Squirrels are strong, agile climbers that can enter a home through remarkably small gaps in soffits, roof vents, and fascia boards, especially where an overhanging branch provides easy access. Once inside an attic, they build nests from insulation and chew on wiring, joists, and stored items.
Activity often intensifies in the fall as squirrels prepare dens for winter and again in early spring when young are born. Trimming branches away from the roofline and having a professional seal entry points — after confirming no animals remain inside — are the most effective long-term prevention steps.