Pest Control

How Do Mice Get Into Upstairs Apartments? Find All Holes!

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A mouse in a cardboard tube 

If you’re like me, you’ve probably had to deal with some unwanted guests in your home: mice.

These furry little critters can be a real nuisance, not to mention a health hazard and a threat to your belongings.

In this blog post, I’m going to share with you my best tips on how to find and seal the entry points of mice in your upstairs apartment, so you can enjoy a pest-free living space.

Why Mice Enter Apartments

First, you need to understand the behavior of mice and their preferred entry points so that you can address and prevent the issue successfully.

So why do mice visit your upstairs apartment in the first place?

Mice are constantly in search of food, water, and shelter, making human dwellings an attractive prospect. Apartments provide a comfortable environment for mice, offering abundant food sources, warmth, and protection from predators. 

Mice are adept climbers and can easily reach upstairs apartments by scaling walls, trees, or even utility lines.

How Mice Can Climb Up to Your Apartment

I’m sorry to be the bearer of bad news, but mice can easily climb up to your apartment, even if you live on a higher floor.

Here’s the proof:

YouTube video

Mice are excellent climbers and can scale vertical surfaces with ease. They use their small toes and claws to find nooks and can climb a large variety of walls, depending on the surface material.

However, they have more difficulty climbing smooth and non-porous surfaces that they cannot grip. They can also climb walls with props like cords, cables, shelves, and wires.

Mice can climb rough vertical walls up to several feet high, as long as the surface is rough, such as concrete or brick.

They can climb vinyl or aluminum siding by gripping corners and edges with their strong, sharp toes.

Brick, gypsum, and wood are the easiest surfaces for mice to climb.

Mice can also use pipes, wires, cables, and other structures to reach higher floors. They can grip tightly around these items with their paws and use their tails to balance themselves.

They can also jump up to 13 inches and slip through surprisingly small cracks and holes, making them very agile and adaptable.

Some common routes that mice use to climb up to apartments are:

  • Exterior pipes or wires that run along the building
  • Roof vents or chimneys that lead to attics or crawl spaces
  • Balconies or fire escapes that have plants, furniture, or other items that provide cover
  • Gaps around windows or doors that are not sealed properly
  • Holes in drywall or insulation that provide access to wall cavities
  • Interior pipes or wires that run through walls or ceilings

Common Entry Points for Mice In Upstairs Apartments

Mice are opportunistic creatures, taking advantage of any vulnerabilities in a building’s structure. They can squeeze through cracks and holes as small as one-fourth of an inch.

Here are the common entry points for mice in upstairs apartments:

Exterior Vulnerabilities, Open Windows and Doors

Mice can gain access through damaged or deteriorating exteriors, such as cracked siding, broken vents, or gaps in the roofline. Any openings larger than a quarter-inch provide an entryway for these tiny intruders.

Cracks In Walls

Small gaps and cracks in the walls or floors, particularly around utility lines or where plumbing passes through, can serve as pathways for rodents to enter an apartment. These gaps may be hidden behind appliances or cabinets, making them difficult to detect.

Gaps Around Pipes and Wires

Utility and plumbing lines often have small gaps or holes that mice can exploit. For instance, gaps around gas lines, electrical conduits, or plumbing vents are potential entry points. Mice can follow these lines to gain access to an upstairs apartment.

Shared Spaces

If there are shared spaces in the building, such as stairwells, hallways, or utility areas, mice can move between different units. They might enter through one apartment and then find their way into neighboring units through gaps in walls, baseboards, or even open doors.

Vents, Ducts, and Chimneys

Mice can use vents and ducts as pathways to access different parts of your apartment. Damaged or improperly sealed vents, including those for HVAC systems or dryer vents, are susceptible to mice infiltration. Similarly, uncapped chimneys can be an open invitation for these rodents.

Signs of Mice Infestation

To detect signs of mouse activity, you should look for the following clues:

  • Droppings. Small, dark, pellet-shaped droppings along their trails or where they feed. Mouse droppings are a health hazard, so always use gloves and disinfectant.
  • Gnaw marks. Mice gnaw on various materials, such as plastic, wood, cardboard, wires, or furniture.
  • Nests. You may find nests in hidden or dark places, such as behind appliances, inside cabinets, under furniture, or in wall voids.
  • Unpleasant odors. In cases of a larger mouse infestation, the strong ammonia-like odor will be noticeable to anyone entering the room.

If you’re wondering where mice hide in your home, read this article.

How to Prevent a Mouse Infestation

Taking proactive measures to prevent rodent infestation is essential in keeping your upstairs apartment rodent-free. Here are some effective strategies:

1. Remove Items That Attract Mice


Mice are attracted to readily available food. Minimize their food sources by storing most items in sealed containers or in the refrigerator.


Dispose of trash promptly and use inaccessible plastic or metal cans to prevent mice from finding edible items.


Maintain a clean and tidy apartment, free of clutter, food remnants, and crumbs that serve as attractive hiding places.

2. Seal Entry Points

Prevent mice from entering your apartment by locating and sealing small cracks and holes that they can squeeze through.


  • Door gaps and frames
  • Window sills
  • Air vents
  • Heating and AC units
  • Pipes

Use steel wool or copper wool with caulk to seal cracks, or consider using DIY kits available online. Installing weatherstripping around your doors and windows can also help.

3. Use Natural Mouse Repellents

To deter mice, use peppermint oil, which has a strong smell, as a preventive measure. Place cotton balls soaked in peppermint oil near potential entry points. Alternatively, create a water and peppermint oil spray (1 part oil to 20 parts water) for application.

Avoid high concentrations of peppermint oil to prevent irritation. Safe mouse-repellent sprays are also available on the market, designed to effectively deter mice without posing health risks.

If the mice infestation problem is recurring, consider hiring professional pest control services to conduct regular inspections and take preventive measures. Pest control experts have highly effective tools to address the infestation and provide long-term solutions.

Make sure you read this article if mice keep coming back to your apartment.

Removing Mice from an Upstairs Apartment

If mice have already infiltrated your upstairs apartment, you must act quickly to get rid of them.

Step 1: Identify the Signs of Mice

Locate areas of high mouse activity, such as nesting sites or droppings. Look for droppings, gnaw marks, urine smell, noises, or sightings of mice in your apartment. These can indicate where they are hiding and how many there are.

Step 2: Set Up Humane Mouse Traps or Traditional Snap Traps

Basically, you can choose one of two paths: you can either use a humane (that catches mice alive) or a traditional mouse trap.

You can also use a big bowl with peanut oil at the bottom:

YouTube video

Set up the traps in areas where you have seen signs of mice activity, such as under furniture, behind appliances, in cabinets, near food sources, or entry points. Remember to handle traps and baits with caution, following the instructions provided.

I also recommend that you notify your property manager as they may have a pest control service that can help you deal with the infestation. They may also be able to fix any entry point or leak that is attracting mice.

You’ll find everything you need to know about effective mice extermination in this article.


Are mice dangerous in an apartment?

Rodents can carry diseases and contaminate food, posing health risks to apartment residents. Their gnawing behavior can also damage structures and electrical wiring, potentially leading to hazards such as fires.

How can I tell if I have a mice infestation in my apartment?

Look out for signs such as droppings, chewed wires or furniture, gnaw marks, and the presence of nests. Unusual odors or sounds in hidden spaces can also indicate a mice infestation.

Can I remove mice from my apartment on my own?

Minor infestations can sometimes be managed with traps and baits. However, severe or persistent infestations are best addressed by professional pest control experts who have the necessary knowledge and tools.

How long does it take to eliminate a mouse infestation?

The time required to eliminate a rodent infestation varies depending on the severity of the problem. It can take anywhere from a few days to a few weeks, especially if professional intervention is necessary.

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About the Author

James Mora is the founder of DailyHomeSafety. He is a home improvement expert, contractor, avid DIYer, and security manager. He is passionate about home repairs, remodeling, and teaching. Read More