How does moisture get into the house?

Moisture intrusion can be the cause of building defects, as well as health ailments for the building's occupants.

Some common moisture-related problems include:

• structural wood decay;

• high indoor humidity and resulting condensation;

• expansive soil, which may crack the foundation through changes in volume, or softened soil, which may lose its ability to support an overlying structure;

• undermined foundations;

• metal corrosion; and

• mold growth. Mold can only grow in the presence of high levels of moisture. People who suffer from the following conditions can be seriously (even fatally) harmed if exposed to elevated levels of airborne mold spores:

• asthma;

• allergies;

• lung disease; and/or

• compromised immune systems.

Note: People who do not suffer from these ailments may still be harmed by elevated levels of airborne mold spores.

How does moisture get into the house?

Moisture or water vapor moves into a house in the following ways:

• air infiltration. Air movement accounts for more than 98% of all water vapor movement in building cavities. Air naturally moves from high-pressure areas to lower ones by the easiest path possible, such as a hole or crack in the building envelope. Moisture transfer by air currents is very fast (in the range of several hundr