Know thy enemy

Wild animals living in your attic can cause damage — chew through electrical wires, shred insulation — and spread diseases, such as hantavirus and salmonella. To rid your attic of these pests, you must know exactly which critter has become your housemate. To identify — then kill or trap — the animal, you must learn to identify the shape, size, and pattern of its scat.

Nick Petti, of the Enviro-Tech pest management franchise, provides a little cheat sheet on pest poo.

  • Mouse: 1/8 inch long, pellet-shaped
  • Rat: ¼ inch long, sausage-shaped
  • Squirrel: ½ to 1 inch long, sausage-shaped
  • Raccoon: Up to ¾ of an inch wide, 2-3 inches long; sausage-shaped
  • Bat: ½ inch, pellet-shaped, found in piles

Once you identify the scat, follow the Centers for Disease Control’s advice on how to clean it up. Here are a few tips:

  • Open windows to air out the infested area for at least 30 minutes before cleanup. Don’t hang around during this part.
  • Wear protective gloves and masks so you don’t touch or breathe the urine- and feces-contaminated dust.
  • To disinfect, spray the area with a bleach solution (1 part bleach; 10 parts water).
  • Use paper towels to clean up the area, and then dispose of trash in a sealed plastic bag.

Attic pest removal techniques

Here are some tips on getting rid of attic pests.

Mice

Because mice multiply rapidly, a small problem can become a huge problem within a few weeks. As soon as you know mice have entered your attic — they crawl up drainpipes or follow electrical wires within walls — set those mousetraps.

Plan to lay several mousetraps ($1 each) because as soon as you hear scurrying overhead, you probably have more than one mouse living in the attic. Don’t bait the traps with cheese, which rodents don’t particularly like; they do like peanut butter, says Petti.

Also, remove traps as soon as the deed is done. A bunch of dead mice will discourage other mice from taking the bait.

Professional fee for mice removal: $500 for trapping, removal, and follow-up.

Rats

Never send a small mousetrap to do a bigger and stronger rattrap’s job. Take a look at this videoto see the size and strength difference between the two.

“A mousetrap will only irritate a rat,” Petti says. And make it unwilling to take the bait from a trap of any size.

Unlike mice, which are curious critters, rats shy away from new items in their environment. So scatter traps around the attic for a week before you bait and engage them.

If you find traps are disappearing — larger rats are known to take off with traps clamped around their bodies — screw the next traps into floor boards, or place them in rattrap covers ($15), which will block escape.

Professional fee: $600 to $700 for trapping, removal, and follow-up.

Squirrels

Before you attempt to remove a squirrel or raccoon from your attic, contact your state extension service or wildlife agency to determine what laws and permits apply to trapping and relocating these pests. A professional trapper may have to do the deed.

If you may trap and remove the squirrel yourself, use a one- or two-door metal cage that traps and allows you to set the pest free outdoors ($27-$47).

Professional fee: Starts at $250.

Raccoons and bats

Don’t attempt to get rid of raccoons or bats yourself. Raccoons can be aggressive when cornered or separated from their young; bats are difficult to roundup and escort out.

Professional fee: $300 to $500 per raccoon; $600 to $2,000 for bat infestations.

Humane attic pest removal

The most humane way to cope with attic pests is to make sure they don’t come into your house in the first place, says John Griffin of the Humane Society of the United States. That means inspecting the outside of your home and repairing holes even as small as a dime, which are frequently found in roof flashing, behind gutters, in rotting fascia, foundation cracks, and tears in vent screens.

Trim tree and shrub limbs 8 to 10 feet away from your house, which will make it harder for squirrels to jump onto the roof.

Once the animals are in your attic, terms such as “humane removal” no longer apply, and the conversation turns to “least inhumane” ways of getting them out, Griffin says. Spring traps, for instance, are preferable because they cause a quick death, whereas glue traps torture struggling rodents that eventually die from stress and dehydration.