One quarter of one inch. The width of a house key. 3 nickels stacked on top of one another. The width of a fettuccini noodle. This is all the space that a mouse requires to gain access to a home or building.
Anyone that has ever been startled by the sudden appearance of a mouse knows that they disappear as quickly as they emerge. For those who have been curious enough to investigate where the mouse came from or went, it can be mind boggling since no apparent access holes are visible.
When discussing rodent access points to homes and commercial buildings the possibilities are limitless and vary greatly depending on structural features. Just a few of the more common examples where suitable entry points exist are listed below:
- Overhead garage doors.
- Utility line entry points on the foundation wall (water, gas, sewer, AC and electrical lines.)
- Dryer vents.
- Exterior doorways.
- Loose siding or siding extending below grade level.
- The soffit or overhang near the roofline along the exterior wall.
- Cracks in the foundation walls.
- Concrete porch stoops that are cut into the header board in the basement or crawl space.
- Roof vents.
- Old coal chutes.
- Crawl space vents.
- Expansion joints in concrete slabs.
- Plumbing lines.
When building occupants begin to notice signs of mice (i.e. droppings or chewed food items) they want to know how the rodents are getting in. Most people believe that it is a simple matter of locating their entry points and then taking corrective action to seal them out. In addition to their ability to squeeze through small openings, mice are excellent climbers, burrowers and jumpers. They are tremendous athletes! While thorough exclusion efforts will often limit rodent access and are recommended, they are seldom successful as a stand- alone solution.
Experienced pest control professionals understand that total exclusion is difficult and focus their control efforts in other areas. Mice exhibit two traits that typically lead to their demise: they are curious and they are nibblers. They will readily investigate all changes to their living environment and are therefore easy to trap. They have an excellent sense of smell and will sample all new food sources within their “home range” which makes them susceptible to baiting programs. The final determination of the best control program is dependent on many factors and will vary from client to client.
Go ahead and seal them out. Caulk all visible cracks, fix the screening, install door sweeps, patch the foundation wall with mortar, tighten up the siding and use expandable foam where the utility lines enter the home. When you are all finished congratulate yourself on a job well done. When the mice droppings keep showing up in the pantry call a professional!