Dreaded Intrusion: Keep Mice Out

As the song goes, ‘Oh the weather outside is frightful, But the fire is so delightful’. That’s the reason why the onset of winter is when we find many outdoor pests trying to invade our space. They may not be planning on sitting in front of a roaring fire exactly, but they do seek the warmth. A very common unwanted house guest that can appear at this time of year is the mouse. In addition to a warmer space, they are looking for food, which has become scarce outside.

Able to squeeze through amazingly small openings, mice can prove very difficult to keep out. Once inside, they inevitably chew their way into food packages and leave disease ridden feces and urine everywhere they go. Their agility, intelligence and sheer determination can make them a formidable foe.

Identifying the Problem

There are a few different types of mice around depending on the area you live in. They are light brown, tan or gray in colour, some with a white underbelly and feet. They grow to a length of 7.5 to 10 cm (3 to 4 in), plus a tail around the same length as their body. As with many unwanted pests, you often see signs of their presence before you see the actual pest. Mouse droppings are very common, as mice defecate and urinate at will.

Little blacks nuggets about the size and shape of a grain of rice or smaller will let you know they are present. Also, look for food containers and packages that they have chewed their way into.

Getting Rid of Mice

There are a variety of traps available to help you rid your home of these little pests. All of them work to a varying degree; most by killing the mouse, but some simply trap the mouse for release outdoors. You can easily and effectively rid your home of a minor infestation by diligently setting traps near where droppings have been found.

Don’t be surprised if you get nothing the first few days after setting the trap, as it can take that long for them to find it and be comfortable enough to approach it. Check, empty and reset traps – wearing rubber gloves – at least once a day, and reuse the same trap over and over, as the accumulating smell will only enhance its appeal.

For bait, set the trap with something sticky that has a strong smell, like peanut butter or cheese spread. This type of bait makes the mouse pull at it, which will be sure to trigger the trap. And be sure to leave traps in place for at least 2 weeks after the last mouse is caught to make sure there isn’t a new generation ready to spring into action.

If you choose the humane trap option, be sure to release the critter at least 100 m from your home – preferable in a field away from other homes – to prevent it from revisiting. And if you aren’t interested in dealing with the hassle of traps, there are also poison bait options for mice problems. Lighthouse Inspections typically recommends a type that dries the corpse from the inside out so there is nothing left to smell or clean up. Just be certain any poison bait is placed well out of reach of children and pets.


Keeping mice out of your house involves sealing off all possible points of entry. Because they can flatten themselves out to slip through small gaps – reportedly as small as a dime – sealing or caulking any area of concern is best.

Pay special attention to;

  • Foundation – seal-up any cracks and openings around windows, doors, pipes, electrical
    wiring, dryer vents, furnace exhausts, etc.
  • Roof, eaves and chimney – mice are excellent climbers, so check for possible entryways along facia, vents and where 2 different materials meet, such as where a brick chimney meets wood siding. Access to the attic means easy access to the inside of walls and ceilings through holes for plumbing and wiring – and eventually the home’s interior.
  • Garage – seal any openings as with the foundation, and carefully inspect the wall(s) that are common with the home’s interior, sealing off access to the attic as well.
  • Doors and windows – inspect and replace any worn-out weather stripping and caulking.
  • Sump pump hole – either screen off the hole itself or the pipe(s) that drains into the sump hole.
  • Another preventative option is a device that emits a sonic signal said to keep mice away, but many people have reported less than ideal results with this method, some even suggesting the mice simply got used to the noise.
  • There are also a number of preventative steps you can take to dissuade mice from living near your home – before they gain entry;
  • Clear out clutter around the house’s exterior and along walls of the garage that could serve as a nesting site.
  • Cut back any grass that grows next to the house.
  • Stack firewood well away from the building.
  • Secure garbage containers with tight-fitting lids.
  • Keep composting containers as far from the house as possible.

In the event of a mouse discovery in your home, there are tips for keeping food safe, such as storing everything in sealed metal or glass containers. But it is important to realize that even if they can’t get into your food, mice will still infect the area. Therefore, if mice are in your home, they will need to be eliminated. And they will always find something to eat.

Clean Up Tips

As mentioned, caution needs to be exercised when dealing with mice because of the
presence of disease and bacteria:

  • Do not vacuum or sweep mouse droppings. This can cause an unhealthy dust that is easily inhaled. Better to lightly spray the area with a mixture of bleach and water to dampen it before wiping up.
  • Wear a dust mask and rubber gloves when setting traps, cleaning up droppings and disposing of the dead mice.
  • Place dead mice in a plastic bag and seal it up well before disposing of it in a garbage can that has a secure lid.
  • Thoroughly wash your hands after cleaning up mice and mice droppings, and put any clothing that may be affected into the laundry right away.

Rat Concerns
Rats, the bigger cousins of the mouse, require special attention. Some varieties can reach a length of 41 cm (16 in)! Though they can’t slip through small cracks in our home’s exterior as easily as mice, they come equipped with much more formidable teeth and claws. With these, rats are able to gnaw and claw through wood to enlarge an opening to suit. Once inside, they can cause considerable damage.

Many of the prevention tips above apply to rats. However, rats can be much more determined and better able to work around our efforts to keep them out. Essentially, the bigger the rodent, the greater the concern. A rat infestation requires immediate attention.

Contact your local Lighthouse Inspections professional for more information about this article or to schedule a complete home inspection by Lighthouse Home Inspections.

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