Photograph of Craig Balchunas inspedcting for mold .

Mold Investigation Tips for Home Inspectors
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Toxic or Black Mold Investigation Tips for Home Inspectors
How to inspect basements for signs of water entry and hidden mold
What are the health risks from mold exposure?
How to inspect buildings for evidence of toxic or allergenic mold
How much mold constitutes "a problem" in buildings?

How should home inspectors handle inspections for mold contamination in buildings? How would a home inspector recognize a mold problem? Are there health risks and other special environmental risks and concerns for home inspectors entering moldy areas?

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.

This document answers these and similar questions. This presentation and paper provide advice to building inspectors intending to inspect or test for toxic or problematic mold indoors, addressing inspection methods, how to find mold, where to look, what is likely to be important or not, and what inspection methods and mold test methods are valid or invalid.

Daniel Friedman is a licensed and certified home inspector, areobiologist, forensic microscopist, and sick building investigator who has worked in these fields since 1978. - Presentation Updated 4/13/06; original presentation 10 Jan 01 at the World Inspection Network Conference, Phoenix AZ, and for 6 December 01 for the NY Metro ASHI News - Metropolitan New York chapter of ASHI, the American Society of Home Inspectors. The page top photograph shows Craig Balchunas, a New York home inspector (now retired), examining a building for mold.

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Basic Facts About Basement Water Entry and Mold

From our environmental investigation and lab work on "sick buildings" I've learned some things about inspecting and testing for mold that have helped our general building inspection skills and which suggest some warnings to home inspectors.

Most inspectors get pretty good at spotting the history of water entry in a building. But I've inspected houses that had severe mold with no evidence of leaks. In one house, nothing suggested that there had been 20" of water on the floor. History provided by the owner told a different story. A burst-pipe put 20"of water in the basement nearly 20 years ago. They found the leak, fixed it, and had the basement pumped and "dried" in hours. Armed by hindsight one could spot very faint flood lines on paneling.

Flooding wasn't recurrent and there was no visible damage. Or was there? The owner pulled the paneling away from the drywall. Stachybotrys mold was so thick that it fell out in clumps onto the floor. People in the house had been sick for more than a decade, quite possibly due at least in part to this mold. You can see a photo of the owner pulling off paneling at http://InspectAPedia.com/sickhouse/0740s.jpg and our lab photo of this mold at http://InspectAPedia.com/sickhouse/1344s.jpg The mold fell right in our face! Was I wearing a respirator? Nope. I was sick with a lung infection for two weeks. Had I been a baby or elderly it could have been a more serious illness.

A Building Inspector's Guide Mold Health Risks

Don't disturb mold. Bystanders and occupants have sued careless inspectors who cutopenings or otherwise produced a burst of mold activity in a building. Risks include contributing to illness of building occupants and contamination of building areas if substantial amounts of toxic mold are present and proper containment methods are not used. This does not mean that invasive inspection techniques are prohibited--but methods of inspection need to be chosen based on the situation.
If you are in a seriously moldy area, wear a HEPA respirator. Repeated exposure toallergens can cause you to become sensitized even if you have not had problems in the past.
If appropriate, keep spectators calm by explaining that you wear the mask because you're entering buildings every day. But keep their noses out of themold too. People who are at particular risk can get sick from a single exposure. (Examples: elderly, babies, people with compromised immune system.)
Other risks may be present, related to the same conditions which caused mold growth: Sewer backups - bacterial hazards; wet areas, damaged electrical orother mechanical components, even shock hazards.

An Owner's Guide to Inspecting Homes and Other Buildings for Mold

Any experienced home inspector can identify conditions that riskwater entry or high moisture levels in a house. These conditions promote thegrowth of mold spores. Mold is a natural organism and it's virtually everywhere. The goal of "zero" mold spores makes no sense. But if conditions promote mold growth problems are more likely.

Just because you don't see water stains, don't assume there was never a flood or a leak.
If a building has had flooding, plumbing leaks, roof leaks, A/C condensate leaks, hidden mold may be at serious levels.
Check HVAC equipment and duct work for presence of mold or other allergens. Pay close attention to duct work downstream from air filters and blowers; check blower compartments and duct work for contamination (including dead mice), and check other areas where condensate may have accumulated in duct lines, supporting mold growth. Clean ducts in one area don't assure clean ducts everywhere; a "clean" air test does *not* guarantee no ductcontamination either as variations in temperature, moisture, and mechanical disturbance can suddenly release mold spores into the building air.
Just because you don't see mold, don't assume a severe mold infection can't be present (behind walls, under carpets, under insulation, in HVAC equipment.) I've found serious toxic mold colonies in walls which showed no external moisture stains nor external mold growth - the clue was other evidence of a history of leaks into the subfloor, confirmed by an impaction air sampler result.
Mold may be present at problem-levels in house air depending on variations in humidity, temperature, season, air movement, and physical activity. Not finding it at a given moment is not an excuse for visual and in some cases invasive inspecting.
A home inspection is not an environmental check for unhealthy mold or other bioaerosols orallergens. But if you see moldy conditions, warn your client.
Do not assert that a specific illness or complaint is caused by mold. The fourtests (proposed by Burge, Harvard School of Public Health) are stringent beyond your means as an inspector. Mold at high levels may cause and almost certainly aggravates or contributes to a wide variety of complaints.

A Building Owner's Guide to Valid Field and Lab Procedures for Mold

While anyone with proper training, a good eye for detail, and a little building science education should be able to recognize the presence of "mold," it takes a trained expert to identify even the most common of the mold. I've attended a number of classes, schools, workshops to learn field and lab procedures for years and still I can by no means identify all of these species. Nor can any of the other more expert sources with whom I consult.

About 80,000 mold species have been identified and named. About 1,500,000 additional species are not yet identified. Luckily not all 1.5 million species grow in buildings. I estimate that there are about 200 most-common molds that are able to grow in indoor conditions.

Some mold test kits are unreliable: Field test kits (petri dish left in house) are being sold by the same folks who hopped on the other Environmental Scare Bandwagons, as well as by some other labs. Finding mold this way might mean something, especially athigh counts.
Air testing can give a false "clean house" indication: But air tests, especially passive air tests, for mold are not reliable, and reliance on air sampling for mold is rejected by experts. You might get a false positive (says mold is present at problem levels when it's not) but youwill definitely risk false negatives (says mold is not present at problem levels when it is). Illnesses result from breathing mold spores butalso complaints are associated with ketones given off by mold colonies evenwhen no spores are detected.
Swab tests and other tests which rely on culturing are also not reliable as an overall characterization of what bioaerosols are present in a property. Deadspores may still be toxic; non-viable biological materials such as mouse dander won't grow in culture but may be a problem for house occupants as may be bacteria, pollen, animal hair, mite fecal pellets, cockroach fecal pellets, etc. What grows on a culture is what likes to growon that individual media, not necessarily what's the most serious problem in the house.
There is a place for each of these test tools, but the fundamental and first method for inspection must include a visual inspection of the property to identify likely problem areas, combined with bulk or surface sampling of visible colonies or other potential contaminants.
Remember to keep alert for other more immediate hazards: I found a wet moldy basement which had as a root cause a blocked gas-fired-appliance chimney which risked killing everyone in the building with carbon monoxide - a moreserious risk than mold in that instance.

How Much Mold is a Problem?

If you see more than 30 sq.ft. of contiguous mold or mold-contaminated surface present in a building, the mold contamination should be cleaned up by a professional (read "expensive")
maller amounts or areas of mold contaminated surfaces can be remedied by a homeowner or cleanup contractor.
Some occupants who are sensitized may respond to very low levels of mold spores (orother allergens). I've conducted tests which proved that a client who was hypersensitive to airborne allergens responded to airborne mold at levels far below commonly accepted levels of indication of mold contamination. So don't assume that everyone will be equally happy with moldy walls. A general rule of thumb is that if mold is present indoors at significantly higher levels than outside, it's a problem.

What To Do About Mold: a Concise Summary of Critical Steps

Mold Action Plan: What to Do About Mold in Buildings a simple step by step procedure for building owners and occupants as well as links to the New York mold remediation guidelines and to other mold cleanup standards are at Mold Action Plan - at http://InspectAPedia.com/sickhouse.htm#action
Small surfaces of mold can be cleaned with a dilute bleach solution (watch your eyes!)
Not all mold needs to be tested: For many situations, expert field and lab analysis are not appropriate. Clean up the mold, fix the conditions that caused it, and clean your gutters.
For larger areas, removal of moldy material and disinfect ion of surfaces is required.
People at extra health risk should be out of the building during cleanup. (Elderly, infant, allergic, asthmatic, immune-impaired, etc.)
People who have health complaints should first see their doctor, not their home inspector.
Where a health complaint exists (respiratory, neurological, immune system) which makes people suspect the house ("I get better when I leave.") andwhere no obvious bioaerosol or allergen or mold is present, an expert might be needed to investigate.
Whoever is doing mold cleanup needs to be alert for the discovery, as demolition progresses, of more serious amounts or types of mold. If necessary, work needs to stop for further testing and possibly for setup of containment measures.

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MOLD CONSULTANTS/INSPECTORS
MOLD CONTAMINATION LEVELS
MOLD CULTURE PHOTOS
MOLD CULTURE TEST KIT VALIDITY
MOLD DETECTION & INSPECTION GUIDE
MOLD DOCTORS - ENVIRONMENTAL MEDICINE

MOLD or INDOOR AIR EMERGENCY RESPONSE
MOLD EXPERT, WHEN TO HIRE
MOLD EXPOSURE, FOOD HAZARDS
MOLD EXPOSURE RISK LEVELS
MOLD EXPOSURE STANDARDS

MOLD FAQ's
MOLD FREQUENCY in BUILDINGS
MOLD GROWTH ON SURFACES, PHOTOS
MOLD GROWTH on SURFACES, TABLE OF
MOLD GROWTH in/on BUILDING INSULATION

MOLD INFORMATION CENTER
MOLD INSPECTORS & MOLD TESTERS
MOLD INSPECTION HOME BUYERS GUIDE
MOLD INSPECTION SERVICE
MOLD INVESTIGATION PROCEDURE TIPS
  Basement Water Entry
  Mold Health Risks
  Inspecting Buildings
  Field and Lab Work
  How Much Mold?
  What To Do About Mold
MOLD INVESTIGATION REPORTS

MOLD KILLING GUIDE
MOLD LAB REPORTS
MOLD LEVEL IN AIR, VALIDITY
MOLD LEVEL REPORTS
MOLD LEVELS IN BUILDINGS
MOLD by MICROSCOPE

MOLD ODORS, MUSTY SMELLS
MOLD on or in CARPETS
MOLD ON DIRT FLOORS
MOLD PREVENTION GUIDE

MOLD RELATED ILLNESS GUIDE
MOLD RELATED ILLNESS SYMPTOMS
MOLD SAFETY WARNINGS
MOLD SPRAYS, SEALANTS, PAINTS
MOLD STANDARDS
MOLD STANDARDS - GOVERNMENT
MOLD STANDARDS - WORLD WIDE
MOLD TOXICITY VARIATION

MOLD TEST KITS for DIY MOLD TESTS
MOLD TEST METHODS, ACCURACY
MOLD TEST PROCEDURES
MOLD TEST REASONS
MOLD TESTING METHOD VALIDITY
MOLD TESTING SERVICES

MSDS Material Safety Data Sheets
MVOCs & MOLDY MUSTY ODORS

Craig Balchunas is an ASHI member, and a licensed New York home inspector and environmental and mold test inspector who previously practiced in Newburgh, NY.
Critique, contributions wanted: Contact Us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Environmental Health & Investigation Bibliography - our technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
Adkins and Adkins Dictionary of Roman Religion discusses Robigus, the Roman god of crop protection and the legendary progenitor of wheat rust fungus.
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

Mold Contamination Testing, Cleanup, Prevention: references & products

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
Aerobiology, Building Science, Microscopy, & Laboratory References, an extensive technical bibliography
Allergens: what they look like in buildings
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
Atlas of Mold Related Illness: Index of Symptoms and health, physical, neurological, psychological, and other complaint which people suspect may be mold or building-related.
Atlas of Indoor Mold, Online Clinical Mold Atlas, Toxins, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
Black Mold that is Harmless Photos of recognizable, usually harmless black mold on wood, bluestain, ceratocystis, ophistoma
Building Floods: quick steps after a building flood or plumbing leak can prevent costly mold contamination
Classes of Mold: what types of cosmetic, allergenic, or toxic mold are a problem? Can mold be cleaned-up successfully?
Clinical Mold References - Detailed bibliography of mold reference texts
"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 Program for Certain Vegetable Crops," David B. Langston, Jr., Extension Plant Pathologist - Vegetables, University of Georgia (PDF document) original source: www.reeis.usda.gov/web/crisprojectpages/209797.html
"Disease Prevention in Home Vegetable Gardens," Patricia Donald, Department of Plant Microbiology and Pathology, Lewis Jett
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
"Management of Powdery Mildew, Leveillula taurica, in Greenhouse Peppers," Ministry of Agriculture and Lands, British Columbia - Original source: www.agf.gov.bc.ca/cropprot/peppermildew.htm
Environmental Health & Investigation Bibliography - our own technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
Fiberglass: Mold in Fiberglass Insulation© 2005 comments about a field study in process, & more about health hazards from fiberglass insulation - DJF
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.
Fungi, Identifying Filamentous, A Clinical Laboratory Handbook, Guy St-Germain, Richard Summerbell, Star Publishing, 1996, ISBN 0-89863-177-7 (English) (buy at Amazon)
Looking for Mold Procedure: what mold is often found where in buildings - simple technical presentation
Meruliporia: the house eating fungus or "poria"
Mold Action Guide: Step-by-Step Instructions, What to do about mold, mildew, and other indoor allergens
MOLD APPEARANCE - WHAT MOLD LOOKS LIKE Photos of what mold looks like in buildings
MOLD APPEARANCE - STUFF THAT IS NOT MOLD Photos of NOT-mold material that is sometimes mistaken for mold
MOLD ATLAS & PARTICLES INDEX, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
MOLD BY MICROSCOPE Mold under the microscope - photo identification of the most common indoor molds found in buildings
Mold FAQs Answers to Most Questions about Indoor Mold, Mold Related Illness, Mold Cleanup, Mold Prevention
US EPA: Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
Mold spores in the Home - a Photo ID Library for detection and identification of mold allergens
Mold Test Kits - How to Collect and Send Your Own Mold Sample to our mold testing lab or to any mold lab you wish
Most Common Indoor Molds Found in Buildings, A Table of
Mycology, Fundamentals of Diagnostic, Fran Fisher, Norma B. Cook, W.B. Saunders Co. 1998, ISBN 0-7216-5006-6 (buy this book at Amazon)
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.

Fiberglass building insulation and HVAC duct work insulation hazards
Sewage and Septic backup contamination in buildings: inspection, testing, remediation, & references to expert sources
Other environmental risks: Asbestos, carbon monoxide, electromagnetic fields, environmental illness, fiberglass, MCS - multiple chemical sensitivity, toxic gases, etc
Indoor Gas Sampling Plan for Residential Buildings lists a number of toxic indoor gases which we test for, depending on the building complaint and building conditions
Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
Pet control - if you can't say goodbye to your bird, cat, dog, guinea pig, hamster, tropical fish, then limit the areas they occupy and limit the airflow from that area to sleeping or other areas of the building, use allergenic bedding, eliminate wall-to-wall carpeting, improve housecleaning including use of a HEPA-rated vacuum cleaner. For more details see our article Dog, Cat, and Other Animal Dander - Information for Asthmatics and Indoor Air Quality
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.
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