Dead Animal Smell in a Wall or Attic: What to Do in Florida

The short answer: a strong, sweet, rotten smell that's worst in one room usually means a rat, squirrel or other animal died inside a wall, ceiling or attic. Find where it's strongest, remove the carcass with gloves, double-bag it, disinfect the area, then find out how the animal got in. Call (844) 264-6254 if you can't reach it.

Why it happens

Animals that get into a house often die where you can't see them. Poison bait is a common reason: UF/IFAS says rodents that eat anticoagulant bait, a common kind, usually die four days to two weeks after they start feeding, plenty of time to crawl back into a wall or attic first (UF/IFAS). Animals sealed inside by a well-meant repair are another. FWC warns that bats shut into a building die there, and that their decay can produce strong odors and draw pests such as cockroaches (FWC).

How to find where it is

• Follow your nose room by room. The smell is usually strongest on the wall, ceiling or closet nearest the carcass.
• Check the attic above that room, especially along the edges where the roof meets the walls, and around insulation that looks disturbed.
• Look for stains on drywall or ceiling, and for flies gathering at one spot on a window or light fixture.
• Think about recent activity. Scratching that stopped suddenly, or bait put out in the last couple of weeks, points to where the animal was living.

Removing it safely

Here are the CDC's steps for dead rodents and their droppings. They're a sensible guide for other small animals too (CDC):

• Open doors and windows for 30 minutes before you start.
• Wear rubber or plastic gloves.
• Wet the carcass and everything around it with a disinfectant or a bleach mix (1 part bleach, 9 parts water), then wait 5 minutes.
• Put the animal in a plastic bag with any used traps, then put that bag in a second bag, and throw it in a covered garbage can that's emptied regularly.
• Don't sweep or vacuum droppings, urine or nesting material. Wipe them up with paper towels after soaking.
• Wash your hands with soap and warm water after you take the gloves off.

If the animal is behind drywall, it may mean cutting a small access hole at the strongest spot.

Why waiting it out isn't a plan

Removing the carcass matters for more than the smell. UF/IFAS advises removing dead rodents promptly so pets and wildlife don't eat a poisoned animal (UF/IFAS). And a dead animal in the wall means there's a way in that's still open. Our rats in the walls guide covers finding it.

Stop the next one

• Find the entry. Look at roof returns, vents and gaps where pipes and A/C lines go through the wall.
• Seal it the right way. For rats, seal the gaps and then trap any left inside. For bats and other animals, seal only once they're out, so nothing is trapped inside.
• Think twice about poison indoors. Traps let you find and remove the animal; bait often doesn't.

See dead animal removal, rats in the attic and rat removal, or call (844) 264-6254.