Moisture, humidity can trigger mold growth.

  • Mold was widespread just two weeks after the 2011 Joplin tornado exposed this home's interior to the elements. MU Cooperative Media Group
    Mold was widespread just two weeks after the 2011 Joplin tornado exposed this home's interior to the elements. MU Cooperative Media Group

PERRYVILLE, Mo.—Homeowners who made repairs after last year’s floods and windstorms may now be finding ghostly shadows—dirty patches of mold and mildew—in parts of the home that got wet. This is a health hazard for people living in the home.

“Remember that mold is everywhere. All you need is moisture and a food source, like your home, to have it grow,” said Frank Wideman, University of Missouri Extension natural resource engineering specialist.

“If you repaired and sealed up walls and ceilings before they were fully dry, you will have long-term mold, mildew and dry rot problems,” Wideman said. “In our climate it can take a few weeks to a several months for those building materials to dry sufficiently if they are left to open air. If they are sealed up with drywall, they will be wet for years.”

A simple moisture meter can help you evaluate the moisture content of those building components, he said. “The moisture meter can tell you if the home has mold from moist wall materials from flood or rain, or just high-humidity indoor air. Wet studding requires the wall to be reopened and left that way for months.”

 To prevent mold growth, materials should have a moisture content of 13 percent or less.

You can buy moisture meters for use with lumber at many hardware stores and online. Many MU Extension centers have moisture meters and can help you check the moisture level and find solutions for problems you find, Wideman said.

Left unchecked, mold can inflict major damage to your home, furnishings and belongings. In rare instances, some molds can cause serious, even life-threatening, health problems.

It can be easy to miss mold growing in dark corners, under floor tiles or behind wallpaper. However, the musty smell of many molds often is a dead giveaway. Using spray or plug-in air freshener simply masks the telltale odor, knocking out a warning sign of mold growth, said Michael Goldschmidt, MU Extension housing and environmental design specialist.

Tests to detect and identify molds can be expensive and aren’t that reliable, Goldschmidt said. Regardless of the type of mold you have, you probably want to get rid of it.

If mold growth covers more than 100 square feet, the Environmental Protection Agency recommends hiring a professional to remove it. If you’re going to do it yourself, make sure you protect your skin, eyes and lungs from the mold and cleaning chemicals while making repairs, Wideman said.

Wear long gloves that extend to the middle of the forearm. Select gloves based on the material you will be handling. “If you are using a biocide such as chlorine bleach, or a strong cleaning solution, use gloves made from natural rubber, neoprene, nitrile, polyurethane or PVC,” he said. “If you are using a mild detergent or plain water, ordinary household rubber gloves may be used.”

To protect your eyes, use properly fitted goggles or a full-facepiece respirator. Goggles should be designed to prevent dust and small particles from entering. Safety glasses or goggles with open vent holes are not appropriate for mold remediation. Respirators should have an N-95 rating, as other face masks may not effectively filter airborne mold particles.