Moisture Control

Uncontrolled indoor moisture can support unwanted biological growth. Moisture in buildings can come from many sources. Water can enter your building by leaking in from outside or by seeping through basement floors. Showers or even cooking can add moisture to the air in your building. When humid air contacts a cold surface, water vapor can condense, much like when moisture condenses on the outside of a cold glass of water on a humid day.

It is important to control unintended moisture in indoor spaces that are both occupied and unoccupied, such as between interior and exterior walls. To control moisture indoors, follow these three basic principles: 

Control Sources of Water and Moisture 

Ensure water does not accumulate inside or around the building. 

  • Fix water and moisture problems promptly. 
  • When materials become wet, thoroughly dry them as soon as possible, ideally within 24-48 hours. Consider removing and replacing materials that can’t be cleaned and dried. 
  • Do not enclose, seal, or paint materials that are wet or show signs of biological contaminant growth, such as mold. 

Control Indoor Humidity and Condensation 

Keep indoor relative humidity below 60 percent indoors, and ideally between 30-50 percent. 

Select the Right Materials for Areas that May Get Wet

Choose materials that do not absorb water and are stable when wet. For example, polyvinyl chloride or PVC molding could be installed in a bathroom instead of a porous material, such as wood.

You can find guidance on implementing these three basic principles by visiting: 

 

 

 

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