Several things can instigate crawl space dampness. Leaky windows, clogged gutters, and groundwater all have the potential to dampen the crawl space. Burst pipes and leaky plumbing system are other vectors.
Heavy rainfall in spring and melting snow can cause soil saturation. Since the soil doesn’t have the capacity to absorb or hold any more water, this water has to find a place to go. Water can seep in through uncovered soil or porous walls and dampen the crawl space.
Open vents are another common vector. They can let in water and moist, warm air into your crawl space. When this air comes into contact with the cool surfaces, like crawl space walls or insulation, condensation occurs. Moisture can linger in the atmosphere for several weeks unnoticed.