The owners of a single-family residence in Saint-Constant, on the South Shore, contacted our team in early fall after noticing worrying signs in their crawl space: droppings two centimetres long, traces of nibbling on polystyrene pipes and a persistent smell of urine. Saint-Constant, an agricultural and residential community adjacent to Delson and La Prairie, is bordered by light industrial areas and cultivated fields that provide natural habitat for Norway rats (Rattus norvegicus). When temperatures drop in the fall, these rodents actively seek warmth from the foundations and crawl spaces of nearby homes. Our exterminator in Saint-Constant took charge of the case in less than forty-eight hours.
Complete inspection and identification of access routes
The initial visit covered the entire property: crawl space, foundation perimeter, shed at the end of the courtyard, adjoining garage and outdoor storage spaces. Technicians confirmed the presence of Norway rats based on the characteristics of their droppings and the nature of the damage observed. Several access routes have been precisely identified. A longitudinal crack of about one and a half centimetres in the foundation concrete on the garden side, as well as unsealed gaps around two sanitary drain pipes running through the slab, constituted the main entrances. The space between the garage door threshold and the floor had sufficient clearance to allow the passage of an adult. Greasy flows along the concrete walls of the crawl space confirmed repeated movements over several weeks. The beginning of a nest, made of torn mineral wool and scraps of paper, had been set up in a remote corner of the crawl space, a sign of a recent but already well-established installation.
Treatment plan: traps and bait stations
The intervention plan combined two complementary methods for rapid and effective control. Secure bait stations were installed at regular intervals along the outdoor foundation and in the crawl space, in locked boxes that complied with the standards of the Quebec Ministry of the Environment. Each station contained a second-generation rodenticide, attractive enough to divert rats from food sources in the house. At the same time, high-sensitivity mechanical traps were installed on the identified castings in the crawl space in order to obtain an immediate effect on the active population. The traps were checked and repositioned during two follow-up visits spaced one week apart. Activity decreased significantly from the first week, and no new traces were observable at the third visit. These methods are described in detail on our page dedicated to rat extermination, where you will find all our protocols for single-family homes.
Sealing of access and sustainable preventive measures
Once the rat population was under control, our team carried out a structural intervention to permanently block the entry routes. Caulking of the entry points included filling the foundation crack with rodent-resistant hydraulic mortar, sealing of pipe penetrations with compacted steel wool and high-density polyurethane sealant, and installation of a reinforced door bottom seal under the garage door. These materials physically prevent the passage of rodents while resisting attempts to nibble on them. Homeowners have also received practical recommendations to reduce pull factors around their homes, such as storing compost bins in airtight containers with locked lids, eliminating standing water sources near the foundation, and pruning shrubs in contact with walls to remove natural shelters. To discover other similar achievements in the region, see our case study on rats treated in a residential area on the South Shore and our documented intervention on mice in a single-family residence. The trust of our customers is based on the expertise of Nova Extermination, recognized for the quality of its residential interventions throughout the South Shore.