If a sweet, rotten smell has turned up in one room, gets stronger over a few days and seems to come from the ceiling or a wall, an animal has most likely died in the roof space, a wall cavity or the subfloor. In a Shire home that animal is often a brushtail possum, since brushtails often take up residence in roofs. Rats and mice die inside walls and ceilings too. The smell alone won't tell you which, but a few other signs usually will.
What does a dead animal smell like?
It is a heavy, sickly sweet smell of rotting meat. Possums and mice living in a roof leave a sharp, stale smell of urine and droppings that builds slowly over weeks. A dead animal smell arrives fast, often over a day or two, and is strongest in one spot rather than spread through the house.
Other signs tend to show up at the same time:
- flies gathering at one window, light fitting or ceiling vent
- a damp, yellow or brown patch on the ceiling plaster
- the smell getting worse on hot days and when the room is closed up
- noises in the roof that stopped a few days before the smell started
A stain under the smell can mean fluids are soaking into the plaster and insulation, and the longer the carcass stays, the more of that material may need to come out.
Was it a possum, a rat or a mouse?
The noises you heard before the smell are the best clue. The NSW Government's brush-tailed possum page says brushtails are about as big as a domestic cat and are active at night. That weight makes heavy thumping across the ceiling after dark. Rats make a faster, lighter scurrying, and mice a soft scratching inside walls.
A cat-sized possum also leaves far more to break down than a mouse, so the smell is usually stronger and lasts longer.
Grays Point sits beside the Royal National Park, and possums are among the wildlife living in the suburb. A Grays Point family who heard thumping across the ceiling every night until a week ago, and now have flies at the bedroom window and a rotten smell above the wardrobe, should book dead possum removal in Grays Point so a technician can find the carcass before it soaks further into the ceiling.
Why shouldn't you go up and get it yourself?
Health comes first. NSW Health's wildlife safety factsheet says wildlife can carry diseases that make people sick. It says disease spreading from animals to people doesn't happen often, but the risk goes up when people handle animals, especially sick, injured or dead ones, and that dead animals may still carry disease. Its advice for the public is not to touch or move a dead animal.
Then there is the roof itself. Finding a carcass means crawling along joists, through insulation and past wiring, and a foot placed between the joists can go straight through the plasterboard.
Last, there is the law. Native mammals, possums included, are protected in NSW under the Biodiversity Conservation Act 2016, and the government's brush-tailed possum page says a possum can only be trapped and removed from a roof under a licence. That matters if a live possum, or a mother with young, is still using the roof.
Bonnet Bay has eight parks covering almost a quarter of the suburb, on sandstone gullies above the Woronora River. A Bonnet Bay owner who notices a brown stain spreading on the lounge room ceiling, under a smell that wasn't there last week, should arrange urgent dead possum removal in Bonnet Bay rather than climbing up to look.
Will the smell go away on its own?
Eventually, but not soon. The smell only fades once the carcass has fully broken down, and over that time flies can breed in it and fluids keep spreading into insulation, plaster and timber. Air fresheners and open windows only mask it.
Timing matters with possums in particular. That same page says young are usually born in May and June, spend about five months in the pouch and then about two more months riding on their mother's back. A possum that dies in the roof between winter and early summer may have had young with her, which is one more reason to have someone look properly.
Illawong takes its name from an Aboriginal word meaning between two waters, as it sits between the Georges and Woronora rivers, with the Illawong Nature Reserve nearby. An Illawong household that can smell something rotten in the hallway, but can't tell whether it is coming from the ceiling or the wall behind the linen cupboard, should book dead possum removal in Illawong and let a technician trace it to the right cavity.
What happens once the animal is found?
A technician follows the smell, the flies and any staining to the right spot, then gets in through the manhole or the nearest safe access point. The carcass is removed along with any soiled nesting material or insulation around it, and the area is treated for odour.
The technician will also look for how it got in, such as a lifted tile, a gap at the eaves or an open vent. Because live possums are protected, any gap should only be closed once it is clear no possum is still living in the roof.
Most streets in Woronora Heights are named after birds, and the suburb is bounded by the Woronora River on its western side. A Woronora Heights family who had possums in the roof last year, and now have flies in the kitchen and a smell above the rangehood, should ask for a dead possum removal service in Woronora Heights and have the old entry point checked at the same time.
Before you book
Note these details so the technician can find the animal quickly:
- which room the smell is strongest in, and when you first noticed it
- any flies, ceiling stains or damp patches, and where they are
- the noises you heard before the smell, and when they stopped
- where your roof manhole is, and whether it is easy to reach
- whether you have children, pets or anyone unwell at home
Send those details when you contact us for local pest control in the Sutherland Shire: call Sutherland Shire Pest Control Pro on 02 8360 3033 or email [email protected].