How do you keep squirrels out of an attic?

Attics are appealing to squirrels because they provide shelter from weather and predators. Squirrels are unwelcome house guests because of the damage they cause and because they can spread disease.

Squirrels sleep at night and forage during the day, so the best time for a homeowner to check for entry and exit holes and seal them is during the day, when the animals are outside and the light reveals the holes. Squirrels also use drainpipes and chimney areas to gain access, and these places may need baffles to keep squirrels out.

If squirrels are already in an attic, sealing entries into the house below and setting up pans filled with ammonia or other foul-smelling substances may get the animals to leave. Once they are gone, the homeowner can remove the pans and seal the exit holes. An alternative is live trapping and relocating the animals. After the squirrels have left and you have sealed their access holes, clean the attic and check all wires and cables for damage, replacing any chewed wiring.

To keep squirrels out of your attic or to evict ones that may be nesting there, hang strobe lights in your attic. You must disrupt the safe, dark environment of the attic. You need strobe lights with plug-in extensions and an extension cord.

1. Make sure the attic is temporarily free of squirrels

   Nesting mother squirrels are very fierce and aggressive and may attack. Before you go up to hang the lights, make some loud noises near the entrance to make sure there is no display of such behavior.

2. Tape cardboard over any attic windows

   Seal the windows so that natural light does not diminish the effect of the strobe lights.

3. Plug in and hang strobe lights

   For smaller spaces, use only one strobe light with the cord hanging over a rafter. For larger spaces, you may need two or three. In any case, make sure all the lights are plugged into an extension cord so that you can turn them on or off without having to go in the attic.

4. Turn on lights and wait

   At first, the lights must be turned on 24 hours a day, seven days a week. After you have not heard the squirrels for some time, the lights may be turned off and reused later if necessary. The point is to make the space seem dangerous and keep it uninhabitable to the squirrels.