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Mice in your attic? How to change the critter culture

Mice in your attic? How to change the critter culture

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Estimated read time: 5-6 minutes

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SALT LAKE CITY -- No matter where you live, creatures surround you. You expect them in the great outdoors — and perhaps have come to accept that somewhat. But the closer the little critters are, the less comfortable you are. These scampering beasts are in the sewer, the woodpile and the shed. They live in your ivy and under your bushes. You may accept they are “out there,” but what if you knew they are above and below you as well? It is quite common for raccoons, mice, rats and other crawly creatures to live in the attic and walls of homes — including yours.

These scurrilous beasts find great creature comfort in your floor joists, your walls and even in your attic. Perhaps you have already heard the scratching sound of tiny little feet as they pitter-patter through your castle. As king or queen of your castle, you may not know how many mouths you are feeding. Worse yet, the creatures are rarely grateful for your unintended hospitality.

Critter culture

Attics and floor joists can be a true blessing to a mouse. They provide protection from the elements, are free from predators and are much cleaner than the mud caves that a mouse’s ruddy cousins live in. Best of all, they provide ready access to loose food in the pantry — or rotting cookies in a child’s sock drawer. Attics are like the high-rise critter condo for mice that enjoy the high life at your expense.

How to know they are there

Sometimes the little varmints will make things easy on you. When they think you’re away, the scratching begins. This is one of the dead giveaways that you have uninvited guests. Don’t think, however, that not hearing them means that your home is OK — most homeowners have no idea when their home is a condo for critters.

Want to know if you have mice? If you have missed the joy of hearing the giveaway scratching sounds, you have another option: head on up into the attic and look around. Furry guests will leave hallways and burrows that are easy to spot in the attic. In more infested attics, you will see mouse feces as well. Hallways on the surface of the insulation will be an inch or two deep, making the surface of the insulation look like a literal rat’s maze. Burrows will be one-inch diameter holes going down into the insulation, burrowing into places where no man has gone before.

The procedure for prosecution

What to do when you find them? Shrieking is a tempting first reaction — feel free to do so. After that task is mostly complete, it will be time to take the beasts out. The first thing you do is eliminate the critter’s front door — and the back. Make sure that pathways to and from the home are eliminated. After that, step two will involve some massacre.

Get out, and stay out!

If you are ready to permanently disinvite your furry guests, you must first seal the entry points. According to, critters can use electrical or gas pipe entrances, outdoor water taps and air conditioner connections. Loose siding can also be a front door for furry friends.

The USU Extension Service also recommends that you seal all holes and openings that are larger than one-fourth of an inch. Use heavy materials such as concrete mortar, sheet metal or heavy-gauge hardware cloth. USU also warns against potential scams: devices that repel mice using ultrasonic waves are advertised widely, but there is no scientific evidence that these contraptions are effective.

As you look around the exterior, be aware of how a mouse may find his way to the opening. The corner bead on exterior siding can make an excellent mouse elevator. Mice can scale brick — and they appreciate branches and vines that give them direct access to the eaves.

Meaningful mouse massacre

Some homeowners place poison pellets in the attic hoping to eliminate the problem. This is akin to Russian roulette: when the varmint takes the bait, you must hope that it waddles outside to die slowly and painfully. When death occurs inside, you will have a decaying carcass in your walls, in your child’s sock drawer or in the attic. Unless you enjoy the smell of warm decaying meat, it’s better to have them out. Rotting mice don’t smell good.

Instead of placing poisons, try using traps. If you choose to disinvite a mouse humanely, you can go with live traps — after all, it was their great-great grandfather’s land before it was yours. If you are not of that persuasion, the old whack-a-mole traps are tried and true. Regardless of the type of trap, the Utah State University Extension Service recommends that you avoid cheese — it goes rancid too fast. Peanut butter or chocolate are much better choices.

No effort at eliminating the little nasties is complete without eliminating “how” and “why” they are entering. Seal up the exterior, trim trees and bushes near the home and keep food protected. Every home gets pests occasionally; the goal is to reduce the number of the uninvited visits.

Garth Haslem is the owner of Crossroads Engineering. He is a structural engineer, an author and a home inspector. For access to free books about home hazards and maintenance, visit Facebook: Garth Haslem — the Home Medic


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