Louisville, KY — The first frost is predicted for next week, which signals the start of the annual rodent migration indoors. Mice can squeeze through a gap the size of a dime.

Our technicians are currently finding entry points in:

• Gaps where AC lines enter the home
• Worn-out rubber sweeps on garage doors
• Unsealed crawl space vents

Inspect your home’s perimeter this weekend. A $5 tube of caulk or a steel wool pad now can prevent a winter-long infestation.

Why Do Mice Move In?

It’s not just about food; it’s about thermodynamics. As outdoor temperatures drop, mice seek warmth. Your home leaks heat through tiny cracks and crevices. Mice can sense these warm air currents escaping from your foundation, doors, and utility penetrations. They follow the heat trail right into your walls.

Once inside, they find insulation for nesting and crumbs for food. They will stockpile food and breed throughout the winter, creating a massive infestation by spring if left unchecked.

The “Dime” Rule

An adult house mouse has a collapsible skull. If they can fit their head through a hole, they can pull their entire body through. This means any gap larger than 1/4 inch (about the diameter of a dime) is an open door.

Common Entry Points to Check:

1. Garage Door Corners: The rubber weatherstripping at the bottom corners of garage doors is often chewed or worn, leaving a gap.
2. A/C Lines: Follow the copper refrigerant lines from your outdoor A/C unit to where they enter the siding. The putty often rots away, leaving a hole.
3. Foundation Vents: Check for holes in the screens of your crawl space vents.
4. Gas/Water Pipes: Look for gaps where utility pipes enter the foundation.
5. Door Sweeps: Ensure exterior doors seal tightly against the threshold.

Prevention Tips

• Seal Gaps: Use copper mesh (Stuf-Fit) or steel wool to stuff gaps, then seal over it with exterior-grade caulk or foam. Mice cannot chew through copper mesh.
• Clear Vegetation: Trim bushes and ivy away from the foundation. Vegetation provides cover for rodents to explore your home’s perimeter safely.
• Remove Clutter: Clear piles of leaves, wood, or debris near the house.

If you are already hearing scratching in the walls or finding droppings, the invasion has begun. Contact Critter Removal of Louisville for a professional exclusion inspection. We seal the holes you can’t find.