Case Study: Rats Burrow Through Foundation in North York

Case Study: Rats Burrow Through Foundation in North York

This article details a rat extermination in North York. Rats were burrowing in the yard and making their way into the house through the foundation. A comprehensive extermination on both the interior and exterior, along with a complete rat-proofing of the deck rid the property of rats. If there are rodents on your property and you want them gone, reach out to The Exterminators.


Our customer contacted us after a previously performed extermination by another company failed to get rid of rats in his home. The homeowner suspected activity inside and outside his house and would like us to prevent rats from entering the property. We started by determining the extent of the problem by inspecting the perimeter of the property. At this point we are looking for any potential entry points through wall cracks, burrowed holes, or wall vents. Our licensed exterminator was able to identify various breached areas including broken sections of the deck skirting.

Rodent Entry Point Under Deck
Damaged deck skirting allows rodents to access the concealed wall structure where they can easily penetrate into the house.

The perimeter of the foundation could also have been infiltrated as it was surrounded by lose dirt. Rats are notorious for digging through dirt in search of cracks in foundation walls.

Gaps in Deck Rat Entry Point
Large gaps along the deck are potential entry points for rodents.

Our recommendation to this homeowner was to perform a full exclusion around the home. This is the most effective way to prevent rodents from entering the structure of a house at ground level. It involves installing a fine galvanized steel mesh along the walls and other exterior structures such as decks, porches, and extensions. The mesh is buried into the ground and bent outwards to discourage the rodents from digging underneath.

We also recommended that a full rat treatment be done to exterminate the present rats.

Exclusion and Treatment

Our exterminator team returned to install the exclusion. First, we dug a one-foot trench around the perimeter in preparation to installing the mesh. The mesh is then put in place and secured to the walls, deck, and porch with screws and a special washer.

Deck Exclusion Steel Mesh
Our technicians dug a trench along the edge of the deck in order to install galvanized steel mesh.

All the material used in our exclusions is made of galvanized steel and is proven to withstand any gnawing or scratching by rodents and other animals.

Galvanized Steel Mesh Deck Exclusion
Galvanized steel mesh was secured to the deck and buried underground to prevent rodents from entering.
Porch Exclusion Widlife-Proofing
The front porch was secured with our galvanized steel mesh to prevent rats from going underneath.

Once the mesh was placed and secured, our technicians replaced the ground cover. A one-way-door was placed at a point of entry into the house. This door is designed to allow any animals that may remain in the home to exit and not be able to re-enter. It is put in place for several days to allow the rats enough time to move out. We will then return to remove the door and patch the hole with mesh.

Rat One-Way Door Toronto
A one-way-door was installed at the point of entry to allow any animals inside to exit the property.

As added protection, we also covered all wall vents with a PVC-coated steel mesh cover. This will discourage the rats from attempting to enter the home through alternative, existing entry ways.

Wall Vent Cover Rat-proof
PVC-coated steel mesh covers were installed over all wall vents.

We then proceeded to the extermination of the rodents. There are two parts to our extermination efforts- indoor and outdoor.

Indoors, our technicians strategically place snap-traps baited with some rat-favourite treats such as peanut butter or bacon. We avoid using foods that quickly perish or rot such as cheeses or fresh meats. These commercial grade snap-traps are highly effective in dispatching rodents quickly and humanely and will ensure that all creatures inside the home are gone.

Rodent Bait Station Exterior
Bait stations were placed on the exterior of the property to control the rat population outdoors.

On the outside of the house, we installed three bait stations filled with commercial-grade rodenticide. These stations are meant to control the rat population that roams outdoors before they become a pest indoors. The rodenticide we use is highly attractive to rats and is formulated to quickly exterminate rodents. These bait stations will be left on the property for quite some time and our technicians will monitor them periodically to determine the level of activity surrounding the home.


We returned to the property after a period of time to not only check on the bait stations, but also to inspect the exclusion work we had performed. Our technician found evidence of rats attempting to burrow holes under the installed mesh. We promptly dug under the areas to verify if the rodents had penetrated to the other side. We found two spots where the pests had been successful in getting under the mesh. We closed the holes and installed more mesh material in order to re-enforce our barrier.

Rat Burrow Hole Foundation Toronto
A hole was found to have been dug under the exclusion mesh.

It is not uncommon for rodents to persistently try to gain entry into their habitual living spaces once we install our exclusion. That is why we provide our customers with a 2-year warranty on all of our exclusion work. If the rats manage to breach our installations, we will return to repair or replace the work done.

Foundation Exclusion Rat-proofing
Our technician strengthened the areas where rats had burrowed holes under the mesh.

We were contacted some months later by the customer to inform us that the rear deck was being reconstructed and that the exclusion work had been partially removed. The customer agreed to having us install the same steel mesh along the foundation walls where the deck was built. This added an extra level of protection to this more vulnerable area of the house.

Rat-proofing Deck
We installed our galvanized steel mesh along the wall under the deck.


Rodents are never a welcomed visitor to a home, much less a permanent tenant. Not only are they a nuisance, but they can cause damage and spread pathogens. Rats in particular can infiltrate walls and subfloors in search of nesting sites. They will severely damage insulation and chew through any wiring they may encounter.

That is why it is important to act swiftly when evidence of rat activity is seen in or around a house.

Our professional and certified exterminators are trained to identify not only existing entry points, but also any potential vulnerable sections of a house that may prove to be breached by rodents.

In this case, we created a complete barrier around the house to prevent any rats from ever entering the home. This solution we provide to our customers is what distinguishes from other companies. We not only eliminate the present problem, but we also give our customers the peace of mind that it will not happen again.

Our extermination is backed by a 6-month warranty, while our exclusions come with a 2-year warranty.