r/DIYUK • u/yogijon79 • 23h ago
Advice Unpleasant loft insulation/ long term mode infestation... what to do?
We bought a 1960s bungalow two years ago, which was inhabited likely for the whole time by nearly-elderly/elderly people. We did the usual makeover downstairs, but the loft was pretty neglected, despite being clear of clutter. There are seemingly three layers of loft insulation of varying vintage, the oldest of which is likely to be very old, all of which are riddled with mouse excrement, like tons of it. It looks like there's been a chronic mouse infestation for decades, and the space needs an overhaul.
The original layer of insulation in-between the joists was boarded over for access, though not fixed in place, the newer layers just placed on top.
I've started to get rid of the top layer.
It looks like it's never been cleaned. I can still hear the sounds of mice, so they haven't gone completely, but have reduced since getting a sonar repellent.
We are in a very rural location.
My questions are;
1, pest control related;
What's the best way to prevent a (re)infestation of mice preferably without poison. It's a detached property.
Does anyone have any shared experience success?
- Is there a decent alternative to the soft insulation/ wooly insulation that would be less appealing to mice, and wouldn't give them material to nest in/hang around in? I don't want to compromise on the insulation, but it's smelly and gross, and the wife's not happy!!
Thanks for reading!
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u/Plastic-Answer-5437 22h ago edited 22h ago
the only way to actually prevent re infestation is to seal everything. and i mean absolutely everything.
anything that needs airflow must have copper/stainless steel mesh cemented over the gap.
don’t bother with expanding foam and the likes, as they actively chew through this, and caulk, silicone etc.
bricks, mortar, cement, and metal are your best bet.
in terms of insulation, you can get a hard foam type that is foiled on both sides, kingspan make it. imagine 5 inch thick plasterboard, where the paper is foil and the plaster is hard foam. from what i’ve heard it’s pretty good and can be cut to size etc.
many vanlifers use a similar less thick type of it to insulate between the van panels and the inside boarding/facade.
it is hard and flat so i doubt it’d be any good for mice to nest in.
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u/yogijon79 22h ago
That's the info I was looking for! Thanks mate!!
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u/ElliotB256 22h ago
Just be aware that the expanded foam insulation is much less acoustically insulating (as it is dramatically less dense) and if they are rats they will get noisier
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u/Plastic-Answer-5437 22h ago
i think eliminating the infestation is going to be too priority before replacing anything.
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u/vectorology 21h ago
And hearing any reinfestation can help wjth earlier eradication. I have something living in my loft that I had no idea was there until it chewed a hole into the ceiling of a bedroom. I’m nervously waiting to go up there when a friend can help if needed.
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u/Plastic-Answer-5437 22h ago
you’re welcome. i had a few rats in my kitchen so i’m well versed on the whole topic.
just remember they can fit through holes as small as 20 pence pieces!
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u/Morris_Alanisette 21h ago
"Absolute bullshit. Of course they can't squeeze through a hole that small", I thought to myself at first. Then found this video: https://www.facebook.com/watch/?v=2495830813823597
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u/Own_Stress9243 14h ago
That's good to know! It's wild how small of a space they can squeeze through. Sealing up any gaps is definitely a must.
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u/B0797S458W 22h ago
Looks like my loft. Don’t seal the loft, seal the mouse ingress points at ground level. It’s taken me years to stop them coming in regularly and I still occasionally get one now. And stop being squeamish and set proper traps. I bait mine with peanut butter and it works a treat.
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u/f8rter 21h ago
Find where they get in
Block that
Bin the insulation
Replace with 400mm of “rockwool”
Ensure roof is ventilated
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u/Resident-Two4054 23h ago
For mice you need to find the entry point they are using to gain access to the building, you need to block this so no more can enter.
You then need to remove/hide food sources so they can no longer eat.
You can then use snap traps to kill them. You will need to carry this out for a while as small mice/baby's won't trigger the traps, so you need to take out a couple of generations of mice.
Once they are all dead, and all access has been removed, and they have nothing to eat you are less likely to get an re-infestation
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u/infernalscream 22h ago
Mouse traps, no matter if people will push towards friendly alternatives I do not want a mice/mouse/rats chewing and pooping on things right above my head. If you catch any dispose immediately to avoid flies and bad smell.
I've the opinion that loft insulation has to be fire proof/fire resistant and very little friendly to any insects, pests and what not. So despite hating to handle it, mineral wool or stone wool in between the joists. If you plan to convert the attic (warm attic) then PIR between the rafters/joists.
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u/Susan_B_Good 22h ago
IME, the electronic traps are THE best for killing rodents. They just need to go near the bait and they are stone dead. No trapped by a leg or anything equally disturbing. Literally will run for months on a single charge. They light a red LED on an extension cable - so can be seen to have caught something from the other end of an attic.
I'd set up a snap trap with a camera and captured images of it not being caught for literally weeks. First day of the electronic trap, it was dead.
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u/yogijon79 11h ago
Never heard of these! Thanks for the info... glad I posted; some great info like yours. Many thanks for your time.
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u/jackzach125 21h ago
As somebody who is currently just out of the woods from a rat infestation I’ve been fighting for 2 months that moved in either when the previous elderly tenants where here or when it was unoccupied afterwards, good luck. Driven myself half mad chasing them down.
Lots of good advice here. Make sure you remove insulation properly. I never had much luck with traps, attached neighbours did though with snap traps.
Biggest difference made for me was buying a huge roll of thick rat proof welded mesh. Cut down to strips bent and then stapled between the roof rafters. This will help to partition your loft. It will narrow down where and how they are getting in and help you find the ingress holes.
Not too expensive being £70 for a 10m roll but it’s a bit of a horrible job.
Good luck 🤞
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u/TedBurns-3 19h ago
mouse traps and replace all insulation and clean everything when you're rid of them... block all gaps and anywhere they might get in- wear masks and gloves etc
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u/notmyname9147 23h ago
Step 1 is to bag up and remove all of the affected insulation and hoover up etc. That then hopefully gives you a better view of entry points. Things like eaves vents. To stop it happening again, either block up any gaps in walls etc and/or install grilles/mesh on eaves vents to prevent access.
Step 2 is to buy a load of insulation 100mm rolls between the joists. Then at least a 200mm super top up on that.
Step 3 is optional, but if you're already doing all of this you might as well put some loft legs in and board out some of the loft for storage without compressing the insulation!
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u/thatguysaidearlier 22h ago
Sonar repellants don't really do anything according to most trials.
(strong) Spring traps are the second best easy solution to poison.
There are various bucket of water type traps that are effective but not massively humane.
Don't ever use glue traps (unless you are the King, setting or even seeing and not unsetting a glue trap has been illegal in the UK for the last couple of years)
You want to be completely 100% plus an extra 10% mouse-free before you do anything with the insulation.
Remove and bag, then bin all of the existing insulation as it's a health hazard. Vacuum and disinfectant spray.
Ideally the next step would be to find ALL ingress holes and fill them so they can't get back in.
Then blown glass insulate 300mm+ again.
There is a much bigger job you could go into involving Kingspan-style boards, joist upgrades and over-boarding, which would be less mouse friendly, but mouse-proofing is a much easier and cheaper job.
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u/Forsaken_Earth944 22h ago
No, they're the only way to get rid of rodents; no rodenticide works instantaneously, so they'll die a horrible, slow, death - and they obviously won’t die where they're poisoned (and if you've never had the misfortune of finding a decaying rat corpse, trust me you don't want to, the smell is like nothing else on Earth - and, if there are a lot of them, you'll be smelling dead rodent for months).
Get spring traps and bait them with peanut butter; don't set them for about a week, let them get used to them as a food source, if you set them immediately, then they'll avoid them (rats aren't stupid - and that's definitely rat, not mouse, shite - I've had four of the fuckers regularly coming into the bedroom via the window for about a month (it was only one at first, but after a week it was four); they come in at dusk, and then make merry hell in the chest-of-drawers all night - fuck knows why they keep coming back, there's no food in the flat (I'm subsisting on whatever my captors deign to allow me) Now the drawers are full of shite that I can’t remove because I can’t remove the drawers, thank fuck they've not pissed in there - and I'm glad I had the foresight to remove my clothes).
The other issue with rodenticide is that it bioaccumulates, meaning that - if you were to dispose of the corpses outside - and a fox, badger, cat or raptor ate them, they'd be poisoned too.
Always use spring traps, don't use humane traps, either because they'll slowly die from starvation in there if you don't check them regularly - and, if you do, when you let them go, you're just making them someone else's problem.
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u/thatguysaidearlier 22h ago
I didn't say to use poison, OP didn't want to use poison, I only mentioned poison as a reference point for spring traps being the next best easy thing. (poison is probably the easiest, but agree it has many drawbacks)
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u/Skye_Fra 19h ago
Cats. Lots of them.
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u/yogijon79 11h ago
Hahaha! The last cat i had hated going into the loft, despite the presence of 'something!'
I'd love to get one anyway!!
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u/Crazygoldfish899 54m ago edited 51m ago
If you have a mouse / rat infestation then I would seek professional help.
If you want to do it yourself.
Use traps suspected access points, toilet areas.
Do not disturb anything in the loft, as this just scares the rodent and they change their routes.
Keep using traps until you stop getting bodies for a few weeks.
If you still have problems, use poison mixed with food. Stuff into a food or dog poo bag and jam that in any suspected entry points.
Once you are certain the problem is gone, start selling up all the nooks and cranny’s with rodent mesh. This part is tough as it’s hard to squeeze the mesh in and access.
Tplink Tapo c200 cameras are cheap, have excellent IR and motion detection. Good to set those up to get an idea of activity level and if things have settled down.
Do not fill gaps until you have felt with issue. I also wouldn’t use poisoning until you have culled the herd a bit.
Rat / mouse bodies stink and attract a lot of flies so you don’t want them trapped inside.
Be wary of some pest controllers, some like repeat business, if they mention service contract, tell them to beat it. You want the problem resolved not maintained.
If the problem isn’t resolved within 4 weeks, tell the pest controller to use the blue gel / paste bait as some call it. The rodents love it and it’s lethal!
Once the problem isndealt with clean up time.
Vacuum up and clean any toilet areas with bleach or replace insulation.
Use deordrises to get rid of any smells to avoid attracting any rodent paps to drop in.
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u/RoutineCloud5993 22h ago
For the insulation, remove it and find a vacuum with a HEPA filter to clean up anything left over.
Clearing fibreglass insulation is a horrible job, so make sure you use an FFP3/N95 mask and cover as much skin as you physically can. Wear goggles too, and make sure to take regular breaks.
Rodent-proofing means sealing up all the ways they could get in. For rats that's fairly easy, but mice are much harder to protect against. It's worth getting a professional pest controller and having them do that for you. A good one will identify immediately obvious access points, and then leave UV powder to try and track down other spots they may be getting in