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Yes, a squirrel can chew through drywall, wood, aluminum, and even some metals. Eastern gray squirrels (Sciurus carolinensis) have incisors that grow up to 6 inches per year, and gnawing is how they keep them sharp and short. When those teeth meet your walls, the result is holes, damaged wiring, and costly repairs. This guide covers which materials are vulnerable, how to spot damage early, and exactly what to do about it.
Key Takeaways
- Squirrels chew through drywall, wood, and soft metals like aluminum, but not solid brick or galvanized steel.
- Signs of damage include scratching noises, chewed holes, droppings, and nests in the attic.
- Seal entry points with 1/4 inch hardware cloth and galvanized steel flashing to prevent re-entry.
- Call a professional if you suspect chewed wiring, structural damage, or an active infestation.
In This Guide
Why Do Squirrels Chew Through Walls?
Chewing is not a bad habit for squirrels. It is a biological necessity. A squirrel’s four front incisors never stop growing. In fact, an eastern gray squirrel (Sciurus carolinensis) grows about 6 inches of new tooth material every year. Gnawing on hard surfaces grinds the teeth down and keeps them at a functional length. If they did not chew, their teeth would grow through their skull.
Beyond dental maintenance, squirrels chew to access shelter and food. Your home’s walls, eaves, and attic represent a warm, dry nesting site protected from predators. The combination of foraging drive and neophobic behavior means a squirrel will test every gap and weak point in your home’s exterior repeatedly until it finds a way through.
What Materials Can Squirrels Chew Through?
Not all building materials are equally vulnerable. Here is a breakdown of common wall materials and how squirrels handle them:
| Material | Can Squirrels Chew It? | Best Defense |
|---|---|---|
| Drywall | Yes, easily | Steel wool or hardware cloth behind drywall |
| Wood (pine, cedar) | Yes, easily | Galvanized metal flashing over vulnerable areas |
| Aluminum siding | Yes, with effort | Replace with steel or cover with hardware cloth |
| Brick (solid) | No | Check mortar integrity; repair cracks |
| Mortar (deteriorated) | Yes, easily | Repoint mortar with Type S or N mix |
| Galvanized steel | No | Use for all exclusion work |
| 1/4 inch hardware cloth | No | The gold standard for squirrel exclusion |
Read our full guide on what materials squirrels cannot chew through for a deeper dive.
Signs of Squirrel Damage in Walls
Early detection is the difference between a simple repair and a major renovation. Listen and look for these signs:
- Scratching or scurrying sounds inside walls, especially near dawn and dusk when squirrels are most active.
- Visible chew holes the size of a quarter or larger along rooflines, eaves, or siding corners.
- Drywall dust or debris collecting below suspected entry points.
- Droppings in the attic or crawlspace; squirrel droppings are oblong, about the size of a grain of rice.
- Nesting material like leaves, paper, or torn insulation near wall voids.
- Strange odors from urine or carcasses trapped inside walls.
Do Squirrels Chew Through Brick Walls?
Solid brick walls are the one material squirrels genuinely cannot chew through. Their teeth are not hard enough to break fired clay brick. However, the mortar joints between bricks are a different story. Deteriorated mortar, especially older lime-based mixes or mortar weakened by freeze-thaw cycles, can be crumbled and scratched away using their claws and teeth. Once a squirrel opens a mortar joint, it can widen the gap to squeeze through – squirrels can fit through holes no larger than 1.5 inches in diameter.
How to Stop Squirrels From Chewing Through Walls
Prevention starts with eliminating access points before squirrels find them. Here are the most effective methods:
1. Seal Entry Points With Hardware Cloth
Cover all gaps larger than a quarter with 1/4 inch galvanized hardware cloth. This is the most durable exclusion material for squirrels. Do not use chicken wire or expanded metal lath – squirrels can bend or chew through both. Secure the cloth with exterior-grade screws and washers spaced every 4 inches.
2. Install Metal Flashing at Vulnerable Points
Galvanized steel flashing installed at a 45 degree outward angle along rooflines, eaves, and the top of foundation walls prevents squirrels from climbing and gnawing at transition points. The angle makes it impossible for them to get a foothold.
3. Trim Tree Branches 8 Feet From Rooflines
Squirrels are agile climbers that launch from tree branches onto roofs. Maintain at least 8 feet of clearance between tree limbs and your roofline. For trees within this distance, install metal baffles around the trunk to block climbing.
4. Use Taste Aversion Repellents as a Deterrent
Capsaicin-based sprays (derived from hot peppers) activate the TRPV1 receptor in mammals, creating a burning sensation that repels squirrels without long-term harm. Reapply after rain. Do not use mothballs or ammonia – these are ineffective outdoors and can be toxic to pets and children.
5. Install a One-Way Exclusion Door
For active infestations, a one-way door installed over the main entry hole lets squirrels exit but prevents re-entry. Leave the door in place for at least 7 days, then seal the hole permanently. Never seal squirrels inside walls – they will die, decompose, and attract secondary pests.
How to Repair Squirrel-Chew Damage in 5 Steps
Materials You Will Need
- Respirator (N95 or better)
- Heavy-duty gloves
- HEPA vacuum
- Biohazard disinfectant spray
- 1/4 inch galvanized hardware cloth
- Exterior-grade screws and washers
- Drywall patch kit
- Spray foam insulation (low expansion)
- Evict the squirrels first. Confirm there are no active squirrels inside. Listen for daytime noise and check for fresh droppings. Use a one-way exclusion door if needed. Never seal animals in.
- Suit up with safety gear. Squirrel droppings and nesting material can carry hantavirus and leptospirosis. Wear an N95 respirator, heavy-duty gloves, goggles, and long sleeves before touching contaminated insulation or debris.
- Remove damaged insulation and debris. Lightly mist the area with water to keep particles from becoming airborne. Use a HEPA vacuum to remove contaminated insulation. Double-bag everything and dispose per local waste regulations.
- Sanitize and seal the wall cavity. Spray all surfaces with a biohazard-grade disinfectant and let it sit for the recommended dwell time. Once dry, seal the interior entry hole with 1/4 inch hardware cloth secured with screws, then patch the drywall.
- Install exclusion on the exterior. From outside your home, seal the same entry point with galvanized hardware cloth or metal flashing. Backfill gaps with low-expansion spray foam. Check your work weekly for the first month for signs of attempted re-entry.
When to Call a Professional
Some situations are beyond a DIY fix. Call a licensed wildlife removal professional if:
- You suspect chewed electrical wiring. Exposed wires inside walls create a serious fire hazard that requires an electrician to assess and repair.
- The infestation is large or ongoing. Multiple squirrels over several weeks indicate a colony or a recurrent entry route a pro can identify.
- Damage extends to load-bearing structures. Chewed support beams or joists need a structural inspection.
- You cannot reach the entry point safely. Steep rooflines, high gables, and crawlspaces with limited access are best handled by insured professionals.
- Local regulations require it. Some states restrict squirrel removal to licensed wildlife control operators, especially for relocating animals.
For a complete overview of professional options, read our squirrel trap guide and electronic repellent review.
Frequently Asked Questions
How big of a hole does a squirrel need to get through a wall?
A squirrel can squeeze through a hole as small as 1.5 inches in diameter. If you can fit a golf ball through an opening, a squirrel can fit its body and skull through it. This is why sealing gaps larger than a quarter is the standard for exclusion.
Can squirrels chew through steel wool?
Squirrels can pull apart or push through loosely packed steel wool. Use 1/4 inch galvanized hardware cloth instead. Steel wool works as a temporary filler for small gaps but must be combined with a rigid barrier for long-term protection.
Will a squirrel eventually leave the wall on its own?
Not reliably. If a squirrel entered seeking shelter or nesting space, it may stay indefinitely, especially during breeding season. It will also gnaw further to expand the cavity. Active removal via one-way door or professional trapping is necessary in most cases.
Can a squirrel chew through a concrete wall?
No. Fully cured concrete is too hard for squirrel teeth. However, squirrels can exploit cracks in concrete foundations created by settling or frost heave. If you have cracks wider than a quarter, seal them with hydraulic cement before squirrels enlarge them.
The Bottom Line
A squirrel chewing through your wall is not a matter of if, but when, if vulnerable materials are accessible. Eastern gray squirrels and fox squirrels possess the teeth, drive, and agility to breach drywall, wood, aging mortar, and soft metals. Early detection through sound and visual inspection is your best defense. Seal all gaps with 1/4 inch hardware cloth and galvanized steel flashing, and do not hesitate to call a professional for wiring concerns or hard-to-reach areas.
Your home is the one place those persistent teeth should not reach. A few hours of preventive work today can save thousands in repair costs tomorrow.
