What is the most common source of water problems in unventilated crawl spaces?

The most common source of water problems in unventilated crawl spaces is the condensation of water after evaporation from the soil. In unventilated spaces, humidity levels can rise significantly, especially when the soil is moist. As the warm air rises, it can lead to condensation on cooler surfaces within the crawl space. This process occurs because when the air warms up, it can hold more moisture, and as it cools down again, it loses its capacity to hold that moisture, resulting in water droplets forming on surfaces.

Understanding this helps explain why it's crucial to control humidity levels in unventilated crawl spaces. Proper ventilation and dehumidification strategies can mitigate condensation issues, preventing structural damage and creating an environment less conducive to pest infestations.