Scratching in the Ceiling at Night? How to Tell What's Up There

Scratching in the ceiling at night: read the clues

Before you climb into the attic, spend a couple of nights just listening and writing it down. Four things narrow it down fast.

Clue 1: When you hear it. Roof rats are most active after dark, with a burst of activity not long after sunset and another before dawn. If you lie awake at 2 a.m. listening to something run across the ceiling, that's the classic pattern. Noise mostly in the middle of the day points away from rats.

Clue 2: What it sounds like. Scurrying and running back and forth, scratching, and sometimes a gnawing sound. Rats sound heavier than you'd expect. Mice are lighter and quicker, more of a patter. A slow, heavy thump-thump across the ceiling is something larger.

Clue 3: Where it is. Over the bedrooms and along the edge of the house, near where the roof meets the wall, is typical for roof rats. Noise inside a wall or between floors, or down near the kitchen cabinets, fits mice a little better, though rats travel in walls too.

Clue 4: What you find. This is the one that settles it. Look at the attic access, the top of the garage walls, and on top of the AC air handler if it's in the attic or garage. Droppings, chewed wires or wood, shredded insulation, and dark greasy marks along the beams are all signs.

Scratching at night but no droppings?

This one comes up a lot, and there are a few honest explanations:

• They're there, you just haven't found them. Droppings get buried in insulation, land in corners you can't see from the hatch, or end up on top of ductwork.
• It's brand new. A rat that moved in last week hasn't left much behind yet.
• It's on the roof, not in the attic. Rats running along a gutter or across a tile roof can sound like they're right above you.
• It isn't an animal at all. Ticking and popping as the house cools down in the evening, water lines, and the AC ductwork can sound like movement, though usually not like running.
• It's something else that got in. A bird in a vent, for example.

The inspection sorts this out. If we don't find signs of rats or mice, we'll tell you so.

What to do now, and what not to do

Do:

• Keep a short noise log: date, time, which room.
• Look around the attic access and the garage for droppings and rub marks with a flashlight. You don't need to crawl through the attic.
• Bring pet food in at night and keep the trash lidded.
• Book an inspection.

Don't:

• Put out loose bait or poison in the attic or the ceiling.
• Seal the gap yourself while they're still coming and going. Sealing comes after the ones inside are trapped, and it's part of what we do.
• Sweep up droppings.

If you do find droppings, here's how to clean them up. Don't sweep or vacuum rodent droppings; that stirs up dust you don't want to breathe. Open doors and windows and let the space air out for 30 minutes first. Put on rubber, latex or vinyl gloves, spray the droppings with a household disinfectant or a bleach solution (1 part bleach to 10 parts water) until they're soaked, and let it sit 5 minutes. Wipe them up with paper towels, bag them and put the bag in a covered outdoor trash can. Then disinfect the spot, and wash your hands after you take off the gloves. If there are a lot of droppings, like throughout attic insulation, call us before you start.

Ceiling noise questions