We're trying to track the origin of a very putrid smell in our condominium. We have a loft type home, which means two floors with a drywall ceiling between the first and second floor.

I first noticed a subtle odor in the kitchen, which is not an uncommon place to notice subtle odors. I checked the usual suspects:

  • Something in the bottom of the trash bin
  • Something rotting away behind an appliance
  • Something putrid stuck in the sink trap
  • Something rotting away in a cupboard

While we are guilty of all of the above and have removed the offending artifacts, the odor persists weeks later and grows in intensity. I realized that the odor seems the strongest from the stock room built under our stairway directly facing and adjacent to our kitchen, in which all ceiling joists for the downstairs level arrive unfinished.

I cleaned out the stockroom, expecting to find the remains of a mouse, but to my dismay there was only one partially dead insect that I quickly dispatched. The odor seems to be emanating from something existentially challenged somewhere in our ceiling.

I've done the following:

  • 'sniff tested' the end of each joist where I can get access to do so. The smell seems to be coming from everywhere.
  • Used a flashlight to peer as far down each joist to joist channel as possible, I can't see anything that could be causing this.
  • Removed and replaced some lighting fixtures in in order to get a better view of what might be in the neighborhood
  • Sent a fish tape through every opening I can find hoping to reel in, or at least determine the location of the cause
  • Duct taped every opening between joists in the pantry area. One by one, eventually all.

The smell keeps getting worse.

What, beyond cutting holes in the ceiling all over my first floor can I do to pinpoint the source of this annoyance? Is there some sort of chemical test or something else I can get to narrow down the location and unfortunate source of this smell?

  • See also: How can I find the source of a mysterious bad smell
    – BMitch
    Commented Dec 5, 2012 at 17:20
  • @BMitch Alas, I tried that and even smelled a mop in the name of finding this. The mop has its own issues, but this isn't one of them.
    – Tim Post
    Commented Dec 5, 2012 at 17:24
  • 8
    Call the mob? see if they're missing anyone? Sorry, I read the title and assumed Goodfellas. Commented Dec 5, 2012 at 17:34
  • 4
    If there is any moisture left in the corpse, a very good IR sensor may pick it up. Commented Dec 5, 2012 at 22:08
  • 1
    @TimPost Sorry for the delay in getting back to you on this (my friend couldn't remember where he'd left the bottle). The stuff he used is a drain-cleaner called BIO-GEL. Hopefully your smell is completely gone by now and you don't even need this information. :)
    – Niall C.
    Commented Jan 14, 2013 at 18:03

2 Answers 2


Oi! this reminds me of an experience I had about seven years ago. Horrible smell with no obvious source. Turned out that the cats had killed a rat and hidden it behind the books on the bookshelf. Only noticed it because of an awesome slimy trail of maggots.

Anecdote aside, my recommendation with this particular occurrence is to wait it out: rodents tend to decompose in a relatively short period of time, and the smell will dissipate within another week. If it persists you're dealing with a larger animal - say a full grown opossum or bigger - which leads to the really pertinent issue: how did the offending critter get to where it got before it died?

As a self-respecting homeowner you should do whatever you can to prevent entry by pests into your home. Sometimes this involves a thorough investigation by a professional but for the most part an observant individual can determine likely points of entry and fix them.

Most modern houses are covered by siding/doors/windows in every location with three major exceptions: foundation line, crawlspace venting, and eaves. All apertures can be sealed with some combination of welded wire, steel wool (coarse) and possibly adhesive by a determined homeowner. The more aesthetically pleasing approaches are less simple and more costly, but there are lots of solutions out there.

As far as your storeroom goes - I recommend rocking->taping->mudding to close any access points for the critters, same with any unfinished space that is prone to pest invasion.

Hope you have a better olfactory experience in the near future!

  • 1
    That's .. pretty much what I did, just sealed up all possible places I could find where the stench could be escaping. The smell is all but gone now. This is the correct answer in this case, if you don't want to bust up walls and ceilings, you better be prepared to wait it out. Several exterminators tried to find it, none could.
    – Tim Post
    Commented Dec 17, 2012 at 14:18

...And wear a full faced respirator and head lamp if and when you go into any confined space.

A bottle of Chlorox clean up spray will kill smells instantly.

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