Mold Basic Information


Molds are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be avoided. Molds produce by means of tiny spores; the spores are invisible to the naked eye and float through indoor and outdoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture.

What is Mold?

Any of various fungus growths often causing disintegration of organic matter. As the mold develops, it produces enzymes to digest organic materials. There are 100,000 different species of mold in the world. Mold is part of the fungi kingdom: a realm shared with mushrooms, yeasts and mildews.


How does Mold Grow?

In order for mold to grow it needs a food source such as wood, insulation, wallboard, drywall, carpeting, clothing, or paper. In addition mold needs a source of moisture for at least 24 to 48 hours.


Preventing Mold:

Inspect the outside of your home for roof leaks, inadequate drainage, improper grading, failing siding, gaps or cracked caulking around windows and doors. Keep the home dry by maintaining proper ventilation. Check your home regularly for signs of moisture or mold especially in the kitchen, bathroom and laundry room.


Moisture & Moisture Source

Typically household moisture problems can be divided into two distinct categories: Humidity and Condensation and Moisture Transport. Relative humidity and condensation affects buildings in several different ways. Condensation can be observed on windows, skylights and basement walls. Attics are also susceptible to condensation and should be carefully observed for surface moisture. Interior mold growth can occur when interior surfaces are cold from air conditioning, while interior moisture levels are too high. Common areas of elevated surface moisture include: exterior walls, closets adjacent to exterior walls, windows, roof sheathing, bathroom or kitchen ceilings.

There are four methods of Moisture Transport: Moisture Intrusion, Capillary Suction, Air Movement, and Vapor Diffusion.

Moisture Intrusion is defined as the unwanted ingression of water into a structure from an exterior location. Problems associated with water intrusion include: faulty or missing gutters and downspouts; failure of flashing around skylights, windows, vents, chimney, etc.; siding failure or improperly installed siding or building paper; roof leaks or inadequate sheathing/roofing paper; improper landscape draining; rising water table or flooding in crawlspace; failing of caulking or sealing around windows, shower units, toilet seats, etc.

Capillary Suction is the absorption of water through porous materials. The following is a list of commonly affected areas: sheetrock and framing in water saturated areas; concrete foundation absorbing groundwater and transporting it into the framing; plumbing leaks saturating through the floor and adjoining wall cavities; groundwater that comes into contact with exterior siding.

Air Movement– proper ventilation will reduce the amount of moisture in the air. The following is a list of moisture sources typically encountered in the home: vapor emission from soil underneath home; improperly vented dryers; outside air in humid, wet climates; kitchens and bathrooms without exhaust fans; humidifiers.

Vapor Diffusion is the process by which water vapor spreads or moves through permeable materials caused by a difference in water vapor pressure. The greater the moisture levels indoors, the stronger the effect of vapor diffusion on the building envelope.