Keeping clean gutters is the first step in keeping squirrels out of the attic. A gutter full of acorns is like a buffet line to squirrels and will attract them to the roof.
Look for any holes near the eves or fascia of the roof that could provide access to the attic for squirrels. Any holes should be sealed and or wood replaced. Metal or wire mesh can also be installed to seal up enterances. Keep in mind if there are already squirells in your attic you will want to make sure that they are gone for the morning before ceiling there enterances.
Sometimes a gap between roof decking and facia will make access for critters all around the houses eaves. In these cases a custom peice of drip edge may be required to bridge this gap.
Lastly tree limbs should be cut as far back from the house as possible. Squirrells have been known to leap great distances to live in comfort. Limbs touching the roof are a highway into your house for these animals.
These are just a few of the ways to keep squirrels out of your attic. Please before stepping foot on a ladder or your roof call Birmingham Roofs.