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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

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. 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 -- Contents.

What is Tape Sampling for Mold?

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. Air sampling and culturing as inspection methods are discussed in other papers at this website.

How Do I collect a Tape Sample for Mold Testing

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

Slide Preparation 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 slides 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.)

Website Contents

More Comprehensive Discussion of Mold Problem Factors

Factors contributing to mold growth in buildings are discussed in-depth at
Mold Levels in Mold Test Samples of Surfaces in Buildings how to report mold levels in mold test samples of surfaces in buildings
Bulk Samples and Their Interpretation - a quick tutorial This web page.
Mold Testing: Air Samples and their interpretation - a quick tutorial describes air sampling, its uses & shortcomings
Validity of Cultures (settlement plates or swabs) to find toxic mold in buildings describes the shortcomings of these approaches which are invalid when used alone.
Mold Levels in Buildings: allergenic or toxic mold, how much means a problem?
Mold Spore Counts in Buildings: are indoor fungal spore counts valid?
Mold Classes in Buildings: cosmetic, allergenic, or toxic mold in buildings
Mold Investigation Reports and Mold Test Lab Reports: What to Look For outlines a professional, useful mold investigation report.
Mold Risk Levels in Buildings Based on Visual Inspection
and our Mold Information Center: What to Do About Mold in Buildings provides a list of key resources about indoor environmental concerns with mold.

More expert information on toxic black mold, mold testing, mold investigation, and building diagnosis and repair

Frequently Asked Questions About Mold -- check this FAQ List/IAQ Site Map to see if you can find a quick answer to your mold concern

InspectAPedia ^TM Home & Site Map - Building Inspection, Diagnosis, & Repair, Environmental Inspection & Testing - Research Website

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

Home Inspection Construction Consulting Services & advice for home buyers

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

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08/14/07 Created 3/28/95 - www.inspect-ny.com/tutorial2.htm - Web page design & content © Copyright 2008-1996 Daniel Friedman