Home moisture problems

Here aresome tips on diagnosing and correcting moisture problems. Parts of this story: ~~Introduction~~ Attic andmechanical ventilation ~~ Houseson crawl spaces and other moisture sources ~~ Caulkingand weather-stripping ~~ Basementwall condensation problems

Finding solutions to moisture problems, be theycondensation or water problems, is often a difficult,time-consuming and expensive undertaking.

• The first stepin any situation is to identify the source of theproblem. This may not be easy because two and often morethings may be working together to create the problem.
• Once you know the source, rethink the basics aboutcondensation and/or water problems. What are the no-costor low-cost solutions you can try first? Can the solution(s) attempted help you in other ways in additionto solving the moisture problem? The addition of stormwindows, for example, can cut heating costs as well ashelp prevent fogging or icing of windows. In such a case,the cost of the solution may be well justified.
• In somecases, you may find you have to rely on outside help,such as contractors, engineers or architects. Do lookinto the backgrounds of these people to ensure that youare getting the best help available and that thesolutions they offer will indeed solve the problems.

Three conditions that increasethe likelihood of condensation problems

Condensation can be a problem in bothwinter andsummer. Three conditions in the home increase the chances
that condensation will occur.

• The first of these is arelatively recent phenomenon. Many homeowners have addedinsulation to cut heat loss and heat gain, while othershave caulked and weather-stripped around windows and doorsto reduce the infiltration of cold air into their homes. The same practices that trap heat in the home also trap
  high levels of moisture.
• A second common condition contributing to moistureproblems in homes is the existence of cool
  surfaces with which interior moisture vapor naturallycomes in contact. In less energy-efficient homes, certainlocations are prime candidates for condensation problemsbecause they commonly have cool surfaces. These includepoorly weatherized and insulated windows (in winter),poorly insulated exterior walls and ceilings (winter),masonry or concrete surfaces (summer), toilet tanks(summer) and cold water pipes (summer).
• A third condition contributing to householdcondensation problems is excessively high humidity levels
  in the air within the home. The normal indoor humidityrange in winter is 15 to 50 percent. In the summer, thehumidity range may be higher because of the higheroutdoor humidity levels we sometimes experience then.

The first step to be taken in attempting to controlcondensation problems is simply to reduce the level of
humidity in the inside air.

During the winter, the humidity level you will want toattempt to achieve in your home will depend on the outside
temperature. As outside temperatures drop, you need tolower inside relative humidity levels to minimize
condensation.

Monitor the interior surfaces of double-pane windowsduring winter. If running water (condensation) is
apparent on them, the interior relative humidity level istoo high and should be lowered.

Levels to achieve in summer are somewhat morearbitrary---they depend mainly on how uncomfortable you
are in high humidity conditions.

Summer problems

During the summer, one of the major functions of anair conditioner, in addition to cooling warm interiorair, is removing humidity from the home. A secondalternative available to lower summertime humidity levels is to purchase and operate a dehumidifier. If humiditylevels remain high in winter, you may need to run it then, too.

Though both air conditioners and dehumidifiersare effective solutions to excessive moisture problems,they are relatively expensive to buy and costly tooperate. Expect increases in your electricity billsduring the months you use them.

The informationin this article comes from Michigan State UniversityExtension bulletin E-2109, Moisture Problems in the Home.