Even though the walls of your crawl space are made of concrete, it might not be as critter proof as you might think. With habitats of certain creatures starting to dwindle, they are in search of a new safe place to call home. The last thing you want is a nest of little animals making your home, their home. These creatures don't usually keep their home as tidy and clean as yours. They leave behind droppings that can affect your air quality and can get inside the home. You crawl space is also home to some important features of your home. Rodents like mice and squirrels could start chewing on any exposed wires and destroy insulation.