Moisture
Whether it's from standing water after a rainstorm or just the dirt floor, evaporating moisture can damage wood and insulation and eventually make its way into your home. Mold in the crawl space and upstairs living areas is a common problem caused by excess moisture
Pests
Moisture in the crawl space is a magnet for spiders, mice, rats, snakes, termites and other nasty pests. Because the crawl space is usually left undisturbed, this provides a safe haven for critters looking for a cozy home. What's more, much like our kids, critters don't usually clean up after themselves. Pathogens from rodent droppings ad urine can affect the air quality inside your home.
Radon
You can't see or smell radon gas, but it's found in almost all soils. It comes from the natural decay of uranium and it moves up through the ground and into the air above and eventually into your home. Studies have linked radon exposure and lung cancer. In fact, radon is the number one cause of lung cancer among non-smokers, according to the Environmental Protection Agency (EPA).
Outside Air
If the air outside is worse than the air inside, then vents into the crawl space will let this polluted outside air into your crawl space and eventually up into your home. The poor air quality can make allergies, asthma and respiratory issues worse.
