How to Find Hidden Mold Reservoirs in the Home - a guide detection of mold allergens
INVISIBLE MOLD - CONTENTS: Where & How to Look When You Cannot Find the Mold Problem in a Building. How to Find & Test For "Invisible" Mold in buildings. Links to Photographs of black mold & other molds of various colors and textures in buildings. Photographs of mold on or behind wallpaper
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
How to find hidden mold contamination:
What do we do when we cannot find a mold problem but we think there is problem mold in a building. Suppose an "air test" says there is problem mold indoors but you don't see where the "problem mold" is coming from? Where and How do we look for hidden mold?
Where to Look When You Cannot Find the Mold Problem in a Building
Where to look for "Invisible Mold" in buildings - important mold reservoirs that cannot be detected by visual inspection
Results of a small test cut to check for hidden mold
Of course some important problematic mold reservoirs may be hidden inside building cavities where you won't see them without making a test cut in just the right place. We find these problems by inspecting "by context", that is, we decide where to make an invasive test cut by studying where leak or moisture problems have been or are likely to have been on a building.
This photo shows the hidden interior side of drywall on the test cut we made using the hole saw shown at the top of this page. The red material was a yeast which accompanied toxic mold which we confirmed was present in this wall cavity.
What's important is the development of a strategy for just where to make such test cuts to look for hidden mold. Random test cuts to screen a building for mold are unreliable.
Some other critical indoor mold problems may be on an exposed building surface or material, but the mold may be totally invisible to the naked eye. Such "hidden in plain sight mold" can be detected by a combination of common sense in recognizing mold-friendly materials and mold-producing conditions.
Exposed insulation may be mold contaminated
For example, fiberglass insulation in the ceiling over a flooded basement or crawl space is highly suspect. In some cases it's more economical and sensible to simply replace suspect material than to spend on testing it for mold contamination.
But where large areas or large expense would be involved, special testing methods can determine whether insulation or other mold reservoir materials are indeed mold-contaminated. We use a combination of vacuum pump and sampling cassettes to examine suspect building insulation.
Here is a photo taken in our laboratory when we examined our sample of insulation which we suspected would be mold-contaminated.
You can see extensive mold contamination of at least two types, Penicillium/Aspergillus spores and spore chains and darker fungal spores which are probably a species of Cladosporium sp. This insulation looked "clean" to the naked eye, but by context we suspected it would be a problem reservoir of mold.
Moldy fiberglass insulation is often missed by casual or inexperienced mold inspectors. The presence of spore chains confirms that we had active mold growth nearby if not in the insulation itself.
Making a larger wall test cut to check for hidden mold
Here we made a larger test cut in mold-suspect drywall because we saw a leak stain on the exposed surface. Even though there was no
mold on the exposed side of this wall, the water stain led us via this test cut to discover a leaky drain pipe that was previously unknown.
We would not make a cut like this unless there was external evidence of probable leakage into this cavity; a borescope might have found this problem too, though views through such instruments are quite limited and do not permit full examination of all materials and surfaces. Notice the evidence of mouse activity at the right end of this test cut?
Removing Wallpaper to Check for Hidden Mold
In our daughter's condominium we peeled down clean-looking wallpaper because we saw evidence of a history of leaks into the wall cavity at the window sill. Even though there was no
mold on the exposed side of this wallpaper, the water stains led us via this test to discover an area of Stachybotrys chartarum that was worth removing.
We often find mold growth behind wallpaper where there has been leakage or high moisture, including wallpapers used in bathrooms. Beware: some antique wallpapers which may be attacked by mold growth can cause the release of poisonous arsenic into the local environment.
Hidden Mold Under Furniture Drawers or Built-in Drawers
Simply pulling out a drawer may reveal problem mold growth. In this case we found this by pulling out the bottom draw of a built-in storage chest in a bathroom in an older home. we have also found Aspergillus sp. colonies growing on the un-finished underside of furniture and game tables.
Hidden Mold Behind Wall Paneling
We pulled down this bathroom paneling even though it's exposed side looked very clean, because other clues indicated that there had been a history of floor flooding in this area.
Hidden Black Toxic Mold Behind Drywall
We made the test cut you see in the photo at left above, even though the architect had directed the mold inspection and testing to be performed in a completely different building area.
That's because we saw water-damaged flooring and because occupants of this area were complaining of severe respiratory and eye irritation. We had to push insulation aside to show the black mold just visible in this photo on the cavity side of the opposing drywall. Our lab test indicated that we'd found Memnoniella echinata (a very close relative of Stachybotrys chartarum) which we find quite irritating.
The second photograph above shows how extensive the mold growth was when the lower wall cavity was cut away. This mold contamination had spread on 100 linear feet of wall in this area due to an air conditioning leak which drained into the channel formed by the steel u-channel used as a sill plate for this steel-stud wall.
Be sure to review our mold-detection guides & articles on where and how to look for hidden mold problems in buildings:
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Ask a Question or Search InspectApedia
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: email@example.com
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com
Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: firstname.lastname@example.org or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions.
Roger Hankey is principal of Hankey and Brown home inspectors, Eden Prairie, MN. Mr. Hankey is a past chairman of the ASHI Standards Committee. Mr. Hankey has served in other ASHI professional and leadership roles. Contact Roger Hankey at: 952 829-0044 - email@example.com. Mr. Hankey is a frequent contributor to InspectAPedia.com.
Arlene Puentes, an ASHI member and a licensed home inspector in Kingston, NY, and has served on ASHI national committees as well as HVASHI Chapter President. Ms. Puentes can be contacted at firstname.lastname@example.org
Wikipedia provided background information about some topics discussed at this website provided this citation is also found in the same article along with a " retrieved on" date. NOTE: because Wikipedia entries are fluid and can be amended in real time, we cite the retrieval date of Wikipedia citations and we do not assert that the information found there is necessarily authoritative.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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
Allergies, Allergens, Allergy Testing in buildings - References & Products
Allergen Tests in buildings advice about how to test, what to look for, in evaluating the level of dog, cat, or other animal allergens in a building
"IgG Food Allergy Testing by ELISA/EIA, What do they really tell us?" Sheryl B. Miller, MT (ASCP), PhD, Clinical Laboratory Director, Bastyr University Natural Health Clinic - ELISA testing accuracy: Here is an example of Miller's critique of ELISA
http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
The critique included in that article raises compelling questions about IgG testing assays, which prompts our interest in actually screening for the presence of high levels of particles that could carry allergens - dog dander or cat dander in the case at hand.
http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue but interestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
Allergens: Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases
Allergens: WebMD discusses allergy tests for humans at webmd.com/allergies/allergy-tests
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
"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
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates 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.
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.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones