How To Keep Mice Out Of The Basement

Do you have mice in your basement? We share the most effective ways to mouseproof the basement and get rid of the ones already living inside.

Mice are crafty and resourceful creatures. They make their way through the tiniest of spaces and turn your home’s basement into their home.

If you have mice in your basement, it’s important to act quickly to get rid of them and prevent them from coming back.

Here’s how to keep mice out of the basement.

1. First, we’ll tackle the why, where, and how mice get inside our basements.
2. Then we’ll cover the best traps to use and how to keep them out for good.

Why Do Mice Like To Live In The Basement?

What is it about basements that attract mice? They are great places to hide.

Whether you have a finished or unfinished basement, it’s the perfect place for rodents to sneak in and make themselves comfortable.

Basements are warm enough to attract the mice and normally provide enough nesting materials to keep them happy. Humans rarely venture down there, so they don’t have to worry about being caught.

But there’s another reason why mice are so attracted to basements. They’re burrowing creatures that prefer to live underground in the wild.

Basements are the next best thing, and they offer extra protection from predators, like birds and foxes.

More importantly, it’s easy for mice to access other areas of the house from the basement. They can sneak up into the kitchen without catching anyone’s attention.

Mice are attracted to human homes because they have everything they need to survive: food, water, and warmth. Common house mice will eat anything they can get their paws on.

Your home kitchen is an all-you-can-eat buffet. They can easily live off crumbs found on the kitchen floor or a few pieces of leftover pet food.

And if you use your basement for storage, those cardboard boxes are excellent for building nests.

In the cold winter months, even a dark, damp basement beats the outdoors.

How Do Mice Get Into Basements?

Most homeowners are surprised to find mice in their homes, but it’s easier than you think for rodents to find entryways.

Mice can make their way into basements through cracks in the foundation, floors, or walls. Because they are burrowing animals, mice can squeeze through tiny openings (as small as 7.5 mm or a 1/4 inch).

They don’t have collarbones, and their fur makes them appear much larger than they really are. In fact, the average mouse is 1-7 inches long and weighs 1 ounce or less.

A mouse’s only limitation is his skull. If he can squeeze his head through a crack or hole, the rest of his body will fit through.

One telltale sign of a rodent problem is finding evidence of mice in basement insulation. You may also find droppings in your basement or nesting materials.

How To Insulate Your Home To Keep Mice Out

Mice can wreak havoc on your home and your health. Rodents are known to carry many types of viruses and bacteria that cause problems in humans. These include:

• Salmonella
• Hantavirus
• Hemorrhagic fever
• Lymphocytic chorio-meningitis
• Rat-bite fever
• Plague
• Tularemia

Exposure to their droppings can make you sick, but health concerns aside, mice can also cause serious damage to your home. They chew wires and just about anything else they can get their teeth on, including cloth, paper, wood, and books.

If you see signs of a mouse in your basement, it’s crucial to insulate your home and use traps to get rid of mice and keep them from coming back. Since as you know if you see one mouse, there are likely many, many more hiding nearby.

Sealing Cracks and Openings

The best way to keep rodents out of your home is to seal up cracks and openings with pest expansion foam and steel wool.

Just as the name suggests, pest expansion foam will expand to fill in tiny cracks and crevices that you may miss with other sealing products (like caulk).

There are two main types of expanding foam:

1. Polyurethane: Porous when dry and can be cut with a bread knife for shaping.
2. Latex: Rigid when dry and difficult to manipulate, but can be sculpted when wet.

When sealing holes, it’s best to first pack steel wool into the opening until it’s sealed tightly. The steel wool serves as a foundation for your foam that mice can’t chew through.

Next, add the spray foam and use a putty knife to shape as desired. Proper sealing of cracks and openings is the best way to keep mice out of your basement and the rest of your home.

Use Wire Mesh

For cracks around drainpipes and wall openings, use wire mesh. Secure the mesh over the openings, and use quick-drying concrete to seal it into place. Mice won’t be able to chew through the wire.

Install Covers When Necessary

You may have entryways that you can’t block off entirely. These areas can leave your home vulnerable to mice infestations.

To keep rodents and other pests out, install a cover with a flap. The flap should face the exterior. This way, mice can get out, but they can’t get back in.

What is the Best Mouse Trap for a Basement?

Insulating your home will keep mice out, but what about the critters that are already in your basement? Traps will do the trick.

Which traps work best?

The three traps we like best for the basement are:

1. Ultrasonic Pest Repellers
2. Electric Mousetraps
3. Plastic Snap Traps

Ultrasonic Mouse Repellers

Ultrasonic repellers are small devices that emit high-frequency or ultrasonic noise. These sounds, which are more than 20,000 Hz, are intolerable to mice and other rodents.

Fortunately, these sounds are undetectable to the human ear and don’t seem to bother household pets. Ultrasonic sounds are believed to cause unpleasant symptoms in rodents, such as confusion and even convulsions.

What’s great about ultrasonic devices is that they’re not traps, they’re repellents. They chase mice away, so you don’t have to worry about cleaning up dead animals or any of the unpleasantries that come with trapping and killing rodents.

The T3-R repeller chases away mice, rats, squirrels, and other rodents using ultrasonic sounds.

Unlike plug-in ultrasonic devices, the T3-R stands on its own and comes with a long, 6-ft cord. The unit uses three specially designed speakers to transmit sound at three locations on the device.

T3-R says most rodents leave within 12-16 days of using the device.

Read more about using ultrasonic pest repellers.

Electric Mouse Traps

An electric trap uses a high-voltage shock to kill mice almost instantly. Most models have similar designs.

• High-value bait (usually a protein) is placed inside a chamber.
• Mice sniff out the bait and walk inside the chamber to eat.
• The trap’s sensors detect the mouse, and the device delivers a shock that kills the mouse almost instantly.

Because they’re powered by a battery, electric traps can be placed anywhere in the home. The mouse remains enclosed in the chamber, so you don’t have to worry about your children or pets finding dead mice around the house.

The Victor M250S is arguably the most popular electric mouse trap, and that’s because it works so well. The no-touch, no-see design allows you to dispose of mice quickly and safely.

The M250S has a 100% kill rate.

• An LED indicator light blinks green when a rodent is caught.
• The trap also has an indicated bait cup, so you know exactly where to place the bait.
• The beveled columns prevent mice from escaping and ensures the safety of children and pets.
• The kill chamber is easily removed for quick and easy cleaning.

The M250S is powered by 4 AA batteries and can be placed anywhere in your home.

For more options, see our article that compares the different types of electric mouse traps.

Classic Snap Traps

When most people think of mouse traps, snap traps are what come to mind. Snap traps are easy to find, cheap, and highly effective if you use the right bait.

While they may seem inhumane, snap traps can kill instantly when set properly. When the mouse takes the bait, it triggers the trap to release a bar that comes down on the neck. The bar snaps the mouse’s neck, killing it almost instantly. The main concerns with snap traps are:

• Having to touch and clean up the dead bodies
• Worries about pets or children accidentally triggering the trap and becoming injured

Snap-E’s mouse trap comes in a pack of six and is completely reusable. The polystyrene and steel construction makes the trap resistant to odors and stains that are commonly found with wood traps.

When properly cleaned, these traps can be reused for many years.

• The pre-formed bait cup makes it easy to bait this trap.
• The vertical strike bar only travels half the distance of a conventional snap trap.
• The trip paddle and strike bar are extra-large to catch rodents from all sides.

When used properly, your hands will never have to touch the mouse.

Check out this article if you’d like to compare the other types of snap traps to see our favorites.

To Recap

To keep mice out of your basement, you’ll need to take a two-prong approach:

1. Sealing and insulating holes to keep new mice from getting inside.
2. Trapping the mice that are already in the basement.

If you’re concerned about trapping your own mice or have a major infestation, call a pest control expert or exterminator to get the job done.