Photograph of Craig Balchunas inspedcting for mold . Building Mold Investigation Procedures for Home Inspectors & Mold Testing Professionals

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Procedures for effective mold inspection & testing 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? 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.

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Basic Facts About Basement Water Entry and Mold

This article is based on classes taught by Daniel Friedman for building inspectors.

Article Contents

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. The first warning is that you need to determine if you should be performing a mold inspection or test by considering your expertise and by a review of the needs of the client.

Should We Test for Mold at All?

Watch out: a superficial "mold test" or "mold inspection" may be inexpensive but also dangerous as there is a high risk of failing to observe or detect unsafe building conditions that may put occupants at risk of serious, even fatal illness. At the same time a building professional should not perform expensive services where they are not appropriate.
See MOLD / ENVIRONMENTAL EXPERT, HIRE ? for help in deciding if and when a professional inspection for building mold contamination is appropriate.

Do we need to test for mold at all? Mold screening tests, as part of a thorough inspection, can help us decide when invasive inspection is needed in a building where there is no large visible mold reservoir.

Do we need to test mold in buildings to identify it? After all if all mold that grows indoors is harmful, why test it at all? Identifying cosmetic mold - that does not need to be tested - can be done by eye if you know what to look for.

But if a building occupant has building related health complaints his or her doctor may want to know what molds are present, and there are other reasons to know what molds were present before beginning a mold clean-up job.

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 and our lab photo of this mold at 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

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.

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.

How Much Mold is a Problem?

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

Mold Inspection Articles

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 2015/09/15; 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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