I can't say I've been near any insulation that smells like a dead animal. The in-laws did have a rat die in the space between the bottom shelf of their kitchen cabinets and the floor.

Good luck.

Mike

I just dealt with that horrible dead varmint smell in my basement. It was driving me crazy for the last week. It too would come and go and I noticed it followed our weather patterns (worse when it was warm). It was coming from the back utility room of the basement. It seemed much stronger at the top of the foundation where the upstairs sub-floor overhangs. I removed all the fiberglass insulation thinking I was looking for a dead squirrel, chipmunk etc. I didn't find one. I went outside after I got a tip from an exterminator. He told me that 98 percent of the time when he is called out for dead smell in the basement that the problem is outside not inside. Underneath our fireplace chimney is a void of about a foot to ground level. There are some decorative bricks that are not attached surrounding the void. I removed them and voila! Two very large muskrats were dead and decomposing right up against the foundation! I used a garden rake and extricated them. I put them in triple sealed garbage bags for our trash man. I didn't want to bury them as I was afraid some dog (maybe mine) would dig them up. Look outside and if you have any kind of alcove, deck or such that offers shelter could be the source of your problem. Honestly, it smelled like they were in the house! I hope this helps some because I was ready to sell the place.

Have you checked the traps in any floor drains? If they dry out, they will let sewer gas in. Fill with water and add a tablespoon of mineral oil to slow evaporation.

I have never heard of exposed insulation smelling like a dead animal. Not even wet insulation. I understand your thought process that a dead animal smell should be constant but then again many bad smells like urine will come and go based on humidity, temperature, etc.

Its not to often that someone describes a real bad smell as the smell of a dead animal. It must be pungent. I would tend to believe it is a dead animal and would suggest you do a very thorough search. Recently someone else posted about a bad smell in a bathroom that would come and go and it ended up being a dead rodent in the bathroom vent.

We had to put rat poison out and now the rat is dead but we believe it's in either the ceiling cavity between floors or a wall cavity. Obviously we can't start to pull the walls and ceiling out, but how do I get rid of or mask the smell. How long will it take to completely decompose and is the smell harmful to our health.

One way to get rid of the odor is to use an ozone-generating air purifier. The ozone will literally destroy the smell by oxidizing and breaking apart the long stink-molecules. The ozone will also give you a dry throat and headaches, so run the unit when you are not at home and turn it off when you return home. After turning it off, the ozone very quickly reacts with everything around it and turns into regular old oxygen. I was able to completely rid our kitchen of fried fish smell in a hour or two, windows closed when I was trying out a unit (Alpine Air Purifier) my neighbor was trying to sell me.

Omg I am having this same issue

@Greatlakesmower, you are a genius! We had exactly the same problem, and it went on for years - a bad smell in a closet, that would come and go. There would be nothing for months or even a year and then, bam, dead animal smell again. I was up in the attic over the closet several times, and nothing.

It happened again today and my wife thought to Google it and found your post. We realized that the smell isn't really dead animal (though it's close) - it's actually drywall patch compound that's getting heated up by the bulb! That stuff has a mild smell at room temperature, but it turns out when it gets hot, it's disgusting. We had a 100 watt incandescent bulb in the closet light fixture and swapped it out for a CFL. We're waiting for the smell to dissipate now, but we think our problem is solved, thank you!!!

Great story. In my area incandescent bulbs are not allowed by code in a closet. Another reason why this may not be a good idea.

Help, im having the exact same problem except that it’s outside by the wooden fence. bith my neighbor and myself have checked our properties and there’s no dead animal

Please don’t use poison, that stuff should be outlawed. It can kill off animals that eat the rodent like neighborhood cats, foxes, coyotes and bobcats. It’s a terrible, slow, painful death. There are a lot of traps out there that work great instead. We had rats get into our car’s engine. It did $7k worth of damage to the electrical system. Managed to kill a rat the size of a large squirrel just by putting a trap in the open section near the battery.

We had the insulation heating up due to the light fixture causing it to be hot. It smelled horrible and dirty. I thought initilally that it was urine under the floor covering over years of use. We noticed that it came and went. Sure enough, it was the light and insulation. What a stench!

Omg thanks to this discussion, we found our ”dead animal” it was the damn lightbulb!!!! THANK YOU I have my bedroom back :)