Q: An air test found Aspergillus-Pennicillum 1200/m3 in the interior air of the home we are buying. Initially we feared mold because the house had a former roof leak, now repaired. A mold remediator says the mold is from puddles of water under the house on top of the plastic moisture barrier. He proposes to wet-vac out the water, spray fungicide on the floor joists throughout the crawl space, and place a new 6-ml moisture barrier. Also, scrub some of the cinderblocks and seal them. Post-remediation testing would be direct-swab tests. Now, I understand the key is to remove the source of the mold, but don't we need to do another air test on the interior? We plan on removing all the interior carpets, and I am worried about exposure from the interior. Do we need some interior cleanup as well?

A: First of all, it is important to determine if there is actual water/mold damage on the wood joists and underfloor due to the water puddles on top of the moisture barrier. If there is mold damage, then the remediation proposed by the remediation contractor is reasonable and should be done. As far as the Pennicillium levels in the inside of the house, it could have been caused by the issues under the house, but may have been due to something else inside the house or a random variant result not associated with mold damage inside the house. As far as doing a mold air test inside the house, it should only be done to determine if the initial result is consistent or random or following any cleaning/remediation inside the house.

As far as removing the carpet yourself, I would recommend that a few locations of carpet be removed initially and if mold damage is observed, then the carpet and mold remediation should be performed by a mold remediation contractor while the family is gone from the house. If no mold damage is observed duirng the initial carpet review, then the work could proceed as planned by yourselves. Caution should be taken only if any mold damage is observed during any of the carpet removal work. It is recommended that following the carpet removal, the floor and any other horizontal surfaces in the house be hepa-vacuumed and then the flooring area sanitized with a detergent or diluted bleach solution. A lot of dust will be generated during the carpet removal work, so isolating unaffected areas by plastic curtains at the doorways will help condense the dust dispersion.

Thanks to Rick Anderson, a professional engineer and facilities director for EFI Global, a firm that provides mold investigation and indoor air quality services internationally.

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