Written by Bob McGuire on January 4th, 2009
Crawl Space
What is that space under my house?
A crawl space is that area under the floor framing of a building which is generally 24 inches in depth. However, the distance can range from eight to 36 inches. The floor is generally dirt. There is usually only enough room in which to crawl–thus the name. They are dark and a good source of bugs. They may smell moldy. Not a pleasant place.
Some crawlspaces are deeper–about 48 to 60 inches, and may have a concrete floor. This space is known as a “Michigan Basement”. This deeper space can be used for storage. Some structures have their furnaces in this space. Since this “basement” is usually partially below ground, it can be susceptible to water or moisture concerns. This becomes serious if your furnace is down there.
If the space below your floor boards is seven feet or deeper, it is called a basement. A hundred years ago basement floors were not paved. Many basements built a half-century ago were made of concrete block. As below-floor space became deeper, more people encountered water and moisture problems. With the invention and use of the ‘sump pump’, ground water that would otherwise accumulate on the basement floor was pumped away.

