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Getting Rid of Mold for Good

Mold has become the hottest topic in housing. Have you ever wondered why? If you think of a house as an integrated system rather than a collection of products and parts, it's easy to understand. If one element does not function properly, it can affect the performance of another element, and another, and the domino effect continues-until you have created the perfect conditions for mold to thrive.

There are four key elements you can control in order to eliminate mold before it has the chance to grow:

Construction Practices. How many times have you seen uncovered stacks of wood at a construction site when it's raining or snowing? Or a partially framed house exposed to the elements for weeks or even months, waiting for the crew to install the roof? Keeping construction materials dry is a key factor in preventing mold's growth. To ensure a dry construction site, consider modular building, where the house is assembled in a dry, climate controlled factory.

Building Materials. Newer building materials, like gypsum board, provide more food for mold than the traditional solid lumber and plaster. For damp areas like bathrooms, choose high-quality materials like cement board or fiberglass-covered gypsum board to help resist mold and moisture. Install high-quality windows to avoid condensation, and use steel framing when possible.

Building Design. Several design elements can have a positive impact on reducing the moisture level in a house.

  • Site the house on a slope to drain water away from the foundation, and ensure that the site is graded in all directions to slope away from the house.
  • Make sure the foundation is well-insulated. For slab on grade construction use frost protected shallow foundations.
  • Pay attention to the flashing around roofs, windows and doors, which can prevent water from entering the building envelope. Properly sealed gutters can also help prevent leaks.
  • Use the right levels of insulation to prevent condensation on ceilings (especially kitchens and bathrooms). The ventilation system is also a key factor, especially when you consider the current trends in building design-adding Jacuzzis and multiple showers in one home. Both lead to higher levels of moisture that needs to be removed in order to prevent mold. Consider installing a whole-house ventilation system or using a humidity-sensing control, and be sure to provide adequate venting in bathrooms and kitchens.
  • Properly sized HVAC systems are also important. Did you know that using an air conditioner that is too large can result in excess moisture, especially in hot climates? Choosing the appropriate size will also lighten your electrical load, letting the system run more efficiently and saving on heating and cooling costs.
  • Make sure all ducts are properly sealed to avoid transferring moisture from one area of the house to another.

Housekeeping. Maintain, drain and watch the rain.

Got Mold?

If you already have mold and you're looking for some cleaning tips, try the latest recommendation: good old soap and water. Apply a mixture of hot water and a strong detergent to the moldy area, then rinse thoroughly and let dry completely. Some sources recommend using a solution of one part bleach to ten parts water, but you must be aware that bleach is a toxic substance. Make sure you are in a well-ventilated area; take frequent breaks to get fresh air; and wear protective gloves, goggles and a respirator. Leave the bleach solution on for ten minutes, then rinse the area, let it dry completely-and whatever you do, don't use full-strength bleach!

For a review of the basics, check out our previous Tip " About Moisture and Mold."


The Environmental Protection Agency offers various resources and publications on mold and moisture including A Brief Guide to Mold, Moisture and Your Home, Mold Resources - an introduction to mold, moistures, indoor air quality and related health issues, and Building Air Quality information for large buildings.

HUD's Healthy Homes Initiative is a nationwide effort to reduce environmental hazards and includes partnerships and interagency agreements with a wide-variety of public and private organizations on the Federal, state, and local level.

Mold in Residential Buildings is a primer on mold and moisture control issues for homeowners and builders, prepared by the National Association of Home Builders Research Center.

Washington State University Energy Cooperative Extension, a resource for information and recent findings on buildings standards, codes, IAQ issues, mold and moisture, and much more.

Content updated on 8/3/2006

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