Is there a dead rodent in my wall?

February 23, 2011 3:40 PM

Bad house smell has come on strong and suddenly. What is it? It's giving me a headache but my dogs don't even seem to notice it.

Dining room has a powerful smell that seemed to cause a headache. I noticed it when I got home from work a few hours ago. At first, I was convinced that one of the dogs had peed in the room. But it's a small room with hardwood floors and a not-very absorbent area rug. There is absolutely no urine in the room. Also, the smell seems to be concentrated at eye level (I'm 5' 10"). I'm going to try to use all my writerly gifts to describe it in words. It's ... very ... bad.

Seriously, it definitely has an ammonia flavor to it, but also like sweaty clothes. Maybe also like laundry that's been left damp in the washing machine for too long. And it's confined to the dining room, even though the dining room is adjacent to the kitchen on one side, and the living room on another side. There is no odor whatsoever in those rooms.

I thought maybe an animal died in the wall. Neither of the dogs (border collie mix, golden retriever mix) seem interested in the odor, though. If it was a dead animal, wouldn't that get their attention?

Is it a dead animal in the walls? Something else?

posted by Buffaload to home & garden (22 answers total)

Do you have a leak somewhere? Could it be mold?
posted by majortom1981 at 3:44 PM on February 23, 2011

The smell you described doesn't sound like a gas leak, but the "seemed to cause a headache" part makes me concerned about carbon monoxide poisoning... do you have CO detectors?

I do think dead animal is the most likely answer, but the most horrific smell I've ever smelled in my life (and was certain had to be a rotting corpse) was actually coming from an unplugged refrigerator that hadn't been cleaned well and was leaking foul condensed moisture. Is there any chance you've got anything nasty leaking from your kitchen (fridge, garbage disposal, etc.) behind the cabinets/appliances and into your dining room?
posted by Jacqueline at 3:46 PM on February 23, 2011

I checked the basement underneath the dining room. We're having a thaw and water is seeping in through the old fieldstone foundation walls (this is normal). So there is some water in the basement, but it's dampness, rather than flooding. Sump pump is working normally. If that were the source, though, I would expect the same, strong smell. But I smell nothing in the basement.
posted by Buffaload at 3:48 PM on February 23, 2011

Stink bugs?

Mildew from a stretch of wet weather? Did you just have a sudden thaw?

Something outside the house near a window on that side? Could you go on a sniffing tour outside the house there?
Something in the basement below that room?

Broken plumbing pipe leaks water into wall/ceiling - is the ceiling or wall at that height damp? Is the smell stronger near the wall? Broken line to the fridge icemaker leaks into crevices and subfloor?
posted by LobsterMitten at 3:50 PM on February 23, 2011

I have some CO detectors upstairs. I will move one of them into the dining room just to be safe. It's definitely not natural gas, but I am not cavalier about CO. Thanks for suggesting it even though I don't happen to think that's part of it. I wonder if the basement dehumidifier in the basement somehow got fouled with mold...Smell is definitely not coming out of the heating grates in the room (forced air furnace).
posted by Buffaload at 3:50 PM on February 23, 2011

Yes, sudden thaw, LobsterMitten. Hypothesis?
posted by Buffaload at 3:51 PM on February 23, 2011

CO doesn't have any smell or taste.

I would say check the dehumidifier and the walls in the room for mold.

Then again, I had a cat with a ridiculously strong hunting instinct just not care about a dead mouse in my closet. Since she hadn't killed it and it was dead, it was of little interest to her. YMMV.
posted by skyl1n3 at 3:58 PM on February 23, 2011

When we had a dead thing somewhere in the house, there were a lot of flies. A LOT of flies. But perhaps it's too cold where you are for flies? (Turned out to be a dead cat under the bathtub. We only found it years later when we ripped the bathtub out. Yay.) Bad rotting refrigerator smells strangely like dog + death. I always thought it smelled like a dead dog would smell. (New Orleans - I know what rotting food in refrigerators after Katrina smells like. Also, bugs would be around in that case too.)

Another bad smell I had to search for once was a very slightly open can of chicken soup in the back of the kitchen pantry. Check all over the kitchen. My stepmother once was distracted and put a packet of raw chicken in a drawer in the kitchen.

I apparently have a lot of stink experience.
posted by artychoke at 4:00 PM on February 23, 2011

I've had animals die in the walls, and that did not smell anything like ammonia or sweaty clothes. Smelled more like sewage, if I had to compare it to anything else.
posted by wondermouse at 4:09 PM on February 23, 2011

I know you said it's not in the kitchen, but it will only take a minute to check the refrigerator drip tray.
posted by qxntpqbbbqxl at 4:12 PM on February 23, 2011

Right. Going on a smell tour of basement, house perimeter, etc. Wish me luck.
posted by Buffaload at 4:13 PM on February 23, 2011

We're having a thaw and water is seeping in through the old fieldstone foundation walls (this is normal).

I had a similar problem and a similar methane-like smell coming from the basement at the end of a long winter a few years back. However, the smell never got into the house, because I had installed weatherstripping on the basement door, and it seals up pretty tight.

The smell turned out to be mold growing on the inside of some drywall that had been installed on wooden studs about 6" over the fieldstone in one semi-finished basement laundry room. On the recommendation of a foundation guy, I ripped out the drywall and now I keep the basement windows open for most of the summer. The trapped moisture is now free to go elsewhere, the mold is mostly gone. But the smell is still faint, confined to the basement and always occurs around now when the fieldstone gets damp and warmish.
posted by kuujjuarapik at 4:25 PM on February 23, 2011

The "old sweat plus ammonia" smell sounds like it could be house mice to me. Do you have any other signs of house mice? Dogs often don't care about mice, so I wouldn't take that as indicative.
posted by Sidhedevil at 5:19 PM on February 23, 2011

Also, if you have a garbage disposal, try running the ever-loving hell out of it for a while. Maybe there's some coagulated funk in there? I don't know if that would make a strong enough stench like the one you're describing, however.
posted by Kloryne at 5:25 PM on February 23, 2011

This would be more of a strong musty smell, I think, but I thought I'd mention it, just in case: one of the worst smells we ever had in our house turned out to be coming from a potted tree -- the roots were all grown-together and rotten. When we pulled the tree out of its pot, it was unbearable. Do you have any plants or trees indoors that could be rotting?
posted by cider at 5:25 PM on February 23, 2011

Holy cow, cider has it. My fiancee just got home and saw me skulking around with my nose against the baseboards. When I explained there were probably dead animals pooping up to the rafters, she walked straight over to a plant on the windowsill in the dining room that just began flowering yesterday. I took a deep breath and got an instant headache again. That was definitely it. I removed it and the smell vanished. Why it made me want to puke and has no effect on her (or the dogs) I do not know. Is that weird? That was weird. Thanks, all. I feel ridiculous, but, you know...
posted by Buffaload at 5:51 PM on February 23, 2011

Complete shot in the dark here, but was the plant a paperwhite narcissus? My mom got one when I was a kid and to me it smelled like musty, rotten urine. I don't think it really bothered anyone else.
posted by Logic Sheep at 7:00 PM on February 23, 2011

I don't know, Logic. It's white. ... OK, just asked fiancee, who said it's a lily. But your description of the paperwhite narcissus reminded me very much of what I experienced.
posted by Buffaload at 7:06 PM on February 23, 2011

I hate the smell of lilies too. You're not a freak.
posted by pseudostrabismus at 8:30 PM on February 23, 2011 [1 favorite]

Was it a Sauromatum by any chance?
posted by Solomon at 2:54 AM on February 24, 2011

You're not alone! Certain lilies, as well as paperwhites, make me nauseated with one sniff. While most people don't seem to notice a strong odor at all.

I think it's like the taste of cilantro or licorice. One of those plant chemicals that hit some of us strongly in the wrong way, but others find pleasant. (I also hate cilantro and licorice.)
posted by themissy at 7:14 AM on February 24, 2011

Oh, lilies!!! They are devil flowers. I really, really hate the smell, to the point where if anyone in my office has one, I can't focus.

(It's not quite the rotting-root smell, but I'm glad you found it!)
posted by cider at 6:09 AM on February 25, 2011