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Photograph: Multiple tape samples on one zip-lok bag - Daniel FriedmanUse Adhesive Tape to Test or Identify Mold

Mold Sampling Procedure for Building Surfaces

How to use adhesive tape to sample building dust, mold, or surfaces for particle identification:

This article explains the advantages and shortcomings of using adhesive tape to collect mold test samples (or virtually any other other dust or particle samples) from indoor surfaces.

In this article series we discuss the validity of nearly all of the popular mold testing methods currently in use, pointing out the strengths and weakness of each approach to mold sampling in the indoor environment.

We discuss 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.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?

Recommendations for Using Tape sampling for Testing Buildings for Toxic Black (or other) Mold

This expert-recommended mold test kit is easy, inexpensive, and accurate *IF* you sample from a representative spot and *IF* you use a competent mold analysis laboratory!15th Annual North Carolina/South Carolina
Environmental Information Association Technical Conference
Myrtle Beach, SC

Daniel Friedman 23 September 2005, latest update: 2019/01/27

Before you buy an over-the-counter or mail-in home test kit for mold you should read this article about using simple clear Scotch tape® in a simple dust or surface or mold sampling procedure that uses very inexpensive materials and, with intelligent selection of sample surfaces, can produce results of superior accuracy.

This article series presents a summary and critique of some popular methods used to examine indoor air quality to test for presence or absence of problematic levels of toxic or allergenic mold or other bioaerosols.

Our page top photo demonstrates that the tape sampling location is critical for accurate identification of particles or mold types in a building - each of the three tapes in this photograph collected an entirely different genera/species of mold.

We describe and critique specific "testing" or "sampling" methods used to "test" buildings for mold in the course of a building investigation. The appropriateness of testing at all is discussed on this and other pages at our website. We will review the following:

How to use adhesive tape for mold identification samples. How to use adhesive tape to screen building dust for mold or other particulate contaminants.

Use of adhesive tape to trace building dust particles to their source. Exact procedural details are

at TEST KIT for DUST, MOLD, PARTICLES: INSTRUCTIONS

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.

Clear cellophane tape is pressed into a sampled surface, then removed and affixed to a clean surface such as a plastic bag or a microscope slide for mailing to a lab. The lab prepares the tape for microscopic examination.

For mold genera and species identification the tape is examined in the laboratory. Tape samples can also be cultured (see Culture discussion below). This is the least-expensive collection method available, and is a preferred tool.

See TEST KIT for DUST, MOLD, PARTICLES: INSTRUCTIONS for a detailed procedure using this particle sampling method.

That article provides a detailed, step by step guide to using clear adhesive tape to collect particles from building surfaces to test a building for a history of exposure to airborne (and dust) presence of allergens, animals (dogs, cats, mice, rats, others), asbestos, cockroaches, dust mites, fiberglass, insect fragments, pollen, soot, or mold.

Building dust samples can also be used to trace dust or problem particles to their source, such as insulation from damaged duct work, or in some cases, failing HVAC equipment.

Using clear adhesive tape pressed into a surface to be tested is the first choice recommended method for identifying mold in a building, particularly when combined with visual inspection as part of a mold investigation, per AIHA and other expert sources.

This method permits rapid identification of genera (family name) and very often species (individual member name), particularly when the mold sampled has uniquely-identifiable spores or where the sample collects the conidiophore or spore-producing body as well.

In some cases genera determination alone is quite sufficient as the some of the common problem-genera (Penicillium sp. and Aspergillus sp.) do not have non-problematic members which grow in buildings. Speciation is more likely to be needed when doing medical diagnosis.

Tape samples can also be cultured if additional speciation is needed. Since tapes can collect the conidiophores and hyphae (when tape spot is chosen with some thought) they give more data than an air or vacuum sample.

For building where large amounts of mold are found or suspected, tape sampling is a qualitative approach which is usually quite successful in addressing the basic question: is there a problematic genera which requires professional remediation?

Combined with a visual inspection to locate target areas of risk and to find visible problems, it is the most essential component of a building mold investigation and is the method recommended by experts writing in the field and by the AIHA's own training materials.

Tape samples are the preferred method of collecting surface samples in buildings. Tape pressed into appropriate portions of suspected mold growing on a surface collects the most material from the surface and often includes sufficient structural material to identify the dominant problematic genera and species present.

A properly collected sample is likely to contain both fungal conidia, conidiophores, and hyphae, the latter two of which are important aids for speciation.

Tape samples of building dust and even tape samples of moldy carpet are also generally useful in this manner but have some limitations discussed below.

Because mold test validity and mold test accuracy are often confused, readers should also

see ACCURACY OF AIR TESTS for MOLD.

People who need to conduct mold inspection and testing indoors should

see MOLD TEST PROCEDURES

and TECHNICAL & LAB PROCEDURES.

A Guide to Using Tape Sampling for Determination of Mold genera and Mold species:

Aspergillus niger in tape sample (C) Daniel FriedmanNearly all building mold genera can be determined by light microscopic examination of tape samples. In the majority of building investigation cases the key question is "is there a problematic genera (toxic or allergenic) requiring containment and professional remediation?"

This can almost always be completely answered from genera alone. This is because within the more common troublemakers, their non-problematic member species may not occur in buildings.

For example, Penicillium notatum, used for the drug penicillin, does not grow in buildings! If you find Penicillium sp. in a building in quantity it needs to be remediated.

Speciation of many mold genera can also be determined from tape sample material alone in many but certainly not 100% of cases.

Some examples of easily speciated molds from among the most common genera and species found in buildings:

Cladosporium sphaerospermum, C. cladosporioides, Ulocladium chartarum, Taeoniella rudus, Pithomyces chartarum, Stachybotrys chartarum, Chaetomium globosum, Chaetomium aureum, Aspergillus niger are just a few examples.

Our photo (left) shows a nicely preserved conidiophore of Aspergillus niger on an adhesive tape sample.

A good mold tape sample which collects the conidiophore and hyphae makes speciation possible for many molds. Many other airborne spores appear in buildings and can be similarly speciated, but are not building molds.

Other airborne molds such as the Aspergillus and Penicillium families are probably a sufficient hazard in buildings that if they are present in a large reservoir, speciation is not needed to decide to remediate.

Shortcomings of tape sampling tests for Toxic Mold:

  1. Everything depends on where you stick the tape.

    Investigators and ordinary building occupants tend to collect that which is easy to see - "black mold" and may miss more important, more health-risky light-colored and highly airborne genera (Aspergillus, Penicillium) which are also present but more difficult to see.

    An expert looks for mold-suspect material that seems to represent the dominant presence in an area by color, texture, and growing surface material. It would be unusual for there to be only a single genera/species of mold in a mold-problem building. Looking and taping requires some guidance and education.

  2. Some smaller airborne mold spores do not settle out of air rapidly and might appear equally 

    as plated-out on walls as in dust on horizontal surfaces.

    In building inspection to search for an unidentified problem source, samples of surface dust may under-represent the presence of these molds, though where a substantial airborne presence exists we have always found a surface dust presence as well.

    By contrast, properly collected tape samples from visible mold growing on a surface does not suffer this shortcoming.

  3. Speciation of genera may be needed for special medical diagnostic reasons.

    From spores alone in any sample method, two of the most widespread problematic genera can be speciated only to a few cases. (Aspergillus niger for example.)

    Therefore for medical use, tape speciation of some genera is too limited, in particular if the sample collects only spores - a problem which can occur if tape is pressed into dust rather than into an area of growing mold, or when tape of a mold colony is pressed into a spore-packed center of a mature colony instead at the edges where the new colony growth and conidiophores are easier to find.

    A little knowledge of mycology is useful to professional building inspectors.

  4. When growing conditions become unfavorable some molds change form into an encysted or encapsulated dormant state,

    forming fungal perithecia, cleistothecia, or pycnidia which may be collected as "black stuff" from building surfaces (particularly wood). While often one finds identifiable material among perithecia that cant' be assured. Culturing of such samples may produce an identifiable fungus if by luck the right culture media is selected.

  5. Tape sampling is qualitative, not quantitative.

    Most experts and competent labs will offer a description of the density of fungal material found in the sample using non-standardized terms like Level 1-2-3-4 or Light, Medium, Heavy, or Dominant, Present, and Incidental.

    These terms lack a standard definition but are of some use provided the lab has and can provide their own standard and definition.

In sum, the determination of the presence of a building mold problem (toxic or allergenic) vs. cosmetic mold can usually be made from tape samples alone.

Tape samples are preferred by the most experienced and trained professionals in the aerobiology field.

MOLD LEVELS on SURFACES where we describe "How to Report Mold Levels on Building Surfaces Using Tape Samples of Indoor Surfaces and Indoor Mold "

 

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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: where can I find a lab to tell me the contents of dust in my house?

I am interested in finding out the content of dust particles I continue to get in my house for the last seven years.

With Aprilaire high efficiency air filters on each of my units, I don't understand the where the dust is coming from.

I'm thinking if I know the content makeup, it may help to determine the source. - need to know to collect a sample for content testing. - need to know the cost per sample. - D.W. 2/22/12

Reply:

Sure DW,

at TEST KITS for DUST, MOLD, PARTICLE TESTS you will read step by step suggestions about dust collection and sample mailing.

Lab test fees vary by test lab, typically between $25 & 50. U.S. per tape sample for tape samples of surface materials, particles, dust or mold analyzed by light microscopy.

In the header section of that article you'll also find links to helpful tips on inspecting your home and choosing a sample location.

Be sure to take a look at

 


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Continue reading at TEST KIT for DUST, MOLD, PARTICLES: INSTRUCTIONS for a detailed, step by step guide to using clear adhesive tape to collect particles from building surfaces or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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Building Dust, Particle or Mold Test Kit Articles

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TAPE & BULK SAMPLING & TESTS for MOLD at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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