Because mold can grow on many different types of materials, it is essential to maintain effective moisture control within a building. The fact that molds need moisture to colonize a surface means that preventing excess moisture in a building usually will prevent mold from growing. Once mold has established itself as a colony, it often can survive in much less moisture than was required to establish the colony. Additionally, the reintroduction of even a slight amount of moisture into an environment where an inactive mold colony exists can trigger new growth of the colony.

Moisture can enter a home through many different means, such as pipe leaks, roof leaks, high ground water and condensation. In addition, many daily activities can produce moisture. Some of these include cooking, showering and drying clothes. In fact, people themselves produce about three pints of water vapor per day while breathing.

Mold growth in a building can be prevented by practicing effective moisture control procedures. Examples of moisture control methods include:

• Fix broken pipes as soon as they are discovered and promptly clean all impacted areas.


• Repair leaky roofs as soon as the problem is found and promptly clean all affected areas.


• Use exhaust fans in kitchens and bathrooms while showering or cooking to remove the humidity that these activities produce.


• Vent clothes dryers to the outside.


• Put clothes away in closets or drawers only after they are completely dry.


• Leave closet doors open to allow air circulation.


• Do not place objects too close to cool walls (such as exterior walls) as this may create a barrier that prevents air and heat circulation and increases the likelihood of condensation on the wall surface.


• Use dehumidifiers to remove moisture from areas with high humidity when ventilation is not an option (such as when the air being used to ventilate is of higher moisture content than the air being replaced).


• Install energy-efficient windows to reduce window condensation.


• Utilize drain tile and a sump pump to control ground water.


• Landscape the area surrounding a building so that moisture is carried away from the building.


• Ensure that rain gutters are clear of debris and as leak free as practical.


• Extend rain gutter downspouts so they do not dump water right next to the building.


• Keep sprinklers from hitting a building (especially open windows).

Begin mold cleanup only AFTER the moisture problem that caused the mold is properly addressed. Mold cleanup should be exercised with caution. Exposure to mold can occur during the cleaning process because airborne mold particles typically are released during the cleaning of mold-damaged materials. If you have allergies to mold, it is best to have someone else clean up the mold. If you have an extensive amount of mold and you do not think you can manage the cleanup on your own, you may want to contact a professional who has experience in cleaning mold. If you choose to do the cleaning yourself, take steps to protect yourself and others during cleanup:

WARNING! Never mix bleach with ammonia!

• Have sensitive people leave the building while the work is being done.


• All workers should wear proper protective clothing (clothing that can be cleaned thoroughly or discarded), gloves, goggles and a dust mask or other breathing protection.


• Seal off the area as much as possible. Cover any air vents to prevent disturbed mold particulates from entering the ventilation system.


• Remove any furnishings from the area for later cleaning.


• Provide added ventilation (open window, etc.) if possible.


• Use a HEPA air filter in the work area if one is available.


• Remove all porous materials that have been inundated with mold growth and cannot be cleaned thoroughly enough to kill and remove all remnants of mold. Bag all materials for removal from the home before they are taken out so that mold particles are not spread during the removal process.


• Scrub any non-porous or non-removable surfaces with a mild non-ammonia containing detergent and dry it quickly. Apply a disinfectant (1 cup of bleach to a gallon of water) to the affected areas after the mold removed; apply (use a sponge or a sprayer) the disinfectant solution to the area and allow to air dry. Repeat the application of the detergent and disinfectant as necessary to kill and remove all mold residue.


• Clean the area with a vacuum. Use a vacuum with a high efficiency particulate air (HEPA) filter if possible.


• Clean or discard any materials (tools, rags, clothes, etc.) used during the mold cleanup process.


• Clean any furnishings that were removed from the area earlier.

Make sure the area is completely dry and will remain dry before replacing any building materials. It is often better to wait before rebuilding, if practical.