One family we worked with had moved out of their home and was living in a hotel, because a mold inspector found mold all over their basement foundation walls. The mold ended up being efflorescence: crystalline mineral deposits due to moisture migration through the concrete. (If you wonder whether a fuzzy deposit on your basement foundation wall is mold or efflorescence, put some in a glass of vinegar. If the deposit dissolves, it’s mineral.) Another family was living in a camper in their driveway, because a testing laboratory had incorrectly identified candle soot on the ceilings of their home as toxic black mold.

In a third situation, a client who lived out of state hired a mold inspector to investigate his bathroom. The mold inspector took one air sample in the bathroom and one outdoors, and sent the samples off to a testing lab. The lab reported a higher concentration of mushroom spores in the bathroom air than outdoors, and the mold inspector recommended that the entire bathroom be demolished. The bathroom was completely tiled – walls, floor and ceiling – and there were no mushrooms present. The spores must have come in through an open window at some point from the outdoors, and settled into the dust in the bath mat.  I told him to wash the bath mat, which saved him $15,000.

If someone recommends that you move out of your house, or that you undertake costly remediation, based on one or two air samples, you may want to get a second opinion.

If you want to understand why and where mold grows, learn how to get rid of it and prevent it from returning, buy a copy of The Mold Survival Guide: For Your Home and for Your Health, Jeffrey C. May and Connie L. May (2004). Jeff May is also author of My House is Killing Me! The Home Guide for Families with Allergies and Asthma (2001) and co-author of Jeff May’s Healthy Home Tips (2008). All three books are published by The Johns Hopkins University Press and are available on amazon.com.