Squirrels are largely tree-dwelling rodents, however, they do seek places of warmth and refuge from predators in residential homes, particularly in the roof and attic spaces. Both are warm in the winter and free of any hungry predators such as feral and domestic cats, coyotes and foxes. Squirrels can nest in a roof space and breed there, creating a cyclical problem. If they die in the roof space, the carcass attracts other wildlife. Stopping squirrels from getting into a roof is a matter of eliminating the attractors and sealing entrances.
Mix together 1 pint of water with 1 ounce of bleach in a spray bottle. Spray the nesting area and surrounding areas with the solution. This helps repel future squirrel invasions into your roof. Measure all openings where squirrels can enter the roof, and use aluminum snips to cut mesh wire to fit over the openings. Secure the mesh wire to the openings with screws using a screw gun.