Mice and rats get into walls through small gaps around pipes, utility lines, vents, roof lines, doors and foundation cracks, then travel and nest in wall voids and attics. They multiply quickly because a female house mouse can breed about five to six weeks after birth and have 5 to 10 litters a year.
Saela Pest Control is a residential and commercial pest control company whose rodent exclusion service repairs the openings mice and rats use. Below is how rodents get in, where they settle and how to stop them.
Scratching in a wall or ceiling is often the first sign that rodents have moved in.
How rodents find their way inside your home
The CDC notes that mice can fit through a hole the width of a pencil, about a quarter inch across, and University of California pest management guidance says rats, especially young ones, can squeeze under a door with a half-inch gap.
Common entry points include:
- Gaps around doors and windows
- Foundation cracks
- Holes where pipes and utility lines enter
- Roof-line gaps and attic or crawl-space vents
- Garage doors that do not seal properly
Once rodents find a weak point, they keep using it and can widen it by gnawing. Rats can chew through plastic, foam, wood and caulk, so a gap patched with soft material may not stay closed.
Clutter and easy access to food make a home more vulnerable.
Why walls and attics make good hiding spots
Inside, rodents look for quiet, sheltered places to nest near food. Wall voids hide them and let them move between rooms unseen, while attics add warmth and insulation. Roof rats typically nest in elevated spaces such as attics, wall voids and ceiling voids.
Norway rats usually stay lower, in basements and ground-floor areas, so where you hear or find activity is an early clue to which rodent you have.
House mice build nests from finely shredded paper and other fibrous material and seldom travel more than 30 feet from their nest and food supply.
Hidden there, an infestation can grow for weeks before you notice it.
How quickly mice and rats multiply
Mice and rats mature fast and breed often. According to University of California guidance, house mice can breed five to six weeks after birth and one female may have 5 to 10 litters of about 5 or 6 pups a year.
Rats breed more slowly, but the average female Norway rat still has 4 to 6 litters a year and can wean 20 or more young. Because mice and rats behave differently, it helps to know how to tell mice and rats apart before you choose traps or bait placement.
More rodents means more activity in kitchens, pantries and storage areas.
Common mouse infestation signs homeowners overlook
Rodents stay out of sight, but they leave clues along walls, near food and in attics. Catching them early helps keep a small problem from becoming an established one.
Some of the most common mouse infestation signs include:
- Scratching or scurrying noises in walls or ceilings
- Droppings near food, pet dishes or baseboards
- Fresh gnaw marks on wires, wood or packaging
- Greasy smudge marks along walls, beams or pipes
- A musky odor in larger or long-term infestations
These signs are easy to dismiss, but waiting gives a population time to grow. If you find droppings or nesting material, the CDC says not to sweep or vacuum them, because that can put tiny droplets containing viruses into the air.
Why DIY rodent control often falls short
Traps reduce the rodents already inside but don’t fix how they got into the walls. If you do set traps, the CDC recommends traditional snap traps rather than glue or live traps, which can scare rodents into urinating and increase your chance of getting sick.
If entry points stay open, new rodents keep coming in. University of California guidance calls exclusion the most successful and longest-lasting strategy for rat control.
Rats are also cautious and often avoid new traps and baits for several days, sometimes weeks.
Without sealing the openings, the problem often comes back.
What professional rodent control involves
Professional rodent service starts with an inspection to find entry points, nesting areas and how far activity has spread. Every Saela plan includes a 50+ point property inspection covering entry points, nesting sites and attics.
Saela’s rodent exclusion service includes inspecting for access points, repairing openings and placing traps for rodents still inside.
In a February 2024 Google review, kay mccallop said Saela identified rodent-prevention issues and repaired them that same day.
The goal is to keep new rodents out, not just remove the ones you see.
How to prevent rodents from getting into walls and attic spaces
Prevention means making your home harder to enter and less attractive. The CDC organizes its advice into three steps: seal up, trap up and clean up. Start outside by sealing gaps around pipes, vents, utility lines, doors and the foundation.
For small holes, the CDC recommends steel wool held in place with caulk, and for larger ones metal, cement or hardware cloth, since softer materials can be gnawed through.
Keep attics and garages free of clutter and store food, including pet food, in sealed containers. For more on what draws rodents in, see what rodents love about your house.
Recheck attics, crawl spaces, basements, under sinks and behind appliances for new gaps or droppings.
How Saela handles rodents in walls and attics
Saela began as Edge Pest Control in 2008 and uses integrated pest management: identify the pest, monitor activity, treat where needed and adjust based on results. For rodents, that includes sealing entry points and reducing the food, water and shelter they need.
Saela quotes by pest, location, property size and visit frequency rather than publishing one price, so see how Saela’s plans and pricing work before comparing quotes. Ask whether sealing, trapping and any clean-out are included in the written scope, since rodent control and building repairs can be separate services.
If you’re hearing scratching in your walls, book a call to schedule a rodent inspection.
FAQs
How do rodents get into walls and attics?
Through small gaps around pipes, utility lines, vents, roof lines, doors and foundations, and once inside they nest in wall voids, ceiling voids and attics.
What attracts rodents to a home?
Food, water, shelter and easy ways in, especially in cluttered homes with unsealed gaps.
How fast do mice and rats reproduce?
A female house mouse can have 5 to 10 litters a year, and a female Norway rat averages 4 to 6.
What are the first signs of a rodent infestation?
Scratching noises in walls or ceilings, droppings, fresh gnaw marks, greasy rub marks and a musky odor.
Are pest control treatments safe for families and pets?
It depends on following directions: use any trap or product as its label directs, and follow your licensed technician on preparation and re-entry. The CDC suggests placing traps away from regular foot traffic, such as in attics and crawl spaces.
How often should rodent control services be scheduled?
Saela’s Protection Program includes every-other-month or quarterly visits depending on the plan, and covered pests vary, so confirm rodents are included.
Who wrote this article?
Devin Hutchings (Marketing Director at Saela Pest Control) wrote this article.
Devin leads Saela’s marketing and growth strategy. He brings more than 15 years of marketing experience across Uber, C.R. England, Lugg, and Neighbor. His background spans customer acquisition, retention, and developing marketing channels for service businesses and consumer marketplaces.
