As climate change leads to increased flooding and more severe freezes, added moisture and humidity means that more homes and businesses are susceptible to mold growth. Mold can lead to a host of illnesses, ranging from asthma and upper respiratory tract symptoms to organ damage and cognitive difficulties. Michael Berg, technical director with Eurofins Environment Testing America, a company that does environmental testing for mold and other potential hazards, cited a research study finding that the economic cost to society of illness resulting from exposure to dampness and mold is over $22 billion.
With Atlantic hurricane season beginning in June, consumers need to know how to address water intrusion and mold in their homes. Since mold can begin growing within 24 to 48 hours, you should respond quickly to water intrusion by immediately removing wet materials (drywall, carpet, padding, etc.), using fans and dehumidifiers to dry out your home, and opening up areas with trapped moisture to airflow. Some lucky residents won’t have mold, but those who smell it, see it, or develop illnesses need to know what steps to consider, and that starts with a mold assessment.
The Importance of Proper Assessment
Because there are no national standards around mold assessment and remediation, standards vary from state to state. Only a handful of states have Indoor Air Quality (IAQ) laws that focus on mold, which leaves uneducated consumers at a disadvantage when facing water intrusion. Doug Hoffman, executive director of the National Organization of Remediators and Mold Inspectors (NORMI), says NORMI has helped write mold legislation in several states. Hoffman said consumers should think of the “mold assessor as the architect” in charge of designing the scope and steps of the remediation project, while the “remediator is the contractor who does the work.” Hoffman says consumers shouldn’t try to save money on testing because testing dictates remediation, and incomplete testing can lead to incomplete remediation.
Mike Marshall, chief operating officer of Mold Inspection Sciences Texas and president of the Texas Mold Assessors and Remediators Association, agreed, saying that “insufficient assessments and testing can result in insufficient remediation”: You can’t fix what isn’t identified. I can vouch for the need for thorough, professional mold assessment. Cleaning and remediation dragged on for 20 months after my home exploded with toxic mold two decades ago. Part of the extended timeline was because insufficient testing led to piecemeal remediations.
However, discarding uncontaminated materials can also create an unnecessary expense. Marshall estimates that remediation can cost 15 to 20 times the cost of testing, so accurate testing can save customers a lot of money through targeted remediation. Berg said that mold testing isn’t needed in cases when there is a clear path to address the issue (such as after a flood or burst pipe) but is very helpful when there is hidden mold growth or when there are insurance claims or disputes. In our extreme mold experience, logic didn’t dictate an accurate remediation plan, so thorough testing was necessary. While the mold explosion began in our shower, tape sample tests revealed toxic mold throughout the house—all three bathrooms, the kitchen, laundry room, and more.
What Happens During a Mold Assessment
Marshall says the best way to prepare is for consumers to understand what happens during a mold assessment. He says consumers often request mold testing because they smell or see something that looks funny, or because someone is sick and they don’t know why. In many cases this happens after a recent water intrusion.
Here’s how an assessment works in Texas, where I live. After a phone screening, a mold inspector licensed by the state of Texas arrives for an in-depth conversation with the homeowner. Then the inspector performs an exterior inspection of the home to determine possible water entry points: a faulty roof, foundation problems, landscaping or mulch issues, window caulking, and so on. Next, the inspector goes through each room with an infrared camera to see recent moisture events hidden behind walls or ceilings. If the infrared detects pooling areas of lower temperatures, a moisture meter is used to see whether water has collected there. They also test areas common for moisture intrusion, such as around windows, doors, and areas containing plumbing lines.
Depending on the size of the room, the inspector will collect one or more air samples if they discover conditions conducive to mold growth. According to Marshall, the industry standard is to pull 75 liters of air for five minutes through a bio-pump with an attached air sampling cassette. The air sampling cassette captures cells (mold, skin, bits of carpet, etc.) on a sticky surface on a microscope slide. The cassette is removed from the pump, sealed, and sent to an independent lab unaffiliated with the testing company under a strict Chain of Custody (COC) procedure for testing. A Chain of Custody documents the transfer of sample from point of collection to delivery at the lab, including date, time, and signatures for each time the sample changes hands.
Hoffman recommends a minimum of six samples for each HVAC area, so a two-story house would require a minimum of 12 air and surface tests. According to Berg and Marshall, the industry standard is to compare indoor air samples to those collected outside. If the sampling reveals an elevated mold species inside the home, then it is safe to assume that one or more sources of mold is inside the home. Hoffman says this comparison may overlook indoor mold in areas with elevated outdoor mold, so NORMI members also compare inside air and surface samples to their best practices standards for a healthy environment.
Marshall says inspectors take surface samples (tape, swab, or bulk) of any mold-like growth or substance they find for analysis. Marshall says labs prefer tape samples over swab and bulk samples. The mold’s reproductive structure can be damaged when swab samples are collected, and bulk samples are difficult to handle and rarely offer advantages over tape samples. Assessors recommend surface sampling to provide targeted remediation. Furthermore, Marshall says that not every moldlike substance is mold. Sometimes moisture, dust, and dirt can look like mold, and you can’t tell until you test it properly.
By the same token, what looks like dust can be mold. Visual inspection, infrared cameras, moisture meters, and surface sampling are critical tools for creating an accurate mold mapping and effective remediation plan. Marshall says that an “agitated wall cavity sample”—when a rubber mallet is banged on a wall while air is collected from inside the wall—is done infrequently under specific conditions because it can produce a sample not collected under normal living conditions.
Berg said that testing hasn’t changed much over the last few decades except that costs have come down and expectations are higher as the industry has become more standardized. Both Berg and Marshall said that at-home test kits should be avoided because they can be misleading and raise more questions than they answer. All three experts emphasized the importance of having an expert on-site to conduct both the visual inspection and the testing.
Where You Can Learn More
Mold can grow quickly, and the learning curve to prepare for and prevent it can be steep. Without national legislation to standardize mold remediation across the country, consumers are left to sift through websites and other sources to find quality guidance. Berg recommended following major industry organizations that address indoor molds through education and training, including the American Industrial Hygiene Association (AIHA), Indoor Air Quality Association (IAQA), The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), and the Environmental Information Association (EIA).
Before you hire an assessor, ensure that they are a certified or licensed mold assessor in states with such legislation, like New York, Florida, and Texas. Similarly, the Better Business Bureau provides information on hiring a mold remediator, dealing with flood damage, and avoiding scams such as “storm chasers.” In this context, storm chasers follow severe weather events and pressure vulnerable homeowners to pay in advance, disappearing before work is complete. You should also screen mold assessors in the same way you would any contractor making extensive changes to your home, and ensure that they have the skills and training needed to conduct a thorough assessment. People who research in advance will be able to respond to disasters more quickly and confidently. Hopefully it will be information you’ll never need.
Marshall says homeowners may want to prepare by researching water mitigation, mold testing, and remediation firms before an emergency strikes. Consumers should take time to understand the firm’s work steps in advance to gauge whether they will be comfortable with the approach. For example, Hoffman mentioned the “spray and pray” technique, then clarified that while fogging with an appropriate chemical can be useful, it should never be the only tool used in remediation—mold and moldy materials must be removed, not just treated. He adds that consumers should beware of firms who plan to fog a room immediately prior to testing, since heavy fogging knocks mold spores to the floor so they won’t be collected during the final air sample. Hoffman says consumers can avoid unscrupulous firms through careful research and select assessors and remediators who are properly trained and certified. It is common sense, and the law in several states, that the businesses conducting mold assessment, performing remediation, and conducting laboratory tests be separate, independent businesses.
Marshall says climate change contributed to a large increase in mold cases in 2021 and 2022. Many homes in the southwest weren’t built to withstand low temperatures, especially when millions of homes lost heat as a result of power outages during extended hard freezes. Marshall says they discovered multiple cases of microcracks caused when pipes froze and expanded. These microcracks cause water to drip down pipes and ultimately cause mold growth inside walls, often without any warning to the resident. In addition to preventative techniques such as better insulated pipes and dripping water faucets during a freeze, consumers can request a plumbing pressure test and infrared scan after such events to ensure there are no hidden leaks. Given our past mold experience, my husband drained the water from our house during both the 2021 and 2022 freeze. We’ll do whatever it takes to avoid repeating that ordeal, and I hope you never have to experience it.