9 Most Common Attic Pests

Attics attract all types of pests because they are dark, warm, and safe. Most attics contain some type of insulation that makes for good nesting sites. Some attics even provide a food source–wood, cardboard, and fabric. Any attic used for human food storage is very attractive to pests.

9 Most Common Attic Pests

For many invading pests, the attic is only the first step if they can find ways into the home’s living areas. Be on the lookout for these pests.


Squirrels may be cute outside, but they are messy, smelly, and costly in your attic. Their constant gnawing will damage framing, attic contents, and electrical wiring–which may cause fires. They are active during daylight hours and make more noise than most other pests.

Keeping squirrels out is easier than getting rid of squirrels in the attic. It is also less costly and time consuming. Squirrels often access attics from overhanging tree branches or by running along wires to house roofs. They chew small holes big enough to use as an entrance.


Mice climb well and can scurry up stucco walls to find an entrance into an attic. They can squeeze through a hole the size of a dime. Most other pests are content to remain in the attic, but once inside mice will spread throughout the house.

Getting rid of mice in the attic usually involves removing insulation and replacing it. They tunnel into it to make a safe nesting site. Their feces and urine ruin insulation and invite mold growth.

Like all rodents, a mouse’s front teeth never stop growing. They will chew on almost anything in the attic to keep their teeth worn down. Including electrical wire and plumbing pipes not made of metal.


The most common rat found in attics is the roof rat–also known as the black rat, ship rat, or house rat. Rats need bigger entrance holes than mice, but they will make small holes larger if necessary.

Find and seal any entrance holes, then trap the ones left inside the attic. Rats can be poisoned, but often die and decay in hidden locations–leaving a foul smell.


Snakes are good climbers that can squeeze through small holes. Black snakes–also called rat snakes–and garter snakes are most often found in attics. They need a warm place for hibernation, shedding skin, or laying eggs.

Snakes may also follow a food source–like rats or mice–into an attic. Finding a snake in the attic often means that there is more than one pest in the attic. Most snakes are harmless to humans but a few have enough venom to produce a reaction if bitten. Handle with care or have a pest removal company get them out.


Outside, bats are very beneficial. Inside an attic, they can be a mess. Bats prefer a year-round home and will continue to live in an attic until removed. Any pups they produce will also make the attic home–multiplying the problem. They produce a large amount of smelly droppings. The feces and urine can carry diseases.

Bats are a protected species in many states. Getting rid of them requires professional pest removal. Once they have been removed the area must be sanitized, the insulation replaced, and all entrances sealed.


Missing attic vents or screens are an invitation to birds like swallows. An attic makes a perfect nesting site–dry, warm, and safe. Birds do not cause additional damage but droppings and uneaten food attract insects into the attic.

Removing birds is as simple as taking down nests and sealing the opening they are using. The most humane method is to wait until the young have left the nest, then get rid of it.


Raccoons are large, crafty, strong, and excellent climbers. They need large entrance holes and will make them, if necessary. Females are always looking for warm, dry, and safe nesting places like attic insulation.

Raccoons mess up an attic quickly once they move in. Torn insulation, lots of feces, gnawed wires, and damaged ductwork. Raccoons get quite aggressive when threatened, so removal is best left to professionals. They even have protected status in some jurisdictions.

Stinging Insects

Attics provide warm dry nesting locations for wasps, hornets, and bees. Finding them around holes in soffit or fascia or torn screens is an indication there is a nest inside. Removing the nest is a simple DIY project but covering all exposed skin and wearing eye protection is wise. Soaking the nest with foam wasp killer that sprays 10 feet eliminates them immediately. Remove the nest in a garbage bag and seal the entrance hole.


Attics always have a few resident insects–flies, spiders, etc. but some can become infestations if left unchecked.

  • Termites. Swarm to create new colonies and can end up in attics. Work their way throughout the house.
  • Ants. Ants are always looking for a source of food. Attics with stored or spilled food may entice them to move in.
  • Cockroaches. Attracted to food sources–kitchens, basements, and attics (if used for storage).
  • Cluster Flies. Named for compact clusters they form to keep warm. Invade walls and attics in the fall and move out in the spring to feed and breed.

Preventing Attic Pests

Keeping pests out of the attic is much less expensive than getting rid of them after they invade. Sealing all of the potential entrance points is time-consuming. Mice can get through holes the size of a dime; insects need much smaller gaps.

Most holes can be sealed using wire screen mesh, steel wool, spray foam, and caulking or combinations of two or three products. Seal large holes–not ventilation openings–with sheet metal. Make sure all wall and roof penetrations are sealed and rotted or missing soffit and fascia is replaced.