Table of Contents
Job Overview
Location: Toronto, Ontario
Structure: Three-story Victorian century home with front deck
Problem: Active rat infestation in basement and crawlspace with interior scratching noises and strong odour from urine and droppings
Service: Rat exterior and interior treatment with full perimeter exclusion
Visits: Three visits between April and October
Summary
Our team addressed an ongoing rat infestation affecting both the exterior grounds and interior spaces of a century home. The work involved multi-visit monitoring, licensed baiting and trapping, followed by a full structural exclusion and sanitation of a low-clearance crawlspace. Activity was resolved after exclusion was completed and confirmed.
Background / Property Context
The property is a multi-level Victorian-era home with an older foundation and a later-built extension. Soil-to-foundation contact, aging materials, and multiple utility penetrations created conditions where burrowing rodents could access the structure from grade level.
Customer Concern
The homeowner reported persistent scratching sounds within the basement and crawlspace walls, along with strong odours consistent with rodent urine and droppings. Activity was noted both inside the structure and around the exterior perimeter.
Inspection & Findings
During the initial inspection, our technician identified signs consistent with rat activity, including burrowing along the foundation, disturbed soil, and gaps at the base of the structure. Interior inspection of the crawlspace showed evidence of droppings and odour buildup. Exterior foundation edges, particularly around an added extension, were identified as primary vulnerability points.
Photos taken during inspection show soil voids beneath the foundation edge, exposed gaps at grade, and active burrow openings. Follow-up images document trenching and the installation of galvanized steel mesh secured to the foundation.
Cause Analysis
The infestation was driven by ground-level access points along the foundation, combined with burrowing behaviour typical of rats. The age of the structure and the addition created seams where soil had settled, allowing rats to tunnel under the foundation and enter the crawlspace. Ongoing exterior food and shelter opportunities supported repeated activity until exclusion was completed.
Treatment / Removal
All pest control work was performed by a licensed exterminator in accordance with Ontario Ministry of the Environment guidelines.
On the first visit, our team installed large, weighted, tamper-resistant bait stations around the exterior in areas of high activity. Inside the home, commercial-grade baited snap traps were placed preventatively to reduce the risk of rats dying within wall voids. Monitoring continued over subsequent visits as bait stations were repeatedly consumed, confirming sustained exterior pressure.
Exclusion & Repairs
After monitoring, the homeowner approved a full exclusion for the affected extension. Our team trenched approximately 56 linear feet around the accessible perimeter of the addition, digging roughly one foot down and six inches out. Galvanized steel mesh was mechanically fastened to the base of the foundation and buried to prevent future burrowing.
A rat one-way door was installed at the primary entry point to allow remaining animals to exit while preventing re-entry.
Following exclusion, the crawlspace was cleaned using a specialized HEPA vacuum to remove rodent droppings. A disinfectant fogging treatment was applied after removal to address residual contamination. Work in the crawlspace was limited by very low clearance, which was noted and managed safely.
Outcome & Confirmation
After exclusion and sanitation were completed, exterior entry points were sealed and monitored. The one-way door was later removed, exclusion materials were inspected, and no further interior activity was reported. The infestation was considered resolved, with rat activity confined to the exterior environment.
Technician Notes
The work was completed over multiple visits due to sustained exterior pressure and the complexity of the foundation. Richard handled inspection, monitoring, and exclusion coordination, with limitations noted only in the low-clearance crawlspace during sanitation.
Contact us at 647-496-2211 if you have any rodent or pest issues on your property.