In the heart of Verchères, on the South Shore of the St. Lawrence, a family owner of a single-family residence built in the 1970s began to hear scratching in the walls in early fall. The house, nestled in a quiet residential area a stone’s throw from the municipality of Contrecoeur, had several features that facilitated the intrusion of mice: a concrete block foundation whose mortar joints had deteriorated over the decades, defective flashing around the ventilation ducts, and an adjoining shed whose wooden planks left many cracks that could be exploited by rodents. Residents had initially ignored the nighttime sounds, attributing the noises to the house working with the cold. It was the discovery of droppings in the pantry that finally triggered the call to Nova Extermination, our company specializing in pest management on the South Shore and South Shore.
Thorough inspection and identification of points of entry
From the first visit, our certified technicians performed a complete rodent infestation inspection covering the entire property, from the basement to the attic. The clues were numerous and telling: house mouse droppings in kitchen drawers and behind the refrigerator, traces of gnawing on crawl space insulation, galleries dug in cellulose insulation around the joists at the edge, and nests made from insulating wool torn from heating pipes. The careful inspection accurately located seven potential entry points on the perimeter of the building. The most active was a space of less than six millimetres around a plumbing pipe running through the foundation wall on the north side, virtually invisible from the inside due to the flooring. A second major breach was in the chimney flashing, where the metal had rusted and was gradually peeling off.
Technicians also noted that pet food was stored in the shed without airtight containers, which is a major source of attraction for rodents in the surrounding agricultural area. This type of detail, often overlooked by homeowners, explains why some properties are routinely re-infested from one year to the next.
Treatment and disposal of the colony
Our mouse extermination strategy for this residence in Verchères combined several complementary methods, adapted to the type of property and the extent of the infestation. Mechanical traps with secure capture were installed along the identified travel corridors, including along the basement walls, behind the stove and in the attic space. Rodenticide bait stations in secure boxes, completely inaccessible to children and pets in the home, have been placed in high-risk outdoor areas along the foundation. A telephone follow-up after five days, followed by an on-site monitoring visit after two weeks, confirmed a gradual and significant reduction in rodent activity. The third visit, three weeks after the start of treatment, confirmed the complete elimination of the active colony. For an overview of a similar intervention carried out in the region, see our realization mouse in a house on the South Shore.
Caulking and long-term prevention
Once the mouse population was under control, our specialists moved on to complete caulking of the entry points identified during the inspection. The work included the application of high-density polyurethane foam combined with stainless steel wool in the gaps around the ducts, the replacement of damaged ventilation grilles with stainless steel models with mesh sizes of less than one centimetre, the sealing of cracks in the foundation wall with hydraulic mortar, and repairing the chimney flashing with corrosion-resistant materials. These mechanical exclusion measures are the most durable and economical defence against seasonal reinfestations, which are particularly common in peri-urban areas such as Verchères, where rodents migrate en masse from fields to inhabited buildings each fall. The owners received a detailed report covering the areas treated, the products used with their technical sheets, and the recommendations for seasonal prevention: storage of all food in airtight rigid plastic containers, reduction of sources of standing water around the property, cutting of plants in contact with the façade, and annual check of the condition of the foundation joints before the arrival of the first cold weather. Our team of exterminators in Verchères remains available for any follow-up or future preventive inspection. Homes built before the 1980s in this area of the South Shore deserve special attention in the fall, when rodents are actively looking to establish themselves before the cold weather.