Mold Testing: Bulk or Tape Surface Samples and their interpretation - a quick tutorial
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An explanation of the validity of surface sampling using adhesive tape as a screen for toxic or allergenic mold in buildings
A description of how to test for mold using adhesive tape
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This paper describes the use and limitations of bulk, surface, or tape sampling for mold testing in buildings. Bulk samples are samples of material taken by direct scrape onto
glass slides, by processing of sample materials, by pressing clear cellophane tape on a surface, or by using a special cassette and vacuum pump to vacuum a
surface. With owner permission, a sample of actual surface material is occasionally removed and brought to the lab for further analysis. Readers should also see MOLD LEVELS on SURFACES where we describe "How to Report Mold Levels on Building Surfaces Using Tape Samples of Indoor Surfaces and Indoor Mold "
Before you buy a "home test kit" for mold you should read this article about using simple clear Scotch tape. After reading this paper you may
want to see our tape sampling procedures Information Accuracy & Un-Biased Reporting are Assured for this website - see pledge link at below-left.
New York State License # 16000005303 - /P>
Bulk or surface samples are a key determinant in evaluating building condition, provided they are collected strategically and in accompaniment of a
careful visual inspection using good inspection methodology. A casual look may find obvious black spores but miss more problematic light-colored fungal
colonies; a colony can, of course be hidden behind building walls or ceilings or under furniture.
Since random bulk samples offer a high rate of
false-negative (no problem) findings, they are not particularly useful. Samples are collected based on clues found during the visual inspection, and are
collected in multiples if variations in mold appearance or growth substrate make it likely that multiple species are present in a given area.
Other
samples, such as of surface dust, are collected from sources known from experience to be more likely to represent ongoing conditions in the building.
These samples are examined to determine the dominant types of particles present. When dominant particles are allergenic or toxic, further investigation
or cleaning are needed. In some cases, recurrent presence of low levels of unusual particles (by species or type) may also indicate a hidden problem in
the building.
Inspectors or consumers who require examination of special samples (i.e. samples not on clear cellophane tape, vacuum cassette, or slides) should
contact us to make arrangements before shipping such samples to our lab. In addition to preparing high-power light-microscope slides from special samples,
we may use both stereo zoom microscopy and in some instances the construction of special particle-removal apparatus to study special samples.
Clear adhesive tape is pressed onto the surface being sampled. A surface may be sampled because it contains mold-suspect material or because it contains settled dust to be screened
for mold, allergens, or other particles.
Detailed instructions for using tape samples to screen for or test and identify mold are provided at our Step-by-Step
Tape Sampling Instructions for Mold
There you may also read some simple strategies for deciding that critical thing: where to stick the tape?.
More information about the validity and invalidity of various test methods for IAQ and mold and procedures for investigating and cleaning up mold or other indoor air quality problems
are at the Mold, IAQ, Sick Building Advice Website
Also see SAMPLING DRYWALL where we explain how to choose the sampling location when using adhesive tape.
Slide Preparation in the mold test lab: For those with more technical interest:
The tape is mounted on a slide using various chemicals and stains; for example, simple KOH, lacto phenol cotton blue, basic fuchsin, or lactic acid stained
with acid fuchsin. Unused portions of samples are kept on file for two years in
case additional investigation is warranted.
For legal work microscope slides of environmental particle samples are prepared using a permanent mounting medium. Prepared slides are observed under a light
microscope at various magnifications including 400x and 1000x.
Variations such as polarized light and darkfield analysis may be used as well. Unless otherwise
stated, analysis is qualitative, not quantitative. (Numbers in our lab reports identify attached microphotographs.)
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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
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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