Wall Vent Mouse Entry Point

Case Study: Mice Enter Basement Through Wall Vents in Richmond Hill

The following article details a mouse removal job in Richmond Hill, Ontario. Mice that were leaving droppings in the basement and making noises at night were quickly removed and excluded from this single-family home. For more information on mouse control, give us a call. We provide solutions to all mouse problems.


The homeowner in this case gave us a call when they found mouse droppings in their basement, and they could hear scratching sounds in the walls. These are common signs of a mouse problem. Given that it was early winter, the mice had probably moved in recently to escape the cold. A member of the Mouse Control team came to investigate the next day.

No matter the job, our technicians perform detailed inspections on both the interior and exterior of the property. This enables us to find the rodents’ entry points and areas of activity, which allows providing more effective treatment. Entry points can be blocked, and bait stations can be placed in the most strategic areas.

In this case, the technician found 3 wall vents that could be letting in mice. Mice can climb brick walls and make their way into these openings. Those that are covered in plastic can be chewed through. Once inside, mice make their way into the walls. To keep them out, the technician recommended having these vents covered in a thick, strong mesh.

Wall Vent Mouse Entry Point
The mesh within the wall vent above was dislodged, leaving plenty of room for a mouse to squeeze through.

The technician then found a gap surrounding the air conditioning’s power line. Mice can very easily climb up cables and walls, then sneak into the house via these openings. This could easily be sealed off with foam or silicone.

AC Line Mouse Entry Point
Mice will take advantage of every hole in the wall. Utility lines are often surrounded by gaps like these.

In the basement, there was some evidence of mouse droppings, indicating a small infestation. To get rid of the mice, the technician recommended having a few bait stations installed in areas of mouse activity. To ensure that no more mice got inside, the wall vents would need to be covered.

Treatment and Exclusion

The homeowner agreed to go ahead with the work, so the technician on duty set up some bait stations right away. Bait stations are small boxes of rodenticide, with openings on their sides to let in mice. These boxes require a key to open, and only a licensed pest control technician can supply them. A few stations were placed around the basement, in areas where feces were found. It is important that stations be placed where mice come and go to guarantee to feed.

In order to encourage the mice to feed on the bait, the homeowner was instructed to keep the basement clean and avoid leaving food around. Having other sources of food around the house will make it harder to get rid of pests and prolong the issue.

Next, the technician covered the wall vents. A 16-gauge, quarter-inch, galvanized steel mesh was cut, shaped, then screwed into the wall over the vents. At this thickness, no rodent would be able to chew through. The spaces would be too narrow for mice to squeeze through, and no animal could tear it off. Our exclusion of wall vents is guaranteed and comes with a 2-year warranty.

wall vent cover
Wall vent covers are excellent for keeping pests out of the home. These are weather-proof and continue to let airflow in and out.
AC Line Exclusion
The hole surrounding the A/C line was closed with caulking.


A few weeks later, a technician returned to the scene to check on the bait stations. Some of the bait was gone, indicating that the program was working. The homeowner also noticed that there was less activity. The technician then refilled the stations to give the process a little more time. Mice can be quiet for some time and go unnoticed, so it is important to give the baiting program a few months.

During this visit, the technician also placed a few stations outside. This would suppress the population outdoors and help avoid a resurgence. This baiting program, along with the excluded wall vents, would guarantee the elimination of this mouse problem.

Exterior Rodent Bait Station
Bait stations are great for eliminating rodents. Stations placed outside can be monitored to estimate the pest’s exterior population.


Within a few weeks, the mice were gone. Closing off the wall vents and targeting the mice directly with bait got rid of this problem in no time at all. The technicians at Mouse Control are trained to recognize the causes of mice problems and they have the experience to get rid of them effectively. If you’ve been dealing with a mouse issue and need help, give us a call and we will help. We provide effective solutions and warranties with all of our services. Call Mouse Control for services in the GTA and beyond.

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