By Integrity Rodent Proofing, Dixon, California. Updated October 2026
Key takeaways
- Daylight at door corners or thresholds means rodents can enter
- Side doors and utility penetrations are easy to overlook
- Garages often connect to wall voids and the attic above
- Seal with construction grade materials, not foam alone
Garage door corners are the classic weak point
The lower corners of a garage door can gap even when the bottom seal looks fine. Doors shift, seals compress, concrete settles. A mouse needs a quarter inch, a rat half an inch. Daylight at the corners means rodents can use it.
Side doors, thresholds, and worn sweeps
A worn sweep, an uneven threshold, or a side door that does not close cleanly can leave room for mice and sometimes rats. Check for rub marks or droppings along the threshold.
Hearing scratching? Finding droppings?
Let's find out how they're getting in.
An entry-point inspection checks the common ways rats and mice get in, shows you what we find, and tells you what needs to be sealed.
Utility penetrations add up
Pipes, cables, and water lines leave gaps where they enter through walls. Together they can connect the garage to wall voids and attic spaces, and they hide behind storage and workbenches.
The garage-to-attic pathway
Firewalls, attic hatches, and shared wall framing can carry rodents from the garage into the attic above. Seal the garage without checking that route and the job is half done.
What you can check yourself
Close the doors and look for daylight at corners and thresholds. Pull storage off the walls and check the base for droppings or gnaw marks. Sealing needs construction grade materials fitted to each opening; foam and caulk alone will not hold.
Common questions
Can mice get in when the garage door is closed?+
Yes. Door corners often leave the quarter inch a mouse needs.
Will replacing the bottom seal solve it?+
It helps, but corners, the side door, and utility gaps need checking too.
I only see droppings in the garage, not the house. Is that a problem?+
Yes. Garages connect to wall voids and the attic, so it is usually the start of a bigger problem.
Written by
The Integrity Rodent Proofing team
Dixon, California. Rodent-proofing specialists serving Dixon, Davis, Woodland, Winters, Vacaville, West Sacramento, Sacramento, Roseville, and Folsom. We find how rats and mice are getting in, explain what we find, and seal the openings.