How Do I Keep Squirrels Out of My Attic?

Scratching and scurrying in the ceiling, usually at dawn and dusk, means squirrels have moved into your attic. The fix has two parts, in this exact order: evict them humanely with one-way exclusion doors, then seal every entry point with metal — never foam or caulk alone. The golden rule: never seal squirrels inside. A trapped squirrel will chew through drywall, wiring, and anything else between it and freedom, turning a nuisance into real damage.

This guide covers how to confirm it’s squirrels (not mice), how to find their entry points, the eviction process step by step, how to seal the attic properly, what not to do, and when to call a wildlife professional. Done right, this is a weekend project costing under $150 — and it permanently solves a problem that only gets more expensive the longer you wait, since every week of squirrel tenancy means more chewed wiring, more compressed insulation, and more entry holes to seal.

Is It Actually Squirrels? Signs to Check

Before you act, confirm the culprit — the fix for mice is different from the fix for squirrels.

Timing is the biggest clue. Squirrels are diurnal: scurrying and scratching in the early morning and late afternoon, quiet midday and all night. Noise at 2 a.m. means mice or rats (nocturnal), not squirrels. Raccoons are nocturnal too, and much louder.

Sound size matters. Squirrels have weight — scampering, thumping, dragging. Mice sound like faint scratching inside walls.

Droppings tell the story. Squirrel droppings are raisin-sized and oblong (~3/8 inch); mouse droppings are rice-grain sized.

Look outside. Squirrels are bold — you’ll often see them on the roof or ridge in the mornings. Chewed fascia or soffits, visible with binoculars, confirm the entry zone.

If the signs point to mice instead — tiny droppings, nighttime scratching — here’s the full guide to keeping mice out in the fall.

Finding the Entry Points

Squirrels need only a 1.5 to 2-inch gap to squeeze through, and they enlarge small holes by chewing. Inspect from both outside and inside.

Outside inspection (ground level first, ladder only if safe): Walk the perimeter and look up at the roofline with binoculars. Focus on:

• Soffits and fascia — the most common entry. Look for chewed holes, gaps where the soffit meets the roof, and water-damaged wood (soft wood is easy to chew through).
• Roof vents — plastic or thin-metal vents are chewable. Check plumbing vent boots and turbine vents.
• Gable vents — unscreened or damaged screens are an open door.
• Roof edges and eaves — gaps where the roof decking meets the fascia.
• Chimney — uncapped chimneys are a classic entry; squirrels fall in and can’t climb out.
• Construction gaps — where dormers, additions, or porches meet the main roof.

Inside the attic: Go up in daylight with a flashlight and dust mask. Turn off the attic light and look for daylight leaking in — every pinhole is a gap. Also look for droppings, chewed wood, nesting material, and dark oily rub marks where fur brushes through openings.

The flour test: Sprinkle flour beneath a suspect hole; footprints by morning confirm it’s active. Mark every hole with painter’s tape — you’ll seal them all, in the right order (below).

The Eviction: One-Way Exclusion Doors

This is the humane, effective, legal-in-most-places method. A one-way exclusion door (also called a one-way trap door) mounts over the main entry hole: squirrels can push out through the spring-loaded or angled flap, but can’t get back in. They leave on their own schedule — usually within a day or two — with no trapping, no poison, no dead animals in your walls.

Step-by-step:

1. Identify the main entry. Squirrels usually have one primary door they use daily, plus secondary gaps. The main entry shows the most wear — chewed edges, rub marks, droppings below it.

2. Seal the secondary holes first. Close every other gap you found with your permanent materials (details in the next section), leaving ONLY the main entry open. This funnels all traffic through the door.

3. Mount the one-way door. These cost $15–$30 at hardware stores or online. Secure it firmly over the main entry — it must sit flush with no gaps around the edges, or squirrels will just go around it. Follow the product’s mounting instructions; most attach with screws to the surrounding wood or siding.

4. Wait 3–5 days. Give every squirrel time to leave.

5. Verify they’re out. Stuff the entry loosely with crumpled newspaper — if it’s undisturbed after 2–3 days and mornings are quiet, the attic is empty.

6. Remove the door and seal the main entry permanently with metal flashing and hardware cloth, as described below.

Critical warnings:

• Never seal animals inside. A trapped squirrel chews through drywall into your living space or dies in the wall. The newspaper test exists for exactly this reason.
• Spring babies change everything. From March through May, a female may have nursing young that can’t use the one-way door. If it’s spring and you suspect a nest, call a wildlife pro for a humane reunion eviction.
• Check local laws. Most states allow homeowners to exclude squirrels, but trapping and relocation rules vary — some states prohibit relocating wildlife. Exclusion sidesteps almost all of this.

Sealing Entry Points: Metal, Not Foam

Here’s where most DIY squirrel jobs fail: people seal holes with spray foam or caulk, and the squirrels chew straight back through it in a night. Squirrel teeth never stop growing — they must gnaw. Your seal has to be something they can’t chew through.

Use these materials:

• 1/2-inch hardware cloth (galvanized steel mesh) — the workhorse. Cut patches larger than the hole, screw them down over soffit gaps, vent openings, and chewed spots.
• 26-gauge sheet metal flashing — for larger holes and fascia repairs. Cut, bend, and screw into place.
• Metal vent covers — replace chewed plastic roof vents and gable vent screens with metal versions.
• Chimney cap — a stainless steel cap with mesh sides ($75–$200 installed DIY-able) closes the chimney route permanently.

Technique matters: screw patches — never staple or glue — into solid wood around the entire perimeter. Leave no edge a squirrel can get teeth under; they’ll peel a loose corner back. For roofline gaps, slide flashing up under the shingles and screw the lower edge to the fascia. Wear gloves — cut hardware cloth is razor sharp.

Repair damaged wood first. If squirrels chewed through rotted fascia, replace it (PVC trim boards resist chewing) before screening over it — sealing over rot gives them a soft spot to reopen.

While you’re up there, look around — frost or moisture in the attic in winter signals ventilation problems worth fixing at the same time.

Prevention: Make Your Roof Uninteresting

Trim tree branches 8+ feet back from the roof. The single most effective prevention — squirrels jump 8–10 feet, and overhanging branches are a highway to your attic. Four feet is not enough.

Remove food incentives. Move bird feeders 20+ feet from the house, secure trash, and don’t leave pet food outside.

Fix gaps before they find them. Walk your roofline every fall and spring. A small gap found early is a five-minute patch; found after move-in, it’s a full eviction.

Cap the chimney. The easiest entry to close, and it prevents a squirrel trapped in the flue.

Tools and Materials

Binoculars, bright flashlight, dust mask and gloves, ladder, tape measure, tin snips, drill/driver, 1/2-inch galvanized hardware cloth, 26-gauge sheet metal flashing, exterior screws, one-way exclusion door ($15–$30), crumpled newspaper (for the vacancy test), and flour or talc (for the footprint test). A reciprocating saw helps if you’re replacing rotted fascia boards.

What It Costs

Address damaged insulation: compressed, urine-soaked insulation loses R-value fast, and some homeowners notice one room staying colder than the rest of the house afterward. Replacing the damaged sections restores comfort and energy bills.

Safety Warnings

• Never handle wildlife with bare hands. Squirrels can carry rabies (rare but real), leptospirosis, and parasites like fleas and ticks. If one gets cornered, back off — a scared squirrel bites hard.
• Ladder safety. Most entry points are at the roofline. Keep the ladder on firm, level ground, maintain three points of contact, and don’t work on the roof in wet, icy, or windy conditions. If the entry is somewhere you can’t reach safely, that’s a pro job.
• Attic hazards. Wear a dust mask — old insulation, droppings, and dust are terrible to breathe. Watch your step: only walk on joists or the attic floor, never on drywall between joists. Turn the attic light on or bring a headlamp.
• Droppings cleanup. Wear gloves and a mask, mist droppings with disinfectant before sweeping (never dry-sweep — it aerosolizes pathogens), and bag everything.

What NOT to Do

Don’t use mothballs. No evidence they work, they’re toxic to breathe in an enclosed attic, and off-label use is illegal in many states.

Don’t use poison. It doesn’t reliably kill squirrels, and a poisoned one dies inside your wall. It’s inhumane and risks poisoning owls, hawks, and pets that eat the carcass.

Don’t trap and relocate. Relocated squirrels usually die, it’s illegal in many states, and trapping without sealing just creates a vacancy for the next squirrel. Exclusion plus sealing solves it permanently.

Don’t seal holes with foam or caulk alone. Squirrels chew through spray foam overnight. Foam is fine as backing behind hardware cloth, never as the barrier.

Frequently Asked Questions

How do squirrels get in the attic? Through roofline gaps — chewed soffits, fascia gaps, unscreened gable vents, uncapped chimneys. They need only a 1.5–2 inch opening and enlarge it by chewing.

Will squirrels leave on their own? No. An attic is warm, dry, and predator-free — ideal denning habitat. They’ll stay and breed unless excluded. Fall is peak move-in season.

Can squirrels chew through my roof? They exploit existing gaps and rotted wood rather than chewing through intact shingles — but given a starter gap, they’ll widen it aggressively.

Do ultrasonic repellents work? No reliable evidence says they do. Squirrels habituate within days. Spend the money on hardware cloth instead.

How long does exclusion take? Most squirrels exit within 24–72 hours. Allow 3–5 days, verify with the newspaper test, then seal permanently.

Will homeowner’s insurance cover squirrel damage? Usually not — most policies exclude rodent and vermin damage. Budget as if you’re paying out of pocket.

When to Call a Wildlife Pro

Call a licensed wildlife control operator if it’s spring baby season (March–May) and you suspect nursing young, if entries are somewhere you can’t safely reach, if squirrels are inside wall voids rather than the open attic, if you’ve excluded and sealed but the noise continues (you may have missed an entry or have a different animal), or if local laws restrict DIY wildlife work. Expect $200–$500 for professional exclusion and sealing — more if insulation replacement or electrical repairs are needed. Get a quote that includes sealing, not just trapping: a pro who only traps without sealing is selling you a recurring problem.