What to do if you hear rats in the roof

Rats and mice are most active from dusk through the early hours, so the noise almost always starts once the house goes quiet. What you hear is scurrying along the top of the ceiling, gnawing, and sometimes the sound of something being dragged as they carry nesting material. In the cooler months across North Brisbane, the roof space offers shelter from wind and rain and stays a few degrees warmer than outside, so activity often picks up from autumn into winter.

A single noisy night is worth watching. Noise that repeats in the same part of the roof night after night points to an established nest rather than one animal passing through, and that is the point to act rather than wait.

This matters more than people expect. In Queensland possums are protected native animals under the Nature Conservation Act, and it is against the law to bait, trap and relocate far, or harm them. Baiting a possum is both illegal and cruel, so identifying the animal before you do anything is the whole point.

As a rough guide, possums are heavier and slower. You tend to hear a deliberate, plodding thump and heavy movement, often around dusk and dawn, and sometimes hissing or a low growl. Rats are light and fast, with quick scratching and scurrying that darts from place to place, plus gnawing you will not hear from a possum. Rat droppings are small, dark and scattered in runs; possum droppings are larger and more pellet-like. If you are not certain, do not assume. Bruin does not treat possums as pests, and a proper inspection settles which animal you are dealing with before any control starts.

Beyond the noise, rats leave a clear trail once you know what to look for. Droppings are the most reliable sign, usually clustered along beams, in the corners above the ceiling, or in the pantry and under the kitchen sink. You may also see gnaw marks on timber, stored boxes and food packaging, because a rat's teeth never stop growing and it chews constantly to keep them down.

Other tells include shredded insulation pulled together into nests, greasy smudge marks along the routes they run, and a persistent musty, ammonia-like smell from urine that builds up in an enclosed roof. Chewed electrical wiring is the one to take seriously, since exposed cabling in a roof is a genuine fire risk. Contamination of stored food, bench surfaces and anything in the pantry is the other, as rodents spread bacteria wherever they travel.

The instinct is to buy a box of bait and throw it into the roof. Please do not start there. Scattered DIY bait thrown into the roof is hard to place safely, can be reached by children and pets, and often leaves you with a dead rodent decomposing somewhere you cannot get to, which brings its own smell and flies. Poison also does nothing about how the rats are getting in, so a fresh group simply moves back in.

A better order is: get the animal identified so you are not touching a protected possum, have the outside of the house inspected to find the entry points, then seal or proof those gaps, and only then bait in a controlled, secured way well out of reach of children and pets. Rats can push through a gap around the width of your thumb, so common entry points are broken tiles, gaps where the roof meets the eaves, and around pipes and cabling. Proofing the building is what actually keeps them out for good.

Call when the noise has repeated over several nights, when you have found droppings or gnaw marks, when you can smell that musty odour, or any time you suspect chewed wiring. Those are signs of an established presence rather than a one-off, and they are worth handling properly before the damage or the contamination spreads.

Bruin is a family-owned Brisbane business based in Wavell Heights and covering the northern suburbs including Chermside, Kedron and Aspley. A technician will confirm whether it is rats or a protected possum, find and proof the entry points reachable from ground and ladder level, and place any bait safely, so the problem is dealt with at the source rather than papered over. Where closing a gap needs a builder or roofer, we tell you exactly what to fix and where.