Noises in the Attic at Night: What They Mean.

Start with the type of sound. Light, quick scratching in short bursts often points to mice. Heavier thumping, rolling or scampering usually points to rats. A dragging or scraping sound can be a rat moving nesting material. Gnawing sounds are dull and repeated, as if someone were slowly scraping a board.

Then note the location. Sound that travels along a wall suggests an animal using a wall void. Sound across the middle of the ceiling suggests the attic floor. Sound near an eave or corner suggests an entry point nearby.

Finally, note the time. Rodents are mostly active after dark, with peaks in the first couple of hours after dusk and again before dawn. Daylight sounds often point to squirrels, birds or a mechanical cause.

• Ductwork and framing that expand and contract with temperature changes, which creates ticking and popping.
• Water pipes that knock or hum when a tap or appliance is used.
• Wind moving loose flashing, vent covers or branches against the roof.
• Birds nesting in a vent or soffit, usually active in daytime.
• Squirrels, which are active by day and make heavier sounds.

A noise that stops when the heating or air conditioning cycles off is probably the building. A noise that follows a regular, nightly pattern and is accompanied by droppings is probably an animal.

Attics are warm, dry, dark and quiet, with soft insulation to nest in. Heat from the living space rises into them. Most are rarely visited, so an animal can settle in for weeks without being disturbed. Many local attics have vents and gaps at the roof edge, and trees that reach the roof give animals an easy route.

Roof rats and squirrels reach attics from the outside, climbing limbs, wires and walls. Mice usually come up from below, through wall voids and gaps around pipes. That is one reason the entry points differ from one animal to the next.

You do not need to go into the attic. In fact, we recommend that you do not, because disturbed insulation and droppings put particles in the air. From the ground, look at the roofline for loose or damaged boards, torn vent screens and gaps near the eaves. Look for branches near the roof and for droppings or stains beneath any suspected entry.

From inside, notice whether any smell has developed in the room below the sound. A sharp ammonia-like odor suggests urine. A heavier sweet-rotten smell suggests a dead animal. Mention both on the call.

The technician walks the outside first, looking for entry points, then checks the attic if it is safe. We note the animal, the signs and the damage. You hear the plan and the price before any work begins. See our rodent trapping and removal page for how removal works.

After removal, the entry points are sealed and the attic is cleaned if needed. Droppings and soiled insulation can hold odor and may carry disease, so we follow public health guidance and do not sweep them dry. Our attic and crawl space cleanup page explains the steps.

Several animals can sound alike. Squirrels are loud in daylight, bats make a faint chittering at dusk and raccoons produce heavy thumps and dragging. Rodents are lighter, mostly active after dark and leave droppings in small, regular shapes.

We look at the droppings, the entry points and the damage. A hole at the roof edge the size of a fist suggests something larger than a rat. A gap the width of a pencil along a pipe suggests a mouse. If the animal is not a rodent, we say so and tell you the right kind of professional to call.

Insulation compressed into tunnels loses value, and urine soaks into it and holds odor. Wiring is a bigger worry. Rodents chew insulation off wires, and exposed wires can arc. If lights flicker, a breaker trips repeatedly or you smell something hot, treat that as an electrical emergency and call an electrician.

In the meantime, avoid storing items in the attic that rodents can nest in, such as boxes of clothes or paper, and keep the hatch closed.

Call promptly if you hear sounds every night, find droppings, smell something sharp or sweet, or notice chewed wiring or insulation. Rodents chew wires, and chewed wiring is a fire risk. If you see sparks, smell burning or have flickering lights, call an electrician as well.

The line is answered 24/7. Same-day visits are offered where the schedule allows, and we tell you honestly what window is realistic.