Our team was mandated to intervene in an apartment building in Saint-Antoine-sur-Richelieu, a rural village in the Montérégie region established on the east bank of the Richelieu River, facing Saint-Denis-sur-Richelieu. The tenants on the top floor had reported to their landlord nocturnal noises coming from the ceiling, as well as persistent smells in a closet adjoining the exterior wall. After checking, the source of the problem was unequivocal: a colony of little brown bats had established its roost between the insulation and the vapour barrier of the flat roof. This type of problem is particularly delicate in a multi-unit building, where the work must be planned in such a way as to minimize the inconvenience for the occupants while scrupulously respecting the legal protections governing these wildlife species in Quebec. Bats can never be killed or trapped in a lethal manner; only human exclusion is permitted.
Diagnosis in a multi-unit setting
The inspection began with a thorough examination of the roof, parapet joints and mechanical duct passages. In apartment buildings built before 2000, flat roofs regularly have bituminous membrane detachments that create cavities accessible to bats. Our technician has identified four active entry points, recognizable by the greasy marks left by the animals’ coats at each pass. A complete photographic survey was given to the owner in order to document all the structural flaws identified and to plan future sealing work. To see another similar case in the region, see our realization of bats in apartment buildings.
The interior of the space between the false ceiling and the concrete slab was inspected via the existing access hatches. The colony numbered about forty individuals. The amount of guano accumulated indicated that the building had been present for at least two consecutive seasons, which explained the intensity of the odours reported by the tenants. Our team in Saint-Antoine-sur-Richelieu is familiar with the particularities of the local built environment and was able to adapt its approach in a targeted and efficient way from the start.
Human exclusion and protection of residents
The complete intervention plan was presented to the owner before any implementation. In accordance with Quebec’s wildlife protection rules, the exclusion was planned outside the calving period, i.e. after mid-August. One-way exclusion devices were installed at each of the confirmed entry points, allowing bats to leave the building each night to feed, without being able to return in the morning. Residents were informed in writing of the nature of the work, its precise schedule and the measures taken to protect their health throughout the operation. The work areas on the roof were secured in accordance with current occupational health and safety standards. To learn more about global methods of capturing and relocating animals, visit our page dedicated to this service.
Our bat capture specialist oversaw the daily checking of the devices for a full week, observing as night fell that the animals were coming out normally and that no individuals were stranded or disoriented. This regular monitoring is essential to ensure the effectiveness of the exclusion process and to quickly detect any unusual behaviour of the colony. Once all the animals were gone, the devices were removed and the openings permanently sealed with durable materials.
Decontamination and fencing work
The decontamination of the infested space required the intervention of a team in full suits with a HEPA filter respirator. The guano was vacuumed and disposed of in accordance with the biological waste regulations, and the surfaces were treated with a registered fungicide disinfectant that is safe for residents once dry. This decontamination of the attic and ceiling spaces neutralized the health risks and eliminated the odors that had been bothering tenants for several months. The owner has received a detailed intervention report and a certificate of work for his building files, useful in particular for the insurer or potential future buyers. Nova Extermination provides rigorous post-intervention follow-up to confirm the absence of reinfestation and guarantee the sustainability of the solution implemented in Saint-Antoine-sur-Richelieu. A control inspection was carried out six weeks after the end of the work, confirming the complete success of the exclusion and the satisfaction of the owner and his tenants.