MOLD PREVENTION -- Steps You Can Take to Reduce the Incidence of Mold
• Make sure the ground
slopes down at least 6 inches within the first ten feet from each exterior
wall.
• Use a properly sized air conditioner.
Make sure your installer calculates the load and selects a piece of equipment
that will provide both comfort and efficiency in a variety of conditions.
• Use an electrically powered dehumidifier
or a natural gas desiccant dehumidifier to keep indoor relative humidity
below 50 percent (as measured in the middle of rooms) and below 60 percent
near the coolest surfaces.
• Remove excess humidity from the kitchen,
laundry and bathroom by using an exhaust fan or opening a window.
• Use a heat recovery ventilator or energy
recovery ventilator to remove excess humidity from the kitchen, laundry
and bathroom while filtering the incoming fresh air to remove airborne mold
spores, pollen, and dust.
• After taking a shower, wipe water droplets
on the shower walls into the drain.
• Hang wet laundry outside or use a clothes
dryer when indoor humidity is high.
• Reduce entry of water vapor from the
soil.
• Keep the air pressure
in the lowest rooms slightly higher than the soil gas pressure to minimize
entry of water vapor through pores and cracks in the concrete.
• Use subslab depressurization to expel
water vapor and radon from the soil to the exterior so they don't leak into
your home through pores and cracks in the concrete.
• Insulate any cold water pipes that
have a visibly damp exterior.
• Avoid storing papers, clothing, or
other "mold food", in contact with basement floors or outer walls
where their moisture content could become high enough to initiate mold growth.
• Make certain that rain water drains
away from the building quickly enough to prevent saturation of walls and
floors that contact the earth.
• Review the additional sources of information
listed below to see how others have prevented or eliminated mold problems.
Molds are incapable of obtaining the moisture needed for their development directly from the atmosphere, but they can obtain it from a substrate, which has absorbed moisture from moist air (60% to 100% relative humidity). The relative humidity of the air has an indirect effect on fungal growth, and the more hygroscopic a material was, the more susceptible it is to mold growth. The minimum moisture content at which mold growth occurs depends on the material and usually ranges from 10% to 14%. Suitable substrates include carpet fibers, gypsum, concrete, bricks, etc.
Information obtained from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).