Can squirrels chew through roof vents or wires?

Squirrels are rodents, and like all rodents their incisors are rootless and grow continuously — wearing them down is a biological necessity, not a matter of hunger or malice. Once a squirrel gets into an attic or roofline, the readily available soft materials are plastic vent housings, thin aluminum flashing, wire and cable insulation, and coaxial or low-voltage lines. All of these are routinely breached wherever squirrels are active, and it happens regardless of whether there's anything edible nearby, because the point of the gnawing is wear, not food.

This is the part worth taking seriously without exaggerating it. When gnawing strips insulation off an energized conductor, the bare wire can arc if it contacts wood, insulation, or another combustible material, and that is a recognized ignition pathway in consumer-safety and fire-investigation literature — the same framework used to evaluate arc-fault risk from any damaged household wiring, not something unique to squirrels. That mechanism is real and it's why chewed wiring genuinely warrants an electrician's inspection. What it does not mean is that squirrel activity makes a fire a likely or routine outcome — arc-fault ignition from any cause remains the low-probability tail of a much larger population of attics with active squirrels and no fire at all.

You will frequently see it claimed that rodents cause 20 to 25 percent of house fires, sometimes attributed to NFPA or a formal study. Neither is accurate. The earliest confirmable published source is a 2012 pest-industry trade magazine article that introduced the figure as an unsourced 'estimate' with no methodology and no underlying dataset — not a study. NFPA does not publish a rodent-specific fire statistic; the fire-incident database that NFPA and USFA draw on has no cause-of-ignition code for rodents or animals at all, which means any percentage attributing fires to rodents is an extrapolation, not a tabulated figure. What NFPA's electrical-fire research actually identifies is arcing as the leading factor in home fires caused by electrical failure or malfunction, with no rodent factor named. The mechanism is real; the number is invented.

It's worth being precise about what kind of damage this is. Chewed vents, wiring, and cable are functional damage — they break a system that's supposed to work, whether that's ventilation, electrical service, or connectivity. They are not structural damage: squirrels are not weakening your roof framing or foundation by gnawing a vent housing or a wire run. The fix, in order, is exclusion first — sealing entries with materials squirrels genuinely cannot breach — then an electrician for any exposed or chewed wiring, and a roofer for any damaged vent. Repairing the system before the squirrels are gone just gives them fresh material to chew through again.