That scratching sound at 2 a.m. behind the bedroom drywall is rarely a one-time visitor. By the time you hear them, rats have usually been nesting in the wall cavity for several weeks. Knowing how to get rats out of walls matters because the wrong move, like a fast-acting poison, leaves a dead rodent decomposing inside the wall and a smell that lasts a month. The right approach evicts them alive or traps them where you can remove the carcass, then seals the entry points so the next family does not move in.
Confirm It Is Actually Rats
Mice and rats both nest in wall cavities, but the eviction strategy differs slightly. Rats are larger, leave droppings up to 3/4 inch long, and gnaw holes 1.5 inches or wider. Mice leave rice-grain-sized droppings and squeeze through openings as small as 1/4 inch. Look in the basement, attic, and behind appliances for fresh droppings, gnaw marks on wood or wire insulation, and greasy rub marks along baseboards.
Rats are also louder. The scratching is usually deeper and more rhythmic, and you may hear them dragging nesting material at dusk and dawn. If you can, leave a smartphone recording overnight near the suspected wall and play it back at 4x speed in the morning.
Locate the Entry Points First
Trapping or baiting without sealing entry points is wasted effort. New rats will replace the ones you remove within days. Walk the perimeter of the house and look for these common openings:
- Gaps where pipes and cables enter the foundation: The single most common entry. Rats squeeze through openings as small as 1/2 inch.
- Damaged soffit and roof line: Roof rats climb downspouts and enter through gaps under eaves.
- Garage door gaps: Rubber seals deteriorate. Anything wider than 1/4 inch is a freeway.
- Dryer vents and bathroom exhaust hoods: Cheap plastic flaps allow easy entry. Replace with metal louvers.
- Foundation cracks: Rats can chew concrete with hairline fractures into climbable holes.
- Crawl space vents without intact mesh screens: Standard fiberglass screens fail in 5 years.
How to Get Rats Out of Walls Without Traps
Some homeowners prefer to make the wall an unappealing place to be before resorting to traps. Rats hate strong smells and disruption. Soak cotton balls in pure peppermint oil and tuck them into wall openings near the suspected nest. Replace every 5 days. Combine with a small ultrasonic deterrent plugged in the nearest room, though ultrasonic devices alone are not reliable.
The most effective passive eviction is removing food and water. Empty pet bowls overnight, fix any plumbing drip, and store dry goods in airtight glass or metal containers. A rat that cannot find calories within 24 hours of foraging will relocate to a neighbor’s house within a week.
The Right Trap and Where to Place It
Snap traps remain the most effective and humane option when used correctly. The Victor M326 Pro and the Tomcat Press N Set are both reliable and reusable. Bait with peanut butter, hazelnut spread, or a small piece of bacon rind tied with thread so the rat has to work for it. A trap with the bait simply placed on top will be licked clean without springing.
Position traps along walls perpendicular to the surface, with the trigger end touching the baseboard. Rats run with one whisker brushing the wall. Set 6 to 12 traps even for a small infestation. Underestimating numbers is the most common reason DIY trapping fails. Check daily for at least 14 days.
Why You Should Avoid Wall-Cavity Poison
Rodenticide pellets work, but they kill the rat 3 to 7 days after consumption, often inside the nest. A decomposing rat in a wall cavity smells like death for 3 to 6 weeks and attracts flies, beetles, and secondary pests. There is no safe way to find and remove it without cutting into the wall.
Poison is also a real risk to pets, raptors, and children. A dog that finds and chews a poisoned rat outside can require emergency vet care. If you must use bait, use only tamper-resistant external stations placed against the foundation, never inside walls or attics.
Sealing Entry Points Permanently
Once you have stopped catching rats for at least 7 consecutive days, seal the openings. Steel wool stuffed tightly into gaps blocks chewing, then cover with caulk or expanding foam to hold it in place. For larger openings, hardware cloth with 1/4-inch mesh nailed across the gap is the gold standard.
Metal flashing sealed with stainless screws closes gaps under garage doors and along soffits. Replace any plastic vent covers with metal alternatives like the Maurice Franklin Louver Vent. The exterior work is the part most homeowners skip, but it is the only step that ends the cycle for good.
Cleaning Up After the Eviction
Rat droppings, urine, and nesting material can carry hantavirus, leptospirosis, and salmonella. Never sweep or vacuum a contaminated area dry. Spray the entire surface with a mix of 1 part bleach to 10 parts water, let it sit 5 minutes, and wipe up with paper towels. Wear an N95 respirator and rubber gloves.
Bag all materials in two layers of plastic and dispose in the outdoor trash. Replace any chewed insulation with rodent-resistant alternatives like rock wool or Havelock sheep wool. Air the area for at least 24 hours with windows open before considering it done.
When to Call a Professional
If after 30 days of consistent trapping and exclusion you still hear activity, or if the infestation involves more than 10 visible droppings per day, hire a licensed pest control company. Pros use thermal imaging and snake-style cameras to locate nests inside walls without cutting drywall. A typical residential rat exclusion service runs $400 to $1,200 depending on home size and severity.
Final Word
Rats in the wall feel urgent because they are. Each day of delay means more droppings, more chewing, and more risk of an electrical fire from gnawed wire insulation. Move fast on traps, slower on poison, and most carefully on sealing the building envelope so this becomes a one-time problem rather than an annual battle.
