Saint-Denis-sur-Richelieu, a historic village in the Montérégie region established on the east bank of the Richelieu River and known for the battle of 1837, is a rural and agricultural area where there are many houses of character dating from the early twentieth century. It was in one of these century-old single-family residences, recently acquired and partially renovated by a couple passionate about built heritage, that mice were discovered in the old wall cavities during the renovation work. The restoration work had disrupted existing structures, opened partitions and created new passageways that rodents quickly colonized. The situation was particularly complex: the century-old brick walls, original wood floors and old materials required an appropriate extermination approach that respected the heritage character of the property. Our exterminator in Saint-Denis-sur-Richelieu has developed a customized treatment plan that takes into account all these specific constraints.
Inspection in a period building: challenges and methods
Inspecting a century-old home poses special challenges that modern buildings do not present: irregular wall cavities created by ancient masonry materials, hidden spaces in the intricately framed old attics, partially fieldstone basements, and the presence of numerous walkways between floors created for the original technical installations. The rodent infestation inspection used a fiber-optic endoscopic inspection camera to assess the inside of the wall cavities without unnecessary demolition of the original plaster and woodwork. This non-invasive technique made it possible to locate active nests in the space between the ground floor ceiling and the upstairs floor, in the exterior walls on the north side where loose mineral wool insulation provided an ideal material for the construction of nests, and in an inaccessible nook behind the central stone chimney. The droppings and traces of passage noted indicated a sustained presence of mice for several months, probably encouraged by the opening of the walls during the renovation work which had temporarily exposed many cavities. Homeowners were informed of each identified area with detailed explanations of the potential risks: structural damage to insulation, health risks from rodent droppings and urine, and the risk of gnawing on old electrical cables whose insulating coating was already weakened by age.
Disposal strategy adapted to the old building
Our approach to exterminating mice in Saint-Denis-sur-Richelieu in this heritage property favored mechanical traps in all discreetly accessible cavities, supplemented by rodenticide baits in blocks in secure boxes positioned in the crawl space and attic. Exceptional care was taken to avoid any placement of bait in areas where mice could die in inaccessible spaces, as the smells of decay in a century-old house with thick walls could have been persistent and difficult to locate. The placement of each trap has been planned taking into account the areas accessible for their rapid removal. Bi-weekly monitoring visits for six weeks made it possible to precisely adjust the system according to the catches observed and to withdraw the catches without delay. To consult a comparable residential intervention, refer to our mouse realization in a house on the South Shore.
Heritage-friendly sealing and decontamination
The caulking of the entry points into this period house required a meticulous approach and materials carefully chosen for their compatibility with the old materials. The deteriorated mortar joints between the bricks of the foundation were repointed with natural hydraulic lime, a material historically compatible with the old masonry and respectful of the differential movements of the structure. The spaces around all modern service crossings have been sealed with stainless steel wool attached to the translucent silicone sealant, invisible from the outside and undetectable on the original brick masonry. The original cast iron foundation ventilation grilles were lined with a fine-mesh stainless steel mesh fixed from the inside, completely preserving the external appearance of the façade. The nests and organic matter accumulated in the accessible cavities were then completely decontaminated after rodents, including the removal of the soiled insulation, the disinfection of the surfaces with a virucidal product compatible with the old materials, and the replacement with a new suitable insulation. Homeowners were given a seasonal monitoring guide specific to century-old homes, with priority areas for inspection each spring and fall. Nova Extermination treats each property with the attention and expertise it deserves, regardless of its architectural complexity or age.