How Animals Get Into Residential And Commercial Buildings

No matter how modern or well-maintained a structure might appear, most buildings have vulnerable spots—some obvious, others surprisingly hidden. Animals looking for shelter don’t need much space to slip inside. Rodents, birds, raccoons, and other wildlife are opportunists by nature, and they’ve adapted remarkably well to exploiting weak points in both residential homes and commercial properties.

Vents are a classic target. Dryer vents, attic fans, soffit vents—any one of these can become a gateway. If there’s airflow or warmth coming through, it often signals to animals that there might be something cozy on the other side. Unfortunately, once inside, they can wreak havoc: nesting, chewing, contaminating insulation, or even damaging wiring.

Gaps around utility lines are another common entryway. Where pipes or wires penetrate the building’s exterior, there are often small openings that weren’t sealed properly. Animals, especially smaller ones like mice and bats, can sense airflow from these gaps and follow it straight into the structure. Over time, even minimal wear and tear—like weathered caulking or decaying trim—can widen these vulnerabilities and give pests the perfect opportunity to sneak in.

Rooflines and eaves also deserve attention. Shingles can lift, flashing can separate, and soffits can loosen—all of which open the door to creatures seeking access to attics and wall cavities. The trouble with roof access is that it often goes unnoticed for far too long. By the time droppings or odors give away their presence, the damage has already been done.

The Lure Of Warmth, Shelter, And A Meal

Animals don’t randomly wander into buildings—they’re following their instincts. When the weather turns cold, warm attics and crawlspaces become highly attractive. In summer, shaded interior spaces and consistent access to food and water become the big draw. Either way, buildings offer stability that nature often can’t guarantee.

Once an animal gets close to a structure, its natural curiosity takes over. Raccoons will pry, scratch, and even peel back loose boards. Squirrels will chew through wood and even light metal. Birds will flutter around eaves and ledges until they find a way in. Many of these creatures have adapted to life near people, and they’ve become alarmingly efficient at breaching human dwellings.

Food sources are another motivator. Dumpsters behind a restaurant, an unsecured trash can, or a pantry venting smells through the range hood—all of these can draw wildlife closer. Once they’re investigating your property for meals, it’s only a matter of time before they start testing for shelter, too. A raccoon drawn in by a smelly bin might discover a loose soffit board. A mouse sniffing out cereal grains can slip in under a garage door seal. It’s a domino effect once the incentive is there.

Small Openings, Big Problems

What surprises many people is just how little space animals need. Mice can squeeze through openings the size of a dime. Rats only need a hole the size of a quarter. Even larger animals like opossums and raccoons don’t need a gaping hole—just a gap wide enough to get a paw in and start tearing.

Weakened building materials are a major contributor to these entry points. Over time, wood softens, mortar cracks, and seals deteriorate. What started as a minor flaw can quickly become a major breach. In commercial buildings, rooftop units and ventilation systems often have thin metal screens that degrade faster than people realize. These screens may appear intact from a distance but are easily bent, torn, or pushed aside by determined animals.

Doorways, too, play a bigger role than many realize. Garage doors that don’t sit flush, weather stripping that’s missing, or even doors propped open for deliveries—all are open invitations. Wildlife doesn’t follow our rules. If there’s an easy opportunity, they’ll take it. And once they’ve found their way in, the real issues begin.

Inside, animals can cause all kinds of complications. Chewed wires can lead to fire hazards. Nesting in HVAC systems spreads allergens. Their droppings often carry harmful bacteria and can trigger respiratory issues. And when they start reproducing, you’re dealing with more than just a single intruder—you’ve got a population.

Commercial Buildings: Bigger Doesn’t Mean Better Protection

It’s easy to assume that large commercial buildings are less prone to wildlife intrusion, but that’s not necessarily the case. In fact, many commercial properties offer more points of entry simply because of their size and complexity. Warehouses, restaurants, retail shops—all have multiple access doors, rooftop units, external storage areas, and often less consistent building maintenance than private residences.

Loading docks are a favorite entry point for animals. The repeated opening and closing of bay doors, paired with gaps around the bottom edges, can offer the perfect chance for an animal to dash inside. Once in, these spaces provide protection and food, especially if goods are stored or processed on-site.

Commercial HVAC systems—particularly rooftop units—are another big vulnerability. These systems often have gaps and vents that may not be properly sealed or screened. And because they’re out of sight, they’re often out of mind. Birds nest inside ductwork, raccoons rip through flashing, and insects take advantage of condensation and moisture. What starts as a tiny opening can rapidly turn into a maintenance nightmare.

One overlooked issue in commercial buildings is the frequency of tenant turnover. In multi-use properties, new occupants bring different utilities, wall penetrations, and usage patterns. With every renovation or changeover, there’s a risk that sealing and exclusion practices fall through the cracks—literally and figuratively. Animals are just waiting for these chances.

Let’s Put A Stop To Uninvited Guests

The longer wildlife remains inside a structure—residential or commercial—the more problems you’re bound to face. Gaps, vents, compromised seals, and overlooked weaknesses give animals the opportunity they’re looking for, and they won’t hesitate to take it. That’s where we come in.

At Varment Wildlife Control, we specialize in identifying and sealing off those hidden access points before they turn into full-blown infestations. Whether it’s your home, your office, or an industrial building, we know exactly where to look, what to watch for, and how to keep animals out—for good. Contact us today if you've seen signs of wildlife or want to take proactive steps before the damage begins. We’re here to help make sure your property stays yours—and not theirs.