The Smell That Came from the Walls!

April 13, 2009 12:46 AM

A terrible, B.O.-like smell emanates from a room in our house at odd intervals. I have a half-baked theory, which we seem to have confirmed tonight. Is it at all plausible? If yes, what can we do about it? If not, what else could it be?

First, to dispense with the obvious, no, I swear, it is neither myself nor my lovely wife who is the source of this smell, nor does it appear to be coming from anything we own. And it seems to come and go unpredictably - it might be months between assaults.

One friend suggested it might be a dead, decaying rodent inside the walls. But that wouldn't explain the on-off nature of the problem. However, I did notice something. Ordinarily, the incandescent, single-bulb floor lamp in the room is turned to 50 watts. Sometimes, when I need more light, I'll turn it up to 100 watts. (It's one of those three-way bulbs.) The appearance of the smell seems to correlate with the brighter light!

So could it be that a dead rat is getting fried a little extra-crispy whenever I crank up the juice? We've never had a rodent or even a roach problem, though. So could it be something else inside the walls - perhaps even the wiring itself? Do any common building materials smell like B.O. when they heat or burn? (We live in a regular old apartment building - I couldn't tell you what's inside the walls, or even what they're made of, but they ain't too thick.) Also, I checked - there's nothing actually inside the lamp that I can see which is smoking/burning (like a dead bug).

We tested out my theory tonight and indeed, the room started to smell after just a few minutes. (We turned down the light before it could get too pungent - the smell can have some serious staying power.) So, is my theory totally cockamamie? If I'm wrong, what might it be? And regardless, is there anything we can do to abate the problem, short of ripping open the walls?

posted by DavidNYC to Home & Garden (19 answers total)

Could it be outgassing from material in the light fixture itself? I replaced a few old fixtures in our last house that smelled off when heated by a bulb, though the smell was more of something burning than it was BO.

Can you get up on a ladder to see if the smell is emanating form the fixture?
posted by dws at 1:02 AM on April 13, 2009

I have lived in 60s & 70s houses where it was definitely a decaying plastic light fitting - some sort of ammoniacal stench would come off when the bulb got hot. Particularly in laundries and other dampish rooms.

Can you get a new light fitting? That's what my money is on.
posted by i_am_joe's_spleen at 1:39 AM on April 13, 2009

Agree with the light fitting theory.

I had a desk lamp once that when turned on emitted a smell identical to cat's piss. It was caused by the plastic housing around the light-bulb socket. The plastic used to heat up and then give off these rank fumes. When it was turned off and cooled down the smell went away. Replace the light fitting and see if it helps.
posted by evil_esto at 1:50 AM on April 13, 2009

Replace both the lightbulb and the light fitting. If either are old they could be the cause of the smell.
posted by fire&wings at 3:19 AM on April 13, 2009

Move the lamp to another room (or even another building) and turn it to the highest setting. This should tell you whether the smell is the lamp or something near the lamp.
posted by onlyconnect at 4:03 AM on April 13, 2009 [2 favorites]

Oveheated urea-formaldehyde resin, such as you might find in an elderly lamp socket, emits trimethylamine as it breaks down.
posted by flabdablet at 4:13 AM on April 13, 2009

I had a stink-light once, and the odor turned out to be the plastic lining of the shade burning slowly from the heat of the bulb.

This happened to a co-worker of mine recently--in this case, it was a fluorescent light built under the overhead shelving of his cubicle that was scorching its plastic housing. Much office humor ensued until the source of the smell was tracked down.
posted by gimonca at 4:37 AM on April 13, 2009

Chinese drywall stinks.
posted by futility closet at 5:00 AM on April 13, 2009

Dead animal in the walls.
posted by fourcheesemac at 5:01 AM on April 13, 2009

I have had electrical outlets emit a nasty smell as they go bad, so I concur with the theory that it could be the plastic in an electrical fixture.
posted by TedW at 5:10 AM on April 13, 2009

Dead animals do not smell like B.O. Once you've smelled a dead rat/mouse, you never forget that smell either. I have no idea what it could be, but I have an old mac laptop that smells like B.O., that weird oniony, sweat smell. It's very strange.
posted by archimago at 5:17 AM on April 13, 2009

Most floor lamps are probably rated for a max of 75 watts, so you're likely overdoing it with 100. I'd swap out that bulb for a lower wattage.
posted by orme at 5:23 AM on April 13, 2009

If changing the bulb doesn't work, it may be that the electrical load of the bulb causes wires to get warm, and those give off the smell.
posted by cmiller at 5:53 AM on April 13, 2009

If I understand correctly, you live in an apartment building? Crank up the stink and make your landlord come on over. It's his responsibility to absorb the cost of repairs. Don't replace anything without making him/her open their wallet first.
posted by alcoth at 6:33 AM on April 13, 2009

Go sniff your window blinds. Seriously. We have this exact same issue in our bedroom and it's caused by the elderly plastic roll-up window shades. (Similar to this.) As the plastic ages, it off-gasses a smell that is nearly identical to unwashed human. We have the same window shades that were there when we bought the house, they're probably at least 10-15 years old (may be as old as 25, we don't know). The smell in our bedroom is intermittent for us too, which is why it hasn't really occurred to me to replace the blinds yet, since it's not a continuing annoyance. But the smell is definitely more noticeable when the weather is warm, when we have a (warm) light on in the room, or when the sun hits the window. Which is, I speculate, what's happening with your mystery smell.

We had stinky blinds on a south-facing window of the house, too... and those were getting constant sun heat so they were really strong smelling. I took that shade down 8 years ago and can still smell it in my memory. Pew.
posted by cuddles.mcsnuggy at 7:58 AM on April 13, 2009

Moreover, dead animal stink in wall will fade and disappear over a few weeks as the corpse desicates.
posted by IndigoJones at 8:03 AM on April 13, 2009

Also i was just told by telephone repair guy at work that some wires are coating with bad plastics that are not firerated and when heated up can release some poisonous gasses. so if your putting a lightbulb that is too powerfull for the fixture and it has old or cheap wiring it could be causing the smell.
posted by majortom1981 at 9:47 AM on April 13, 2009

Response by poster: Thanks for all the answers, everyone. I'm inclined to go with the "cheap/overpowered lamp" theory. I will test it out!
posted by DavidNYC at 11:31 AM on April 13, 2009

I have experience with this and it is very likely the urea resin stuff you are smelling but I am guessing, if you have a wall switch, it is the wall switch that is burning up. This is a potentially dangerous situation as it is a fire hazard. One thing to check out also is whether you have aluminum wiring in the house. If you do, then all outlets, switches and the like wil need to be "pigtailed" with copper to be safe. This isn't as expensive as it sounds and is really important for your safety.

Have it inspected by a certified high-voltage electrician.
posted by bz at 8:51 PM on April 13, 2009