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HIDDEN MOLD, HOW TO FIND
  Photo Guide to Finding Hidden Mold
  Recognizing Cosmetic Mold
  Hidden Mold Behind Paneling
  Spotting Hard-to-See Mold
  Use of a flashlight to find mold
  Wall test cuts to spot hidden mold
  Light colored toxic molds
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  Other Places to Look for Hidden Mold
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More Places to Look for Hidden Mold in Buildings - Looking for Mold
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Description and photos of oft-forgotten places to look for hidden mold

Our site offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at inspect-ny.com/appointment.htm.

This article provides suggestions for where else to look for mold in buildings - places that are often forgotten but places that can harbor significant toxic or allergenic mold reservoirs. The fact that mold is said by some inspectors to be "hidden" in buildings does not mean one cannot find it by careful inspection and testing.

We look for mold in buildings where it is not obvious by using context: where do we see leak stains, or where do we see building practices most likely to have produced a hidden leak or moisture problem? Ice dam leaks in walls, hidden plumbing leaks, roof spillage by the foundation, are all common clues that often track to a wet building wall or ceiling cavity and from there to a hidden mold problem which may need to be addressed.

This 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. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

Other Places to Look for Hidden Mold Contamination or Mold Growth

There are many places to look for mold growth. Here are a few others that you might not have considered:

Underside of carpets or carpet padding that have been wet - check for moldy or water-stained carpet tack strips;
Previously wet cardboard boxes and their contents;
Ceiling penetrations like 120-V smoke detectors;
Top of poorly-insulated exterior walls; behind wallpaper below windows which had a one-time or recurrent leak.
Furniture: we often find extensive mold on the un-finished side of drawers, tables, game tables, and chairs that have been in a wet or damp environment.
Imported Mold: Sometimes mold is imported into a "dry" building on furnishings or contents that were previously stored in a wet location or in another moldy building.
Building Insulation is often moldy even if it looks clean.
Appliances: Don't forget to clean your refrigerator, including gaskets, coils, and evaporator tray.
Air Conditioning Systems: take a careful look at your window or wall-mounted air conditioner and be sure to make a complete inspection of central air conditioning system ductwork, registers, and air handlers, as well as any heating air handlers and duct work. Check especially downstream of the air handler on cooling systems since condensation there may promote mold growth.
Have You Found Other Places to look for mold? Send us your own discoveries - your tips may help other people who are bothered by indoor mold but who have not been able to find its source.

Photos of more places to look for hidden mold in buildings

Here we provide a photo tour of mold which was hidden at least from some investigators and occupants, with photo and text tips on spotting problem mold in air conditioning systems, behind and under bath and other cabinets, mold under and in wall to wall carpeting, mold on stored paper files, file folders, and books, mold on, in, and under furniture, and mold behind wallpaper.

Hidden mold in Air conditioning equipment interiors:

Photo of mold in a Florida Air Conditioning air handler unit - Mark Cramer, Tampa

Hidden mold behind bathroom and other cabinets:

Photo of mold behind a bahtroom vanity cabinet - a small area of toxic mold

Photo of mold behind a bahtroom vanity cabinet - a small area of toxic mold fully exposed after removal of the cabinetry

Photos of mold behind a bathroom vanity cabinet base - shower water leaked across the bath floor, under the vanity, and into the wall cavity.

This was a small mold cleanup area, less than 10 sq .ft. and suitable for handling by a homeowner or handyman. The second photo shows the extent of mold after the cabinet was removed.

When we rebuilt this bathroom, since the tile floor slopes slightly down from tub towards the vanity base, as precautions against future mold growth we sealed all of the new vanity underside surfaces to reduce moisture and thus mold growth, and we caulked the vanity carefully at the floor level to prevent water from passing below.

Hidden mold below built-in drawers:

The previously-hidden toxic black mold (Aspergillus niger) shown in this photograph was found beneath a built-in bathroom storage drawer - shower water leaked across the bath floor, under the built-in, and into the wall cavity. I found this incompletely cleaned area during a post-remediation mold clearance inspection and test.

This was a small mold cleanup area, less than 10 sq .ft. and suitable for handling by a homeowner or handyman had there not already been a costly mold remediation project at this property. In this case the remediator returned to complete the work.

Failing to simply pull out a drawer to look into the built-in cavity is an indication of superficial workmanship on a mold cleanup job. Here is a mold test lab photo of Pen/Asp spore chains that I had found in my mold clearance inspection sample of settled dust taken near this bathroom. Here is a mold test lab photo of the actual Aspergillus niger colony sample I collected from the pine tongue and groove subflooring in the moldy area shown above - this is a probable source of the spore chain found in my screening sample.

Hidden mold below wall to wall carpeting:

Photo of moldy carpet tack strips indicating moldy wall to wall carpeting and prior leaks or flooding

Photo of clean carpet tack strips confirming that there has been no water entry at this location since carpets were installed

Hidden mold in and under wall to wall carpeting is notorious and widespread in areas which have been subject to wet conditions such as basements or floors on leaky slabs.

The first photo at left shows moldy carpet tack strips which confirms a history of water entry and makes the carpeting highly suspect of serving as a problem mold reservoir. (We tested the carpeting further using a special vacuum mold test method.) The second photo shows clean carpet tack strips, indicating that at least since this wall to wall carpeting has been installed there has been no water below the carpet in this area, and suggesting that the risk of mold in this carpeting is low.

Of course mold may be visible on the surface of carpeting too, such as in this closet. In this case we suspected that the visible carpet mold was the "tip of an iceberg" of hidden mold below.

Hidden mold on stored papers and files in cabinets:

Photo of moldy paper files in a law office basement

Photo of moldy file folders in a law office file cabinet subject to prior flooding

Paper files and documents and file folders, even stored in metal file cabinets, can become quite moldy when left in a damp basement. In these photos the file cabinet was never itself wet, but the floor beneath it had been wet several times leading to extensive mold growth on these law office files.

There are procedures for cleaning and salvaging moldy books and paper files, but the cost is high, making it appropriate only in special circumstances such as the preservation of works of art or valuable books or historic papers.

Hidden mold on and in furniture:

Upholstered furniture can be quite moldy if it has been exposed to flooding. Only in unusually severe circumstances will upholstered furniture be visibly moldy. Don't forget to look on the underside of couches, tables, and chairs, especially since the un-finished but hidden surfaces such as raw wood under a table or cabinet more easily take up moisture and support mold growth.

The condition of the moldy green chair in the photo above, from a lakefront cottage in Elk Lake Michigan, was pretty obvious after it had spent a decade in the damp cottage. Moldy furniture like this must either be discarded or stripped to its bare frame for cleaning before reupholstering.

Remember to use your light (as we describe here and in other articles) to look along finished wood surfaces as often light colored problem mold is hard to see but may be quite extensive.

Hidden mold behind wallpaper:

Building wallpaper may include problematic molds such as Aspergillus sp. and Stachybotrys in areas subject to leaks such as below the window in the condominium in New Jersey, or in bathrooms where wallpaper was applied.

We suspected mold and convinced our daughter to peel down the wallpaper below this window because she had told us that there had been a history of wind-blown rain leaks at this particular opening.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

HIDDEN MOLD, HOW TO FIND
  Photo Guide to Finding Hidden Mold
  Hidden Cosmetic Molds
  Hidden Mold Behind Paneling
  Spotting Hard-to-See Mold
  Wall test cuts to spot hidden mold
  Light colored toxic molds
  Moisture Gradients and Mold
  Other Places to Look for Hidden Mold

About the Author

Daniel Friedman www.inspect-ny.com/sickhouse.htm

Daniel Friedman is a mold/indoor air quality investigator and home inspector as well as a professional writer in Poughkeepsie, New York. He is a member of the American Industrial Hygiene Association and the American Society of Home Inspectors. He presently chairs ASHI's national Standards of Practice Committee and has led ASHI's Education and Technical Committees as well as serving on ASHI's Exam, and Ethics/Professional Practices Committees. His poetry has appeared in Emphasis, a national publication of MENSA, and his non-fiction articles and essays have appeared in The Journal of Light Construction, the Old House Journal, The ASHI Technical Journal, Progressive Builder and New Shelter. His news reporting and photography have appeared in the Journal of Light Construction, and in various newspapers including the New York Times, Richmond Times Dispatch, Richmond News Leader, and the Poughkeepsie Journal.

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

More Information on Finding, Recognizing, and Proper Testing for Mold, More on Building Diagnostic Inspections and Repairs

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,
Associations: Sick House, Sick Building, SBS - Air Quality, Government, Private Associations and Information Resources
Mold Test Kits - How to Collect and Send Your Own Mold Sample to our mold testing lab
How to find a mold inspector or test consultant: Directory of IAQ,Sick Building, Mold Allergen Testing, Building Investigation Service Providers
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
When to hire a professional to inspect for toxic mold or other allergens
Contact Us to arrange mold/IAQ building on site inspection and testing.

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