All About Homes Residential Inspection Service

Q. I’m a real estate agent, and I am often asked by my clients whether or not a mold test needs to be done on a house that they want to purchase. I know some home inspectors offer this service, but my past experience with mold tests is that they are very vague. Is testing for mold something I should be recommending to my clients? If my clients want a mold test, is a home inspector the best choice for the service? B.L., East Bay

A. The basic questions that most people want answered about mold are, “Is there mold in the house, and do I need to worry about it?” The truth about mold is that it is present everywhere in our environment, and even in the air we breathe. Molds have been around since the beginning of time, and actually provide an ecological benefit. Molds are a type of fungus that decomposes dead organic material such as leaves, wood and plants. They can also infect living plants and animals, and this is why they can be a concern to humans. The difficulty with mold is that mold spores are usually too small to see without a microscope unless they are growing in an established colony. Once established, mold spores often appear to be black or green and can be visually seen.

Testing for mold is done in basically two ways; by taking air samples, and by taking spore samples (tape lifts) off infected material. The problem is that mold testing can be very deceiving because at best it is inconclusive, and more importantly, there are no specific standards to base the tests on to determine if the results represent a definitive health concern. Let me explain.

The reason we are concerned with mold is the fact that too much exposure to lots of mold can affect people’s health, and damage or destroy building materials. Most people are not affected by exposure to mold unless they are exposed to “too much mold” over long periods of time. The problem is that the scientific community does not what "too much mold” is, nor do they know how much time someone has to be exposed to mold to create health concerns. What we do know is that certain individuals with asthma, certain allergies, or suppressed immune systems are more susceptible to mold exposure than healthy individuals.

This leads to the question of whether or not mold testing should be routinely done on a house that is being purchased. Under most circumstances, mold conditions can be identified by either sight or smell. If you see mold, or smell mold, you’ve got mold. We’ve all seen mold growing in bathrooms in the grout joints of tile surrounds, and have smelled that “musty” smell in damp, unventilated areas. If visible or excessive mold is observed, it should be removed. You don’t need a mold test to tell you this. If there are no visible signs of mold, there probably isn’t any.

Unless mold sampling and testing are performed to determine specific information, it produces very little useable knowledge for the consumer. The best information that mold tests can provide is the type of mold present, and whether or not the mold count inside the house is greater than the mold count on the outside. The drawbacks with these tests are there are no numerical standards to gage the results. There are no standards or levels for mold counts to state whether a house is safe, healthy, or unhealthy. That’s why the EPA and most state agencies do not recommend testing for mold to determine if mold needs to be removed.

Mold needs three things to grow, and without these three conditions, it will not. Mold needs water, temperature between 40 and 100 degrees F, and food (organic material). Organic material includes wood and paper products. However, mold can grow on inorganic materials such as glass and tile if there is a minute layer of a food source such as dirt and debris on the material.

If the source of mold is not readily visible, then a visual inspection should be performed looking for signs of water or excessive moisture. Check in closets and the base of sink cabinets where damp air can exist, and look for leakage. Often times, the source of the moisture or leakage can be easily located.

If there is a substantial infiltration of mold present, or if occupants of a building are experiencing symptoms of mold exposure and the mold cannot be visually identified, then mold testing should be done. In California, an individual must be certified as an industrial hygienist to be able to sample and advise on environmental hazards such as mold and asbestos and their remediation. Most home inspectors do not have this certification, and therefore should not be relied upon for this information.

For balanced and credible information about molds you can contact the California Department of Health Services, Indoor Air Quality Section in Berkeley, at (510) 540-2476 or visit their web site at www.cal-iaq.org . Or contact the EPA’s Indoor Air Quality Information Clearinghouse at (800) 438-4318. Their web site is www.epa.gov/iaq. To locate a company qualified to provide accurate testing for mold, contact the American Industrial Hygienist Association at www.aiha.org

John R. Schneider is a licensed general building contractor and an ICC certified residential code specialist. He is president of All About Homes, a residential inspection company, and has been performing code and construction consultations since 1985. Readers may address their comments to John Schneider, 24326 Mission Blvd., Suite 7, Hayward, CA 94544, Fax number: 510-537-8666, or on the web at www.allabouthomes.com . Schneider will answer questions of general interest in the paper. He reserves the right to edit the letter for brevity and clarity. Readers are encouraged to contact a competent contractor or code consultant for specific information regarding questions they may have about their home.

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