Definition of indoor air quality problem status:
How to decide if a building has an indoor mold or similar IAQ problem? This article describes how a building owner or occupant may conclude that there is evidence of an indoor air quality problem - enough to decide to take further action.
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An expert who is asked to determine whether or not a building has an actionable mold contamination problem (or other indoor air quality problem) will interview building occupants, owners, maintenance staff, conduct a thorough inspection of the building inside and exterior to identify both visible mold and conditions that make a hidden mold problem likely, and s/he may conduct tests of indoor surfaces, settled dust, or air to help identify problem areas.
Not every mold worry merits a costly onsite investigation. But failing to hire an expert when one is needed can itself be a costly mistake.
There are both obvious evidence as well as more subtle clues that assist a building owner, occupant, home inspector, or buyer in deciding if a building has or is likely to have an indoor mold contamination issue, including the following:
Watch out: the EPA and other experts warn that the absence of apparently-building-related symptoms does not guarantee that the building indoor air quality is acceptable. For example, some diseases (such as asbestosis or lung cancer) might be due to long term exposure to airborne asbestos, radon, or other chemicals, carcinogens or pathogens. [5]
If you feel unsafe, follow the advice given above.
Additional information is at
I was hoping to get some quick advice from you regarding my mold problem, and the sooner the better.
I feel as though my management and landlord are pressuring me to just do a paint job and don't want to admit there is mold because of their liability and costs, and I don't know that I can trust expert advice if I call in mold specialists (as you articulate in your amazing guide to mold). I also do not have the money to call in experts and seek advice, as I am currently a student and in a great deal of debt.
I understand that you cannot give me exact advice based on a photograph, but I am at least hoping that you can just give me an opinion as to whether I should call in an expert for the problem.
I live on the 10th floor of a fairly nice apartment complex, and this mold has appeared in my bedroom. The room is not ventilated with open windows, but it has the sole convector that is both the AC and heat in my building. It appears like it originated from upstairs, or for the convector (which is just under the visible window in the picture). The mold grew rather quickly and spread fast, and I believe it may be irritating my mild asthma. I live in Washington DC, which is a very humid place.
My concern is this: I do not want to have to rip out walls as I am in the middle of a school semester and that would not be ideal since I would have to relocate; meanwhile, I don't want to bleach and paint over it, only to have this problem arise again. I understand that you may not be able to give me expert advice through a simple photo, but in case you can tell me whether this problem looks serious or not, I thought to email. Because of my asthma, I understand that you may be obliged to recommend an expert, but if that was not a concern and a paint job will suffice, that would be ideal for my school work.
I know this may be unreasonable, but I am hoping you can get back to me tomorrow as my landlord is coming to see the unit and I want to be able to make a good argument and uphold my right to have a livable apartment. However, your advice would be much appreciated whenever you can give it, whether tomorrow or weeks or months from now.
Thank you so very much, and more specifically, thank you for your guide - it was the most helpful thing on the internet! - S.M., D.C.
My opinions below are based on your email, your photograph, and my own field and lab experience in building mold contamination diagnosis and remediation. Naturally a competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem and that would permit recommending the proper steps to correct these conditions. That said, here are some things to consider:
Extent of Visible Mold:
Your photo shows heavy black material on a ceiling that from your description sounds and looks as if it is almost certainly mold. It would be unusual for only one mold genera/species to be present under these conditions, so it would be an error to assume that the black mold you see is the only mold there nor even that it is the largest mold reservoir nor that the black mold is the most harmful mold present.
For example, if the mold growth was caused by leaks into the ceiling cavity from above, there could be a larger reservoir of mold in that space.
The mold growth pattern suggests that it is following a previous paint pattern, though there could be other explanations. More significantly, there is almost certainly more than 30 sq.ft. of contiguous moldy surface in this area. In your photo it looks as if mold growth is extending down the building walls from the ceiling area.
Health Risks of Occupants
Your concern for irritation of asthma is a very reasonable one. In my experience both chronic exposure and short term high level exposure to at least some molds can increase mold sensitivity and even induce severe allergic or asthmatic reactions in some people. The longer you are exposed the greater the risk.
Conclusions: hire a mold expert
Under these conditions, and as we discuss at MOLD / ENVIRONMENTAL EXPERT, HIRE ? it is very apparent that professional inspection and diagnosis of the location and extent of mold growth and the steps necessary to not only remove it but stop future mold growth in the area are what's needed.
My conclusion is that the problem looks serious and that you need a competent onsite professional to confirm the extent of mold growth, its cause, and the steps needed to correct the condition. As you are renting this apartment you will want to determine who is responsible for fixing this apartment mold problem, and even if you bear none of the responsibility you'll want to assure that it is handled correctly.
See RENTERS & TENANTS GUIDE TO MOLD & INDOOR HAZARDS
Warnings about Mold "Tests" and "Treatments"
I don't mean just "mold testing" - which would not be helpful.
In addition, because of the amount of moldy surface, it's likely that dust containment, negative air, and steps to protect your own belongings as well as the apartment contents will be needed during demolition and cleaning of the surfaces.
Simply painting, spraying, or surface treating these areas would be an inappropriate approach. YOu'd be leaving mold-contaminated ceiling materials in place, perhaps a significant problem in the ceiling cavity, and almost certainly the cause would by that approach remain un repaired. When there is moldy drywall the proper repair is to remove that material - it cannot be reliably cleaned and the hidden side would remain un inspected and untouched as would any mold in the cavity above.
Does it Make Sense to Try an Emergency Seal-Off of the Moldy Area?
While I do not recommend it in this case, in an emergency in which an occupant simply cannot move out of an area to permit necessary mold cleanup work, it might make sense to install a continuous 6-mil poly plastic temporary mold barrier covering over all of the contaminated surfaces as a short term stop-gap measure.
The problem with this approach is that no one has adequately determined the extent of mold contamination: the barrier may be incomplete or inadequate. Also the barrier, by trapping moisture, is likely to increase the mold growth problem, and finally, because the cause of growth has not been determined I'd have little confidence that it would not appear soon outside the barrier.
Need to Move Out of a Moldy Apartment? Protect or Clean Items to be Moved
I am sorry to say that in the case that you describe the problem room needs to be isolated from the rest of the apartment. If this cannot be achieved then indeed you may need to move elsewhere during the remediation. That question will be answered by a professional inspection and by the mold premeditation company. Watch out: if your apartment contents become contaminated with mold growth, or more likely in this case, moldy dust, they may need cleaning before you move them to the new residence.
My husband, 5-month old son, and I recently moved into a water-front basement apartment (about two weeks ago) and immediately noticed our allergies flair up. My husband and I are both allergic to mold, but we can't find more than small amounts on the floor boards. In the closet of our bedroom, there is a boarded up septic pump that smells terrible and might be contributing to our problem. Our landlord is not terribly concerned at the moment. What can we do to test the area? We have all developed colds and wake up each morning with terrible congestion, drainage, and headaches. - Rosi B.
There are a few things an experienced investigator hears that trigger a sort of "red flag" or prejudiced expectation of trouble, including basement+apartment+waterfront. The worry-o-meter points up a bit more for "mold allergies"
and more for "septic odors".
You are describing at least two possible problem areas: mold and sewage pathogens/sewer gas. And there could be serious health risks. Notify the landlord in writing of your concerns immediately. You can hire an experienced environmental investigator (search our website for "Mold and Allergen Inspectors & Testing Consultants" for a directory that might be helpful. Discuss the inspector's experience, and the extent of actual inspection, not just "testing" before hiring someone. Tests performed without an expert inspection are not worth much.
I was hoping to get some quick advice from you regarding my mold problem, and the sooner the better.
I feel as though my management and landlord are pressuring me to just do a paint job and don't want to admit there is mold because of their liability and costs, and I don't know that I can trust expert advice if I call in mold specialists (as you articulate in your amazing guide to mold). I also do not have the money to call in experts and seek advice, as I am currently a student and in a great deal of debt.
I understand that you cannot give me exact advice based on a photograph, but I am at least hoping that you can just give me an opinion as to whether I should call in an expert for the problem.
I live on the 10th floor of a fairly nice apartment complex, and this mold has appeared in my bedroom. The room is not ventilated with open windows, but it has the sole convector that is both the AC and heat in my building. It appears like it originated from upstairs, or for the convector (which is just under the visible window in the picture). The mold grew rather quickly and spread fast, and I believe it may be irritating my mild asthma. I live in Washington DC, which is a very humid place.
My concern is this: I do not want to have to rip out walls as I am in the middle of a school semester and that would not be ideal since I would have to relocate; meanwhile, I don't want to bleach and paint over it, only to have this problem arise again. I understand that you may not be able to give me expert advice through a simple photo, but in case you can tell me whether this problem looks serious or not, I thought to email. Because of my asthma, I understand that you may be obliged to recommend an expert, but if that was not a concern and a paint job will suffice, that would be ideal for my school work.
I know this may be unreasonable, but I am hoping you can get back to me tomorrow as my landlord is coming to see the unit and I want to be able to make a good argument and uphold my right to have a livable apartment. However, your advice would be much appreciated whenever you can give it, whether tomorrow or weeks or months from now.
Thank you so very much, and more specifically, thank you for your guide - it was the most helpful thing on the internet! - S.M., D.C.
I had energy efficient windows installed in my townhouse over a year ago. This past spring one of the master bedroom windows leaked after a rain storm because the caulking failed. The company immediately came out and re caulked the window and it hasn't leaked since. My concern is that I now have a water stain under the window on the drywall, and since I have a mold allergy, I'm wondering if there might be mold on the inside of the drywall.
I read your article on testing the dry wall but as mentioned in the article would rather not cut into it unless it's necessary. I looked at other articles but didn't see one with a picture resembling the water stain I'm concerned about. What would you recommend? By the way, this is a very helpful website. I was considering using ozone for any possible mold in my place but see from your article that's not a good idea. Thank you. - G.N.
A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem with mold, hidden mold, and with tracking down just how much water leaked into the building and where it went. Indeed a basic axiom in deciding the level of risk of an actionable hidden mold reservoir is to identify places where water has leaked into the building, asking how much water leaked where for how long and just where did it go in the building? Follow the water.
That said, here are some things to consider:
First, how disappointing that your new windows leaked - certainly a wet wall below a leaky window is not particularly energy efficient, and indeed it could become a mold reservoir.
Second, the risk of a mold problem that you can't see but that is significant enough to merit removal is not something I nor anyone should guess at by email with so little information. In the article above at MOLD / ENVIRONMENTAL EXPERT, HIRE ? we give some suggestions on how to decide if it's justified and appropriate to hire someone to perform a more competent mold inspection at your building. Testing alone is not reliable.
Third, I would not rely on "mold tests" alone to decide if further investigation is needed. A "mold test", especially an air test for airborne mold, performed without an expert diagnostic inspection of the building is just not reliable in cases where the result is "negative".
We moved into a basement apt last nov and both scott and myself have been on and off sick ever since we moved in, we had management come to investigate the problem and so now they are going to replace the windows, my question is this, by replacing the windows, which were the main causes of mold in our apt, i know its in the carpet and in the walls, we both suffer from hiv and we want to move out of this place, how do we go about getting out of our lease without getting taken advantage of?
our lease is up oct 31 and we cant stay that long, we have already applied for a new apt in a different area and got accepted and plan to move out on sept 10th,our lease agreement states that if we break our lease we will have to pay 1 and a half times our rent which is about $1500 and we just cant do that, what advise can you give us before we go and give our notice? please advise, thank you
clay and scott
I would NOT assume that your windows were the main cause of a mold problem, though certainly leaky windows or lots of condensate running into walls could be significant. Often a basement apartment has a history of leaks into walls, sometimes prior floods or water entry, and thus there is a risk of larger hidden problem mold reservoirs that can be found by an expert who combines visual inspection, history taking, and strategic testing, perhaps even some careful looks into wall or ceiling cavities in highly suspect areas.
As tenants you may have trouble with the cost of a competent inspection (about as much as your rent) and with the need for invasive measures. If you've notified the landlord in writing and no one will act, and you want to move, you need to consult a real estate attorney. Typically the combination of actual credible evidence of a habitability issue that the landlord won't or can't address is enough to justify breaking a lease.
Beware: if your apt is really moldy your possessions may need to be cleaned before importing them to a new home.
Thank you for your excellent site! I am in a quandry about mold testing & remediation. We live in a relatively new home (about 10 years). Because I suffer from allergies & sensitivities, we had this house thoroughly inspected when we purchased it 7 1/2 years ago, by both structural inspectors & an environmental inspector (for mold & radon); both inspections were passed easily, and the environmental inspector's report called our home "one of the cleanest" he had ever tested. But I am now (and for some time) smelling mold. Nobody else does, but everyone knows that my nose knows. We have had several inspections done by various professionals, and so far we have found and corrected 2 small leaks and small mold problems ... but I still smell mold.
The only possible source I can imagine is the cathedral ceiling, which we cannot inspect properly because there is no attic there. The attics on the sides of the houses have been inspected & seem clean, and the roof has been inspected and declared good, no leaks.
One friend has suggested that perhaps there is simply inadequate air circulation in the cathedral ceiling which allows some mold growth in the insulation. We have had an infrared camera inspection, and no obvious leaks/cold spots were found (but some vaguely cloudy areas that the operator could not interpret). I have called more mold inspectors, who want to do very costly sample testing. I don't see the point: I smell the mold, I want to know WHERE it is and get rid of it; I don't really care what kind it is.
So, my question: Can we simply seal the attic/ceiling to prevent air infiltration and avoid ripping out the entire ceiling of our home? If not, what can we do to reliably verify if this is the source of the smell, or where else there could possibly be mold, other that ripping out our ceiling? Thank you! (And apologies for the long & disjointed letter)
Lisa, if you smell mold, there is probably a mold contamination source to be found and remedied. It may be possible to home in on the problem if your "expert" really is one - someone with both training and experience in finding building mold. We use a combination of case history, occupant complaints, and a thorough visual inspection of the building for history of leaks, likely moisture problems, and similar clues to identify the "most likely" areas of hidden problems that justify further investigation - often by a small test cut into a cathedral ceiling to use your example.
Your description of your "experts" makes me wonder about the services you received:
I wouldn't expect an experienced professional to "pass" or "fail" a building. Those terms are simply too much of an over simplification; most experienced inspectors speak with more caution, and will tell you whether or not they were able to find evidence of a problem that merits further investigation or not.
I would not just "seal" the ceiling as a mold "cure" without first finding out where the problem mold is, how large the mold reservoir is, and what caused it. Why?
So first let's find out if there is a mold problem that needs removal and find out if there is a roof leak that needs repair.
I recently had a air quality sample done of our house. Asp/Pen outside was 920, on the first floor it was 644 and in the basement it was 2850. There are no visible signs of mold. Should I be concerned and do I need a mold remediation specialist? It's a finished basement.
thanks! - John G. 10/7/2011
John, my best advice on deciding if you need to hire a mold investigator or mold specialist is summarized in the article above. There you'll see that we list a variety of factors one would consider in making a decision to go further or not. Depending on various factors such as occupant health risks, building complaints, visual observation of water or leak history, etc., even a small visible mold colony could prompt further investigation.
Your high indoor Pen/Asp count is roughly 3x the outdoor count (and of course the outdoor count might not even be the same mold spores as found indoors) and your basement count is highest, suggesting that if there is a substantial problem mold reservoir that's where to start looking. That alone might be enough to prompt further inquiry.
Did you ask the expert you paid to perform mold tests for an interpretation of the rest results? If not, you're not getting what you paid for.
I was wondering I could email you a few photos of my basement rafters (I can not figure out how to attach the photos to this comment). The area is below my living room (no overhead water source) and this mold-like staining is on several rafters intermittently, as there are rafters between the stained ones that have no visible mold. There has been no water intrusion and the rafters have been dry. In the room is our HVAC and other mechanicals. I have reviewed your articles and it seems like it may be the cosmetic variety that is harmless. However I do notice a moldy odor in the basement during the rainy/humid seasons. I am getting conflicting ideas based on your articles about mold odor meaning there is definitely mold that should be dealt with and cosmetic mold. - Anon 12/26/11
Mold on basement rafters?
We would be glad to take a look at photographs that help explain a question you pose to InspectAPedia experts. Use the CONTACT links found at the top or bottom of our web pages. While examining a photograph is never a substitute for an expert on-site inspection, and while often an expert will find important conditions that a layperson may have not noticed, photographs do provide excellent information that can often allow us to make useful comment.
I and my kids have been sick constantly for the past 4 months with respiratory issues. My husband thinks it's just because my son started preschool but I was concerned so I hired a professional to do a mold inspection and test. The inspector found no visible sources of mold, water damage, etc. He thought our house was pretty clean.
But then the air samples he took came back from the lab with around 300 count of Penicillium/Aspergillus mold spores in the bedrooms where the samples were taken. The final report called for $2000 of professional remediation cleaning of the bedrooms using HEPA vacuuming, etc from their company to solve the problem solely based on the air samples taken because the inspection otherwise found nothing.
At this point, I"m not sure what to do. I'm not sure whether I should move forward with this costly remediation when there isn't a source of mold found. I'm not sure this remediation of cleaning out the rooms with even make a difference overall. And I'm not convinced we have a problem with an Aspergillus/Penicillium spore count of 300 in the air. If I was convinced then I would spend the money but it's a lot of money for us. I'm not sure what to do. - Felicia 5/29/2012
To clarify a bit further. The outdoor asp/pen count was 90. So the inside count was 3x the amount as outside at 300. But I did read in another inspectapedia article that clean building counts ranged from 250-600ish. I read the article above but am still not sure what to do. Thank you for your help. - Felicia
Felicia the report and advice you received sound very questionable to me; if there is a high indoor Pen/Asp count then one needs to look for and find the source of that material. Just surface cleaning of exposed areas is premature and a waste of money - it's treating the symptom without finding and fixing the cause.
An expert inspector examines the entire building, inside and out, and when there is no visible mold of consequence, but testing and case history and other observations suggest a mold problem, then s/he looks for and investigates further into the most likely locations of a hidden problem, often by looking at the building leak history or design that points to most likely locations for hidden leaks or moisture traps.
Watch out: For an article with many examples of how one might interpret various mold inspection or mold test results with different "spore counts" take a look at MOLD EXPOSURE STANDARDS. But keep in mind that very trivial changes in how a "test" is conducted can result in several orders of magnitude difference in the "count" number obtained, and worse, some tests that detect mold are detecting the mold that liked a culture not the mold that is a problem in the building.
1. Comparing indoor to outdoor mold spore counts, while a common practice, is highly unreliable as it's often comparing apples and oranges. For example outdoor Pen/Asp could be a completely different genera/species than the indoor mold, thus making their comparison irrelevant;
Also even very low spore counts can indicate an indoor mold reservoir in certain cases, such as finding Pen/Asp spores in connected spore chains.
2. Please take a further look at the article above, including the FAQs section, intended to give you some criteria to help decide when it is justified to dig further into this question for an individual building. Then let me know what questions remain.
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