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Understanding Mold

By Jennifer Sidden

By now, virtually everyone has heard horror stories about the damage mold can wreak on a home and on the health of its occupants.

While the stories that have garnered the most media attention certainly aren’t typical and most homeowners will never have a serious problem with mold, understanding what mold is and how to prevent it from growing in your home can be key to maintaining a healthy house.

Mold is a type of fungus that is a natural part of the environment. Yeast and the antibiotic penicillin are both types of mold. So is the mildew that sometimes grows in showers and bathtubs.

The spores, or reproductive cells, that create mold are everywhere and enter homes through open doors and windows, heating and cooling systems or your clothing or your pets’ fur. They thrive and grow in warm, damp areas with temperatures between 40 and 100 degrees Fahrenheit, such as bathrooms, kitchens and basements.

Like many allergens, indoor and outdoor mold can cause some people to develop health problems, such as asthma, stuffy or runny noses, itchy eyes, wheezing, inflammation in the lungs, skin rashes or fevers. Other people have no problem at all when exposed to the same mold.

Since the symptoms associated with mold are similar to those associated with a variety of allergens, you shouldn’t automatically assume your home has mold if you suffer from itchy eyes and a stuffy nose. However, a musty odor or blotchy discolored spots are a good indicator of the presence of mold.

Mold’s affection for damp, warm environments means that parts of the home that have gotten wet from flooding, leaking pipes or even over-watered plants will be particularly welcome habitats for mold growth.

Any serious water-related problems, such as sewer back-ups, overflowing toilets and leaking roofs or windows, could lead to the growth of mold within as little as 24 to 48 hours. Be certain to clean and dry any wet or damp areas thoroughly, and repair leaks as soon as possible to keep mold at bay.

While it may not be possible to avoid all water-related accidents, there are many things you can do to keep mold from growing in your home. Regular vacuuming and cleaning to remove sources of mold growth is one step. Also, in areas susceptible to moisture, use washable area rugs, or install flooring that can be easily cleaned, rather than wall-to-wall carpeting.

Be sure your home is well insulated, as moisture traveling through the air during the cold winter months can condense when it comes into contact with cold walls. Not only will you save money on energy costs, but you’ll help prevent condensation from forming on your walls and creating mold.

Your builder also has taken precautions before and during construction to prevent mold from contaminating your home.

When materials, such as drywall or the wood used in framing, are delivered to the construction site, a reputable builder will inspect the materials for mold problems. If mold is found, most builders will either send it back to the supplier or remove the mold using established procedures.

Building materials that are not used right away should be stored and protected from the weather. Whenever possible, builders try to store materials such as wood framing under a roof. When that’s not possible, materials can be stored off the ground to avoid getting wet from storm water runoff and permit air to circulate underneath.

If it rains while your home is under construction, there’s no way around the materials getting wet. However, as long as the framing materials are allowed to dry out before being covered with insulation and drywall, the rain shouldn’t be a problem. A typical construction schedule generally allows plenty of time for wet building materials to dry.

Once your home is built, talk with your builder if you don’t know how to operate any features that could impact the amount of moisture in your home, such as the heating and cooling system, exhaust fans, water valves and the sump pump.

However, if – despite the best efforts of you and your builder – you discover that you have a mold problem, don’t despair. There are things you can do to get rid of it.

Non-porous items, such as those made of glass, metal and hard plastics, can be reused after a thorough cleaning with hot water and detergent or non-ammonia soap. Be sure to rinse the items and then dry them thoroughly.

Semi-porous items, such as those made of wood or concrete, can be scrubbed with a cleaning pad or stiff brush, while most porous materials, such as carpeting and insulation, should be thrown away if they have more than a small area of contamination.

Certain porous materials, if you decide to try to clean them, can be treated with a mixture of one part liquid chlorine bleach to nine parts water. Commercially manufactured treatment solutions are also available, or you can try putting a cup of hydrogen peroxide in a squeeze bottle and spraying it onto the moldy areas, then scrubbing the areas with a thin paste of lemon juice and borax.

Be sure to use protective gloves and eye goggles, along with a respirator, and work in a well-ventilated area.


  • Clean the door gaskets on your refrigerator and freezer doors regularly, as well as the drip pans. Doors that don’t seal properly create another moist spot for mold to take over.
  • Make sure your gutters and downspouts are clear of debris that could block the flow of water from your home’s roof.
  • Check that the areas around your home’s foundation and under the downspouts are graded so that rainwater flows away from the house, not toward it. Sprinklers should be set so that the water doesn’t hit the house or areas next to the foundation.
  • Use exhaust fans that vent to the outdoors in the bathrooms and kitchen.
  • Keep the humidity level in your home at no more than 60% relative humidity during the summer and 40% or less relative humidity during the winter.
  • Don’t store papers, books, clothing or other possible sources of food for mold in humid parts of your home.