How to Keep Mice Out of Your Attic

Seal entry points with steel wool and caulk, remove food sources, and install proper screening over vents to create a barrier mice cannot penetrate.

  1. Find Every Possible Gateway. Walk around your home's exterior and examine the roofline, eaves, and foundation for gaps larger than a quarter inch. Check where utilities enter the house, around roof vents, and near the soffit. Mice can squeeze through surprisingly small openings, so look carefully at any crack or hole you can fit a pencil through.
  2. Block What Mice Can't Chew. Stuff steel wool tightly into holes and cracks where mice might enter. Push it deep into the opening, leaving about a quarter inch of space for caulk or expanding foam. Steel wool works because mice cannot chew through it, unlike other materials they can easily gnaw past.
  3. Lock in Your Defense. Cover the steel wool with exterior-grade caulk for small gaps or expanding foam for larger openings. This creates a weatherproof seal that mice cannot penetrate. Let the material cure completely before moving to the next area.
  4. Screen Out the Invaders. Cover attic vents, roof vents, and soffit vents with quarter-inch hardware cloth or fine mesh screening. Cut the material slightly larger than the vent opening and secure it with screws or heavy-duty staples. Make sure the mesh lies flat against the surface with no gaps around the edges.
  5. Cut Off Their Access Roads. Cut back any tree branches that hang within six feet of your roof. Mice use overhanging branches as highways to reach your roofline. Keep vegetation trimmed away from the house to eliminate these natural pathways.
  6. Starve Out the Problem. Clear your attic of anything that might attract mice, including stored food, pet food, birdseed, or cardboard boxes with food residue. Store necessary items in sealed metal or thick plastic containers that mice cannot chew through.
  7. Stay Ahead of New Threats. Inspect your prevention measures every few months, especially before winter when mice seek warm shelter. Look for new gaps that may have opened due to settling or weather damage, and reapply sealants as needed.