04:50AM | 03/07/03
Member Since: 03/06/03
7 lifetime posts
We have dealt with a very stubborn odor in our home that has come and gone for the past 5 months or so...we originally thought it was from one of children (who sleepwalks) urinating on the carpet because the smell was a very strong ammonia-like smell. After deodorizing and cleaning carpets, we found that the smell was not coming from the floor, but ceiling - and almost certainly from the air ducts in his room. We then thought the problem was due to a loose fitting on an outflow drain pipe on his bathtub which is in his bathroom off this room where the smell started. This loose fitting had caused water to leak onto the floor and through the ceiling below. However, after more investigation, the strongest source of the smell was coming from the bedroom - not the bathroom - and most certainly from the air vent. We have searched the attic and the duct for a dead animal and honestly - after five months, it would seem that if it was an animal, it would have decomposed by now.

To better describe the smell and the situation surrounding it: it is an ammonia/urine type smell. It is very pungent at night and on occasion, other times during the day but it is not constant throughout the day. It literally disappeared for a month or so and then it came back with a vengeance. It is so pungent that at times, it almost hurts to breathe in there and my son has to sleep downstairs.

Does anyone have any insight to this very bizarre mystery???


02:13PM | 03/07/03
Member Since: 09/17/02
524 lifetime posts
Is it possible you have racoons in your attic? I know a guy who is in animal removal who once told me sometime they urinate in the attic so much people think they have a roof leak.


02:49PM | 03/07/03
Member Since: 03/06/03
7 lifetime posts
My husband went up into the attic and didn't see anything in the area above the house. Although we have considered a couple of fox squirrels that run around out in front of the house...we just haven't seen any evidence of a nest or anything. It is so frustrating because at times, unless we keep our son's bedroom door shut (it is right at the top of the stairs) the smell wafts is gross.

Thanks for your input though - I REALLY appreciate any and all help!


03:33PM | 11/13/03
Member Since: 11/12/03
3 lifetime posts
We have the EXACT same problem!
We've contacted pest control people because we thought we had rats. We've had contracters and plumbers here, but no one can find the problem! We've had it for over a year.
Please let us know if you've solved the problem!


09:12AM | 11/15/03
Member Since: 11/12/03
3 lifetime posts
Thanks k2 for your response. It was helpful to read the posts you mentioned. I posted a more detailed account of our problem.
I emailed the originator of this post, as her problem she described sounds most like ours, but I have not heard from her.
If our problem is pest-related, how come we can't see where they are coming in? Or hear them? Or see evidence? Unless it is in the vent?
I'm thinking we'll just get the heating vents cleaned out anyway, just to see if that helps before we tear into walls.
Thanks again for checking in on this post!


04:08PM | 11/15/03
Member Since: 09/10/03
67 lifetime posts
have you recently did any additions to this room Iwould take a sample of the insualtion in the attic, also, I would suggest that you check the drain pan on the a/c system to see if may be stopped and staginated water accumalated.have you checked your sons closet for possible spray cans of either,starting fluids or cleaning fluids of any type. Have you recently installed a new carpet araea near the return vent area using chipcore board as an underlay or any new plywoods which contain formalhyde glues. also, check the vent on the furnace and make sure free and not stopped up; also, does this room have flexible ductwork or does your complete house haave same. some old types of refrigeraton systems contain ammonia and could have a possible leak. are you positive it is not sewer gas. is your water heater gas, and if so,are you sure your dont have a vent stopped or came loose. have you installed a new roof over this area using underlays with formahided glues.


02:41PM | 02/19/15
i have the same problem in my sons room. the attic door is in his room and there is an animal up there because i can here him moving around :( the smell of ammonia is so strong its hard to breathe at times. It started today. Yesterday it was fine, and its already horrible. we keep the door closed and you cant smell it anywhere except in that room. Its definately bigger than a mouse, does it sound like a racoon with that much pee smell that fast?


08:26PM | 09/29/15
Member Since: 09/29/15
1 lifetime posts
We just moved into a house and are experiencing the same smell on the top floor only. It was only in the master Bathroom but now it is all over sometimes. it disappears for a week and then come back for 1 or 2 days.
the smell is so strong that we cannot sleep well.

I sprayed Arm and Hammer Stain & odor Eliminator in the AC intakes and it seemed it improved the situation all over but now in the Master Bathroom the smell is strong only.
I have request pest control to come in tomorrow to check all including the attic.
If anybody has new ideas let us know please.


04:01PM | 05/29/16
With a simular problem I had I took off a vent cover and found a very
old deoderizer in there when I removed it the smell also left


08:55PM | 09/29/16
We have the same problem going on. We had a new furnace installed this summer and it seems to prevail only since I turned the heat on this fall...what's odd is that it's only one room in the house.


11:33PM | 12/30/16
Same problem with our house. We had new furnace installed also this past summer and now terrible smell in one the bedrooms upstairs and now it's almost in every room of the 2 nd floor coming from the vent.


03:16AM | 05/10/17
Bed bugs can leave a musty odor


01:41PM | 08/15/17
Fee are experiencing the same thing. It started three days ago. At first I thought my dog had an accident so I scrubbed the floors and steam cleaned the area rugs. It has happened again the last two nights.
The smell is just in our kitchen and dining room area and comes at night then disappears throughout the day.
I have no idea where to look or what it could be.


01:43PM | 08/15/17
We are experiencing the same thing. It started three days ago. At first I thought my dog had an accident so I scrubbed the floors and steam cleaned the area rugs. It has happened again the last two nights.
The smell is just in our kitchen and dining room area and comes at night then disappears throughout the day.
I have no idea where to look or what it could be.


12:52AM | 08/26/17
I knew I wasn't going crazy!! I have a smell that I thought may have been a decomposing animal in my attic closet. The smell was so horrible, but we waited over 6 weeks for the decomposition to be over... the smell went away then came back! it was on and off for months when I finally smelled it really strong one morning and called our landlord. He was there within an hour and wouldn't you know... there was no smell at al while he was therel.... it came back 2 days later, but I didn't tell the landlord for risking sounding Holanda Since it is summertime now, windows are always open, so its hard to tell if its still there.
Has anyone who experienced this ever gotten an explanation?


09:22AM | 12/25/17
Have same problem, Just wondering if it could be due to fungus or mould ... but I'm in Malaysia, damp n humid here ...


10:36PM | 05/02/18
Hello. Has anyone on this blog been able to solve their problems? I am now just dealing with similar problems. And I’m about to loss it. No one can give us any answers. Any answers would be greatly appreciated!!!


06:43AM | 06/16/18
Yep. That mildewy urine odor appears on my porch coming from outside, from late evening until the break of dawn. It's just nauseating. There is no crawlsspace on my porch. It is flat cement slab.
I shut my porch door at night, because if I don't, half of my home reeks of it.
I have seen some raccoons in the area, but I do not think they have a nest near my home, and do not here activity inside.
I guess no one can answer what the heck it is from the looks of things.
I am guessing fungus, or a bum is pissing on the trees every evening.


09:37PM | 07/09/18
Has anyone ever come to any conclusions on this smell issue? We are having the SAME problem & can not find the source! Its frustrating & nauseating! Ughhh!!!


10:26PM | 07/10/18
I also have the horrible cat urine smell. Just moved into house and it was here from the first day. Asked previous owner if they kept a cat in that room - no animals ever. On cool days no smell but when the attic gets hot the one bedroom has the smell. Sniffed the walls, the floor, outlets, ac vents, no moldy window sills and it's mostly in the doorway. Nights when the attic cools down, the smell is mostly gone. Could it be mold on attic insulation from a leak in the roof?


04:19PM | 07/15/18
I live in AZ and noticed in summer time the ammonia smell, especially when temp raise up to the 113. I think it comes from plastic materials in my bedroom ( a vynil massage table, plastic window decoration, a vynil decoration wall sheet) in winter time smell disappeares.
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