Winning the War Against Mold (Part One of a Two Part Series)

Chances are, most of us are trying to kill it right now. Everything it needs to grow is already in your home: the ideal temperature, plenty of food sources…the only other thing it needs to thrive is moisture. I’m talking, of course, about mold. Not only does it look and smell bad, but for people with allergies or compromised immune systems, mold can bring on headaches, asthma attacks or worse. While many of us have been running to the store for more bleach since flood clean-up began, here’s some surprising news: while the CDC‘s guidelines approve the use of bleach in mold mitigation, the EPA, HUD, and OSHA all advise against it and FEMA recommends its use only in a 10% solution (one part bleach to nine parts water) as a disinfectant during flood clean-up.

Why so many differing opinions among the Federal experts? For one thing, the different agencies have different concerns. The CDC and FEMA are pro-bleach in some cases because it is an effective disinfectant which is important because, as we all know too well by now, flood water potentially carries many germs and pathogens (including MRSA) along with it.

But the case against bleach stated by those other agencies is almost verbatim the same: biocides (such as chlorine bleach, hydrogen peroxide, tea tree oil, and grape seed extract) are toxic to not only mold but also humans and animals. Another strike against bleach is that its chemical properties prevent it from soaking down into porous materials (such as untreated wood and concrete, drywall, carpeting, and ceiling tiles) to kill the roots or mycella of the mold.

The EPA’s recommended course of action is to replace porous materials that have been exposed to standing water or are visibly moldy and to scrub all mold off non-porous (such as metal, treated/painted/sealed wood and concrete, and granite) surfaces with detergent and water and then allow to dry completely.

Be aware that once clean-up is complete, mold spores will almost always still be present. Just like pollen, mold spores are in the air. The key to stopping the growth of mold in the home is controlling moisture.

Keeping moisture out is not just a matter of making sure there are no leaks in your roof  and pipes and removing standing flood water. If, for instance, your air conditioning system is too large or small for the space it is cooling, it will fail to remove water vapor from the air while it is cooling it.

Improperly vented clothes dryers, bathroom or kitchen exhaust fans are all prime offenders. Also, with the weather taking a turn toward winter and many homes unprepared for the colder temperatures, it is very important to note that unvented gas or kerosene space heaters can generate enormous amounts of water vapor and other air contaminants and should NEVER be used as a primary heat source.

In order to keep mold from growing, the relative humidity needs to stay below 60 RH. Once the RH reaches 70 and stays there for any extended period of time, mold is almost guaranteed to grow. Don’t know what 60 RH vs. 70 RH feels like? Check out any home and garden store for something called a hygrometer. They come in analog and digital styles and a variety of sizes and designs to fit your décor and budget.

And if humidity is a persistent issue in your home, a dehumidifier is a wise investment.  Before you buy, however, make sure you choose the correct size for the affected area.  A dehumidifier that is too large will waste energy and one that is too small will not correct your humidity problem.  Here is a helpful overview and a chart to find the appropriate size for your situation.  Most importantly, make sure that your home is completely dry (using a moisture meter) before you begin new construction to avoid wasting money on mold-susceptible materials.

Jen Ralston, The Bloomsburg Daily
Photo Courtesy of Marcus Povey

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