Case Study: Mice Climb Brick Walls to Attic

Case Study: Mice Climb Brick Walls to Attic

The following article details a mouse removal and pest-proofing job in North York. It was December, and the homeowner in this case was hearing noises in the attic. Invasions like these are common in the fall and winter when pests need a warm place to stay. A complete inspection, removal program, and pest-proofing were carried out to rid this property of mice and keep them out for good.

Inspection and Initial Treatment

The homeowner in this case first called The Exterminators when they heard noises coming from the attic. They believed that mice were getting into the attic through the roof and were therefore interested in having the mice removed and the roof excluded to prevent this from happening again. A technician quickly came to the scene to investigate.

The first step of the inspection process is to walk around the exterior of the property. The technician here examined the outer walls of the home for openings that a mouse could fit through and took note of every vulnerability. Mice can fit through openings the width of a ballpoint pen, so it is important that everything is checked carefully. Here, the technician found wall vents along the sides of the house that could let mice inside. These could be covered with mesh to keep rodents out.

Missing Brick in Deck
A missing brick in the side of the front deck was prone to letting rodents nest inside. From there, they could get into the house. The technician recommended having this fixed as soon as possible.

Following the exterior inspection, the technician checked the attic. Fresh mouse droppings were found within the attic’s insulation, proving that mice were infesting the area. The technician then recommended to the homeowner that they have bait stations installed to get rid of the mice.

Mouse Feces in Attic Insulation
Mouse droppings are a clear sign of an infestation, even when you’ve never seen the mouse themselves. Droppings appear like dark grains of rice and appear wherever mice feed and walk around.

Bait stations are small plastic boxes that contain rodenticide. The technician in this case placed a few of these in the attic, in areas of mouse activity. Mice would consume the bait, then retreat into their burrows to perish. Bait stations are highly effective for removing mice and can only be serviced by a licensed exterminator.

Rodent Bait Station in Attic
Some bait stations were placed near the piles of feces to target the mice directly. The technician would return within a few weeks to check up on the bait stations and see how much the animals were eating.


Following the placement of bait stations, the technician on site excluded the wall vents. A quarter inch, 16-gauge mesh was placed over the openings to keep mice out. Weep vents were also covered with little pieces of stainless-steel mesh. This would continue to let the wall aerate while keeping pests out.

Wall Vent Exclusion
Galvanized steel is weather-proof and it cannot be chewed by rodents at a thickness of 16-gauge.

By the end of December, most of the activity had stopped, but a more detailed inspection of the roof was needed to determine the extent of the exclusion required. The homeowner expressed that mice were found in the attic every winter, so the roof had to be excluded. This house’s roof was very high up off the ground, so it needed experienced technicians to take a look. Two technicians returned to the scene, in March, to examine the roof. Ropes and safety gear were brought with them to reach the attic safely.

A gap, about 20 feet long, was found between the soffits and the brick walls of the house. While it may be hard to believe, mice are very good climbers. They can climb brick walls, all the way up to the soffits, then crawl their way into the attic. To exclude this gap, the homeowner was interested in having matching black flashing installed.

In the end, a combination of mesh and sealant was used to secure the 20 feet along the soffits of the roof. Two soffit panels were removed as well, to reinforce them and prevent animal entry. Two wall vents that were higher up the walls were also covered.

Soffit Exclusion with Mesh
First, a mesh was installed, then sealant was applied on top. This combination of sealant and mesh would secure the mesh to the wall and ensure that no more mice would get inside.


By April, the noises in the attic had stopped and mice were no longer feeding on the bait. The exclusion performed and the bait program eliminated the mice on this North York property.

This case study exemplifies just how agile mice are and how much our homes are at risk. Mice are flexible, athletic little creatures that can jump, climb, and swim their way into our homes. Like us, pests would rather be inside for the winter, and they will do whatever it takes. In many cases, it takes more than a bait program to get rid of mice. It takes persistent work and a fool-proof exclusion to keep them from coming back.

Call The Exterminators

If you have been struggling with a mouse problem like this one, give us a call. Our technicians go above and beyond. We perform thorough inspections so we can tell you where the pests are coming from and keep them from coming back. Our mouse programs are also guaranteed, so if the mice come back, so will we. Call us for high quality exclusion and pest removal.