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How to Minimize the Risk of Mold Problems In Your Home

Dear Marie: I live in a fairly new (8 year old) house in a dry region of the country (Nebraska). Recently we have noticed a moldy odor in the house, especially in the Summer. What could be causing this? What can we do about it?

These are both excellent questions. Contrary to what one might think, mold in the home can be a problem anywhere in the country, not just warm wet regions like Louisiana or Florida. Likewise, mold problems aren't just found in the basements and attics of very old homes.

It is true that moisture is needed in order for molds of all types to grow. They also need an organic food source, usually celulosic materials (more about that later). But, the reasons for the increased moisture inside homes might surprise you. For example, new homes are often more prone to mold problems than older homes might be. Here's what gives.

Most newer homes are tightly sealed to reduce heat loss (or gain), whereas most older homes aren't. This is good from an energy efficiency standpoint, but it increases the potential for mold problems and other indoor air quality issues.

The reason for this is that tightly sealed homes can trap moisture inside them, unlike older homes that allow much more air to pass through walls and ceilings. In the words of one industry specialist, this makes modern homes "giant petri dishes", just right for mold growth. Keep in mind that any increase in the indoor humidity above 55% increases the risk of mold growth.

Another reason for increased mold problems in newer homes has to do with the materials used in their construction. Remember earlier when I noted that molds also need a food source? Well, this is where I explain that.

Older homes usually had plaster walls, the bathroom floor and walls were normally tiled, and floors in the rest of the home were typically wood. The walls in new homes are almost always made from gypsum board (drywall) that wicks moisture when wet AND provides a food source for the mold (the paper skins on the wallboard).

New homes also use plastic tub & shower enclosures that trap moisture behind them if there are any leaks, and the wood framing provides a food source. Carpeted floors with rubber or other synthetic, sealed backings trap moisture in the padding (the food source).

So, what does one do to reduce the risk of mold growth in new homes? There are several things ranging from simple preventative measures to installation of special equipment like humidifiers and air exchangers (see my column on air exchangers). but number one on the list by far is to control the moisture. Toward this end Clemson University Extension has compiled a very convenient checklist of steps you can take to reduce the potential for elevated moisture levels in the home.

Click here for a copy of the Clemson University Checklist.

Marie S. Spodek, DREI, GRI is a highly regarded real estate educator and author. Her seminars have been attended by thousands throughout the U.S.

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