Many homes with crawlspaces are built based off of building codes that are outdated and typically 20 years behind building science. Almost all homes built with crawlspaces have vents spaced throughout the perimeter. These vents allow moist humid air to infiltrate the crawlspace. This humid air can increase chances for mold, mildew, fungus, and insects to invade the wood structure your home is constructed of. Installing a crawlspace liner and dehumidifier, along with a drainage system if needed, can significantly lengthen the useful life of your home and greatly improve your air quality.