Mice in the house: find an exterminator in Montreal

Signs you have mice

• Black droppings, 3 to 6 mm long, shaped like grains of rice, along walls, under the sink or in the pantry.
• Light scratching at night in walls, ceilings or behind appliances.
• Chewed packaging: cardboard, bread bags, pet food.
• Dark, greasy marks along baseboards where they always travel.
• A nest of shredded paper or insulation in a quiet corner of the basement, garage or attic.

Droppings of 1 to 2 cm, or heavier noises, point to rats instead. Mention it in your request: the treatment is different.

How they get in

An adult mouse fits through a gap of about 6 mm, the width of a pencil. The usual entry points are:

• gaps around pipes and wires that go through the foundation or siding;
• the bottom corners of the garage door seal;
• foundation cracks and open mortar joints;
• dryer and range hood vents with no screen;
• the underside of the siding where it meets the foundation.

In a duplex, triplex or row house, mice also travel between units through shared walls and plumbing chases. Treating one unit alone buys time, not a solution.

What an exterminator does

1. Inspection. Inside and outside, to find the entry points, the nests and the size of the problem.
2. Control. Traps or locked bait stations placed where mice travel, out of reach of children and pets.
3. Exclusion. Sealing entry points with materials mice cannot chew: steel wool, metal mesh, mortar, sealant.
4. Follow-up. One or two return visits, a week or two apart, to check activity and adjust.

Ask whether sealing the entry points is included in the price. Without it, new mice use the same paths next fall.

What mouse control costs

These ranges come from prices published by Montreal-area pest control companies in 2025 and 2026. The number of visits, the size of the home and the sealing work explain most of the gap. Taxes are extra.

What you can do in the meantime

• Store food, pet food included, in hard, closed containers.
• Set snap traps along walls, at a right angle to the baseboard, with a dab of peanut butter.
• Do not sweep droppings dry. Wet them with disinfectant, wait a few minutes, then pick them up with paper towel and gloves.
• Note where you see signs. It saves the exterminator time.

Skip ultrasonic devices, whose effect does not last, and loose poison in a home with children or pets.