Wall Vent Mouse Opening

Case Study: Mice Crawl Through Wall Vents to Reach Kitchen

This case study details a mouse removal job in Old Toronto. Mice that had crawled into the home via the wall vents were quickly removed and excluded from the property. A bait program and covering of the wall vents has left this home mouse-free ever since. For more information on Mouse Control in Toronto, give us a call at: 647-496-0492.


The homeowners in this case called Mouse Control when they started seeing mice in their home. They had spotted some running across the kitchen and could hear them scratching in the walls. Unsure where the pests were coming from, they gave us a call for help. A member of the Mouse Control team came to check on the situation the next day.

Upon arrival, the technician performed an inspection of the home’s exterior. This is done with every pest control job so that our technicians can find the sources of the problem. Finding the pests’ entry point would allow the technician to block it off, which would solve the problem faster.

Here, the technician found 5 wall vents that may have been letting mice in. Mice are good climbers that have no difficulty climbing straight brick walls. The wall vents in question had mesh within them that was wide enough to fit mice. Once in, they could make their way into the walls of the home. To fix this, the technician recommended having them covered with a narrower mesh.

Wall Vent Mouse Entry Point
Wall vents are prone to animal entry. Animals can tear them off or climb their way through them. The warm air that escapes these vents is attractive to pests looking to escape the cold.

In addition to the wall vents, the technician recommended having the foundation secured. Rodents are common in Old Toronto and have been found to dig under the ground, then into basements. Digging a trench around the home’s exterior, then securing a mesh along its sides would keep rodents out.

Inside, the technician found some evidence of mouse droppings in the kitchen cabinets. Bait stations would need to be placed here to get rid of the mice living indoors. Following the interior inspection, the technician informed the homeowners of what was going on, then recommended a bait program and full exclusion of the exterior. The homeowner agreed to have bait stations installed and the wall vents covered, so the technician got to work right away.

Treatment and Exclusion

First, the technician placed 3 bait stations throughout the home’s exterior. These are little tamper-proof boxes of rodenticide that need a key to open. They have holes in their sides to let in mice, who find the bait attractive. After a few ingestions, the mice retreat into their nests and perish. Only professionals have access to these stations, and they work better than the baits available in stores.

Stations were placed in areas where mice were spotted or where their feces were found. Bait stations work best when placed in areas of mouse traffic because mice are skittish creatures that follow the same paths everyday. Placing them away from their daily routes will not work.

Outside, the technician covered the wall vents with a quarter inch, galvanized steel mesh. This mesh is weather-proof and strong enough to resist rodent chewing. Rodents have very powerful teeth, so it is important to use a mesh they cannot chew through. All four vents were covered.

Excluded Wall Vent
The mesh installed on the wall vents would keep pests out for good. Screwing it into the wall would also prevent raccoons from tearing it off.

A few weeks later, the technician returned to check on the bait station. Missing packets of rodenticide showed that the mice were indeed consuming the bait. The bait was refilled, then the technician returned another few weeks after that. Consumption slowed, then stopped.


Within a few weeks, the mice in this case study were gone. Excluding the wall vents and placing bait stations within areas of activity got rid of the pests effectively. If you’ve been dealing with mice, consider getting the help of a professional. A professional can find entry points and fix them for you. They will also use effective rodenticides that are safe for household use. Call Mouse Control for affordable mouse removal and exclusion within the GTA and beyond.

Call Us Now