How Fast Can Mold Grow in a Basement?

Mold details

• According to the Washington State Department of Health, mold will grow where there is moisture. Water damage encourages growth, as does warm, moist air. The surface must have sufficient organic material -- such as wood, cellulose, dead skin flakes or other nutrients -- to germinate.

  Different species of mold have different growth rates. These fungi require a temperature of between 60 and 80 degrees Fahrenheit to grow effectively, according to the Department of Public Health in North Carolina.

Identification and Growth

• The North Carolina Department of Health and Human Services found that mold can grow within 24 hours on any item or surface that stays consistently wet.

  The U.S. Environmental Protection Agency recommends eliminating dampness and standing water quickly. If your basement is dry within 24 hours, in most cases, the mold will not have a chance to grow.

  If you see fuzzy white, green, gray, brown or black growth, you have mold. If your basement smells musty, mold has been growing.

Expert Insight

• Mold grows at optimal levels at 70 percent relative humidity, according to the Kansas State University Extension Service.

  Lowering the relative humidity will not completely eliminate mold growth, however; it will merely slow it. The Kansas State Extension service found that at lower humidity levels, mold releases more spores. When humidity levels rise, you may end up with more mold than before.

Prevention/Solution

• The U.S. EPA recommends homeowners keep basements at less than 60 percent relative humidity to help prevent mold growth; humidity of 30 to 50 percent is preferable.

  Ventilation in moist areas will also help prevent mold growth.

  To kill mold already growing, the EPA recommends a three-step process. Wash the area with detergent and let dry. If mold is still present, wash with a bleach solution (1 cup of bleach to 1 gallon of hot water). Use gloves when cleaning mold.

Types of mold

• The Toxic Black Mold Information Center offers identification and details on the many types of mold commonly found in homes and basements. Here are some of the more common discovered in water-damaged basements.

  Cladosporium mold is pigmented dark green to black in the front, and black on the reverse with a velvety to powdery texture. It tends to live outdoors, but also likes air ducts.

  Penicillium has been discovered in cellulose, paint, carpet, wallpaper and interior fiberglass duct insulation.

  Aspergillus has more than 160 different species of mold; 16 of these are known to cause illness in humans.

  Fusarium has been found growing in humidifiers and water-damaged carpets.

  Stachybotrys chartarum is toxic. It thrives in water-damaged, cellulose-rich material in buildings.