Mold is easy to detect. If you can see it or smell it, you have mold. It can usually be detected by a musty odor. Often people say "My basement smells musty." That is a signal that there is mold growing in that basement. Mold comes in many different colors. It can be white, green, pink, brown, orange, or black. The color is not by itself, an indicator of toxic mold.

What do I do about mold in spaces I cannot see? Mold can grow in areas of your home that are hard to see. Such areas include the backside of drywall, wallpaper, or paneling. Molds can grow on the top side of ceiling tiles, or underneath carpets in the padding. It might be found inside walls around leaking pipes, or in the duct work in your home.

There are two ways to keep mold out of your home: 1) Keep it clean; and 2) Keep it dry. Keep your home clean because mold grows on surfaces contaminated with soil and grease. If you clean up the mold, but do not fix the water problem, most likely the mold problem will come back. Some air filters will trap the larger mold spores, but not all.

People produce 3 pints of water daily just by breathing. Other moisture sources include cooking, cleaning and taking showers. About one pint of moisture comes from a 10-minute shower. Moisture coming from the basement walls and floors can be up to 100 pints per day with wet soil.

The moisture required for mold to grow can come from water leaks, flooded areas, high humidity, condensation, and other sources. Controlling moisture is the key to preventing indoor mold growth. You will want to act quickly to clean up and dry any water-damaged areas. Mold can begin to grow in 24-48 hours.

• Run exhaust fans when cooking and showering
• Fix plumbing leaks, drips or "sweating" pipes
• Increase air flow in areas where problems may occur. Move furniture away from outside walls and open closet doors
• Increase the temperature when you notice condensation
• Humidfiers often provide a growth medium and distribution system for mold
• The condensation pan directly under the coil of your centeral air conditioner can harbor mold
• Dry and clean flooded materials
• Store freshly cut firewood outdoors, as it can emit large amounts of moisture
• Cut down on the number of houseplants in the home-soil can be a good place for molds
• Poor or inadequate attic insulation can lead to problems such as wet insulation, water-damaged ceilings, rotting wood
• Regularly check the condition of the roof and exterior finsih for any places where water might enter
• Direct runoff away from the foundation by grading and landscaping
• Make sure gutters and downspout systems are connected, workingproperly, and free of debris
• Prevent leakage around doors, windows, flashing etc.
• Seal cracks in basement walls and foundations and waterproof them
  Install vapor barriers

Some air cleaners will remove larger mold spores from the air, but they cannot remove many of the smaller mold spores and they do nothing to remove mold spores that have settled out of the air and fallen onto surfaces such as walls, floors, furinture etc. Air cleaners that produce ozone are not effective at eliminating mold. Ozone is a lung irritant and should not be used in an occupied space.

The air duct system in your home can become contaminated with mold and depending on the construction of the system, it may be able to be cleaned and disinfected. If you have insulated air ducts a and insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.

If conditions causing mold growth in the first place are not corrected, mold growth will reoccur.

EPA does not recommend that air ducts be cleaned except on an as-needed basis because of the continuing uncertainty about the benefits of duct cleaning under most circumstances. If a service provider or advertiser asserts that EPA recommends routine duct celaning or makes claims about its health benefits, you should notify EPA by writing to the address listed at the end of this guidance. EPA does, however recommend that if you have a fuel burning furnace, stove, or fireplace, they be inspected for proper functioning and serviced before each heating season to protect against carbon monoxide posoning. Some research also suggests that cleaning dirty cooling coils, fans, and heat exchanges can improve the efficency of heating and cooling systems. However, little evidence exists to indicate that simply cleaning the duct system will increase your system’s effeciencey.

If you think duct cleaning might be a good idea for your home, but you are not sure, talk to a professional. The company that services your heating and cooling system may be a good source of advice. You may also want to contact professional duct cleaning service providers and ask them about the services they provide. Remember, they are trying to sell you a service, so ask questions and insist on complete knowledgeable answers.

Extension Publications

Controlling Mold Growth in the Home — MF2141 Kansas State University 9/95
How does mold grow? Conditions that support mold growth. Preventing mold growth.

Home Moisture Problems — EC 1437 Oregon State University Extension Service
Indoor and outdoor causes of moisture. Drainage problems and how to fix them. Symptoms of wood decay and ventilation and dehumidification.

Other Resources

EPA Residential Air Cleaners Indoor Air Facts No. 7 2/1990
The agency does not recommend air cleaning devices or manufacturers. There is no certification on air cleaning devices.

EPA Use of Home Humidifiers Indoor Air Facts No. 8 2/1991
www.epa.gov/iaq/pubs/humidif.html
Proper care and cleaning, types, and associated pollutant of humidifiers.

EPA Mold remediation in Schools and Commercial Buildings (EPA 402-K-01-001 3/01)
Guidance on prevention, water damage, protective equipment, and mold sampling.

News Release

Controlling Mold Growth in the Home

Purdue Fact Sheet

Preventing Mold Growth

Mold Outside Your Home