How to Find Mold Contamination in buildings InspectAPedia® -
How to find hidden or less obvious mold contamination sources in buildings
Mistakes to Avoid when Locating Mold for a Mold Cleanup Project
What a Mold Inspector and Mold Test Consultant Need to Know
Essential Steps to Follow When Screening or Testing a Building for Mold
Questions & answers about how to find & test for mold contamination in buildings
How to find indoor mold contamination sources: This document is the starting point of our mold guide that describes the essential steps needed when searching for problematic mold in buildings. This article provides an easy to understand step-by-step guide for
dealing with toxic or allergenic indoor mold and other indoor contaminants: what to do about mold.
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The steps in this document will be sufficient for many building owners who want
to do their own mold investigation, mold testing, mold cleanup, and mold prevention in their home or office.
Extensive, technically detailed in-depth articles are also organized at our Mold Information Center. This is a chapter of ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD.
HOW TO FIND MOLD: How to Inspect Homes and Other buildings for Mold - the Basics of How to Find Problem Mold Indoors
OK, if you don't want to read our general advice below about how and where to look in buildings in general, and how to stay out of mold trouble, jump right into the articles listed as links here:
Much too often we are contacted by a property owner who has just paid a substantial sum to "remove black toxic mold" from a building only to learn that conditions in the property are no better, sometimes worse, than before. What went wrong with the mold cleanup project?
Incomplete mold cleanup projects: The owner or mold remediator was quick to address a visible mold problem without first making sure that all of the important mold reservoirs in the building had been found and listed for cleanup as needed. The result unfortunately is that another cleanup may be needed. Worse, we sometimes find people addressing the wrong mold problem in a building, for example scrubbing off cosmetic black mold that was harmless while leaving a real problem with mold-contaminated building insulation that looked "ok" to the eye.
In-valid mold testing: relying on a quick air test, swab, or culture to locate the problem mold or to pass a post-mold-cleanup clearance test without including a decent inspection of the premises, the remediation containment system, checks for cross contamination, etc. Sometimes this happens because the same people are providing the mold assessment, the mold cleanup, and the post-cleanup inspection and testing. These conflicting interests are risky for everyone concerned.
Questionable mold cleanup procedures: were followed such as inadequate dust containment, or reliance on simple biocide sprays where physical cleaning or removal of moldy materials was needed.
What does an Effective Mold Investigator Need to Know?
Building science: where do leaks and moisture problems occur in buildings, how do air and moisture move in a building
Mycology: what molds are harmful, which are cosmetic, how, when, where, and why does problem mold grow n a building
Industrial Hygiene or Sampling Methods: what sampling and test methods are sound and produce valid results, and which are magic and speculative.
Field Investigation & Mold Test Lab Experience: Where do problems occur in buildings, how do we find them, what test methods are valid, what do labs do with mold samples, what do lab results mean, how do we interpret "mold counts" or other measures of moldiness in buildings?
Listening & looking skills, writing skills: listen to the experience and concerns of the occupants, owners, clients; look carefully everywhere at the site. Write down mold investigation findings and recommendations that are sound, clear, and easy to follow.
Essential Steps in Screening a Building for Harmful Mold Contamination:
If you don't see water stains don't assume there was never a flood or a leak.
If a building has had flooding, plumbing leaks, roof leaks, A/C condensate leaks, hidden mold may be at serious levels.
Check HVAC equipment and duct work for presence of mold or other allergens. Pay close attention to duct work downstream from air filters and blowers;
check blower compartments and duct work for contamination (including dead mice), and check other areas where condensate may have accumulated in duct
lines, supporting mold growth. Clean ducts in one area don't assure clean ducts everywhere; a "clean" air test does *not* guarantee no
duct contamination either as variations in temperature, moisture, and mechanical disturbance can suddenly release mold spores into the building air.
If you don't see mold don't assume a severe mold infection can't be present (behind walls, under carpets, under insulation, in HVAC equipment.) I've found serious toxic mold colonies in walls which showed no external
moisture stains nor external mold growth - the clue was other evidence of a history of leaks into the subfloor, confirmed by an
impaction air sampler result.
Small changes in building conditions can themselves make huge changes in the detected level of airborne mold, from not-detected to severely contaminated. Mold may be present at problem-levels in house air depending on variations in
humidity, temperature, season, air movement, and physical activity. Not
finding it at a given moment is not an excuse for visual and in some cases
invasive inspecting.
A home inspection is not an environmental check for unhealthy mold or other bioaerosols
or allergens. But if you see moldy conditions, or if there is evidence of a history of building leaks, plumbing backups, moisture problems, or visible mold, further more expert investigation is probably warranted.
An industrial hygienist or mycologist may not know enough about how buildings work to complete a reliable building inspection and test. Industrial hygiene is not residential hygiene. Mycology is not building science.
Do not be hasty to assert that a specific illness or complaint is caused by mold. The
four tests (proposed by Burge, Harvard School of Public Health) are
stringent beyond your means as an inspector. Mold at high levels may
cause and almost certainly aggravates or contributes to a wide variety of
complaints. If a significant reservoir of problematic mold is found in a building it should be removed, independent of any efforts to approve causation between the problem mold and occupant health complaints.
List of Detailed Articles on Finding Mold in buildings
If you are looking for evidence of a mold problem in a building you should review these articles.
Stuff that is not mold but is often mistaken for it - things you may not want to test. Also, not all "black mold" is toxic - here are examples of harmless black mold.
List of Articles on In-depth information on mold investigation in buildings
Mold Investigation Tips for Home Inspectors how to find mold, where to look, what is likely to be important. Advice to building inspectors intending to inspect or test for toxic or problematic mold indoors, mold inspection methods, and mold test methods which are valid or invalid
Mold Testing Methods - Brief Tutorial: Toxic Mold and Toxic Gas Testing Methods Compared -
valid vs. invalid tests, recommendations. Lists mold testing methods and protocols, links to longer articles describing air tests for mold, surface tape or bulk mold tests, and gas testing such as MVOC's or toxic gases. Longer articles explain the shortcomings and discuss mold testing protocols.
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Additional technical contributors & reference sources for this article are listed below.
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Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home",
U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
Allergies, Allergens, Allergy Testing in buildings - References & Products
Allergen Tests in buildings advice about how to test, what to look for, in evaluating the level of dog, cat, or other animal allergens in a building
"IgG Food Allergy Testing by ELISA/EIA, What do they really tell us?" Sheryl B. Miller, MT (ASCP), PhD, Clinical Laboratory Director, Bastyr University Natural Health Clinic - ELISA testing accuracy: Here is an example of Miller's critique of ELISA
http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
The critique included in that article raises compelling questions about IgG testing assays, which prompts our interest in actually screening for the presence of high levels of particles that could carry allergens - dog dander or cat dander in the case at hand.
http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue but interestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
Allergens: Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases
Allergens: WebMD discusses allergy tests for humans at webmd.com/allergies/allergy-tests
Animal Allergens: Dog, Cat, and Other Animal Dander - Cleanup & Prevention Information for Asthmatics and regarding Indoor Air Quality.
Recognizing Allergens: What various indoor allergens look like - identification photos to help identify pollen, dust mites, animal dander, toxic or allergenic mold - Common Mold and other Allergens, Irritants, Remedies & Advice
Rodent control issues, including dander, fecal, and urine contamination of buildings and Building insulation are discussed at our
Associations: Sick House, Sick Building, SBS - Air Quality, Government, Private Associations and Information Resources
Atlas of Clinical Fungi, 2nd Ed., GS deHoog, J Guarro, J Gene, & MJ Figueras, Centraalbureau voor Schimmelcultures, Universitat Rovira I Virgili, 2000, ISBN 90-70351-43-9 (you can buy this book at Amazon) - The Atlas of Clinical Fungi is also available on CD ROM
Atlas of Indoor Mold, Online Clinical Mold Atlas, Toxins, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
Black Mold that is Harmless Photos of recognizable, usually harmless black mold on wood, bluestain, ceratocystis, ophistoma
Building Floods: quick steps after a building flood or plumbing leak can prevent costly mold contamination
Classes of Mold: what types of cosmetic, allergenic, or toxic mold are a problem? Can mold be cleaned-up successfully?
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
"Disease Prevention Program for Certain Vegetable Crops," David B. Langston, Jr., Extension Plant Pathologist - Vegetables, University of Georgia (PDF document) original source: www.reeis.usda.gov/web/crisprojectpages/209797.html
"Disease Prevention in Home Vegetable Gardens,"
Patricia Donald,
Department of Plant Microbiology and Pathology,
Lewis Jett
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.
Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
Rot concerns in buildings-some building mold such as Meruliporia incrassata "Poria" risks serious rot and hidden structural damage
US EPA: Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
OTHER IAQ ISSUES: How To Find and Address Other Indoor Air or Indoor Environment Contaminants Besides Mold
Mold or allergens may not be the only or even the main indoor environmental contaminant. Don't let media attention to mold
cause so much enviro-scare fear that other, possibly more urgent hazards go un-addressed.
Ozone Warnings - Use of Ozone as a "mold"
remedy is ineffective and may be dangerous.
Pet control - if you can't say goodbye to your bird, cat, dog, guinea pig, hamster, tropical fish, then limit the
areas they occupy and limit the airflow from that area to sleeping or other areas of the building, use allergenic
bedding, eliminate wall-to-wall carpeting, improve housecleaning including use of a HEPA-rated vacuum cleaner. For more details
see our article Dog, Cat, and Other Animal Dander - Information for Asthmatics and Indoor Air Quality
Rodents, Mice, Squirrel Control - I find high levels of mouse and rodent dander, fecal dust, and urine-contaminated dust in some buildings,
and high levels of these materials in building insulation in those locations. If you have a mouse problem, particularly if mice and their waste (fecals or urine) are contaminating
the building HVAC or building insulation, may need both steps to clean up or remove infected materials and steps to stop an ongoing
rodent problem. If squirrels are a problem, the cleanup needs to include closing off entry openings into the building. Get some
help from a licensed pest control expert.
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