Mice in the Garage, Shed and Car: Protecting What You Store for Winter

In November, we put away the bike, the lawn mower, the patio cushions and sometimes the motorcycle or the trailer. At the same time, mice are looking for a dry, quiet shelter for the winter. A garage, a shed or a car that is rarely driven gives them exactly that: little disturbance, nesting material and often some forgotten food. Here is how to protect what you store, whether you live in a Montreal plex with a shed in the alley or in a house in Laval, on the North Shore or on the South Shore near open fields.

Why garages and sheds attract mice

A garage is not heated like the house, but it is sheltered from wind, snow and predators. Mice find cardboard boxes, old clothes, insulation and all kinds of bags. An attached garage is also often the gateway into the house: a mouse living near the shared wall eventually finds a way in around pipes, wires or the inside door.

What attracts them most

• bags of birdseed, pet food or garden seeds;
• recycling bins and bags of bottles that were not rinsed;
• cardboard boxes sitting directly on the floor, against the walls;
• cushions, tents, sleeping bags and outdoor clothing stored loosely;
• firewood and piles of materials that create hiding spots.

Stored cars, motorcycles and trailers

A vehicle that does not move for weeks becomes an attractive shelter. Mice can nest in the engine compartment, in the cabin air filter housing or under the seats, and chew wiring or insulation. Repairs can be expensive, and a lingering smell can settle into the ventilation.

• Empty the cabin completely: no wrappers, no crumbs, no dog food in the trunk.
• For a trailer or RV, remove all food and paper products, then inspect pipe openings under the floor.
• Open the hood and take a quick look at the engine compartment from time to time, and start the vehicle regularly if you can.
• Avoid mothballs (naphthalene) in a vehicle or an attached garage: the fumes are harmful to people and do not solve the problem.

Signs of mice in a garage or shed

• Black, pointed droppings a few millimetres long on shelves, on the floor or in workbench drawers;
• chewed bags or boxes, shredded cardboard corners;
• small nests of paper, fabric or insulation in a corner, a box or a piece of equipment;
• runways along the walls, sometimes visible in dust or in the snow near the door;
• a strong urine smell in a closed corner.

Prevention: what to do before the deep cold

1. Check the bottom seal of the garage door. A cracked or flattened rubber seal often leaves enough room for a mouse.
2. Seal openings around pipes, wires and the corners of the slab with steel wool or metal mesh, then caulk. Foam alone gets chewed through.
3. Store items up high and in hard, closed bins rather than in cardboard boxes on the floor.
4. Take food out of the garage: keep birdseed and pet food in metal or thick plastic containers, or indoors.
5. Clear around the shed: dead leaves, branches and materials leaning against the walls make hiding spots.
6. Check the door between the garage and the house: it should close tightly at the bottom, with a threshold in good condition.

Traps and repellents: what really helps

Snap traps set along the walls, out of reach of children and pets, help you confirm activity and handle a single mouse. Scent repellents and ultrasonic devices do not replace sealing entry points. If you catch one mouse after another, there is still an open entry point or an established population. Also avoid scattering poison in a garage or shed: pets or wildlife can eat it.

When to call an exterminator

Call if you see signs in several places, if mice move from the garage into the house, if a vehicle has been damaged or if activity continues despite your efforts. A technician finds entry points, installs locked, tamper-resistant stations and follows up. Mouse treatment is covered by a 6-month guarantee.

ExtermZone serves Montreal, Laval, the North Shore and the South Shore, 24 hours a day. Call us at (514) 295-7696 for an inspection. To protect the inside of your home too, read our article Mice in the Fall: How to Keep Them Out Before Winter.