Ask Captain Crawl Space: Is dead mold harmful?

Hey Captain Crawl Space,

We purchased our house in October and the home inspection report said there was light mold in our crawl space that should die out in the winter. The seller refused to do anything but we loved the house and purchased it anyway- should we be concerned?

Tyler M.- Glen Allen VA.

Hi Tyler and thanks for your question. We see home inspection reports on a regular basis that use terms such as “light mold”, “seasonal mold”, “white mold”, or “non-harmful mold”. Sometimes home sellers will “kill” the mold with some type of anti- microbial spray based on the home inspection recommendations.

The 1st question is should you test the mold?
According to the Environmental Protection Agency- “In most cases, if mold is visibly present, sampling is unnecessary. Since no EPA or other Federal limits have been set for mold or spores, sampling cannot be used for compliance”. Sampling may be used to check if an area has been adequately cleaned.

If mold is visible, it doesn’t matter what kind of mold it is, or if it is dead or alive. Mold needs a relative humidity above 60% and temperature above 60 degrees to survive- so in Eastern Virginia, mold in an unconditioned crawl space will usually die in the winter (this of course, depends on weather conditions). This is still a problem- dead mold can be just as harmful as live mold.

One of the most common misconceptions about mold is that it can be removed simply with an anti- microbial spray. Disinfectants and biocides really just stop the mold from reproduction. Dead mold dries out and can easily get into the air affecting exposed individuals to allergens and other potential health risks. It is not enough to kill the mold or leave mold to die, it must be physically removed from the affected area, or the affected area needs to be removed from the building.

This was a great question Tyler and I hope I answered it for you fully. EPA mold guidelines can be found here:

Do you have a question like Tyler’s, or do you have something else you would like to ask Captain Crawl Space- please send it to

Dec 29, 2015 | Posted by in Capt.'s Blog | 0 comments

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