What You Should Know About Mold

It stinks. That is the first sign a building is under attack by mold but know that a bad smell is just the start. Mold problems lower property values, says Mary Malotke, a mold expert who runs awareness seminars for the Institute of Real Estate Management, The University of Cincinnatti and local and state Realtor boards. In extreme cases, mold destroys parts of a building (drywall is particularly susceptible), but even in less advanced cases, mold makes a building harder to sell and units harder to rent.

"Mold is perceived as a health risk," Malotke says, and many people claim allergic reactions to it, including headaches, sneezing and worse. A few years ago, worries about mold were epidemic, and even though it is no longer top of mind, mold is every bit as much a problem as it ever was. "It's cheaper to implement mold treatments than it is to re-tenant a unit," Malotke says.

Many Variations
"Mold is common everywhere, in every part of the country," says Jeffrey May, author of The Mold Survival Guide and a Cambridge Mass-based mold expert. Mold is in our air, both inside the building and outside. It takes destructive root, growing briskly on drywall, or the dust on carpets and pipes. The source that lets mold thrive: water. "Wherever there is water, mold has a good chance to grow," says Dr. Ed Sobek, Ph.D., president of MDDS Laboratories in Knoxville, Tenn., and a nationally recognized mold authority.

Leaks, May adds, are behind many mold outbreaks—"when a roof leaks or plumbing does, there may be mold." But leaks aren't mandatory. High relative humidity can trigger condensation and, particularly in below-grade spaces (think basements and crawl spaces), that is frequently enough to get mold growing. "Add water to dust, in the presence of airborne mold spores, and you have mold," May says. "When you smell that musty odor, there's a mold issue, no ifs or buts." Sometimes there is no smell but rather visible mold growth—so use both eyes and the nose in detecting mold outbreaks.

Fighting Back
Run a dehumidifier. When relative humidity dips below 50 percent it is difficult for mold to flourish, May says. Dehumidifiers are especially appropriate in basements.

Find and fix any leaks. Take away the water and that's robbing mold of the ingredient it needs to multiply.

Focus on prevention. Stagnant cold air in basements can lead to moisture condensation on the walls, so circulate air with dehumidifiers, Sobek suggests. Exhaust fans help defeat mold in bathrooms and kitchens, so be sure they have the capacity to adequately vent these rooms. Another hint: mold loves some building materials (cellulose, for example) and dislikes others (fiberglass). Some paints and primers also are treated with mold inhibitors—this is a large help particularly when staining cedar plank siding and painting materials exposed toutdoor conditions. Ask at the paint counter for mold-inhibiting paints recommended for your region.

Be cautious about laying carpet. Mold experts particular warn against carpeting basements, bathrooms and kitchens. Putting carpet in areas likely to get wet is akin to inviting mold into the building.

Never let mold grow. See it and stop it immediately. Don't put off cleanup because, experts warn, a small nuisance can erupt into a major outbreak in as little as 24 to 48 hours. (See Sidebar for cleanup tips.)

"We know how to prevent mold," Sobek says. "It just takes a little work and adequate planning."