How Can i Keep Mice from Crawling Under My Garage Door

I would like to use my garage as a cool dry place to store winter squash and potatoes but there's huge gaps where mice can get in around and under the rubber flashing that's there to stop drafts.  It's an electric "Genie" garage door that has a burnt out motor, so total replacement is a viable option.  It's a small garage that I don't plan on parking a car in ever again, so building a wall with a smaller door would be an option too, but I like being able to have it wide open occasionally.  

Just fishing for tips and ideas if you got em, thanks!

My experience has been that preventing mice from entering is an impossible task.  They seem to be able to get in through the smallest openings. I have successfully used a 50/50 mix of Jiffy Cornmeal Muffin Mix and baking soda.

John F Dean wrote:My experience has been that preventing mice from entering is an impossible task.  They seem to be able to get in through the smallest openings.

That's what I told my wife and she ain't having it. lol

Does the garage door have a door sweep installed? That would be my first step in discouraging rodents from trying to use it as an access point. It is essentially a rubber strip that helps close up any gaps.

I've seen that they typically chew through the rubber sweep at one end or the other to get in.  I wonder if, for an infrequently opened door, the sweep could be replaced with a piece of metal flashing that is form fitted or cut to match the shape of the cement it mates up to.  I also wonder if as the slab heaves with frost, if that perfect fit would change and the mice would laugh and just walk under it.

If the rubber sweep could be replaced with a spongy stainless steel pool noodle or draft sock, that might solve the problem.  If you get rich off this idea, please send me some thank you money :)

Timothy Norton wrote:Does the garage door have a door sweep installed? That would be my first step in discouraging rodents from trying to use it as an access point. It is essentially a rubber strip that helps close up any gaps.

Yes, in my ignorance I described it as "rubber flashing".

Lol if I can't get rich inventing a stainless steel pool noodle, I might as well hang it up

Mice & rats HATE raw coffee beans. I worked as a barista, for a while, in a local coffee shop a couple years ago, and though the back room was cluttered with bags of raw coffee waiting to be roasted, I noticed there was never a single mouse poop. When I brought it up to the owner, to ask how he was deterring them, he said he'd never had a problem - in the whole shop, because the caffiene in raw coffee is so toxic to them, they just stay away. So, I bought some, ran a bit around all the places where they seemed to be coming into our attached garage, and haven't had trouble, since - even though I've not bought any to freshen it. The key seems to be leaving it there.

When I was a kid, folks attached an old garden hose to the bottom of the garage door.

Would that work nowadays?

Does the garage door sit on the same plane as the interior with a drop down lip on the outside? A couple of times I have added insulation to garage doors to help keep the heat out and found that lip to be uneven with gaps where air could easily get through. I took a cold chisel and moved the lip just behind the door so it would sit down further and eliminate the gap. It might not be a perfect fix, but it could at least make it more difficult for mice to get through. You can use a masonry blade on an angle grinder, but that also makes a huge mess you don't want to breath.

Steel wool is a standard way of blocking entry points for rodents. You can get it cheaply in rolls  of 10 to 15 feet specifically for rodent control.

How To Use Steel Wool For Pest Control

Amazon search: steel wool mice control

It is absolutely amazing how small a crack a mouse - particularly a young mouse - can get through! We have a tiny crack under the door to our back workshop, and they'd get in. So we put a couple of pieces of 2x4 against the crack. If the wood gets put there, the mice are kept out. If someone "forgets" to put it back, the next thing we know, we're seeing evidence. They're partial to peanut butter, so leaving a jar with "essence" of p-butter on the outside of it will be the first area to show signs of them. I have a mouse trap balanced on top of the jar so I can see from a distance if it's been disturbed!

So, rather than attaching something permanently to the door and having to deal with things like thermal contraction, I'd consider what Mike Haasl was suggesting, but making it a floating piece. Is the garage door metal? A different spot where we'd had issues, but we wanted some air flow, I used magnets to hold a piece of hardware cloth bent at a right angle. Again, something like that would allow a bit of flexibility, but still deny access.

If you use the area for projects, I can see that keeping the garage door and fixing the gap would be beneficial. However, if you want to be able to get people in most of the time, there are garage doors that have an integral "people door".

John F Dean wrote:My experience has been that preventing mice from entering is an impossible task.  They seem to be able to get in through the smallest openings. I have successfully used a 50/50 mix of Jiffy Cornmeal Muffin Mix and baking soda.

I was an exterminator for over 5 years.        Mice do not have bone they have cartilage,   they can fit thru  a 1/4 inch gap.    

What happens this time of year each fall is the abundance of mice loose their food sources, plants / insects so they will turn to any place inside.

The door seal has to be a fortress, so I agree that the  baking soda method is one of the safest and best ways to deal with the problem,   sealing all gaps is best and feeding them the baking soda mix is the way to go.

Like many wanting to store both human and animal feed through the winter, we deal each winter with rodent issues.  In the end, we just went with as many steel cabinets as we could find of the type shown below.  Before the pandemic, these used to sell for a bit over $100 at many of the big box retailers.  Haven't seen a new one now for under $250, but also haven't checked for a while.  Fortunately, the Craigslist/FB Marketplace source now routinely has such cabinets for ~$100 or less for a 6 ft tall cabinet.  We maximize the space in these by removing shelving or other occlusions in order to stack up winter squash and bags of potatoes (in buildings where we know they won't freeze solid).  And being steel, they are impervious to rodents.  Don't worry about stacking bags of potatoes 6 ft high....they are stored in piles much higher than that for commercial sale.  Depending on your volume and needs, this may be a good solution without remodeling the garage... :-)     Good luck!

John Weiland wrote:Like many wanting to store both human and animal feed through the winter, we deal each winter with rodent issues.  In the end, we just went with as many steel cabinets as we could find of the type shown below.  Before the pandemic, these used to sell for a bit over $100 at many of the big box retailers.  Haven't seen a new one now for under $250, but also haven't checked for a while.  Fortunately, the Craigslist/FB Marketplace source now routinely has such cabinets for ~$100 or less for a 6 ft tall cabinet.  We maximize the space in these by removing shelving or other occlusions in order to stack up winter squash and bags of potatoes (in buildings where we know they won't freeze solid).  And being steel, they are impervious to rodents.  Don't worry about stacking bags of potatoes 6 ft high....they are stored in piles much higher than that for commercial sale.  Depending on your volume and needs, this may be a good solution without remodeling the garage... :-)     Good luck!

I have also found the mice I have do not make it thru 55 gal barrels plastic.       I have heard reports of rats chewing thru concrete, but mutant rats are another level of difficulty...

This was another reason for me testing 55 gal barrels underground.....     For long term storage it works for me.