Mold

The presence of mold and its effects on our health have been increasing concerns for real estate owners and managers. Mold spores circulate in indoor and outdoor air almost constantly. When they land, they only need a little humidity to grow. Mold grows on wood, paper, carpet, and food, so there is no practical way to eliminate all mold and mold spores in an indoor environment. The only way to control mold is to control moisture.

Mold grows at humidity levels from 65% to 99% at the surface on which it grows. Maintaining relative humidity below 50% inhibits mold and mildew growth, dust mite infestations, and bacteria. In colder climates, wintertime humidity levels must be even lower at generally 25% to 40%. To keep peoples’ respiratory systems healthy, humidity should be above 25%.

Although The New York Times reported (May 26, 2004) that a government panel of experts found no evidence that toxic mold poses a serious health threat to most people, many criticized the findings. In 2002, insurers in the United States paid out $2.5 billion in mold-related claims. The controversy continues.

Following is a list of practical steps to reduce and control moisture in order to control mold growth:

• Check the ground slope from exterior walls. The ground should slope at least six inches within the first 10 feet from the wall. Rain and water should not be allowed to stand and possibly saturate walls or floors that contact the earth.
• Use the proper size air-conditioner for the space and/or room.
• Use dehumidifiers.
• Install exhaust fans in places such as kitchens, bathrooms, and laundry rooms.
• Use a heat recovery ventilator or energy recovery ventilator to remove excess humidity from kitchens, baths, and laundry areas.
• Reduce entry of water vapor from the soil. Lower-level rooms should be kept at an air pressure slightly higher than the soil pressure to prevent water vapor from seeping through pores and cracks in concrete.
• Do not store anything in basement areas in contact with the basement walls.
• Pay special attention to carpet on concrete floors.
• Do not shut down ventilation systems during unoccupied hours. (Note that in commercial buildings, the HVAC is turned off at night and on weekends.)

Removing Mold
Most small areas of mold can be cleaned with detergent and water.

• Be sure to completely dry the surfaces after cleaning them.
• Wear a mask, safety goggles, and gloves to prevent inhaling spores or allowing them to contact your eyes and hands.
• Begin by vacuuming surfaces with a vacuum cleaner that has a high efficiency particulate air (HEPA) filter or an exhaust system that connects externally to the building.
• Next, clean the surfaces with detergent and water and thoroughly dry them.
• Concrete surfaces may require a second cleaning with TSP (trisodium phosphate). Dissolve one cup of TSP in two gallons of water. Stir for two minutes.

TSP must not come in contact with skin or eyes. Saturate the surface with the solution and keep wet for at least 15 minutes. Rinse the surface twice with clean water and dry as quickly as possible.

• Mold on drywall may be vacuumed and washed, provided the mold is only on the paint surface.
• If mold has penetrated the drywall, a mold clean-up contractor should replace the drywall.
• If the source of dampness has not been removed, the new drywall is likely to become moldy.
• Proper cleanup after flooding and/or leaks is critical.
• Check carpeting, furniture, ceiling tiles, and drywall:

• Wet ceiling tiles should be removed and disposed of within 24–48 hours of water damage. An exception might be a tile that was damaged by a steam leak but the shape of the tile has not changed.
• Absorbent materials may need to be replaced.

IREM Resource: IREM publishes “Mold -What Every Professional Real Estate Manager Needs to Know.” This useful key report discusses strategies for mold detection, prevention, and eradication.

Resources:

• http://www.epa.gov/

Search for the following:

• An Office Building Occupant’s Guide to IAQ
• Biological Contaminants
• Building Air Quality Action Plan (for commercial buildings)
• http://www.osha.gov/

• The U.S. Occupational Safety and Health Administration (OSHA) released a Safety and Health Information Bulletin in October 2003 titled, “A Brief Guide to Mold in the Workplace.”