I get where you’re coming from about the ultrasonic stuff—seen plenty of critters just ignore those. But I’ve actually had some luck with motion lights in crawl spaces. Maybe it’s the sudden brightness? Not a cure-all, but seemed to spook them for a bit. Hardware cloth is gold though, especially if you double up in corners. Funny how those little gaps you’d never notice become mouse highways overnight...
Motion lights are a decent trick, but I’ve found they only buy you a little time. Critters get used to them quick, especially if there’s food or warmth on the other side. I’m with you on hardware cloth—nothing else really holds up long term. I swear, the first winter after I moved in, I thought I’d patched every gap, but mice still found their way in through a crack behind the dryer vent. Didn’t even see it until I pulled the vent off to clean it.
One thing I started doing is stuffing steel wool in any weird little holes before covering with hardware cloth. It’s not pretty, but they hate chewing through it. If you’ve got plumbing running through crawl spaces, those spots are magnets for rodents too. Pipes seem to give them a roadmap straight into the house.
Curious—have you ever tried those expanding foam sealants? I used one rated for pest control and it worked for a while, but then I noticed mice just chewed right through it. Kind of felt like a waste of time and money, honestly. Wondering if anyone’s had better luck with a specific brand or if it’s just another gimmick.
And about those “mouse highways”—it’s wild how they’ll squeeze through gaps you’d never even think twice about. Makes me wonder what else is sneaking around under the floorboards when we’re not looking...
I hear you on the foam sealants, but I’m actually not a fan of using steel wool either, at least not by itself. Had a neighbor who did that and ended up with rust stains around the holes a year later. Plus, if it gets damp (which happens a lot near pipes), it can break down pretty fast. I stick to copper mesh—same idea but it doesn’t rust, and mice hate chewing through it just as much.
On the expanding foam, I’ve tried a few brands labeled “rodent resistant.” In my experience, they’re only good if you use them as a filler and then cover with something solid like hardware cloth or metal flashing. By itself, foam’s just too easy for critters to tunnel through.
And yeah, those tiny gaps are sneaky. Last winter I found one behind the water heater that was barely the width of a pencil... but sure enough, that’s all they needed. Sometimes feels like you need x-ray vision in these old houses.
Copper mesh is definitely the way to go—learned that one the hard way after trying steel wool and getting exactly the same rust mess you mentioned. Agree 100% that foam alone is just a temporary fix. I’ve seen mice chew right through the “rodent-proof” stuff in a matter of months, especially if there’s anything remotely edible or warm on the other side.
Here’s my usual checklist for those gaps:
- Copper mesh packed in tightly
- Layer of hardware cloth over that
- Then, if it’s a weird-shaped gap, I’ll fill in with foam just to seal air flow, but always cover it up with metal flashing or something solid
It’s wild how small an opening they can squeeze through. I once found droppings inside a kitchen cabinet and couldn’t figure it out until I pulled out the dishwasher—there was literally a hole the size of a dime behind it. Turns out, that’s all they need.
Curious if you’ve ever tried those ultrasonic repellents? I gave them a shot last winter out of desperation and honestly didn’t notice any difference, but maybe I just had stubborn critters. Or maybe I’m just too skeptical of gadgets in general.
Also, when you had your burst pipe, did you end up having to rip out drywall to get at everything? Sometimes feels like these old houses are just a collection of patched-up emergencies waiting to happen...
Never had much luck with those ultrasonic things either—felt like I was just plugging in another thing to collect dust. I get the appeal, but if the mice are hungry enough, they’ll ignore just about anything that’s not physically blocking them. When my pipe burst (kitchen, right under the sink), I did have to cut out a section of drywall, but I tried to keep it as small as possible—used one of those little oscillating saws and patched it up myself. Not pretty, but cheaper than calling someone in. Ever run into any surprises behind your walls while patching stuff up? Last time, I found an old newspaper from the 70s stuffed in as insulation...