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How to Prevent House Mold

Mold spores are everywhere; no one knows how many different species exist -- there could be more than 300,000, according to the CDC. No disinfectant can guarantee a mold-free household; mold spores in the air can alight and grow roots whenever the three ingredients for growth -- moisture, oxygen and nutrients -- are present. Moisture is vitally important, though, and if you can control it, you can control mold.

Mold-Preventing Chemicals

Mold tends to grow around leaks and condensation.

You can choose from a number of mold-preventing chemicals that are safe and long-acting, but contrary to popular belief, chlorine bleach isn't one of them. Bleach molecules form enough surface tension between them to prevent the compound from penetrating porous surfaces, such as wood, drywall, concrete and tile grout. Bleach may kill mold on contact, but it won't do much to prevent its return. You don't have to look far to find more effective disinfectants; vinegar kills 82 percent of mold spores, and baking soda has deodorizing and disinfecting properties. Borates, which are compounds that contain the element boron, can control certain forms of wood-destroying fungi.

Locate Vulnerable Areas

Although it's impossible to mold-proof your house, you can follow a strategy to make it more mold-resistant, and that strategy begins with identifying the most mold-prone parts of the house. These are usually in the basement and bathrooms, as well as dark corners far from light and ventilation, such as inside closets, cabinets and drawers. You can often detect the musty odors of mold and mildew -- which are names for the same thing -- coming from these areas, even if no growth is visible. They may be in different parts of the house, but they have one thing in common: They are areas of low ventilation, high moisture or both.

Tips for Controlling Moisture

Moisture often comes from the air, so you should take steps to reduce humidity in mold-vulnerable areas -- ideally, relative humidity should never rise above 50 percent, according to the CDC. Control it by increasing air circulation -- open windows or run a dehumidifier, if necessary. Dry out the insides of cabinets and drawers by opening them regularly to allow air to circulate.

Moisture can also come from condensation created by temperature differences between indoor and outdoor surfaces, which usually indicates the need for better insulation or more caulk. It also comes from leaks in the walls or roof, which also indicate the need for sealing with caulk. To keep water out, make sure your gutters are in good repair, and cut back tree branches that provide a path for water to flow on the walls or roof when it's raining.

Disinfecting for Mold Prevention

If you see it or can detect its presence by its odor, clean mold with detergent and water, then thoroughly dry the surface and spray or wipe it with a commercial borate mildewcide or a solution of 1 cup of boric acid per gallon of water. If you don't rinse it off, the thin borate film prevents many types of mold from growing, but it won't prevent all of them. To increase the potency of your disinfectant, add a cup of vinegar, which can soak into porous surfaces and kill spores and roots. Prevent mold growth on bathroom surfaces by running the exhaust fan to keep them dry and wiping them regularly with full-strength vinegar.

About the Author

Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. As a landscape builder, he helped establish two gardening companies.

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