Just about everyone has heard something about the growing issue of mold in residential structures over the last ten years. There’s a lot of information – and misinformation – going viral on the internet. Here’s a dose of truth: if your house has wood components (studs, flooring, joists, rafters) or drywall, then you already have some level of mold in your house. It doesn’t matter how old the house is, or how well you’ve maintained it. It’s there. Most likely it’s a very insignificant amount, but over the last few years of major rainfall totals and flooding events – and 2018 will most likely be the wettest year in this region on record – no structure is immune from dampness or some level of mold growth.

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There is no agreed upon standard as to when mold remediation is necessary, and the danger levels differ by species. It’s not only important how much mold you find, but what type. According to the Environmental Protection Agency (EPA)’s website, “Standards or Threshold Limit Values (TLVs) for airborne concentrations of mold, or mold spores, have not been set. Currently, there are no EPA regulations or standards for airborne mold contaminants.” (Bit.ly/2BTJQSM)

The EPA and the American Council for Accredited Certification have certification programs for mold remediation professionals, but they have not set any health standards for the levels of mold that are considered dangerous.

Again, from the EPA website: “In most cases, if visible mold growth is present, sampling is unnecessary. Since no EPA or other federal limits have been set for mold or mold spores, sampling cannot be used to check a building’s compliance with federal mold standards. Surface sampling may be useful to determine if an area has been adequately cleaned or remediated. Sampling for mold should be conducted by professionals who have specific experience in designing mold sampling protocols, sampling methods, and interpreting results.

“Who should do the cleanup depends on a number of factors. One consideration is the size of the mold problem. If the moldy area is less than about ten square feet (less than a roughly a three-foot by three-foot patch), in most cases, you can handle the job yourself. Follow the ‘Mold cleanup tips and techniques.’

“However, if there has been a lot of water damage, and/or mold growth covers more than ten square feet, consult EPA guide ‘Mold Remediation in Schools and Commercial Buildings.’ Although focused on schools and commercial buildings, this document is applicable to other building types.”

Normally a reputable mold testing company will sample the air both inside and outside of the structure being tested; the outside sample forms the baseline from which the inside sample will be judged. When an air test is done, there are only two species of mold that are considered dangerous at a level below 200 spores per cubic meter of air. According to United Water Restoration Group’s 2014 blog post on this subject, a measurement of 1,500 spores per cubic meter of air is the level at which “an issue may be apparent, unless a corresponding number in the outdoor example exists.” Even up to 3,000 spores per cubic meter may be attributed to a dusty air duct system if no water intrusion or mold source has been found.

Because of the complete lack of Federal guidance and testing on this subject, even the State of Maryland is holding off on further action. Maryland passed the “Mold Remediation Services Act of 2008,” which requires certification and licensing of mold remediation firms and technicians, but the implementation of the act was delayed indefinitely. However, a mold remediation contractor who performs any type of structural renovations (for example: tearing out and rebuilding walls, repairing drywall, replacing floors, etc.) is required to hold an MHIC contractor license.

This has a huge implication on how real estate transactions handle the suspicion of a positive test result for mold. Many buyers want a certainty that the current state of testing and evaluation simply cannot provide, leaving sellers with unpleasant choices of either losing a contract or an exorbitant expense that provides no concrete certification of safety.

In the end, if you think there could be areas of moisture, dampness, or outright water penetration, it’s best to take care of the situation before your house goes on the market. Use the links above to get the current EPA documentation on how to clean an area yourself, or when to hire a certified remediation specialist. Waiting for the buyer to request it as part of the home inspection process can be an expensive, frustrating mistake!