What Makes Crawl Spaces Wet In Central NC

To understand home humidity, you need to go back to high school science class.

Basements and crawl spaces, being partially or fully underground, are naturally moistened and cooled by the earth around them which keeps their temperature more consistent year-round.  This becomes an issue in the hot, humid NC summers.  Any air that enters that space from outside will be moist and cooled, too.

Fact 1:  Average Summer high in Raleigh is 88 degrees with 78% relative humidity (at 100% the air is full and it rains).

The higher the relative humidity number is, the closer the air is to becoming fully saturated with water. Warm air holds the most water but as air cools and compresses and it’s able to hold less water.

That hot, humid air humid air now moves into your crawl space or basement. This cool, underground space drops the temperature of the air from 88 to 75 or less. Because of this, the air’s relative humidity goes up, even if no new water is added to the air. For every 1 °F the temperature drops, the relative humidity of the air will rise by 2.2%.  This means that 88 degrees at 78% humidity turns into 75 degree air at 106% humidity.  It is now the equivalent of raining in your crawlspace.  This is on a SUNNY day!  Imagine what happens when the outside air is at 100% humidity outside and it’s raining.

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  info@moldmoisturemedics.com
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  919.702.4870
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  Durham, NC

   Wake Forest, NC