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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. Readers of this article should also see USING LIGHT TO FIND MOLD. Also see MOLD GROWTH on SURFACES for an index of what mold genera/species are frequently found on various building surfaces and materials.

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.

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USING LIGHT - How to use proper lighting to see mold contamination in buildings

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.

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.

For larger mold contamination problems (more than 30 square feet) you should hire an expert to survey your home, or send your own mold sample to a competent testing laboratory. The services of an experienced mycologist or aerobiologist are necessary to know what you've got. (C)DJF Copyright protection trap.(C)Daniel Friedman

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ALLERGEN TESTS for BUILDINGS
ALLERGENS in BUILDINGS, RECOGNIZING
ALLERGY TESTS for PEOPLE
ALLERGY TEST ACCURACY
MOLD INFORMATION CENTER
FLOODS & MOLD CLEAN/PREVENT
MOLD ACTION GUIDE - WHAT TO DO
MOLD DETECTION & INSPECTION
HOW TO LOOK FOR MOLD
  CHOOSE SAMPLE POINT
  SAMPLING DRYWALL
  SAMPLING MISTAKES
  USE A FLASHLIGHT
  USING LIGHT to FIND MOLD
WHAT MOLD LOOKS LIKE
ATTIC MOLD
BASEMENT MOLD
CRAWLSPACE MOLD
DRYWALL MOLD
FIBERGLASS MOLD
MOLD ON DIRT FLOORS
MOLD ON or IN CARPETS
ITCHY FABRICS
HIDDEN MOLD, HOW TO FIND
  Photo Guide to Finding Hidden Mold
  Recognizing Cosmetic Mold
  Hidden Mold Behind Paneling
  Hidden Mold Between Framing & Sheathing
  Hidden Mold in Flooring & Subflooring
  Hidden Mold in Wall Cavities
  Spotting Hard-to-See Mold
  Use of a flashlight to find mold
  Wall test cuts to spot hidden mold
  Light colored toxic molds
  Moisture Gradients and Mold
  Other Places to Look for Hidden Mold
INSULATION MOLD
DO-IT-YOURSELF WARNINGS

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Mold and Allergen Recognition and Identification - Not All "Black Mold" is Harmful; Some Suspect Stuff is Not Mold

• How to Find and Test For Mold in Buildings - Looking for Mold - A 'how to' photo and text primer on finding and testing for mold in buildings
• Recognizing Mold: What mold looks like mold identification photos to help identify mold - choosing what to sample in buildings
• Recognizing Allergens: What various indoor allergens look like - identification photos to help identify pollen, dust mites, animal dander, toxic or allergenic mold - Common Mold and other Allergens, Irritants, Remedies & Advice
• Stuff that is not mold but is often mistaken for it - things you may not want to test. Also, not all "black mold" is toxic - here are examples of harmless black mold.
• Mold Action Guide: an easy step by step outline of what to do about mold
• How to find mold without hiring anyone, for do-it-yourself'ers
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• Meruliporia: the house eating fungus or "poria"
• Mold Investigation Tips for Home Inspectors how to find mold, where to look, what is likely to be important. Advice to building inspectors intending to inspect or test for toxic or problematic mold indoors, mold inspection methods, and mold test methods which are valid or invalid
• Mold Risk Levels in Buildings Based on Visual Inspection - simple visual clues help decide on action
• Mold in Fiberglass Insulation© 2005 comments about a field study in process, & more about health hazards from fiberglass insulation - DJF
• 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
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