Common rodent entry points around Naperville houses

Begin at the ground level

Check door sweeps, garage seals, foundation gaps, and openings where pipes or cables enter.

Look upward too

Roofline transitions, soffits, vents, and damaged screens can also create access depending on the animal and building.

The CDC lists interior clues too

The CDC advises checking behind appliances, around pipes under sinks, in closets, and where floors meet walls. A gap outdoors becomes more meaningful when fresh signs appear along a plausible interior route. Document both ends of the suspected path. An exterior-only glance may miss the opening that matters most.

The CDC advises looking for gaps inside and outside the building, especially where utility lines enter and where foundations, doors, and roofs meet. Note the material around each gap: a damaged door sweep, cracked mortar, and a pipe penetration need different repairs. Ask how each proposed seal will hold up to weather and normal building movement.

Utility and vent gaps are not ordinary cracks

An opening serving a furnace, dryer, drain, or electrical line has a function and may require a particular repair. Ask a qualified trade before covering it. A soft filler chosen only because it is quick may not withstand chewing or weather. The question is not simply whether a hole can be filled, but whether it can be fixed safely and durably.

Finding a hole does not show whether an animal remains inside. Ask how activity will be confirmed and how removal will be coordinated with exclusion. Closing every opening too early can trap an animal in a wall or occupied room. The sequence of work matters as much as the seal itself.

Why active animals change the repair sequence

If a rodent is still inside, sealing a likely exit immediately can leave it trapped in a wall or attic. Ask how current activity will be assessed and controlled before closure. If the animal might be wildlife rather than a mouse or rat, the service and legal questions may differ. The first decision is identification, not a tube of sealant.

Garages are easy to overlook. Pet food, grass seed, stored paper, and a gap under the door can create a separate route. Inspect for gnaw marks and droppings without disturbing them. The CDC cautions against sweeping or vacuuming rodent waste dry; follow its cleanup guidance when cleanup is needed.

What to monitor after closure

Keep a dated note of fresh droppings, gnawing, or sightings near the original area and other likely routes. An old mark is not new activity, but a fresh sign can indicate another gap or an animal already inside. Ask what would trigger a return inspection. Food and trash management remain part of prevention even after the building repair is complete.

A later inspection should test whether the repair changed the pattern. Compare fresh signs at the same locations and check seals after seasonal movement. Keep a dated map of observations. If activity remains, a second opening or a mistaken identification may need investigation.

Old and active routes are different

A chewed edge can remain long after an animal has left. Fresh droppings, new tracks, or a current sighting are stronger evidence of active use. Keep photographs with dates and ask how the provider connects indoor signs to an exterior opening. An exclusion quote should explain which gaps are confirmed or suspected, not present every crack as an active entry.

Sequence matters before sealing

If rodents are currently inside, sealing a route without a control plan can trap them in a wall or attic. Ask whether activity has been confirmed, how it will be managed, and which repairs must wait. Preserve necessary ventilation and drainage; a vent should be screened or repaired appropriately, not simply filled.

A mouse after a new garage door

A replacement door can still leave a gap at a corner or threshold, but do not assume it is the only route. Look for fresh signs near the door and along the wall into the home. Ask the installer or contractor about adjustment if the seal is not closing properly. A pest assessment can connect the visible gap with actual activity and identify other openings. Keep a photo of the closed door so the repair question is specific.

A roofline gap seen from the yard

Photograph it from the ground instead of climbing up. Note any sounds, stains, or droppings that might connect to the attic, but remember these signs can have different causes. A roofer or wildlife specialist may be needed depending on the opening and suspected animal. The order matters: identify and manage any current occupant before closure, then repair the building safely. Ask who is responsible for each stage.

Photograph before repair

A wide and a close view of an opening can help connect it to the building and preserve its condition. Include any fresh sign nearby, but do not handle waste or put fingers into a cavity. If a contractor later repairs the area, keep the before-and-after record for follow-up.

After sealing, keep looking

Continue monitoring the original area and nearby routes. If signs move, a second opening may have been overlooked or an animal may already have been inside. Ask when a follow-up inspection is appropriate and what evidence to collect. Food storage and waste management still matter; a repaired hole alone does not remove every reason a rodent approaches the building.