Mouse-proofing is the least exciting part of dealing with mice and the part that matters most. Closing gaps and taking away food and shelter is what keeps next winter quiet. If you want to know how to mouse proof your house properly, the job comes down to three things: the right materials, the right places, and a routine to check your work.
This guide works from the outside in, then covers the two rooms mice care about most: the kitchen and the pantry. If you already see fresh droppings, pair it with our plan for how to get rid of mice in your house, since sealing keeps new mice out but does not remove the ones inside.
The Short Answer
To mouse proof your house, close every gap larger than about 1/4 inch with materials mice cannot chew, fit doors and windows tightly, screen vents, store food in sealed hard containers, and cut down clutter where mice can nest. UC Integrated Pest Management (UC IPM) recommends closing all gaps and openings larger than 1/4 inch, and the CDC says a mouse can fit through a hole about the width of a pencil. Then inspect regularly, because patches wear out.
Pick Materials Mice Cannot Chew
The material matters as much as the gap. UC IPM says plastic screening, rubber, vinyl, expanding foam, wood, and other gnawable materials are ineffective for plugging holes. Use these instead:
- Steel wool plus caulk for small holes. The CDC recommends steel wool held in place with caulk or spray foam. NC State Extension notes steel wool rusts and is flammable, and says to always caulk over it. Our guide to steel wool for mice covers the details.
- Copper mesh or lath screen for odd-shaped gaps. NC State Extension says both resist rust, and recommends caulking over copper mesh.
- Hardware cloth with 1/4 inch mesh for vents.
- Sheet metal, metal, or cement for larger holes, per the CDC.
How to Mouse Proof Your House From the Outside In
Step 1: Walk the Exterior
Use the CDC's outside checklist: the roof line, rafters, eaves, and soffits; windows and doors, especially those without weather stripping; the gap between the foundation and the ground; attic and crawl space vents; and holes for electrical, plumbing, cable, and gas lines. For a full entry-point map, see how mice get into your house.
Step 2: Seal the Foundation and Utility Openings
UC IPM recommends sealing cracks in foundations and openings around water pipes, vents, and utility cables with metal or concrete. The CDC recommends caulk for gaps between the foundation and the ground.
Step 3: Tighten Doors, Windows, and the Garage
UC IPM advises making sure all doors, windows, and screens fit tightly, and notes it may be necessary to cover door and window edges with metal where mice gnaw. NC State Extension says exterior doors should have no more than 1/4 inch of clearance at the floor and recommends rodent-proof door sweeps filled with metal mesh, which are not the same as weather stripping. The CDC also says to seal garages and outbuildings.
Step 4: Screen the Vents
NC State Extension suggests 1/4 inch hardware cloth for attic and crawl space openings. Check dryer vents and floor vents too, which appear on the CDC's inside checklist.
Step 5: Tidy the Yard
UC IPM recommends thinning or removing plants next to or climbing up buildings, because house mice are excellent climbers. The CDC recommends keeping woodpiles 100 feet or more from the home and at least one foot off the ground, keeping compost bins at least 100 feet away, and keeping bird feeders away from the house.
How to Mouse Proof Your Kitchen
To mouse proof a kitchen, start with the gaps on the CDC's inside checklist: under, inside, and behind cabinets; around pipes under the sink; around appliances; and where the floor meets the wall. Pull the stove and refrigerator out once and look behind them with a flashlight.
Then remove the reasons to visit. The CDC recommends cleaning up spills right away, washing dishes soon after use, and keeping indoor trash in a thick plastic or metal can with a tight lid. For pets, UC IPM suggests feeding only the amount they will eat at a single feeding, and the CDC says not to leave food or water bowls out overnight.
How to Mouse Proof Your Pantry
NC State Extension notes that mice chew through packaging and take small tastes of food, so a pantry full of paper bags and cardboard boxes is an open invitation. To mouse proof a pantry:
- Move dry goods into thick plastic, metal, or glass containers with tight lids, as the CDC recommends. The National Pesticide Information Center (NPIC) lists jars, tin boxes, and durable plastic.
- Store pet food and birdseed in the same kind of sealed containers, per NPIC.
- Check the floor corners and the spots where pipes or wires pass through pantry walls, and seal any gaps.
- Look for nibbled packaging regularly so you catch a problem early.
Storage Areas, Attic, and Basement
UC IPM says good housekeeping reduces shelter and food for house mice. NPIC recommends removing nesting materials like cardboard boxes and newspapers. For attics, the National Pest Management Association (NPMA) suggests keeping the space well ventilated and dry, and storing family heirlooms in sealed plastic containers instead of cardboard. The CDC lists the attic, basement, and crawl space on its inside checklist, so seal gaps there too.
Keep It Up
Mouse-proofing is not a one-time job. The CDC says regular inspection of the inside and outside of a home is important for spotting signs of rodents. UC IPM notes that steel wool may rust over time, so recheck patches, door sweeps, and vent screens each fall.
Cheat Sheet
- Close every gap about 1/4 inch or larger.
- Use steel wool with caulk, copper mesh, hardware cloth, metal, or cement.
- Do not rely on foam, wood, vinyl, rubber, or plastic as the plug.
- Fit rodent-proof door sweeps, including on the garage.
- Seal behind kitchen appliances and under the sink.
- Move pantry food and pet food into sealed hard containers.
- Swap cardboard storage boxes for sealed plastic bins.
- Recheck patches, sweeps, and vent screens every fall.
Where BioGuard Fits
We sell BioGuard Natural Rodent Repellent, a pack of 12 scent balls infused with peppermint and cinnamon essential oils. In a mouse-proofed home, it can add a scent layer in the garage, shed, storage areas, and near exterior entry points. Keep it away from food, so not in the pantry or kitchen cabinets, and out of reach of children and pets. Replace it every 4 to 6 weeks. It is a repellent, not a removal product, and results vary.
Frequently Asked Questions
What is the best material to mouse proof a house?
Metal and cement. The CDC recommends steel wool with caulk for small holes and hardware cloth, metal sheeting, or cement for larger ones. NC State Extension adds copper mesh and lath screen, which resist rust.
Does spray foam keep mice out?
Not by itself. UC IPM lists expanding foam as ineffective for plugging holes, and NC State Extension says mice may chew through it. The CDC uses foam only to hold steel wool in place.
Are plastic containers mouse proof?
Thick plastic with a tight lid is one of the CDC's recommended options, along with metal and glass. Thin bags and cardboard boxes are not enough.
When is the best time to mouse proof a house?
Before the cold sets in. UC IPM says house mice frequently enter homes in autumn as nighttime temperatures get colder, so the weeks before nights turn cold are the best time. If you missed that window, start now.
Sources
- CDC, How to Seal Up to Prevent Rodents
- CDC, Controlling Wild Rodent Infestations
- UC Integrated Pest Management, House Mouse
- NC State Extension, Surveillance and Management of Common Structure-Invading Mice
- National Pesticide Information Center (Oregon State University and U.S. EPA), Mice
- National Pest Management Association, How to Spot Mice or Rats in the Home