How to Use Light to Find Mold or other Surface Contaminants
LIGHT, FLASHLIGHT for MOLD - CONTENTS: How to make proper use of lighting to locate mold contamination indoors. A photographic guide to using a flashlight properly to find mold. How to use light and how to angle light to spot mold, dust, contaminants on building surfaces
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How to use a flashlight or other light to spot building contaminants on surfaces.
If you don't know exactly how to aim your flashlight
you won't see important, possibly toxic, light-colored molds. In this mold testing article we tell you how to use your light effectively look for hard-to-spot mold growth.This document describes how to make proper use of the level of light and direction of light to find mold and test for mold in buildings.
This mold detection 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. The fact that mold is "hidden" or hard to spot on some surfaces in buildings does not mean you cannot find it.
USING LIGHT - How to use proper lighting to see mold contamination in buildings
Light colored mold next to obvious black mold
Aiming a bright flashlight along this wall surface where dark mold was obvious shows a light gray/green fungal colony which in fact was far more toxic
and thus important to select as an additional source for surface sampling using adhesive tape.
How and where you shine light is of crucial importance when looking for mold in buildings.
Light-colored mold such as some members of the Aspergillus sp. and Penicillium sp. groups are often
the dominant problem-mold in buildings but these offenders are often missed by a casual inspection because they can be hard to see on surfaces.
You need a bright flashlight and as simple as this seems, you need to know how to use it.
Shine the flashlight along the surface being examined, not straight at the surface. If you shine the light directly at the surface being inspected you may not see a thing.
As you'll see in the mold photographs shown here, using your light carefully can make a big difference in what mold you find and where you find it.
We inspect for any mold growing on building surfaces. White, gray, light green, red, yellow, or other colored-molds may be allergenic or toxic. Looking only for "black mold" touted in
the popular press risks missing the most important mold in a building.
Some black molds such as the Ceratocystis/Ophistoma group are simply
cosmetic. Other toxic black molds such as Stachybotrys chartarum are rarely airborne unless mechanically disturbed such as by demolition.
These "toxic black molds", especially if the genera/species are heavy, sticky, not-normally-airborne mold spores (Stachybotrys chartarum is an example) may actually affect building occupants less than highly-airborne but small, light-colored, hard to see mold spores such as members of the
Aspergillus sp. family.
Finally, finding any mold growing on building surfaces is an indicator of mold-friendly conditions and means, in turn, that other non-black but still highly-toxic or allergenic problem mold genera/species might be present. So it's usually reasonable to interpret any mold we see in a building as evidence of mold-conducive conditions which may, in turn, justify further investigation.
Light colored toxic mold on paneling can be hard to see in ordinary lighting and requires careful inspection. But notice how the lighting shows
that this paneling is buckled. I'd suspect that it has been exposed to high moisture if not water, and that there is risk of hidden mold on the cavity side of this material.
This is a case in which the careful use of light shows not mold but rather undulations in the wall paneling surface which in turn means moisture and mold risk.
Further inspection was needed - an inspection of the
hidden side of paneling, drywall, and the wall cavity. We did not actually find mold inside this wall - which goes to show that where there's moisture there is not always a mold problem. But the evidence merited looking for mold.
Light colored toxic mold on paneling is not visible
because light is being shone directly onto the wainscot wood paneling surface.
The angle of reflected
light back to the inspector's eye makes it difficult to see small particles on the surface even though the
light is very bright.
Now try shining a light along the surface - this easily shows the white mold colony.
The angle of illumination along the sides of small particles shows their presence more easily than in the direct-illumination example just above.
When we work in the forensic laboratory with a microscope, we use both transmitted and angular reflected light to examine small particles as different information is provided by each method.
The point of these illustrations of using light to help look for mold in buildings is to demonstrate that "hidden mold", like the purloined letter, may in fact be hiding in plain view - you just don't know how to see it.
Recent news articles have made some people terrified at the mere mention of "toxic black mold" such as "Stachybotrys chartarum." Actually it is common to find Stachybotrys chartarum in
small amounts in houses where there has been prolonged leakage or water entry. It's a toxic mold that should be removed.
But don't assume that anything and everything black on a building wall is a highly toxic mold.Some black stuff is not mold at all. Other common mold species look black but may be of low or no toxicity.
For example, Chaetomium globosum™has been reported to be allergenic rather than toxic. Cladosporium sphaerospermum is often found growing indoors on bathroom tile or refrigerator
gaskets. It's a member of the most common mold family, Cladosporium, the "universal fungus." It can look pretty "black" on some surfaces.
Can you tell what genera or species a mold is that's growing on a surface just by the naked eye? No. Though I've inspected and tested so many molds on so many surfaces that like a bird watcher, I know what's likely to be present in a given habitat. (Refrigerator gasket mold is usually
a Cladosporium, often C. sphaerospermum and mold growing on window muntins will be a genera/species tolerant of UV light. A normal person can't do this.
You cannot determine the mold genera and species just by looking at it on the wall, and please skip those do-it-yourself mold test kits. The methods the kits use are fundamentally inaccurate and
in a few cases so are their laboratories. For small mold problems, spend your money on some soap and water instead.
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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.
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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.
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
"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 in Home Vegetable Gardens,"
Department of Plant Microbiology and Pathology,
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.
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.