I suspect an easy passage into the cavity for a mouse. Will check!

[joe90]

Despite having a well sealed warm roof we had a Mouse that got into the cavity, over a few days we heard it’s progress around the house eventually getting into the loft where I caught it with a trap. Turned out it got into the cavity where an external socket was being installed in the brick skin. Not had one since.

[jack]

It's that time of year I guess.

 

We were woken a couple of nights ago by an ungodly scraping noise in our pantry. It was so loud that I thought it was the dog scratching at something, but when I got down there I realised something else was chomping on a wood panel behind the pantry cupboards. 

 

I've now found mouse crap under the units, but I can't see any evidence of the chewing. I can only assume it's on the back panel of the units that I can't get to, where it's trying to chew through to where the food is kept. Humane trap down but so far no hits. 

 

This isn't the first I've found in this general area. They seem to enter along a gap in the internal service void behind the plasterboard. How they're getting into that void from outside (through 300mm of cellulose insulation) is the bigger question, and I don't want to block off the gap until I know the answer!

[Radian]

11 minutes ago, jack said:

We were woken a couple of nights ago by an ungodly scraping noise in our pantry.

 

For such a small creature they don't half make a racket! I'll also swear I could hear our latest one snoring when I was working in the loft shortly before we trapped it.

 

I find WiFi cameras extremely useful for aiding the removal of these pests. I have a Raspberry Pi camera permanently in the loft for this purpose. The Rpi Cam Control software  has motion detection and I've set it up to notify my phone when triggered. I find with the trap I made I need to get to it asap as the mouse has nothing better to do than chew its way out.

 

These days you can get a WiFi camera up and running for less than £8 each if you don't mind programming an ESP32. Makes for an almost disposable item!

[bgmill]

We've had a constant battle with rodents in our donor bungalow every winter since we moved in - we planned to only spend one in here but we're now on our third and almost certainly will see a fourth too. I gave up on humane traps a long time ago and now have a loft full of poison and snap traps as it seems this is the only effective method.

 

I plan to pay very close attention to rodent/bug proofing our new build!

[jack]

3 hours ago, Radian said:

For such a small creature they don't half make a racket! I'll also swear I could hear our latest one snoring when I was working in the loft shortly before we trapped it.

 

I was convinced it had to be a rat (if not a badger!) based on the noise. I sounded like someone loudly gouging out wood with a chisel.

[Mike]

17 hours ago, Radian said:

I think I know where as there's a very obvious entry point into the soffit box. This seems inevitable because it's where the eaves meets a perpendicular roof at a valley something like this:

If you're up for modifying the roof, I'd create a vertical abutment in plywood where the dormer eaves meet the roof, with lead flashing, here:

[Susie]

Have you considered the plug in ultrasonic type repellers. We have a few in our house and despite being an old farm building, feeding birds a lot, not airtight in any way, we have only had 2 visitors  in 5 years. Both times same cereal cupboard in kitchen.  Outside we see field mice in the barns. I think they work quite well and no poison involved. 
 

[MJNewton]

Mice catching discussions always remind me of a friend who had a mouse issue but couldn't possibly entertain the idea of anything that'd cause them harm so naturally he went for some humane traps... The thing is he forgot about them and when he went back to inspect them found to his horror that they'd been successful, but the poor blighters had since expired having likely suffered a long drawn-out death trapped inside these tiny boxes! I think it still haunts him to this day...

Edited January 7, 2022 by MJNewton

[joe90]

My favourite mouse story was my brother in law looked in the cupboard to find a snack and found some chocolate chip cookies his wife had made, when he congratulated her on them she replied “but I didn’t have any chocolate chips!” (Mouse droppings ?).

[Onoff]

Just now, joe90 said:

My favourite mouse story was my brother in law looked in the cupboard to find a snack and found some chocolate chip cookies his wife had made, when he congratulated her on them she replied “but I didn’t have any chocolate chips!” (Mouse droppings ?).

 

That's just taking the mickey.

 

[Radian]

3 hours ago, Susie said:

Have you considered the plug in ultrasonic type repellers. We have a few in our house and despite being an old farm building, feeding birds a lot, not airtight in any way, we have only had 2 visitors  in 5 years. Both times same cereal cupboard in kitchen.  Outside we see field mice in the barns. I think they work quite well and no poison involved. 
 

 

Hopefully that might be useful to maintain a pest free space but when I know a mouse is present I'm always going to deploy the humane trap which definitely works. Since I learned that mice like to run along edges and avoid open spaces I can almost guarantee a catch the first night after setting it up next to a gable wall.

 

I'm sure sufficiently high-powered ultrasound would be uncomfortable for mice but it is easily attenuated by the plentiful insulation materials found in a loft. The higher the frequency the more easily it is absorbed. The problem then is that compared to the cold, wet and dangers present outside - once the mouse feels warm, dry and safe then it's probably going to habituate to the noise as soon as it finds a relatively quieter spot. There is some research on the subject but I can't find any I would trust. The majority of online resources that dismiss ultrasound repellents seem to be published by pest control companies that would prefer to sell you a service visit. If I ever get the time I would be interested to experiment on one of my guests to see their reaction. A bit of code running on the camera Pi could generate an Ultrasound sweep while the camera records the response. If there's a particular 'sweet spot' for upsetting a mouse then this might be a good way to find it.

[Radian]

3 hours ago, Onoff said:

 

That's just taking the mickey.

 

[Radian]

Having trapped the mouse on the 6th of January, we now have another one running around in the attic less than two weeks later. After we got rid of the previous one I spent the day going around the perimeter of the house looking for entrances. There was nothing. But at head height, the sloping roof of our lean-to utility room had about 1cm gap between the eaves vent and the stonework of the house. This could have gotten a mouse into the soffit box, up the outside of the insulation panels and into the second attic. A generous squirt of acrylic sealant sorted that gap.

 

But this new mouse definitely didn't get in that way. The acrylic plug is still intact. As is the squirty foam filling I did in the main attic at the valley junction between the two roofs. Just to explain, the two roofs create two attics because indoors, the two halves of the house are separated by a double-height hallway that goes all the way up to the ridge. The steel beams supporting the ridge and wall plates, however, form three tunnels linking the two attics. Handy for wiring but also highways for vermin.

 

The problem now is that there are a couple of obvious entrances either side of this dormer window:

This is the same kind of problem where the soffit stopped at the junction between roofs. I could get at that junction from inside the attic to block it but this dormer isn't as accesible. I can't see inside and around the corner to this gap. So I'm not sure how to close it from the inside or the outside. I don't want anything to bridge between the slate and wooden fascia.

[SimonD]

Speaking of mice, we've got some in the very unfinished portion of the house. I've gone round and blocked up all the holes I think they can get in through yet still they come. One of them is very clued up as it's noticed the dangers of the humane traps I've been using and did something about it - not just once but 3 times!:

 

 

[Radian]

16 minutes ago, SimonD said:

and did something about it

You mean it shifted all those stones into it? Why I wonder - was it trying to protect its mates?

[jack]

43 minutes ago, SimonD said:

Speaking of mice, we've got some in the very unfinished portion of the house. I've gone round and blocked up all the holes I think they can get in through yet still they come. One of them is very clued up as it's noticed the dangers of the humane traps I've been using and did something about it - not just once but 3 times!:

 

 

WTAF? 

I wonder whether it's viewing the trap as a potential nest, and dragging in some materials to close off the entrance a bit?

[Onoff]

12 hours ago, Radian said:

Having trapped the mouse on the 6th of January, we now have another one running around in the attic less than two weeks later. After we got rid of the previous one I spent the day going around the perimeter of the house looking for entrances. There was nothing. But at head height, the sloping roof of our lean-to utility room had about 1cm gap between the eaves vent and the stonework of the house. This could have gotten a mouse into the soffit box, up the outside of the insulation panels and into the second attic. A generous squirt of acrylic sealant sorted that gap.

 

But this new mouse definitely didn't get in that way. The acrylic plug is still intact. As is the squirty foam filling I did in the main attic at the valley junction between the two roofs. Just to explain, the two roofs create two attics because indoors, the two halves of the house are separated by a double-height hallway that goes all the way up to the ridge. The steel beams supporting the ridge and wall plates, however, form three tunnels linking the two attics. Handy for wiring but also highways for vermin.

 

The problem now is that there are a couple of obvious entrances either side of this dormer window:

This is the same kind of problem where the soffit stopped at the junction between roofs. I could get at that junction from inside the attic to block it but this dormer isn't as accesible. I can't see inside and around the corner to this gap. So I'm not sure how to close it from the inside or the outside. I don't want anything to bridge between the slate and wooden fascia.

 

[Onoff]

12 hours ago, Radian said:

Having trapped the mouse on the 6th of January, we now have another one running around in the attic less than two weeks later. After we got rid of the previous one I spent the day going around the perimeter of the house looking for entrances. There was nothing. But at head height, the sloping roof of our lean-to utility room had about 1cm gap between the eaves vent and the stonework of the house. This could have gotten a mouse into the soffit box, up the outside of the insulation panels and into the second attic. A generous squirt of acrylic sealant sorted that gap.

 

But this new mouse definitely didn't get in that way. The acrylic plug is still intact. As is the squirty foam filling I did in the main attic at the valley junction between the two roofs. Just to explain, the two roofs create two attics because indoors, the two halves of the house are separated by a double-height hallway that goes all the way up to the ridge. The steel beams supporting the ridge and wall plates, however, form three tunnels linking the two attics. Handy for wiring but also highways for vermin.

 

The problem now is that there are a couple of obvious entrances either side of this dormer window:

This is the same kind of problem where the soffit stopped at the junction between roofs. I could get at that junction from inside the attic to block it but this dormer isn't as accesible. I can't see inside and around the corner to this gap. So I'm not sure how to close it from the inside or the outside. I don't want anything to bridge between the slate and wooden fascia.

 

Got exactly the same issue in 4 places on my dormer. Mine is a lot more jerry built than yours though. I did think about folding some stainless mesh into a V.

 

 

Edited January 19, 2022 by Onoff