May 11, 2007

Recent heavy rains and flooding across most of the state left many Nebraskans with water-damaged homes and the potential for molds to develop.

Mold spores are everywhere, but what determines where they actually settle and start growing is the presence of moisture and organic food sources, such as wood and paper, said Shirley Niemeyer, housing and environment specialist in the university's Institute of Agriculture and Natural Resources.

"The recent storms damaged many homes which now may have ideal conditions for mold growth," Niemeyer said.

Porous materials, such as carpets and pads, insulation, ceiling tile and wall board that are not dried within 24 to 48 hours may need to be tossed, she said.

Wet wall, ceiling and floor cavities should be opened up to dry completely. Concrete also needs to be dried. Niemeyer recommends first removing as much moisture as possible. Wet floors need to be wet vacuumed and dried out as soon as possible or if there is extensive water entry a professional may need to be hired.

Air conditioning and dehumidification can help dry the surfaces and materials. Additional air circulation also helps, she said.

It may take weeks before some materials are dried out and can be replaced, Niemeyer said. Covering up damp structures and cavities too soon can lead to mold growth. Moisture meters, which are available through some plumbing, heating and cooling businesses, can help determine the moisture content of wood and other materials.

"It's better to be cautious now and take extra prevention steps than to deal with a mold problem later on," Niemeyer said.

Molds long have been recognized as allergens, Niemeyer said. Mold allergens can cause symptoms including respiratory congestion, eye irritation, headaches and fatigue in those sensitive to mold. Some molds can even trigger asthma attacks.

"If you see a mold problem, find the source of the moisture, make the needed changes to reduce or control the moisture source, and safely get rid of the mold," Niemeyer said. "Any mold should be treated with respect and cleanup handled very carefully, whatever the type is."

Personal Health

Professionals can be hired to clean up mold and are recommended if there are large amounts — more than a 10-foot square area — and if someone in the household is sensitive to mold.

"The decision to clean up mold or to hire it done is up to the individual," Niemeyer said. "Anyone who attempts to clean up mold by him or herself should obtain complete detailed information before tackling the cleanup."

For more information about cleaning up molds visit your local UNL Extension office. More detailed resources are available from the U.S. Environmental Protection Agency by calling (800) 490-9189 or searching its publication catalog at http://www.epa.gov/epahome/publications.htm.

Those cleaning up mold should protect themselves by wearing goggles without vent holes, gloves, clothing that covers the entire body and at a minimum, an N-95 HEPA filter to filter out particles. Such filter masks are available at many hardware and home supply stores and lumberyards.

"Molds can give off toxins and special filters are needed for toxins," Niemeyer said.

Removing Mold

Niemeyer recommends physically removing as much mold as possible. Wet floors need to be wet vacuumed, dried out and vacuumed again.

"Use a quality vacuum with a HEPA filter, empty the contents outside and clean the vacuum cleaner when done," she said.

Contaminated porous materials are not easily cleaned and should be removed and disposed. Disinfecting contaminated materials may kill mold on the surface, but some of it may survive and start to grow again -- especially if conditions are right for growth. Keep humidity levels between 35% and 50%, Niemeyer said.

To prevent spreading mold spores, contain the mold infested area with plastic sheeting from floor to ceiling. Spreading mold spores throughout the house can be reduced by carefully encapsulating moldy materials being removed. Items should be carefully wrapped in large plastic bags or tarps and sealed with duct tape.

"This will protect people from mold and be sure the mold is not spread through the house during the removal process," Niemeyer said.

Mold on surfaces, such as wallboard, that will be cut or pulled away can be held more stable by applying sheets of contact adhesive paper to avoid spreading the spores. Larger plastic sheets can also be taped to surfaces, such as wallboard, before it is removed.Mold contaminated materials should be removed through the nearest window or door to avoid spreading the spores, she said.

Cleaning Surfaces

Hard or non-porous surfaces can be cleaned with a solution of household detergent and water, then rinsed with plain water and dried, Niemeyer said.

"A disinfectant may not be needed if the wet areas are from clean water," she said. "However, if people choose to use a disinfectant such as chlorine bleach, they should follow the label directions. Wear protective gloves and goggles and ventilate the area." In addition, allow the disinfectant to contact the area for about five to 15 minutes. Don't follow with a water rinse as this may reduce the disinfectant's effectiveness.

Running a dehumidifier and/or air conditioner can help reduce moisture problems, Niemeyer said.

Sandi Alswager Karstens
IANR News Service