Mice in the closed-up cottage: how they get in, and what to do

You open up the cottage on a Friday in November, and there are small black droppings in the cutlery drawer and along the kitchen baseboards. A forgotten bag of rice has a hole in it. Mice moved in while the place was closed — here’s what to do, in order.

What to do right now

1. Air the place out before you clean

Open doors and windows and let the air move for a while before you start. Rodent droppings, urine and saliva can carry viruses, including hantavirus, which spreads mainly by breathing in contaminated dust. The Public Health Agency of Canada asks you not to stir that dust up.

2. Don’t sweep or dry-vacuum

This is the most common mistake, and the Public Health Agency of Canada names it outright: sweeping or vacuuming releases particles into the air. Instead, wear rubber or plastic gloves, spray the droppings, nests and surrounding area with a disinfectant — or a mix of one part bleach to nine parts water — let it soak for ten minutes, then pick everything up with paper towels. Bag it and seal the bag. Wash the surfaces, then your hands.

If the infestation is heavy, or it’s in an enclosed space like a crawl space or attic, leave the clean-up to a professional.

3. Check wires and cords

Mice chew everything, including the jacket on electrical wiring. Look at appliance cords, behind the stove and fridge, and at any exposed wiring in the basement. If you see a chewed wire, smell burning or hear crackling: don’t plug anything back in, and have a master electrician take a look. Bare wire is a fire risk.

4. Remove what draws them in

All food goes into glass or metal containers, or back to the city. Birdseed, pet food, candles and soap too. Empty the garbage and leave nothing under the sink.

5. Set traps — and skip poison at a closed cottage

Snap traps along the walls, where you see droppings, are a good first step. Poison in a house you’re about to close up is a problem: the mouse often dies inside a wall or under a floor, and the smell is waiting for you next time. Bait is also dangerous for pets.

6. Find where they’re getting in

That’s the step that solves it for the long run — more on that below.

7. Call pest control if it keeps happening

If droppings keep coming back despite the traps, or you find them in several rooms or in the attic, bring in a pest-control company that holds the permits Québec requires for pesticide use.

Why it happens — especially at a Townships cottage

In the fall, mice look for shelter. When the cold comes, field and woodland mice move toward buildings. A cottage with the heat turned down, quiet and full of nooks, is ideal.

An empty house doesn’t bother them. No noise, no movement, no cat. They settle in, nest in the insulation or the drawers, and breed undisturbed.

They squeeze through surprisingly small openings. Health Canada puts a number on it: a mouse can squeeze through a crack about the size of a dime. The usual ways in:

• the gap under an exterior door or a badly fitted garage door;
• where pipes, wires and the dryer vent pass through the wall;
• cracks in the foundation and the joint between the foundation and the wood framing;
• damaged soffits and the bottom edge of the siding;
• vents with no screen, or a torn one;
• a chimney or fireplace with no cap.

Townships cottages have lived a little. The wood cottages of Sutton, Frelighsburg or Potton, added onto over the years, have seams between sections, crawl spaces and pipe runs put in after the fact. Plenty of doorways — and the woods and fields around them supply the visitors.

Prevention: what you can do, and what belongs to a professional

What an owner can do:

• Walk around the house in the fall with a flashlight and note every opening.
• Plug small holes with steel wool before covering with sealant, and screen the dryer vent and other vents with fine metal mesh, as Health Canada recommends: mice chew straight through foam on its own.
• Put a tight door sweep on the exterior doors.
• Store dry food and pet food in metal or glass containers before closing up, and take the rest home.
• Cut back vegetation and keep firewood away from the walls.

What belongs to a professional:

• Treating an infestation with pesticides: a pest-control company holding the required permits.
• Repairing soffits, siding or a cracked foundation: an RBQ-licensed contractor.
• Repairing or replacing chewed wiring: a master electrician.
• Cleaning out a contaminated attic or crawl space and replacing soiled insulation.

In an empty house, how long before anyone notices?

At a closed cottage, nobody sees the first droppings. Mice have all the time they need to settle in and chew through insulation, packaging and wiring. If the next visit is three weeks away, that’s three weeks of nesting, damage and, sometimes, chewed wires behind an appliance.

Spotting the first signs early means you can set traps and close off the entry before a few visitors become a colony. If insurance comes into it, ask your broker: damage caused by pests is often treated separately.

What we look at on a visit

Every visit, we look along the baseboards, in cupboards, drawers and near heat sources for fresh droppings. We note pierced packaging, torn exposed insulation and chewed cords, and we check for electrical smells in each room. We log the condition of any traps you or your pest-control company have set, without adding bait unless you say so. Outside, we look at the soffits, the bottom of the siding and the foundation. Every finding is photographed and time-stamped in the report.

If something’s off, we call you the same day, with photos. If needed, we meet a pest-control technician, an electrician or an RBQ-licensed contractor on site and document the work.