10/25/2014

Effects of Poor Moisture Control

Controlling the amount of moisture in the air within buildings is an important consideration when building a new home. If moisture levels are too high, it may cause damage to the building structure over time and can allow mold and mildew to grow. These allergens, as well as the poorly controlled moisture levels in general, can have an impact on the health of the building residents and occupants. Moisture levels that are too low can also have detrimental effects on building inhabitants, causing symptoms such as skin dryness and nosebleeds.

When planning moisture control strategies for a building, it’s important to consider proper air-sealing, proper vapor barriers, and vapor diffusion strategies.  The entire building envelope should be designed not only to prevent moisture entering the building but also account for a way for moisture that does enter a building to escape.  People and their activities (cooking, showers, drying clothes, etc.) are a big source of moisture so proper ventilation are also important to maintain indoor humidity levels within an acceptable range.

Effects of Poor Moisture Control

Moisture can enter buildings from outside through heat transfer, air currents, and diffusion through building materials. Moisture can also be generated within buildings during activities such as cooking and showering. Poor moisture control can compromise the effectiveness of insulation and make temperature control more difficult. This can increase heating and cooling costs and impact comfort levels, in addition to having damaging effects on the health of occupants and the longevity of the home.

Building Structure Damage

Moisture is the most common cause of decay in historic buildings and can have adverse effects on a building no matter what the age. Failure to control moisture levels using a combination of suitable building sealing techniques and ventilation will allow the moisture to seep into building materials and cause rot and decay. Moisture will also affect the endurance capabilities of paint, wallpaper, molding, flooring and many other features of a building.

Building Occupant Health

The growth of bacteria and fungi are fostered by dampness and mold in buildings. Exposure to these allergens can contribute to existing health conditions such as asthma or generate reactions within individuals. Common reactions to mold include itchy, watery eyes, sneezing, wheezing, and respiratory complications. In some cases, building inhabitants may develop conditions such as hypersensitivity pneumonitis, a type of lung inflammation that can cause muscle aches, fever, and weight loss.

Controlling Moisture within a Building

There are several considerations for controlling moisture and water flow into a building, including:

  • Proper construction to direct precipitation away from the building
  • Thorough sealing of the basement or crawlspace to prevent wicking of water into the walls
  • New or well-maintained roof to prevent leaks
  • Building materials which help to prevent diffusion of moisture
  • Construction techniques which discourage condensation
  • Properly sized and maintained air conditioning unit

For more information on controlling moisture within a building, visit:

http://www.epa.gov/iaq/homes/hip-moisture.html

http://www.cdc.gov/niosh/topics/indoorenv/mold.html