In Sainte-Madeleine, on the South Shore of Montreal, a family owner of a single-family residence in the Hauts-de-la-Rivière sector discovered droppings and mouse nests that had accumulated in the attic for several seasons. The particular humidity of this wooded neighbourhood, located not far from Sainte-Julie, had favoured a silent infestation whose health consequences required a complete professional intervention. The owners had first noticed a lingering smell in the second-floor bedrooms, then spotted a few droppings along the ridge beam during a routine visit to check the condition of the insulation. Our team was on site within forty-eight hours of the call to make an accurate diagnosis and safely decontaminate.
Inspection and assessment of the extent of damage
From the first visit, the technicians carried out a thorough inspection of the attic. They found mouse droppings on the entire insulating surface, several nests made from shredded insulating wool, as well as traces of urine revealed under ultraviolet light. The contamination affected approximately forty square metres of loose insulation. Poorly sealed ventilation areas had allowed rodent access over an extended period of time. Our team documented each affected sector before starting the work to ensure rigorous follow-up. Secondary mould was also found on the wood joists in the wettest area of the attic, indicating the presence of rodents for at least two consecutive winters. All of these observations were recorded in a photographic report given to the owners before any work began, allowing the family to understand the true extent of the contamination and to approve the proposed response protocol.
Safe removal of contaminated materials and disinfection
The protocol of our decontamination service requires the wearing of certified personal protective equipment: Tyvek suits, N100 cartridge respirators, gloves and protective eyewear. The soiled insulation was vacuumed using high-capacity industrial equipment and then collected in airtight bags certified for biologically contaminated materials. Each bag was sealed, labelled and disposed of in accordance with Sainte-Madeleine’s municipal by-laws. This careful removal prevents any dispersion of dust loaded with pathogens, in particular hantavirus, during the work. Once the materials were removed, the lumber surfaces were treated with a registered biocidal agent applied in two passes by low-pressure spraying. This product kills bacteria, viruses and secondary mould from the decomposition of droppings. Ventilation areas, top plates and joists have received special attention. A contact time of at least twenty minutes was respected before the final passage of a disinfectant wipe on the smooth accessible surfaces. A targeted fungicide treatment was applied to joists with traces of mould, with visual verification to confirm complete removal of visible spores. For homeowners who want to understand the extent of an attic decontamination after infestation, this step is often the most demanding step in the process.
Sealing of entry points and re-insulation
Decontamination is worthless if the rodents can return. Our team of exterminators in Sainte-Madeleine therefore caulked all the openings identified: ventilation grilles replaced by stainless steel models with fine mesh, cracks in the top plates filled with expanding foam reinforced with metal fibers, and redone seals around the plumbing ducts through the roof. A new layer of cellulose wadding insulation was blown in to restore the original thermal values and improve the energy efficiency of the house. This last step also makes the attic less attractive to rodents thanks to the natural repellent properties of the boron salts in cellulose. The owners received a written report detailing the work carried out and a personalized prevention plan, including recommendations on pruning trees near the roof and managing outdoor food sources. To see examples of our comparable work, consult our residential decontamination achievements and our recent preventive interventions on the South Shore. For any service request, the Nova Extermination website contains all our contact information.