You hear them at dawn — the scurrying, scratching, occasional thump overhead that tells you something bigger than a mouse is living between your ceiling and your roof. Squirrels in the attic are one of the most common wildlife nuisance calls in North America, especially in spring when females look for safe nesting sites. Eviction is solvable for most homeowners if you understand their behavior, do the work in the right order, and never skip the step that actually prevents them from coming back.
How to Confirm It Is Squirrels
Before you spend money evicting the wrong animal, confirm the species. Gray and fox squirrels in the attic are active at dawn and dusk, moving around with quick scampers and clear claw-scratch sounds. They often drop nuts, acorn caps, or gnawed pine cones that roll audibly across rafters. Red squirrels and flying squirrels are smaller; flying squirrels are nocturnal, so evening scurrying suggests them rather than gray squirrels.
Other common attic invaders sound different. Raccoons are heavy-footed and drag objects. Bats chirp at dusk and leave brown/black pellet droppings on insulation. Rats scurry continuously day and night. Squirrels generally rest midday and are loudest at sunrise.
Step 1: Find the Entry Point
Squirrels rarely make only one way in. Walk the exterior at midday when they are quiet and look for:
- Gable vents: screen damage or chewed louvers. The most common entry.
- Roof vents and turbines: loose flashing or bent baffles.
- Soffit corners: gnawed holes where soffit meets fascia.
- Construction gaps: where dormers or chimneys meet the roofline.
- Fascia and rake board rot: soft wood is an invitation.
- Attic fans: housings that do not seal tight.
A 1.5-inch diameter hole is enough for a gray squirrel. You will often find dark greasy rub marks around the entry from repeated use.
Step 2: Eviction — One-Way Doors
The humane, legal, and effective method is a one-way exclusion door. Mount a steel mesh cone or commercial squirrel one-way door over the main entry, oriented so squirrels can push out but cannot come back in. Products like the Tomahawk Squirrel Excluder ($40-70) or a homemade hardware cloth cone work well.
Leave the exclusion door up for 3-5 days during normal squirrel-active weather. Check daily. After 72-96 hours with no activity, remove the device and seal the hole permanently.
Critical timing caveat: in spring (March-May) and late summer (July-August), check for baby squirrels first. A female with a nest of blind babies will die in the attic if excluded. Listen for high-pitched squeaks from the attic in mornings. If you hear babies, wait 6-8 weeks for them to mature, or hire a wildlife control professional who can manually remove the litter.
Step 3: Seal Every Entry Point
Once the attic is confirmed empty, close every hole you found — not just the main one. Squirrels can and will chew open secondary entries if you miss them.
- Small gaps: fill with copper wool or stainless steel mesh, then seal with construction adhesive or exterior silicone.
- Holes in wood: replace rotted boards, back with hardware cloth, caulk the seams.
- Gable vents: install 1/4 inch galvanized hardware cloth behind the louvers on the interior side. Staple every 2 inches.
- Soffit corners: apply soffit closure strips and metal flashing.
- Roof vents: retrofit with heavy-gauge steel vent covers designed to block wildlife.
Never use spray foam alone; squirrels chew right through it. Metal mesh behind any filler is non-negotiable.
Step 4: Clean the Contaminated Attic
Squirrel urine, feces, and nesting material carry salmonella, leptospirosis, and occasionally hantavirus. Cleaning is as important as eviction.
- Wear an N95 respirator, nitrile gloves, and disposable coveralls.
- Vacuum droppings and loose debris with a HEPA-filter shop vac, not a regular household vacuum.
- Remove any urine-soaked insulation. Bag in heavy contractor bags and dispose per local rules.
- Wipe down beams and decking with a 10 percent bleach solution or an enzymatic wildlife cleaner.
- Replace removed insulation with blown-in fiberglass or cellulose to R-value matching the rest of the attic (R-38 to R-60 depending on climate zone).
If contamination is extensive (more than a few square feet), call a professional wildlife remediation company. Budget $800-3,000 for full decontamination.
What Not to Do
Several popular tactics are worse than useless.
- Mothballs or ammonia-soaked rags: illegal as repellents in most states, ineffective, and toxic to the family living below.
- Ultrasonic repellers: no peer-reviewed evidence they deter squirrels.
- Poison: dying squirrels in wall cavities smell for weeks and the poison risks pets and non-target wildlife. Illegal in many states for squirrels.
- Trapping and relocating: illegal in many states without a permit, and relocated squirrels usually die of stress or competition within weeks.
- Sealing them in: traps them to die inside your walls. Do the exclusion door correctly instead.
Costs of Professional Help
A licensed wildlife control operator typically charges:
- Inspection and assessment: $75-200 (often waived if hired).
- Exclusion and eviction: $350-800.
- Entry point repairs: $200-1,500 depending on complexity.
- Attic decontamination and insulation replacement: $800-3,000.
DIY can handle the whole job for $150-400 in materials if you are comfortable on a ladder and know your way around a staple gun and caulk tube.
Long-Term Prevention
Trim tree branches within 8 feet of the roofline — squirrels jump farther than you think. Install metal tree guards on the trunks of trees they use to reach the roof (24-inch tall sheet metal wraps). Replace any rotted fascia boards immediately. Cap the chimney. Install critter guards on every roof vent and gable vent. Do these steps once and the risk of repeat squirrels in the attic drops to near zero.
