Basement Mold: How to Find and Test for Mold in Basements InspectAPedia® -
How to inspect & test for mold in building basements
How to inspect & test for moldy basement insulation or basement contents & stored items
Questions & answers about how find, remove, and prevent mold contamination in building basements; where to look for both obvious and more "hidden" mold growth in basements
This document gives advice on how to find and deal with mold in building basements and in basement insulation.
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This article is part of our series:
FIND MOLD in buildings, HOW TO which describes how to find mold and test for mold in buildings, including how and where to collect mold samples using adhesive tape - an easy,
inexpensive, low-tech but very effective mold testing method.
This procedure helps identify the presence of or locate the probable sources of mold reservoirs in buildings, and helps decide which of these need more
invasive, exhaustive inspection and testing.
Our page top photo of very mature basement mold growth on entry stairs was provided by reader Chase Falke.
BASEMENT MOLD: finding the problem mold, allergens, or other particles in basements
Leak History: Examine the basement for its evidence of recurrent leaks and water entry.
Finished Basement Organic surfaces: Look carefully at organic surfaces such as wood, drywall, and carpets in a finished basement:
Walls: drywall, especially low on walls, in wet corners, behind furniture, and in areas of leaks from above
Ceilings: drywall, especially in areas of leaks from above, such as under baths or kitchens, and at the walls below roof eaves
in cold climates where ice dam leaks may have sent water into wall cavities; look at hot water heating baseboard locations
for bleeder vents or other leak points
Ceilings: suspended ceilings: look on both sides of ceiling tiles for visible mold or leak stains; don't ignore possible mold in fiberglass-based ceiling tiles.
Ceilings: inspect framing - the joists of floors above, and the exposed side of subflooring of the floor above. See our warning about mold growth on pine boards discussed at Attic inspections above.
Floor: wall to wall carpeting is a very common mold and allergen reservoir. Don't ignore possible reservoirs of high levels
of mite fecals and pet dander including pets from prior owners. Look for other signs of pet presence in the building such as
scratches on doors and trim.
Un-finished basement mold: Look carefully at organic surfaces in un-finished basements or behind or above finished surfaces. Our photo of mature mold growth on floor joists that form a basement ceiling was provided by reader Chase Falke.
Look for evidence of prior basement water entry - mold is more likely to have grown on wetter surfaces first in a
basement. Stains on the floor or remnants of cardboard boxes that were there, wet, and then removed, are important clues.
Inspect the exposed sides of all framing, joists, girders, posts
Inspect the exposed under-side of subflooring of the floor overhead. See our warning about mold growth on pine boards discussed at Attic inspections above.
Inspect the back side of stairs, especially the lower treads and risers
Don't assume that because there is no visible mold on surfaces that there is not a problem mold reservoir in exposed insulation.
Basement contents be sure to inspect furniture and stored materials in a basement where mold is suspected, such
as cardboard boxes and their contents and the under-side of furniture and game tables. Often we find serious mold growth on
the un-finished surfaces of wood objects, probably because the absence of a coating means that such surfaces take up more
moisture than other sides of the same item.
Mold hidden in basement insulation or on basement contents
Even when there is no visible mold, don't ignore exposed fiberglass insulation as a possible mold reservoir.
A basement which was previously moldy or wet, or a basement which stored a collection of moldy boxes or cartons of moldy papers and files may have been
may have left behind a large mold reservoir in the basement fiberglass insulation and in settled dust.
In the first photo shown here the basement insulation looked clean to the naked eye, but a history of basement
flooding led us to test the insulation.
We found high levels of Aspergillus contamination in this
yellow fiberglass insulation which, to the naked eye, looked quite clean.
If there is visible mold on other basement surfaces, don't forget to also check the condition of basement insulation that
your insurance company, mold consultant, or mold remediator may want to leave in place because it "looks clean".
In the photograph shown
here, not only was there extensive Stachybotrys chartarum contamination visible as "black mold" on the
basement drywall, a special vacuum test of the fiberglass insulation in this basement ceiling disclosed high levels of Aspergillus versicolor, Aspergillus sp., & Penicillium sp..
These three photos of fiberglass insulation, drywall, and a wall cavity which was cut open
show the value of exploring building cavities where there may have been leaks from above, regardless
of whether we're exploring in above-grade level living space or below-grade level basements.
A roof leak had wet
these wall cavities, leading us to test the insulation for mold and to inspect further for moldy drywall. The photos
also illustrate that luckily not every building leak into every building cavity is going to cause visible mold
growth on the hidden surfaces of drywall.
See BASEMENT MOLD WATER IMPACT for a discussion of movement of moisture (and mold) from a wet basement or crawl space up through the occupied building space and into a wet moldy building attic.
Questions & Answers regarding this article
Questions & answers about how find, remove, and prevent mold contamination in building basements; where to look for both obvious and more "hidden" mold growth in basements
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Chase Falke, an InspectApedia reader and a building professional generously contributed photographs shown here of extensive white fungal growth in a building basement in Lima Ohio.
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
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)
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.
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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