Healthy Indoors Magazine
Issue link: https://hi.healthyindoors.com/i/1398331
24 | July 2020 By Jeffrey C. May, ©2021 I 've worked with many clients who spent thousands of dollars unnecessarily. In one situation, a woman was told that her base- ment was full of mold growth and that she should immediately move out of her house. She was given an estimate of about $3,000 to "de-mold" her basement. She moved into a hotel and called me for a second opinion. The mold growth was efflorescence: crystalized minerals from the foundation's concrete. When moisture migrates through concrete, it dissolves some of the minerals in the masonry that then crystalize on the inner sur- face of the concrete when the moisture evaporates into the air. Efflorescence on a block wall. May Indoor Air Investigations, LLC To confirm that staining is efflorescence and not mold, you can scrape some of the material off the surface and put it in vinegar. If the material is efflorescence, it should dissolve, sometimes with bubbling. The woman had to stop moisture from migrating into her foundation wall by taking better care of her gutter system: keep- ing the gutters and downspouts clean, and being sure that the downspouts emptied onto splash blocks, a drywell, or preferably into underground piping that emptied to daylight downhill from the house or at the edge of a deep landscape furrow. The house also had reverse grading (the ground sloped toward rather than away from the house), which can lead to moisture intrusion be- low-grade. If she had spent that $3,000 to have the foundation walls cleaned and sealed and had not done these corrections at the exterior, efflorescence would have again reappeared. And as time went on, the moisture in her basement could have raised the relative humidity, possibly leading to mold growth on cool surfaces. Luckily for her, mold growth had not yet occurred. Aspergillus mold growth on a basement beam. May Indoor Air Investigations, LLC In another situation, a young couple bought a house, waiving the home inspection contingency to sweeten their offer in the face of fierce competition for the property. They were then told that leaking windows had resulted in extensive mold growth in wall cav- Identify the Problem First