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Publication #FCS3257

Moisture Control in Your Home, Part 2: Room by Room Tips1

Hyun-Jeong Lee and Virginia Peart2

Effective moisture control is an important part of home maintenance. Too much humidity can result in mold growth and indoor air quality problems and can cause allergic symptoms in some people. Mold can also damage your valuable possessions and can even harm the structure of your house.

Mold spores need three things in order to grow: moisture, nutrients, and warm temperatures. Many mold experts agree that the most effective way to control mold growth is to control moisture. But how does moisture enter our homes? How can we find out if our homes are “dry enough” to be free from mold? And how can we control moisture in our homes?

Research being done at the University of Florida indicates that although mold can (and does) occur in almost every room in the house, bathrooms, closets and bedrooms are the three areas that most commonly experience mold problems. Here are some tips from experts to control moisture in these three mold hot spots and in other rooms in your home.

Bathrooms

Many signs can indicate a bathroom moisture problem. Paint or wallpaper may be peeling. You may see water on windows or condensation on walls or toilets. Windowsills may begin to rot, and flooring tiles may start to curl. Water may be seen dripping from vents.

What can we do to prevent mold problems in bathrooms? Of course it is important to keep bathrooms clean, but even tiny amounts of soap scum or body oils from showering can support mildew growth. This means that it is also important to keep bathrooms as dry as we can.

  • Try to use cooler water for showers. Cooler showers put less moisture into the air and use less energy.

  • Get the water into the drain. Some people keep a window squeegee in their showers and take a minute or two after showering to squeegee excess water into the drain.

  • Use your exhaust fan to vent out humid air during and after your showers. Turn on your exhaust fan as soon as you start to shower, and allow it to run for about ten to fifteen minutes after you finish. After that, turn it off. You do not want to bring too much outside air into the rest of the house.

  • Open windows to bring in outside air only if the outside air is dry. Otherwise it's best to allow the bathroom exhaust fan to pull conditioned air from other rooms of the house.

  • If you are battling a serious mildew problem, you may want to carry wet towels to a rack in the garage or on the porch to dry.

Closets

Moisture can get into closets much more easily than it can come out. Anything damp you put into a closet, even a little moisture in shoes or clothing, can add to moisture problems.

  • If the closet is in the bathroom, keep the door closed when shower moisture is present.

  • Louvered doors encourage closet air movement and will keep a closet drier. Keep solid closet doors open (except when you have visitors) if the closet has a musty smell.

  • Open shelving (plastic-coated wire) allows air circulation.

  • Keep items off the floor. Moisture can be trapped under them.

  • Add a source of heat. A low-wattage light bulb, placed far away from clothing or anything that can ignite, will raise the temperature in a closet and reduce the relative humidity. A low location is best, since hot air rises.

  • Desiccants (materials like calcium chloride that absorb moisture) are of little use in a closet. If the rest of the house is humid, the space to be dehumidified is large compared to the moisture holding capacity of such materials.

Bedrooms

Many people like to sleep with their windows open. But when the humidity is high, which, in Florida, is most of the year, too much moisture can come in. Moisture is also produced when we breathe while we sleep. How can moisture problems in this part of the house be reduced?

  • Don't open windows unless the outside air is dry.

  • Air must be circulated in the bedroom. If there is no return air duct in the room or if neither air conditioning nor heat is being used, the bedroom door should be left ajar at night.

Kitchens

Signs of a moisture problem in the kitchen include water streaming down the windows, condensation on walls, rotting windowsills, moisture under the sink or counters, peeling paint or curling tiles, and difficulty in closing and opening cabinet doors.

  • Use the vent above the oven range every time food is cooked. It helps reduce moisture in the kitchen.

  • Do not let foods simmer for excessive lengths of time.

  • Caulk any area that comes in contact with water (such as the edges of the sink) so that water does not leak into the cabinetry below.

  • Check to make sure that no pipes are leaking.

Living Areas

  • Open the drapes in order to let sunshine in the room.

  • Move the furniture away from the interiors of the outside walls.

  • Leave the doors to bedrooms open in order to help air circulation. If necessary, trim the doors or install louvered doors in order to increase air circulation.

  • Do not use humidifiers or unvented gas space heaters.

  • Have your air conditioning unit inspected in order to be certain the unit is not causing any of your moisture problems.

For More Information

For more information on moisture control, refer to FCS 3256 (Moisture Control in Your Home, Part 1: The Basics).

References

Kansas State University Agricultural Experiment Station and Cooperative Extension Service. (1995, September). Controlling mold growth in the home. Author.

Lankarge, V. (2003). What every home owner needs to know about mold (And what to do about it). New York: The McGraw-Hill Companies.

U.S. Environmental Protection Agency. (2001, March). Mold remediation in schools and commercial buildings. Washington, DC: Author.

Footnotes

1.

This publication combines, updates, and supersedes FCS3042, FCS3211, FCS3212, FCS3213, FCS3239, and FCS3245. This document is FCS3257, one of a series of the Department of Family, Youth and Community Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: January 2007. Please visit the EDIS Web site at http://edis.ifas.ufl.edu.

2.

Hyun-Jeong Lee, assistant professor, and Virginia Peart, former associate professor, Department of Family, Youth, and Community Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.