Chris McLaughlin, sales manager for JES Foundation Repair, a company that works on foundations, crawl spaces and basements in the D.C. area, says that musty, dank smell is usually the first clue that you have a mold problem.
“The thing is, most people don’t even realize there is a problem. They grew up with a moldy smell in their basement or closets, and they never really knew what it was or thought to do anything about it,” McLaughlin says. “But one day, someone comes in to do some work, and they start opening up drywall and they find mold all over the place.”
The Centers for Disease Control and Prevention advises that if you smell or see mold, you need to remove it as soon as possible — there are numerous varieties, but it’s not necessary to test it to see what kind it is — as it can pose a health risk. McLaughlin stresses that mold has serious health implications and should be removed and monitored by a professional mold remediation company. And once it’s removed, you should hire a professional to deal with fixing the environment (moisture and humidity) that is conducive to the mold growth.
Georgetown University Medical Center’s Richard A. Calderone, a professor and the chair of the Department of Microbiology and Immunology, and Joseph A. Bellanti, a professor of pediatrics and immunology, explained in an email that people exposed to mold-filled buildings are more likely to suffer from mild respiratory symptoms (such as sneezing, runny nose and itchy eyes), asthma, hypersensitivity pneumonitis (a rare inflammatory lung disease), respiratory infections, hay fever, bronchitis and eczema — illnesses that none of us want to deal with, especially during the coronavirus pandemic.
Calderone and Bellanti say that molds are fungi that grow as threadlike structures called filaments both indoors and out. As they grow, the filaments produce thousands of airborne spores. In nature, these spores normally return to their environmental origins, but if they are contained in moist, damp environments, the spores thrive and grow and eventually create the potential health risks listed above. Mold spores can enter your house through doors, windows and vents, or they can attach themselves to your clothing, shoes or pets.
McLaughlin adds: “If you give those spores moisture and an organic material like paper, drywall or wood, you have a recipe for disaster.”
Mold can be difficult to identify, because you don’t have to see it for it to be present. For me, it was that musty, rotten smell that indicated mold, but other signs to watch for are greenish black spots in the home, water-stained building materials or excessive water damage. Mold is most commonly found in basements and crawl spaces, where humidity and dampness are highest. McLaughlin also says closets can be an issue, because there is often little air flow and circulation.
To combat mold, experts emphasize the importance of keeping moisture in your home at levels below 60 percent by using dehumidifiers and running your air conditioner. (The CDC recommends levels between 30 and 50 percent.) This is particularly important during the stormy summer months, when humidity is higher and flooding is more likely.
It’s best to use air-conditioning units with high-efficiency particulate air (HEPA) filter attachments, because they will trap mold spores and prevent mold accumulation; make sure you replace the filters twice a year. HEPA filtration can be added by upgrading your existing HVAC filter and using a high-quality dehumidifier that has a HEPA filter. Also, keep your air-conditioning drip pans and drain lines clean, using either distilled vinegar or a product formulated for this purpose, available at many home-improvement stores. Make sure that your ductwork does not sweat. Look for white residue that is left on the bottom edges of ducts, where the water drips on to the surface below.
If you live in a very humid climate (daily levels at or above 60 percent), Calderone and Bellanti recommend choosing linoleum, hardwood or ceramic flooring instead of potentially moisture-retaining, wall-to-wall carpet. And because mold can grow on paper, bedding and clothing, store them in airtight, waterproof containers. They also recommend cleaning hard surfaces such as glass, plastic or tile, which can be breeding sites for mold, with a bleach solution, soap and water, or a commercial product. You should clean them immediately if you see mold, but these surfaces (most often in bathrooms and kitchens) should be cleaned weekly to prevent mold growth.
In the bathroom, Calderone and Bellanti say to always use an exhaust fan or an open window to cut down on humidity. In the kitchen, keep a lookout for mold in refrigerator drip pans, door seals and garbage pails. Whatever you do, McLaughlin says, never paint or caulk over mold; remove it instead. McLaughlin says mold will never go away unless it is mechanically removed. When the spores are treated with spray, the growth can be killed at the time, but if the environment still supports mold growth, the problem will recur. A common method of mechanically removing mold is soda blasting, which is a pressurized system using baking soda or dry ice that minimizes damage to the surface but is abrasive enough to release the spores. This process, used in conjunction with HEPA filtration of the air, will capture loose spores.
There are also precautions you can take outdoors to prevent mold growth. McLaughlin recommends moving outdoor sprinklers away from your home, cleaning gutters and directing all water flow away from walls. Also, promptly fix leaky roofs, windows and pipes. If you live in an area that is susceptible to high rains or flooding, McLaughlin recommends installing a sump pump.
If you do discover mold in your home, realize that hiring someone to remove it will probably be a Sisyphean task unless you address the underlying issue: moisture. As long as it exists, mold will probably return. “If you fix the moisture problem, you fix the mold problem,” McLaughlin says.
Mayhew, a “Today” show style expert and former magazine editor, is the author of “Flip! for Decorating.”