Skunk animals in a home © D Friedman at Six Steps to Finding & Curing the Source of Building Odor Problems
Procedure Used to Find & Remove Odors Gases & Smells in or around Buildings

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Six-step procedure to track down the source or cause of odors or smells in or around buildings. Here we describe six areas of investigation that can help direct the inquiry as to the cause or source of an odor or smell in or around a building.

These articles explain how to diagnose, test, identify, and cure or remove a wide range of obnoxious or even toxic odors in buildings, in building air, in building materials, or in the building water supply. We discuss odors from a variety of sources including animals including pets, dogs, cats, or unwanted animals or dead animals, formaldehyde odors in buildings from building products or furnishings, plumbing drains, plastic or vinyl odors from building products, flue gases, indoor mold odors, oil tanks or oil spills, pesticides, septic odors, sewer gases, and even abandoned chemicals at properties.

Our page top photo shows our local skunk rummaging on a nearby golf course. This is about as close as you want to be, especially if you see a skunk meandering in daylight. This skunk was found dead two days after this photo was taken, most likely due to rabies. .

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Six Step Process for Odor Cause or Source Detection

Chemcial drums abandoned at a property being inspected (C) Daniel FriedmanTake an Organized Approach to Finding & Curing an Indoor Chemical Odor

The photo at left shows steel chemical drums that we discovered on a residential property during a home inspection.

Not only did these steel drums raise a question of possible environmental contamination of this site, even worse, they were uphill and close to a stream, raising a still more broad question of area contamination.

Hire an Inspector or Consultant vs Do-It-Yourself?

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem such as this one. It is a frequent frustration to discuss with readers and clients the common experience of hiring a costly investigator or hygienist to help with a problem only to find that that expert does the easy part - conducting a few (sometimes unreliable) sample collections, sends them to a lab and gives you a report. Such tests alone, without a translation into sufficient diagnosis as to permit action, are of limited use.

How to Track Down & Remove Source of a Building Smell

Smell test method (C) Daniel FriedmanRegardless of who is working on the odor source problem, several directions of investigation suggest themselves:

1. Try odor source tracking: try the
SMELL PATCH TEST to Track Down Odors
method to see if you can isolate the odor to a particular surface. It's cheap, easy, and can sometimes give dramatic results. When I refined and field tested this method, first suggested to me by Jeff May (Cambridge MA), the person we used as the "smeller" was in fact a pregnant woman whose sense of smell was reported to be particularly sensitive.

At left the author demonstrates a smell-patch test that can be used to track down odors to their source in buildings.

2. List building and building condition factors causing odors:
at ODOR DIAGNOSIS CHECKLIST, PROCEDURE we give a procedural checklist that can help track down the source of an odor by reviewing a laundry-list of types of odors, odor sources, and building and even weather conditions that can be diagnostic. Just as one example we've tracked certain odors to plastic windows or window screens that emitted smells principally after some time in direct sunlight.

If you suspect sunlight related odor emission note:

3. List & investigate building history, materials, location: in the odor checklist cited at item 2 we provide examples of building history that can point to a particular odor source. Add some more detailed considerations such as

Plumbing Vent leaks (C) Daniel Friedman Cheryl Lidawer

4. Use surface testing to confirm an odor source: best performed after we have some most-suspect surfaces in mind, it may be possible to collect and send a small physical sample to an appropriate test lab for confirmation of what we're looking at.

For example, at a home where I suspected amateur application of pesticide (chlordane), I cut a small sliver of wood that we sent to an independent test lab (my lab specializes in particle forensics not chemicals) who confirmed that the wood had indeed been soaked with pesticide.

5. Temporarily Contain odors & smell-related risks: if odors appear to originate in just a single room in a building, temporarily, try keeping the offending room's door shut and are minimizing exposure to risk.

Watch out: for odor desensitization: anyone who remains in an area where odor-producing substances are present, eventually becomes desensitized to the odors and can be thus fooled into thinking that the odor is not present or has been diminished. A good test is to consider how things "smell" to you or others on entering the condo just after you've spent hours or longer out in fresh air.

6. Remediation of odors or smells:  don't do anything expensive or disruptive towards a "cure" before you have a reasonably confident idea of what the problem is..

At ODORS GASES SMELLS, DIAGNOSIS & CURE we list many sources of odors & smells in buildings - the list itself may suggest some candidates for you that can help tracking down your own complaint.

Separately at ODOR DIAGNOSIS CHECKLIST, PROCEDURE we offer a procedural checklist that can help in tracking down an odor

How to Find Cures for Building Odors

Reader Question:

I found your site and have found it full of helpful possible explanations for an intermittent odor experienced in our condo rental. ... After intuiting possible causes of the odor I was interested in what cures or remedies were suggested and could not find any. ... I haven't yet found any cures or remedies related to my suspicions. ... I would like to describe our situation and see if I can be directed to a source or information that suggest possible cures or remedies.

We rented a condo where we are now living in May 2014. Prior to signing a lease, I noticed an odor that was somewhat pungent but dissipated after being inside for awhile. I thought it was the previous occupant's belongings or poor choice of scented products that left a lingering odor.

The odor has never completely disappeared and is intermittent. We've invited neighbors to witness it with some success and other times it disappeared too quickly for one to "smell". We've complained to the owner and management but haven't found a source and no one takes responsibility to remedy. A contractor that claimed he can rid odors with a machine was summoned but wouldn't guarantee an outcome without figuring out a source. Here's what we've observed and what we've done to date:

Odor is pungent and most obvious upon opening front door and strongest in the foyer.

Holding our breath and walking into the unit past the foyer, the odor is not as strong unless the place has been closed up for a longer period of time, then it is everywhere.

HVAC, air filters, all plumbing, gas logs, washer, dryer vents etc have been checked.

Does not smell like gas, septic or mold. Pungent is our best adjective and on occasion can seem like a lingering body odor. I've painted with oil and latex numerous times and refinished furniture and it is not like those odors.

Have put out vinegar, washed surfaces, aired out daily with fans, open windows and running the HVAC fan.

Have left for an hour or two and upon our return it can be as strong as before airing out. OR we recently left for 7 days and it was hardly noticeable upon our return.

The condo is about 1500 square feet. Building contains flats with a total of 24 units. Believe there's concrete between the floors with HVAC ducts and sprinkler system between our ceiling and the units above and below. The building was built in 2008. We believe the unit was empty for several years until it sold. The owner said she just thought it was new building smell and she lived in it for a couple years.

The hallways do smell of concrete but is different than what we are experiencing.

No other resident has complained.

Unit is on 2nd floor with one unit above, one unit below and garage below that.

There is a wood product floor and carpet. The foyer is the wood product, think it's wood flooring that's glued down to the concrete. Other materials are painted Sheetrock and wood trim, cabinetry, tile, plastic shower floor.

The building has had some gutter issues with rain leaks in other areas I've heard about.

The occupant above keeps a dog indoors and has had complaints about her trash and her doggie pads, but that's not the odor we have experienced.

I've kept a log on and off and think higher humidity/rain does impact the intensity.

I thought the test your site has with paper towels and aluminum foil was interesting but even if that does isolate it to our foyer floor for example, and it could be speculated where the location is, what are the possible remedies? How does one identify the odor itself?

Thanks for guidance you can suggest. - S.B. 10/3/2014

Reply: find & remove the odor source

There are no trivial or external "odor cures" that are valid, such as generic sprays or ozone. Rather, the proper approach is to find the cause or source of the odor and remove that source by cleaning, sealing, or if necessary removing contaminated or outgassing materials, or where odors are traced to a mechanical system such as a leaky plumbing vent, fixing that problem.

A Summary of Building Odor Diagnosis & Cure Strategies:

You can start tracking down the cause or source of an odor in one or more of several ways:

  1. ODOR DIAGNOSIS SIX STEPS - taking an orderly approach to odor source tracking - this article
  2. ODOR DIAGNOSIS CHECKLIST, PROCEDURE- an easy checklist of stuff to examine or test
  3. ODORS GASES SMELLS, DIAGNOSIS & CURE - includes a catalog of places to look when tracking down an odor source
  4. SMELL PATCH TEST to FIND ODOR SOURCE - procedure for testing specific surfaces or items to see if an odor source of if they have absorbed and are re-emitting an odor

The smell patch test procedure we describe at SMELL PATCH TEST to FIND ODOR SOURCE and which you note you've reviewed is useful when an odor seems strongest in a particular room and we want to determine if it is emanating from a specific surface or material.

If we confirm that that's the case, then depending on what the surface or material is we can decide on an appropriate action such as clean, seal, remove, or in some cases, cut open (a wall or ceiling cavity for example) to investigate further for a buried odor source such as a dead animal, a chemical leak into a cavity, or wet insulation such as some UFFI formulations that may outgas when moist or wet.

Check for Odor Transport from Other Locations

You might also want to look at the heating and air conditioning systems and also possible air leaks between your unit and neighbors to see if air movement or air delivery are transporting odors from another location (neighbor's pet, spills, etc.) For example

"Pungent" Odor Sources?

I'm uncertain what different people really are experiencing when they describe "pungent" odors since that term is often used to describe smells that are "sharp" or "penetrating" - but you might want to look also at CHEMICAL ODOR SOURCES that might have been left by use of a paint, cleaner, deodorant, spill, treatment, etc.

Keep an Odor Log to Identify Conditions or Equipment Operation that Relate to or Cause Smells

Keeping an odor log, some of which you've done in an incomplete form, can also help find an odor source that relates to weather, temperature, humidity, changes in building use, occupancy, or the operation of mechanical equipment - or other things that vary in or around a building.

Use either of the three files listed below to record various data that can help figure out the source of a mystery odor or smell - we recommend the first Odor Checklist Form listed below as it is the most detailed version. When using the Odor Checklist Form, also review our Checklist of Possible Causes/Sources of Odor or Smell Complaints that begins in this article, just below

Removing Odors by Machine?

You cite a contractor who says he can remove odors by using a machine in your home.

Really? Without finding and curing the odor source you will not remove a smell from a building, though you might temporarily disguise it with a cover-up scent (not recommended). Worse, you might create a still more terrible and expensive odor problem in the building if you permit a mis-use of an ozone generator (by overdosing the building and oxidizing some of its contents). See

At "More Reading" below you'll find additional odor diagnosis and odor cure articles listed by topics or by common odor problem sources or types.

Finding Odor Cure articles at

By using the search box found near the top right (in the light blue area) or at the end of each InspectApedia article you can also find information that you did not see in the recommended links found at Continue reading where we provide an INDEX to RELATED ARTICLES that includes live links to the entire topic.

Articles that describe cures for odors are referred to by just about any odor-related article or page you land-on at InspectApedia but can also befound by searching InspectApedia as I've described.


Continue reading at ODOR DIAGNOSIS CHECKLIST, PROCEDURE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


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ODOR DIAGNOSIS SIX STEPS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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