photo of a moldy basementIndoor Mold Contamination FAQs
Questions & answers about building mold contamination

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Frequently-asked Quest ins & Answers about indoor mold contamination:

Questions about What to Do About Black Mold and other Indoor Air Quality IAQ Contaminants.

Questions about How to test, remove, or prevent mold contamination. And questions on How to deal with mold related illness.

This website answers just about any thing you want to know about what to do about mold contamination in buildings: how to find, test, remove, clean-up or prevent indoor mold contamination. These mold-action & indoor environment investigation & cleanup articles provide expert, un-biased information for owners, occupants, inspectors.

How to recognize mold, how to test for unsafe mold, how to clean up or remove mold, how to prevent mold contamination in buildings, and what mold related illnesses and symptoms have been reported are all discussed in depth.

Green links show where you are. © Copyright 2017, All Rights Reserved.

How to Find, Test, Inspect For, Remove, & Prevent Indoor Mold Contamination: what to do about mold in buildings

Stachybotrys spores (left) and structure (right)In this article series we give detailed and authoritative information and procedures for finding, testing, cleaning and preventing indoor mold, toxic black mold, green mold, testing building indoor air quality, and other sick house / sick building investigations.

[Click to enlarge any image]

To find what you need quickly, if you don't want to scroll through this index you are welcome to use the page top or bottom SEARCH BOX to search InspectApedia for specific articles and information.

These questions & answers were posted originally at MOLD CONTAMINATION IN BUILDINGS - topic home.

On 2017-08-02 by (mod) Advice for sick tenants in mold-infested apartment in Tennessee


I'm sorry that you've suffered illness and loss of your black lab. Some "black molds" indoors can be harmful (Stachybotrys chartarum) though usually those are the molds you see but not the most seriously-harmful ones, as less-obvious but often present in moldy conditions are species of Aspergillus and sometimes Penicillium that more-often cause respiratory illness as those spores are smaller, inhaled into the lung, and are notorious among experts.

An "air test" is a dangerous approach to rely upon, especially where people are already sick and a dog has died. That's because air tests can give results varying enormously depending on how the test is conducted, and because the test does not find where the problem mold is nor tell us what remediation is needed - often people end up paying double the total cost of testing when they have to then hire an inspector to actually diagnose the problem and specify the cleanup needed.

If you know that your home has significant indoor mold contamination - more than 30 sq. ft. of contiguous mold - by simple visual inspection, confirmed by illnesses, then testing is not going to make one iota of difference in what needs to be done in the building.

The only reason you might want some mold testing done is to inform your doctor about just what has been your exposure, in the off chance that that would change the doctor's approach or treatment. If your doctor wants that information, then an air test is, again, unreliable because the most-harmful molds might not be the ones in the air that the test finds.

So what's needed is a visual inspection by an expert to find the mold, take physical (usually tape) samples of the dominant or largest mold reservoirs by type and appearance and location, and give those results to your physician. Tape testing to collect mold samples to send to a lab is technically easy - TAPE & BULK SAMPLING & TESTS for MOLD and any qualified mold lab can process those. What requires some experience and sense is recognizing where to stick the tape - where to collect the samples.

1. I suggest discussing testing usefulness first with your doctor.

2. If you need an onsite expert you might try calling Walter H. Carter, Inc. Chattanooga: 800-564-5537 environmental investigations - see Walter's information at in our ENVIRONMENTAL & MOLD TESTING SERVICES directory. (We have no financial nor business relationship with any consultant, product, service we discuss)

3. Beware about moving - which may indeed be appropriate for your case - that you

- do not move into another building that's also moldy
- do not carry moldy things from your old home into the new one: clean them before bringing them into the new home: laundering soft goods, using household cleaners, paper towels, etc. to clean hard items, HEPA vacuuming may also help.

See details about handling these concerns at RENTERS & TENANTS: MOLD ADVICE

Your doctor can refer you to a specialist in environmental medicine or mold related illness; you or your doc can also find medical experts at

On 2017-08-01 by Jeremy - town house that is infested with mold my black lab died

I live in Memphis and we having mold issues with our town house that is infested with mold my black lab died 2 weeks ago from a fungal parasitis disease in his lungs. We believe that his illness occurred because of the indoor air quality of our place because the side effects from being exposed he had all of them .

Also my other lab is starting to show some signs so and we've been fighting with allergies and breathing problems respiratory issues like stuffy nose all that good stuff.

Also we had mentioned that to our veterinarian who said there's a good possibility it could be directly related to the mold spores I looked at the descriptions of black mold and the symptoms my fiance and I are also experiencing some adverse medical issues as well

so the big question is it's is there somebody in the Memphis Tennessee area that could do a free mold inspection and also an air quality test to check for spores in the air.

We don't really have the money because we are going to be moving soon but we want to know if we've been you know if we can into any contact with the stuff in the pits responsible for my dog so does anybody in this area do free testing I saw where it said that you do it for the elderly and for disabled individuals I have PTSD anxiety ADHD depression just the name for you so I definitely have disappeared a couple could you let me know please thank you very much

How Should a Building Mold "Test" be Conducted?

Reader Question: does my mold test result indicate a bad problem? do I need a mold specialist?

We had a flood in our basement a month ago and before having any reconstruction done I wanted to make sure there was no mold present. I have a respiratory condition. The company that did the testing found mold present in one area and an elevated spore count in one area of the basement.

The mold identified was aspergillis penicillium and the advice was to get a company to get rid of it. The count for outside was 210 spores per m3 and in the basement 2600m3.

The basement was dry, but one area had a visible grey fuzz that was identified as mold. The main floor count was 110 spores per m3. I simply want to know how BAD the problem is and is it something that can be removed by a non specialist.

Do these numbers warrant professional intervention? How much would this cost, any idea? Your input would be appreciated. I think this website is very informative, and I would highly recommend it. Thanks,- N.M. 8/23/2013

Reply: what should your mold test consultant actually have done to provide useful information, and what should s/he report to you?

With respect I have to say I'm troubled that you paid someone to "test" your home for mold or perhaps better, "inspect" for mold contamination and then are left having to ask others to interpret and advise you on how to proceed. What the heck did your testing company take your money for if they're not going to actually try to be of use? More about actualy usable mold test and investigation reports can be read

Incidentally, "aspergillus penicillium" as your report stated, or Pen/Asp as many labs report, is a name used to describe the presence of either or both of two completely differnt mold genera/species - Aspergillus sp. or Penicillium sp. - a result that is offered when the lab has only undifferentiated spores that cannot be named more specifically.

Either of these mold families are common in outdoor air and are found indoors too, but when found indoors at high levels usually this indicates that further investigation is needed to find and remove the mold; The comparison of incompletely identified Pen/Asp spores found indoors with incompletely identified Pen/Asp spores found outdoors is somewhat nonsensical: we may be comparing counts completely different mold genera/species.

With that caveat and gripe stated and out of the way, your "count" shows that there is probably an indoor mold reservoir that needs to be found and removed - cleaning hard surfaces, disposing of stuff like drywall or insulation that can't be cleaned; then you want to know for sure that the cause of mold growth was properly identified and corrected as well. Details about common mold test report "mold levels" and test accuracy and precision are found at

And the work to clean up mold contamination needs to be done properly so as not to blow moldy dust elsewher, contaminating the home and leading to a new costly round of cleaning.

A "mold test" that just has someone stop by to grap an air, dust, or worse, culture sample to come up with some sort of "mold count" is, alone, not very helpful, and certainly not worth more than about $50. in my opinion. Such a mold test, especially if results are negative, are extremely unreliable. And even when a "mold test" such as yours is suggestive of a problem, you are left wondering

Watch out: by no means do I suggest that every building needs a costly mold investigation by a true expert. The article: MOLD / ENVIRONMENTAL EXPERT, HIRE ? can help you decide if conditions warrant bringing in someone who actually knows something and who will actually help you. I would not go back to yor first company again.

Small areas of mold, if that's all you've got, say less than 30 sqft of contiguous moldy material, are usually handled as a normal cleanup job without heroic efforts, For a small or DIY mold cleanup project see

Larger areas of mold contamination, or if a larger area is discovered in cleaning the small one, do indeed merit professional cleaning. When a professional mold cleanup job seems to be needed, these articles will be helpful

A proper "mold contamination inspection" inspection includes

But nobody can possibly make a confident, safe statement about just what mold remediation you need from an email alone nor can a simple mold test in air or on surfaces define the extent of mold contamination nor cleanup that may be needed at a building.

On 2017-06-22 by (mod) worried about fiberglass insulation

You'll need an onsite expert for an accurate diagnosis and action plan.

Meanwhile you can reduce the health risk by making the crawl area negative air pressure comp ared with the space above, using an exhaust fan or two.

Wet Insuation gets removed and thrown out.

On 2017-06-22 by Lauren Hoshoian

1 month in a newly constructed home with a crawl space. The crawl space has pink fiber insulation from headers to floor, wrapped in vapor barrier that has not been sealed..

.the reason given is that the exterior was wrapped in Tyvek. The space is wet! There is moisture behind some of the vapor barrier and it is dripping through the pink and down to the cement floor....builder used some wood that has mold on it and states that since the mold is dry it is not a problem...

we have a de-humidifier running 24/7 to help the new building dry...we are worried about the spread of mold as there is lung disease in one of the owners...any solutions and should we be worried!

On 2017-05-27 by (mod)

Our email is at the page top or bottom CONTACT link.

I hope you'll read the thermal tracking articles as that will help you recognize the possible stain patterns and causes that you've mentioned.

On 2017-05-26 by sethrobyn1

Not sure from the pictures on your there a way for me to send a picture? And would bleach remove thermal tracking? Why would they just start to appear? Thanks!

On 2017-05-24 by (mod) What is causing my exterior plaster walls inside my cupboards to turn dark in patches as if it is stained?

I can't guess from just your e-text, but it's possible that what you're seeing is not mold but thermal tracking stains. Use the search box just above to find our articles on THERMAL TRACKING to check out the stain locations and patterns in your home, then let me know what you think.

On 2017-05-24 by sethrobyn1

What is causing my exterior plaster walls inside my cupboards to turn dark in patches as if it is stained? It just started six months ago and the first time it happened, I cleaned it with bleach and they disappeared. Now they are back again. Our house is approximately 90 years old. What is causing it? Regular cleaning doesn't work...only with bleach. My kitchen is very humid and we have a dehumidifier going most of the time. I can supply a picture.

On 2017-03-23 by (mod) possible illness related to wet ductwork


If your doctor agrees, your description is enough to raise a question of building related illness, (as it sounds to me as an amateur), still it'd be odd that you'd import so much dust or chemical from your prior home into the current one to fully explain the symptoms. From a quick read I see that Sarcoidosis is itself a disease of unknown origin.

Clothing, linens, etc. that have been laundered or dry-cleaned wouldn't be likely to continue to be a significant source of imported contaminants, but other soft-goods such as upholstered furniture or rugs that weren't cleaned / HEPA vaccumed can sometimes import reaction-able levels of mold, allergens, or other contaminants. Hard-surfaced goods can certainly be simply cleaned with a household cleaner.

It might make sense to have someone competent inspect your present home for obvious hazards including the basics. Then to study the dust or residues you describe you'd need both a pesticide chemical test and particle identification of in both cases representative samples of - a surface swab or pesticide-suspect-contaminated material and of representative settled dust or a vacuum-cassette sample of soft goods surfaces

Use the search box just above to search InspectApedia for DUST SAMPLE METHOD to see an easy way to collect surface dust,
Search for VACUUM CASSETTE FILTER SAMPLE TESTS for DUST / MOLD to read how some professionals might sample upholstered goods or a carpet.

The chemical test lab that you or your consultant would select will have advice about what pesticide testing might be most useful and how such samples should be obtained.

If you search InspectApedia for a 3rd article WHEN TO HIRE AN EXPERT there's help deciding if/when such an expense seems justified.

Steer clear of "experts" who for a high fee (or not) stop by to collect a few samples to toss over the wall to a lab who will toss over their wall a report to you - that's not of much use.

On 2017-03-23 by Yva

I recently moved from a place that has quite a bit of water damage but I'm not certain if that is the root of my problem.

While living there, my room was connected via the closet to a grow tent in the garage where pot was being grown. There was a large duct that ran through my closet up and out through the attic.

This duct was often ripped and at one point there was a bug bomb set off for spider mites, there was also powder mold on the plants in addition to other mold in the walls and carpet as well as dust and dust mites and many animals in the home. I have so many allergies and now that I've moved all of my belongings taken from that room trigger my allergies with a burning sensation on my skin, in my lungs, mouth and throat.

I don't know if the culprit is mold, bug spray, dust or what. Is there any way for the lab to tell me what kind of offensive residue is on my belongings.

Some of it feels greasy, other residue feels dusty and powdery. It all burns and itches horribly. Please help. I've pretty much lost all that I own and I am disabled with many medical conditions including Sarcoidosis. I think that I now have CIRS from living in the aforementioned conditions.

On 2017-03-23 by (mod)



Hi Anna, I read a your original post discussing your mold issue. That is an unfortunate situation to be in. You made mention of insulation and attempting to seal from the exterior and adding caulk to seems to eliminate air flow. Although this is a step in the right direction, I don't think it will completely solve your mold problems.

The reason is more to do with air pressure when your HVAC system is running. No matter the level of crevice sealing you do, the air intake will pull moldy, stale air from your unfinished basement/crawl space into the duct work, and release the contaminated air into your home. The only real solution is to stop the water and moisture issue at its source.

I know you aren't in a great position to encapsulate or waterproof your entire home, but I think you could benefit from viewing the material on our website. We have information that discusses mold remediation and waterproofing and insulation. We don't offer services in your location, but I certainly recommend contacting a local encapsulation specialist for a consultation.

They may can at the very least offer you an idea of what will be required to solve your mold issue. In the meantime, please view [ online articles about mold remediation ] to learn more about waterproofing. I will say that in addition to solving your mold issues, encapsulation can help reduce your annual utility bills, which can help offset some of the costs you may initially incur to solve the problem.

Good Luck,

Jason Mullins, Crawl Space & Basement Technologies
Raleigh, NC

On 2017-03-14 by (mod) 8 out of 23 kids in my sons university dorm have been sick

Jackie some mold exposure standards are at MOLD STANDARDS (found by searching for "mold exposure standards" using the search box just above)

Keep in mind that mold spore toxicity varies significantly by size, species, genera, even what the mold is growing upon, and that individual vulnerability also varies widely.

Also, unless there is a specific reason to suspect that mold related illness is at work - such as visible mold, mold odors, or building leak history - it could be a serious error to jump to the assumption that mold is the primary target of a building health and safety investigation.

An on site industrial hygienist familiar with the issues should be involved, or a similar expert, as should the doctors who can express a view of possible causes.

Justa as an example, mis-application of a chemical spray, pesticide, or something else could be at work.

On 2017-03-14 by Jackie

My 8 out of 23 kids in my sons university dorm have been sick with weight loss, skins rashes, and hair loss. The university did a mold test but I have no idea how to tell if the levels are high or potentially causing these illnesses. Do you have a suggestion for having the test interpreted?

On 2017-03-05 by (mod)

Thank you SmithD. We work hard to provide researched and unbaised useful information so as editor I'm really happy when readers find it so. We also welcome questions, content suggestions, critique, content contributions - working together makes us smarter.

On 2017-03-05 by Smithb116

Some really quality content on this website , saved to fav. kegbgfeacdedgkag

On 2017-03-05 by Smithd969

I appreciate, cause I found just what I was looking for. You have ended my 4 day long hunt! God Bless you man. Have a great day. Bye cggkggaafccceeaa

On 2017-01-19 by Anna


I have appreciated your advice before and I am hoping you can help me out again!

We have a house built in 1958 that is made of brick. It had a long history of water problems in the unfinished block basement, and after we moved in we discovered mold in the attic. We have since ventilated the attic at the soffits and ridge and dried up the basement with gutters, grading, and exterior waterproofing and a curtain drain on the wettest side. We have a very large humidifier keeping our basement below 50% humidity currently.

We have extensive brown and black mold covering the ceiling of our attached garage. The garage has standing water after rain. We plan to fix drainage on the garage side in the spring and rebuild the cracked and bowing wall that is allowing the water in. At that time we will take down the drywall in the garage and replace it with something more mold resistant.

This winter we discovered that we have mold growing inside our living space. We have found spots of brownish mold behind the kitchen backsplash, behind the bulkhead above our cabinets, behind our baseboards, and inside our closets. We think the mold may be due to the high humidity for so many years in the basement, but other theories are possible too:

The exterior of our house is solid masonry. Furring strips are nailed to the masonry and foil paper is either behind or on top of the furring strips (we can't figure out which) with drywall as the final layer. Besides the foil paper, the house is completely uninsulated. We live in Vermont and routinely experience subzero temperatures. We wonder if the mold, particularly the baseboard mold, could be caused by condensation between our very cold walls and the warm and humid house. All of the mold that we have found in the house, with the exception of a very small amount in a closet, has been located on an exterior wall.

We have started caulking every gap in our exterior wall drywall and trim to reduce air bypass leaks. We can't afford to replace cabinets, trim, or drywall so we are hoping that a combination of caulking and drying up the basement will be enough to solve our problem, and the mold will be contained enough not to be a health concern. Do you think this is a reasonable expectation?

Also, we can't insulate our house right now due to cost, but we do want to sometime in the future. We have heard conflicting reports about the best way to insulate brick houses. From what we have read, insulating from the exterior is the most thorough solution, but also the most expensive when you consider the cost of siding and extending the roof overhang to accommodate the increased wall thickness. A contractor suggested just layering foam board over the existing drywall, but we feel this could invite mold growth in the drywall material caught between the insulation and the block. Another option we have researched is tearing out the drywall, foil paper and furring strips and applying spray foam directly to the masonry from the interior. What is your suggestion?

Thank you for all of your help. We have used your advice to address our attic and basement problems and hope you can help us here as well.


Question: Watch out for scare-tactic mold abatement contractors

watch out ,watch out, watch out !Watch out for scare tactic doomsday mold abatement contractors. and i use contractors loosely. sold a custom spec house to a very unhappy in general lady doc who rented 1st floor of 3 out and tenant soaked floor and surounding area from shower. after 3 years of blaming me for everything wrong with her home and life i stupidly agreed to help her. big mistake

. i cut out about 10 sq ft of d wall after removing alittle base and floor.

got a mold test from one of these mold mongers and all three floors were off the chart. needless to say all my fault. they recommended 12k of abatement work. no guaranty ,could need more.

yaa $$$ i sprayed the area in bath w/ 50/50 bleach h20 daily for 3 weeks. re tested w/ a different co. and guess what, that's right a miracle ..... no mold ..... 4 bucks o bleach B- WARE - Greg G 5/27/2012


Greg G

I agree that the skill level of mold contractors and investigators varies widely.

One step that can protect you is to never use as a mold investigator someone who has any business or financial or other relationship with the mold cleanup company who would do the work if a mold problem is found. For example I have come across a mold remediation company whose principal owner is the mold investigator, a handsome fellow who uses a temperature sensor to find oool spots on the walls claiming it's a "mold detector".

Like any good falsehood, there is a slight possible element of truth, but basically he's not much different than those window salesmen who used to run around with a light meter telling homeowners it was an energy loss meter. True, but false.

Also, anyone who is relying on "bleach" as a mold cure is telling you in advance they don't know what they're doing.

Question: foul odor from a storage room

I have a foul oder coming from a storage room that has no outside ventilation or windows.

This roon has no plumbing nearby and has clean smelling air to the top attic area and below and to the right wall and entry area. The only walls i am unable to check is the two outside walls. There is a smell that smells like sewer smell and have no idea what to look for next. - Bill 10/1/12


Check for a dead animal in a building cavity. Check contests for something that leaked. See ODORS GASES SMELLS, DIAGNOSIS & CURE our odor diagnosis procedures for details about how to track an odor to it's source & then remove it.

Question: where should outdoor air samples be taken?

Should an outside air sample be taken at the ground level or on the porch which is five feet off the round? - Dan Tewell 9/26/2012



I would never collect an outdoor airborne mold sample right at ground level unless the purpose is fungal research - that is, an effort to collect fungal spores that are at or on ground level materials.

Few people spend much time inhaling air with their nose on the ground. There are other defects in outdoor air mold level comparisons, as we discuss in mold test validity articles here.

As for taking an air sample on an outdoor porch, that may give a more representative sample, and depending on wind direction and other weather conditions, might avoid severe sampling errors that can occur when using a typical portable slit impaction air sampler or vacuum cassette outdoors in wind.


Continue reading at MOLD CONTAMINATION IN BUILDINGS - home, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see this

Article Series Contents

Suggested citation for this web page

MOLD CONTAMINATION in BUILDINGS, FAQs at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Frequently Asked Questions (FAQs)

Click to Show or Hide FAQs

Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.


Ask a Question or Search InspectApedia

Questions & answers or comments about how to find, test for, remove, clean up and prevent mold contamination in buildings

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman