How to Find and Seal Mice Entry Points

The common house mouse can squeeze through tiny cracks and holes about the size of a dime. This ability allows them to easily enter people’s homes and apartments in search of food, warmth, and nesting spots.

Finding and sealing these entry points is an important part of long-term rodent control, since it prevents more mice from getting inside.

In this article, we’ll cover the basics of searching for mice entry points and how to seal them.

Common Mouse Entry Points

The search for mice entry points requires you to look for any crack or opening larger than the size of dime. These can be potentially used by mice as a means of getting into your home.

To find them, you may need to look outside, inside, above, and below your home.


  • Transitions from one wall material to another
  • Weep holes in brick
  • Trees or branches near a window
  • Plumbing pipes and faucets
  • Cable and gas lines
  • Plumbing pipes 
  • Dryer vents


  • Windows and windowsills
  • Gaps between exterior doors and the floor
  • Gaps between the floor and wall juncture
  • Floor corners in closets
  • Floor vents and dryer vents
  • Fireplaces
  • Basements and crawl spaces
  • Pipes going to hot water heaters and furnaces


  • Inside, below, and behind kitchen cabinets
  • Stoves, refrigerators, and other large appliances
  • Pipes under the sink 
  • Kitchen vents


  • Shower and bathtub drains
  • Pipes under the sink
  • Bathroom vents 

Laundry Rooms

  • Household dryer vents
  • Laundry room floor drains
  • Pipes around washing machines


  • Roof rafters
  • Roof eaves
  • Roof vents

Signs of Mice

Entry points being actively used by mice to get into or around your home might have one or more of these common signs.

However, not seeing any of these signs around a particular crack, hole, or gap doesn’t rule it out from being an entry point. Any crack, hole, or gap can be an entry point for mice and rodents, or may become one in the future.

1. Tracks and Footprints

To help find footprints and tracks of mice in your home, try sprinkling talcum powder or flour along the floors in areas with suspected mice activity. This allows you to see footprints along the flooring.

2. Droppings

Spotting mouse droppings is a more obvious way to recognize if you have an infestation. The more dried up droppings are, the older they are. If you have a large amount of droppings, that can determine how big of an infestation you’re dealing with. 

3. Gnaw Marks

Mice commonly gnaw on or chew through wooden objects such as door corners, baseboards, joists, or wall studs. They do this to find spots to burrow or create their nests. Mice tend to leave behind cleaner cut markings in comparison to rats that leave behind more rough markings.

Sealing Mice Entry Points

Once you’ve determined where mice are getting into your home, you can take steps to seal these entry points to prevent more mice from getting in.

Here are some helpful materials for blocking off mice entry points: 

  • Steel wool or aluminum mesh: Mice are unable to chew through these materials. Use steel wool for small gaps around the house. Steel wool has a tendency to rust quickly. If you find that this is happening, try copper wool or aluminum mesh. 
  • Exterior caulking: Use exterior caulking to reseal holes once you’ve mended them. 
  • Wood putty: Use wood putty to reseal holes once you’ve mended them. 
  • Sheet Metal: Use sheet metal to seal any holes in the apartment’s foundation. 
  • Cement: There may be rules prohibiting the use of cement in an apartment building, however, it’s a great resource to permanently seal gaps around foundations and pipes. 

Check your property regularly for possible entry points even after you’ve plugged any holes to ensure no new holes have been made. It’s also important to check on old holes you’ve filled up to ensure they are still intact. 

About MMPC

For professional help with rodent proofing and exclusion around New York City, contact MMPC today! We offer one of the top-rated pest exclusion services in the Tri-State Area. Call (212) 219-8218 or contact us through our website to learn more!