Squirrels are common in urban and suburban environments, but they become a nuisance when targeting structures for shelter. Homeowners frequently encounter damage and wonder if this wildlife can breach the sturdy barrier of aluminum. This is a valid concern, particularly regarding the integrity of roof vents, soffits, and flashing. Understanding the biological drive behind their chewing and the limitations of aluminum helps explain how squirrels penetrate a home’s defenses.
Squirrel Incisors and the Need to Chew
The ability of a squirrel to chew through materials is rooted in its unique dental structure, shared across the rodent family. Squirrels possess four incisor teeth—two upper and two lower—that are classified as elodont, meaning they grow continuously throughout the animal’s life. This growth averages about six inches per year, which necessitates constant gnawing to keep the teeth filed down to a functional length.
The incisors have a hard, iron-mineralized enamel layer on the front and softer dentin on the back. This differential hardness causes the teeth to wear unevenly, naturally sharpening them into a keen, chisel-like edge with every bite. If a squirrel does not chew regularly, its incisors can overgrow, leading to malocclusion. Chewing is a necessity for survival, preventing the teeth from curving back into the jaw or skull.
How Squirrels Compromise Aluminum
Squirrels cannot effectively chew through solid, heavy-gauge aluminum sheeting. However, they are capable of compromising the softer, thinner aluminum components commonly used on homes. Aluminum is a soft metal, making it vulnerable to the powerful, self-sharpening incisors of a determined squirrel. They frequently target thin-gauge materials like aluminum window or roof screening and roof vent covers, chewing through them to gain access.
Squirrels often exploit existing structural weaknesses rather than creating a hole in a flat, solid surface. They use their sharp incisors as a prying tool to widen small gaps, seams, or loose edges, such as where flashing meets a soffit or roofline. They may first chew through adjacent, softer materials like rotten wood, plastic vent housing, or vinyl siding. The resulting opening provides leverage to tear or chew the surrounding aluminum.
Reinforcing Entry Points
To secure a structure against persistent chewing, homeowners must replace vulnerable materials with options squirrels cannot penetrate. The most effective material for exclusion is galvanized steel mesh, often called hardware cloth, which should be used to cover all vent openings and potential entry points. This material is significantly harder than aluminum.
The mesh should be at least 16-gauge to 22-gauge thickness with a size no larger than half an inch to physically block the animal. The reinforcement strategy should focus on areas where the roof meets the walls, such as soffits, fascia boards, and roof vents.
Any existing gaps, cracks, or small holes must be sealed using durable, animal-resistant products like high-density metal flashing or concrete mortar. Regular inspections of the roofline and eaves are necessary to identify initial signs of damage or loose construction materials. This allows for prompt reinforcement before a squirrel can establish a secure entry point.