When animals invade your attic

What is a simple, easy and quick fix to get animals living in attics to pack up and leave?

A fox squirrel perching on top of a roof. Photo by Joseph Berger, Bugwood.org

A fox squirrel perching on top of a roof. Photo by Joseph Berger, Bugwood.org

Michigan State University Extension often receives callers disturbed by scrabbling, squeaking or chewing sounds in their attic caused by an uninvited animal guest. They’ve heard of using mothballs or cloths soaked in or pans filled with every stinky liquid imaginable. They’ve heard of putting a radio in the attic and turning it up as loud as it can go, and even turning on lights to illuminate the area as brightly as possible. Some of these can be dangerous; radios and lights could cause a fire, and mothballs and foul liquid fumes can settle into the living area of the house. After trying all these timewasters, they are now calling for another quick fix. Sadly, there are no quick, permanent fixes. It all comes down to repairing the entrances and exits so the animal parade cannot go on.

Let’s take a look at some of the ways mammals can get into an attic. Trees that have branches overhanging or are within 6 feet of the house are vertical expressways. Squirrels and raccoons can easily climb the tree and run out on a branch and jump onto the roof. If a tree trunk is 6 feet or closer to a house, animals will just climb the trunk and jump, but a tree this close to a house will eventually damage the foundation, walls or roof. A close tree shading the roof shingles can cause the shingles to dry slowly, failing sooner than they should. Vines, either on or off a trellis, can provide a ladder to happiness, too. Don’t forget the little guys either. Mice and possibly chipmunks can climb a rough brick or block chimney.

However, all of these depend on having an opening once the animals reach the summit of Mt. Animal House. This opening might be a torn or missing screen in a gable-end vent. It could be a ripped or missing screen in a square roof ventilation unit referred to as cans. If the animal can push past a torn screen, they are in. This includes bats.

Bats can squeeze into a crack not much bigger than the tip of your little finger. A bat could get into a crack between the brick or block chimney and the roof. As the house ages, the chimney settles in one direction and the house settles in the other. The top surface of the roof is protected by roof flashing and tar, but the underside where the under-hang and chimney meet has a crack. If bats have been regular visitors to this area, there will be a grayish smudge where the bat squeezed into the crack. Oil rubs off their fur onto the under-hang and dirt accumulates on the oil.

In the roof area, it is possible to have fascia boards pop loose at the corners and leave small cracks or have damaged soffits. Everything must be inspected. It is possible to use a very bright flashlight at night inside the attic and shine it on walls and corners to see if a person outside can see the light.

There is no “quick and easy” when talking about getting rid of animals looking for free rent. They have plenty of time to do a thorough house inspection every year, even if you don’t. Repair damage correctly to make sure you are not hearing the pattering of little feet over your head.

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