How to Get Rid of Mice in Walls

Dealing with a mouse infestation in your home can be very frustrating. When mice get into your walls, it can be even harder to get rid of them. However, there are several effective methods you can use to get rid of mice in walls and prevent them from returning.

Signs of Mice in Walls

Here are some signs that may indicate you have mice living inside your walls:

Scratching or scurrying noises coming from inside the walls – This is the most obvious sign. Pay attention for noises coming from inside your walls, especially at night.
Small holes in your walls or baseboards – Look for small, pencil-sized holes along your baseboards or in your walls. These may be entry points for mice.
Droppings along baseboards or inside cupboards – Mouse droppings are small, around 1/4 inch long. Finding them near walls is a giveaway.
Stains or greasy rub marks – Mice leave grease stains or rub marks along walls from rubbing against them. Look for these near suspected entry points.
Strange smells – The urine and droppings mice leave behind can give off an unpleasant musky smell.

If you notice any of these signs, it likely means there are mice nesting and living within your walls. Taking action is important before their population grows.

Dangers of Mice Living in Walls

While a few mice may not seem like a big deal, letting them live and nest in your walls can lead to some serious problems down the line:

Structural damage – Mice can chew through wood, insulation, wiring, and drywall. This can cause major structural problems.
Health risks – Mice droppings and urine can spread diseases. Nesting materials can also harbor bacteria.
Allergies – People with allergies to mice may have serious reactions to an infestation in walls.
Fire hazard – Mice are prolific chewers and can damage electrical wiring in walls, creating a fire risk.
Spreading mice – A few mice can quickly multiply into dozens. An untreated infestation will just keep spreading.

Dealing with mice inside walls requires proactive measures before things get out of hand. Ignoring the problem will only lead to worse damage over time.

Removing Mice From Walls

Getting rid of mice living and nesting inside your home’s walls involves two steps:

Force them out of the walls.
Seal up entry points so they can’t get back in.

Here are methods to drive mice out of walls:

Use Ultrasonic Pest Repellers

Ultrasonic pest repellers emit high-frequency sound waves that rodents cannot stand. The sounds irritate them and drive them out of the affected area.

How to use them:

Buy plug-in or standalone ultrasonic units designed specifically for mice and rats.
Plug in or place units close to affected walls where you think mice are getting in.
Move units occasionally to cover all infested areas.
Use according to directions over several weeks to drive mice from walls completely.

Pros:

Non-toxic to humans and pets.
Can cover large areas.
Doesn’t require trapping or killed mice.
Relatively inexpensive.

Cons:

Effects can take several weeks to work fully.
Outdoor mice may re-enter unaffected areas.

Apply Rodent Repellent Sprays

Special rodent repellent sprays make areas undesirable for mice. They hate the smells and will avoid sprayed surfaces.

How to apply them:

Buy repellent sprays made specifically for mice and rats. Look for organic and natural options if you have pets.
Read and follow label directions carefully.
Spray repellent along baseboards, entry points, and anywhere mice can access walls. Reapply every few days.
Spray inside (if possible) or outside wall holes. Focus on entry points.
Continue using for several weeks until all signs of mice are gone.

Pros:

Also repels rats, chipmunks, and other rodents.
Easy to apply.
Works fast alongside trapping methods.

Cons:

Strong smells may be unpleasant. Open windows if applied indoors.
Reapplication required every few days.

Use Electronic Mouse Repellers

Electronic mouse repellers use high-frequency tones and electromagnetic waves to drive mice away. The sounds and pulses irritate mice and make them leave the area.

How to use electronic repellers:

Purchase electronic units made specifically for mice. Look for plug-in or battery-powered options.
Place repeller units near affected walls and areas mice are entering.
For full coverage, use multiple units around the perimeter.
Use continuously over several weeks until all mouse activity stops.

Pros:

Covers a larger area, up to 1,200 square feet.
Silent to humans but irritates mice.
Just need to plug in or turn on – no spraying or traps to deal with.

Cons:

Some models may not have as much range or power as advertised.
Mice can get used to sounds over time. May need to change frequencies.

Use Mint Oil

Mice hate the smell of mint. The strong aroma overwhelms their senses and drives them away.

How to use mint oil:

Obtain 100% pure peppermint oil. Also works well with spearmint oil.
Soak cotton balls in the mint oil until saturated.
Place soaked cotton balls inside wall holes, along baseboards, and near any other entry points.
Re-soak cotton balls every few days to renew scent potency. The smell must remain strong.

Pros:

All natural method.
Also repels insects and spiders.
Pleasant scent for humans.

Cons:

Scent fades over time, requiring reapplication.
May not work as well solo for severe infestations. Works better alongside trapping.

Play Predator Sounds

Mice are skittish by nature and scare easily. Sounds of their predators trigger their survival instincts and make them flee.

How to use predator sounds:

Obtain an electronic device that plays cat, dog, hawk, owl, or snake sounds. Many options are battery powered.
Place devices near affected walls and entry points mice use.
Change sounds regularly so mice don’t get accustomed. Varying sounds confuses them.
Use the devices continuously until mice vacate the area, usually after a few weeks.

Pros:

Scares mice away without poisons or traps.
Easy to set up with battery-powered devices.
Can scare away various rodents and pests.

Cons:

Limited to smaller areas, unlike ultrasonic repellers.
Mice may learn to ignore sounds over time. Requires changing sounds.

Sealing Up Entry Points

The key to keeping mice from getting back into walls is finding and sealing up all of their entry points. Here are some methods:

Inspect Inside and Outside Walls

Closely check walls, both outside and inside your home, for potential holes or cracks mice could squeeze through. Common entry points include:

Small cracks or holes along the foundation.
Openings around outdoor plumbing, utility lines, or water spigots.
Gaps around heating and cooling vents or ductwork.
Any small gaps or holes where cables, pipes, or wiring enter the home.
Cracked walls, missing mortar, or gaps between bricks.
Missing screens or gaps in window frames and doors.
Loose siding or trim boards.

Be meticulous – mice can squeeze through gaps as small as 1/4 inch wide.

Seal Holes with Caulk, Wood, or Foam

Once you locate all holes and gaps, seal them up. Materials commonly used include:

Caulk or sealant: Great for smaller gaps and cracks. Look for concrete or metal-grade sealant for foundations. Make sure to only seal holes on the outside of homes.
Steel wool: Made of fine, sharp wires that mice hate chewing through. Stuff loosely into holes.
Copper mesh: Forms a durable barrier mice won’t gnaw through. Works great to seal large gaps.
Wood or metal: For larger holes, cut wood, metal flashing, wire mesh, or lath metal to size. Secure firmly in place with caulk or sealant.
Expanding foam: Foam sealants expand to fill gaps and harden in place. Look for pest-resistant foam.

For best results, use a combination of materials, like caulk and steel wool, to thoroughly seal openings.

Make Home Exteriors Inhospitable

Adding extra deterrents outside makes it harder for mice to gain entry in the first place:

Clear vegetation or mulch several feet back from the foundation. Mice use these as cover to stay hidden.
Seal gaps around outdoor AC units or crawl space vents with wire mesh. These are common entry points.
Apply repellent sprays around the perimeter and potential entry areas. Renew monthly.
Place mint oil-soaked cotton balls near exterior holes you can’t fully seal.

Trapping Mice in Walls

Trapping mice that remain in walls is sometimes necessary if the infestation is severe. Trapping involves:

Baiting traps with peanut butter, chocolate, or dried fruit. Place traps along walls and near entry points.
For electronic traps, turn on and place against walls. These kill mice via electric shock.
Glue traps and snap traps are also effective inside walls. Use sticky glue boards to catch mice exiting the walls.
Check traps daily and dispose of dead mice far away from home. Wear gloves when handling traps.

When catching mice, take precautions against hantavirus:

Do not sweep or vacuum up rodent droppings. The virus particles can become airborne.
Dampen droppings with disinfectant and remove with paper towels. Or use bleach solution.
Ventilate rooms when cleaning. Do not breathe in particles.
Disinfect all surfaces mice touched.

Wear proper safety gear like gloves and a mask when trapping mice or cleaning droppings. The virus can otherwise infect humans.

Stop setting traps once catches decline and mice appear to be gone. Monitor for any recurring activity. Immediately seal up re-entry points.

Natural Predators That Eat Mice

Another biological weapon against mice are natural predators. Certain animals prey heavily on mice and can eliminate infestations:

Cats – Excellent hunters, cats will kill and eat rodents. Some breeds like Maine Coons are mousers. Free-roaming barn cats help control mice.
Rat terriers – Bred to hunt rats and mice. Their strong prey drive makes them relentless exterminators.
Foxes – Foxes kill and eat mice and frequently invade their burrows. They help control outdoor populations.
Snakes – Certain snakes like the black racer and garter snake eat mice and raid nests for food. They follow scent trails left by rodents.
Owls – Nocturnal hunters like barn owls feast on mice and rats. One owl can consume over 1,000 rodents per year.
Hawks – Large hawks and falcons eat mice they can spot moving through open fields.

Encouraging natural predators, especially snakes, owls, and foxes, can provide free ongoing pest control of mice around your property. Unlike poisons, they don’t leave toxic residues behind.

Preventing Mice in Walls

Prevention is the best long-term solution to keep mice out of walls for good:

Seal all interior and exterior holes, no matter how small. Mice can squeeze through tiny gaps.
Install weatherstripping around doors, windows, and garage doors to close gaps.
Use wire mesh to seal large openings like attic vents, crawl spaces, and plumbing access.
Keep landscaping well trimmed away from the home’s exterior. Eliminate protective cover mice can hide under.
Stack firewood, mulch, and debris up off the ground so mice can’t burrow underneath.
Clean up any food spills right away, especially pet food bowls left out overnight. Don’t give mice a food source.
Store human and pet food in airtight containers to prevent access to pantry items.

With diligence, you can successfully get rid of mice and keep them out of walls for good. Be proactive and persistent, and employ multiple control methods together until all signs of mice are gone. Consistent prevention will also stop future infestations before they start.

FAQs About Getting Rid of Mice in Walls

How can I find where mice are entering my walls?

Look for small holes inside and outside along the foundation, around pipes, wiring, vents, windows, doors, and the roofline. Seek out rub marks, grease stains, and droppings around openings. At night, listen for scurrying noises in walls to pinpoint locations.

What smells do mice hate?

Mice have a strong aversion to mint, ammonia, garlic, and vinegar. Cotton balls with mint or ammonia can help repel mice from entering specific areas. They also dislike spicy scents like chili powder.

Do ultrasonic repellers really work for mice in walls?

Yes, ultrasonic repellers can effectively drive mice out of walls. The high-frequency sounds irritate mice and make them leave the area. Models that produce varying frequencies work best, so mice don’t acclimate. Place units around affected walls and infested areas.

What’s the best bait to use in traps for mice in walls?

Peanut butter is very effective bait for trapping mice in walls. They cannot resist peanut butter’s smell and taste. For best success, use small spoonfuls of creamy peanut butter on snap traps or glue boards near affected walls and entry points.

Are mothballs safe for repelling mice?

No, mothballs contain toxic chemicals and must be used with extreme caution. The fumes are hazardous to people and pets. Never place mothballs in walls or anywhere they can’t be sealed off from living spaces. There are much safer natural repellents to use.

What chemicals are deadly to mice?

Warfarin is the most common active ingredient in rodenticides lethal to mice. Just a small amount causes internal bleeding once ingested. However, these products also pose risks to children and pets, so are not generally recommended.

How do I keep mice from coming back once they’re removed?

Prevention is key. Seal all holes, cracks, and gaps both inside and outside your home to permanently block entry points. Use caulk, steel wool, wood, foam, wire mesh, and other materials to close openings. Trim back vegetation and tidy up debris mice can use for cover.

Conclusion

Mice infesting the walls of your home can certainly be a nuisance. However, with diligence and the right pest control methods, you can effectively rid your walls of mice and prevent future invasions. Focus on exclusion methods to identify and seal off all possible entry points so mice can’t gain access in the first place. Trapping, natural repellents, and establishing natural predators can also help drive mice out and deter them from your home. Keeping up prevention measures is key to keeping unwanted mice out of walls for good.