Crawl Space Humidity Problems

Moisture Sources

• Moisture in crawl spaces can come either from outside or inside. Inside moisture can seep down to the crawl space or outdoor moisture can be pushed up through the soil and enter through the foundation. Which happens depends on the temperature of the crawl space versus the outdoor temperature, and the pressure differences of the air, which can pull and push the water vapor in the air.

Dangers

• Moisture in crawl spaces caused by high humidity can be hazardous to the house. If there is too much moisture, the wood in the foundation can start to rot, destroying the floors of the house. High levels of humidity can also provide an excellent growing environment for mold and mildew, which can create dangerous spores and ruin the wood that they grow into.

Dehumidifiers

• Crawl space dehumidifiers are devices that cycle the air inside the crawlspace through a simple evaporator that draws out the water vapor from the air and channels it to a drain before it can do any harm. These dehumidifiers can be expensive and are typically only used in climates that receive a large amount of rain and heat, which can easily build up moisture in the crawl space.

Extra Vents

• Crawl spaces that have humidity problems can also be dealt with by installing extra vents that lead to the outdoors. These vents are designed to allow increased air flow between the crawl space and outside, equalizing air pressure and allowing water vapor to escape more easily. Sometimes larger vents and duct work are installed in the place of smaller versions to allow for increased airflow.

Foundation Vents

• Foundation vents are those vents normally placed in the foundation to channel air throughout the crawl space. In the winter these vents should be closed, since the air is drier and the heat escaping from the vents can increase energy costs. In warmer months, the vents should be opened to get rid of extra moisture.