History of Crawl Space & Basement Design
A little history...
Crawl spaces, cellars and sub-cellars are all types of basement foundations. Basements have been around for centuries, however they're more common in areas where it's easier to excavate the soil, in regions that aren't prone to earthquakes or flooding, and areas have a higher rate of tornado activity.
Once industrialization took hold in the US, it became more common to build a basement or partial basement in new buildings. However, it wasn't until the 1950s that basements started to gain popularity in the U.S. At this point people began using the basement as a living space instead of just storage.
Crawl Space vs. Basement
Unlike basements, crawl spaces are typically low and cannot be used as living space. In the past it was common practice to build vented crawl spaces. It was believed that venting the crawl space would keep it dry, we now know this isn't the case. Studies have shown that sealing your crawl space is the best way to keep it healthy and dry.
According to The Science and Sense of Crawl Space Encapsulation by Jesse Waltz, PE:
"Properly sealing the crawlspace and removing the moisture from the ground and air is part of the solution that helps provide a mold-free and insect-free environment, which leads to a more energy-efficient and healthier home.
To avoid moisture's negative affects, a crawlspace should be completely sealed and isolated from the ground and the humid outside air. An effective method to lower crawl space humidity, tested and perfected throughout the U.S., Canada, the U.K., and Ireland, is a proper crawlspace vapor barrier system. This involves installing a 20-mil 7-ply sandwich of high and low-density polyethylene with polyester-cord reinforcement on the dirt floor that is extended, and fastened to the walls.
In some cases, a high performance dehumidifier air filtration unit is added in the crawlspace to assure that humidity levels stay under 50%."
Basements originate from root cellars which were used to store food before refrigerators were invented. This is because the space is below ground and stayed cooler than the living areas of the home.
Modern basements come in a variety of shapes and sizes. From root cellars to look out basements or daylight basements, all serve as additional storage space. But the same reason why basements were used for food storage can also create basement waterproofing and moisture problems. So it's important to have a waterproofing system in place if you plan to use your basement as storage space.
Both basement and crawl space walls are a part of your home's foundation. Dependant upon the type of foundation, the walls will rest on a footing or be connected to a footing.
The footing is designed to distribute the weight of your home across the soil and minimizes settling and sinking. However if the footing was not designed for your soil type then your home could experience settlement problems which could also lead to waterproofing problems.Additional Resources: