A crawlspace is a shallow area between the soil and the first floor of a house. It is often used for storage or access to pipes or other architectural substructures. A crawlspace is frequently used for the repairing and maintenance of many household systems, including, electrical, heating, plumbing, and air conditioning systems. Although they are not often built into homes anymore, they were popular in the earlier and middle parts of the 20th century. Crawlspaces are subject to poor ventilation, moisture, fungus, termites, and a variety of other problems.
Usually less than a few feet tall, a crawlspace is generally built directly on top of the soil, and is accessed through opened planks on hinges or tiny doors on the outside of the house. The crawlspace ceiling is usually made of beams holding the floor, and often suffers problems of water control. Moisture from the house can seep into a crawlspace, or moisture from the ground or from precipitation can flow up into the space.
Wood destroying fungus is also found in the wooden beams of a crawlspace, and wood eating insects have been known to dwell in the cool wood of the space. The emergence of fungus and mold in a crawlspace is of particular danger to a house because of the rising effect of air inside of a home. Air infected by germs from mold spores rises through the insulation vents or ducts into the rooms of the house, causing the inhabitants to breathe unhealthy air. Some fungi and types of mold can be avoided by the insulation of a plastic barrier over the soil, which provides an inorganic shield against many germs in the soil.
A crawlspace built into newer homes is subject to a number of regulations, and can be inspected for violations. The crawlspace must have a minimum access opening, which is made larger if mechanical equipment is kept within the space; a minimum clearance between the soil and the beams; and a minimum of ventilation, requiring an outlet to air every certain number of square feet within the space.