Photograph of tape samples of mold on drywall .

How to Report Mold Levels on Building Surfaces Using Tape Samples of Indoor Surfaces and Indoor Mold

How to report level of mold contamination on building surfaces
Using and reporting on tape samples to check for mold on building surfaces
References

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This article explains how to report and understand the significance of the level of particles of mold or other particles found on indoor surfaces. Readers should also see MOLD TESTING USING ADHESIVE TAPE where we provide a quick tutorial on "Mold Testing: Bulk or Tape Surface Samples and their interpretation"

If collected by an expert during a careful visual inspection, and thus if representative of conditions in a building, surface particle samples collected in buildings provide an important building diagnostic which can be expected to be more reliable than other popular mold testing methods including some which, sadly, may be little more than junk science.

If an indoor particle sample is representative of the area being inspected, then the identity of significant or dominant particles present is important information about conditions in the building.

Reporting the Level of Mold Contamination on Building Surfaces

When we examine surface test samples collected in buildings, properly obtained by following a visual inspection of the building and by using a clear, consistent sampling procedure, then we can report the following Non-Quantitative Particle or Mold Levels Based on Samples

Our mold level terms "Significant/Dominant, Present, Incidental" are defined below. Other labs may use similar terms such as "heavy, medium, light", or "high, moderate, low. "

Depending on where a tape sample is collected, moving the sample source by as little as on inch can completely change both the quantity of mold present (by several orders of magnitude) and actual genera/species detected. Therefore quantitative reporting of mold concentrations found on surfaces (such as spores/M³ or CFU/M² on a surface) in buildings should not be attempted except for narrow purposes of scientific research under controlled conditions. The variation in tape and other sampling methods is explored at MOLD TESTING METHOD VALIDITY.

The purpose of this paper is to seek consistent use of surface particle sample descriptive language among microbiology lab and field investigation professionals. The definitions that follow are a work in progress and need support by example lab photomicrographs and quantitative study.

Particles Significant/dominant in a sample means that within the sample these particles were the most-frequent particle in the sample or that the particle was present in most or all sample focal fields under the microscope at 400x or higher magnification.

Problematic mold or allergenic particles listed in this category are likely to be of significance to occupants in the building. Where the particle is a mold genera or species capable of growing indoors a finding at this level makes it likely that there is one (or more) mold reservoir or mold colony in the building.

This term refers to the sample content itself. A visual inspection of the property is needed to determine if the mold is present in extensive or large areas in the building. When the significant/dominant particle(s) present is/are allergenic or toxic mold or an allergen, building investigation to find and clean/remove the problem source is needed
Particles Present in a sample means that these particles were frequently present in the sample. They are less likely to be of significance to occupants of the building than "Significant/Dominant" particles except when particles named 1. are particularly allergenic or toxic 2. suggest an undiscovered building problem.

If the building has a history of leaks, water entry, or other hidden moisture problems, the presence of even a few toxic or allergenic spores which are not often found in outdoor air samples may indicate a hidden problem. If control samples from outdoors or from non-complaint areas of a building do not show the presence of these particles, further investigation is in order to determine if there is a significant presence elsewhere in the building than from where this sample was taken.
Particles Incidental in a sample means that we found only occasional, or low-levels of fungal spores in the sample provided-below the level we usually find in indoor air samples in buildings where there has been a history of leaks, flooding, or known mold contamination.

This is a positive description of the quality of indoor air insofar as fungal spores are concerned, but one cannot unequivocally conclude that there is no possible health hazard present because: 1. individual exposure, sensitivity, and health status vary widely; 2. even a zero count does not guarantee that a particle is not present in the building. It means only that particle was not in the sample provided.

A careful, expert look at the building may disclose particles that an occupant or inspector was unable to recognize and thus did not send to the laboratory for determination.
Particles not detected in a sample means that the particle named was below the detection limit of the inspection, sampling, and examination methods used in the field and laboratory. It does not mean that none of these particles are present in the building.

Types of Mold Level Reporting Errors in Buildings

Type I Errors - missing a problem that's present: Occasional occurrences of certain mold genera in samples might suggest a hidden or un-noticed mold problem in the building somewhere other than at the spot from which the sample was collected. This is particularly true if the sample was collected by someone who is not expert at building science, indoor air quality, mycology, and related disciplines.

Type II Errors - asserting that a problem is present when it is not: Conversely, occasional occurrences of certain mold in samples might also seem to point a problem in a building where in fact none is present. This is a greater risk where mold "counts" are used in air sampling than it surface sampling combined with visual inspection. Occupant indoor air or environment-related complaints or a building history of leaks would suggest that additional investigation is in order.

To avoid both Type we and Type II errors the building consultant needs to understand mycology (e.g. what mold is likely to grow in buildings), the significance of the particles found (e.g. Pen/Asp spore chains vs. individual spores), the history, construction, and materials in the building and the details of the inspection itself when interpreting the importance of low levels of mold in building samples.

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

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.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.

Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd

Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
Environmental Health & Investigation Bibliography - our technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
Adkins and Adkins Dictionary of Roman Religion discusses Robigus, the Roman god of crop protection and the legendary progenitor of wheat rust fungus.
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

Mold Contamination Testing, Cleanup, Prevention: references & products

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
Aerobiology, Building Science, Microscopy, & Laboratory References, an extensive technical bibliography
Allergens: what they look like in buildings
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 Mold Related Illness: Index of Symptoms and health, physical, neurological, psychological, and other complaint which people suspect may be mold or building-related.
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?
Clinical Mold References - Detailed bibliography of mold reference texts
"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
"Management of Powdery Mildew, Leveillula taurica, in Greenhouse Peppers," Ministry of Agriculture and Lands, British Columbia - Original source: www.agf.gov.bc.ca/cropprot/peppermildew.htm
Environmental Health & Investigation Bibliography - our own technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
Fiberglass: Mold in Fiberglass Insulation© 2005 comments about a field study in process, & more about health hazards from fiberglass insulation - DJF
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.
Fungi, Identifying Filamentous, A Clinical Laboratory Handbook, Guy St-Germain, Richard Summerbell, Star Publishing, 1996, ISBN 0-89863-177-7 (English) (buy at Amazon)
Looking for Mold Procedure: what mold is often found where in buildings - simple technical presentation
Meruliporia: the house eating fungus or "poria"
Mold Action Guide: Step-by-Step Instructions, What to do about mold, mildew, and other indoor allergens
MOLD APPEARANCE - WHAT MOLD LOOKS LIKE Photos of what mold looks like in buildings
MOLD APPEARANCE - STUFF THAT IS NOT MOLD Photos of NOT-mold material that is sometimes mistaken for mold
MOLD ATLAS & PARTICLES INDEX, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
MOLD BY MICROSCOPE Mold under the microscope - photo identification of the most common indoor molds found in buildings
Mold FAQs Answers to Most Questions about Indoor Mold, Mold Related Illness, Mold Cleanup, Mold Prevention
US EPA: Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
Mold spores in the Home - a Photo ID Library for detection and identification of mold allergens
Mold Test Kits - How to Collect and Send Your Own Mold Sample to our mold testing lab or to any mold lab you wish
Most Common Indoor Molds Found in Buildings, A Table of
Mycology, Fundamentals of Diagnostic, Fran Fisher, Norma B. Cook, W.B. Saunders Co. 1998, ISBN 0-7216-5006-6 (buy this book at Amazon)
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.

Fiberglass building insulation and HVAC duct work insulation hazards
Sewage and Septic backup contamination in buildings: inspection, testing, remediation, & references to expert sources
Other environmental risks: Asbestos, carbon monoxide, electromagnetic fields, environmental illness, fiberglass, MCS - multiple chemical sensitivity, toxic gases, etc
Indoor Gas Sampling Plan for Residential Buildings lists a number of toxic indoor gases which we test for, depending on the building complaint and building conditions
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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