What causes scratching sounds in walls at night?

Most often rats or mice, which are nocturnal and become active after dark, moving through wall voids and gnawing. Occasionally it can be birds or insects, but nighttime scratching with gnawing points to rodents.

Why is it always at night?

Rats and mice are most active at night when the house is quiet and dark, so that is when you hear them travelling their routes and chewing.

Should I worry about scratching in the walls?

Yes, act on it. Rodents in wall voids chew wiring (a fire risk), damage insulation, and multiply quickly, so the sooner you respond the smaller the problem stays.

Why You Hear Scratching in the Walls at Night

It nearly always starts when the house goes quiet: a faint scratching, scurrying or gnawing somewhere inside the wall. It is unsettling — and it usually has one explanation.

It's almost certainly rodents

Rats and mice are nocturnal. During the day they stay hidden; after dark, when the house is quiet, they move along their routes through wall voids, under floors and above ceilings — and they gnaw as they go. That is the scratching you hear.

Why the walls?

Wall cavities are a rodent's ideal highway: warm, dark, hidden, and connected to the whole house. Pipes and cable runs give them ready-made paths from room to room.

Why you shouldn't ignore it

Inside the walls, rodents chew electrical wiring — a genuine fire risk — shred insulation, and breed. A faint scratch this week can become a real infestation within a month or two. (See are rats in the walls dangerous.)

What to do

Find the entry points — check where pipes and cables enter walls; seal gaps larger than 2 cm.
Cut off food and water — the reasons they are travelling to begin with.
Make the space hostile — a deterrent that keeps them from settling in the voids and rooms.

The EchoRepel Ultrasonic Rat Repellent fills problem areas with ultrasonic sound that rats and mice want to avoid — poison-free and safe to leave running overnight, which is exactly when the scratching happens.