A Crawl Space is a term used to describe a tight space, typically small enough that you need to actually crawl into it, that is associated with your basement or your attic. Crawl Spaces are categorized as such after 4’. So anything smaller than 4’ is a crawl space, anything grater is considered a basement (partial or full head height).
How they are Made:
Crawl Spaces are made in similar ways to regular basements except they are smaller. For poured concrete foundations this means that the forms to size up the walls are shorter. They can be created in stone foundation, concrete block, cinder block, or poured concrete fashion. Pre-fabricated basements tend to not be constructed in Crawl Space sizes due to their special limitations and circulation problems.
Contractors would rather build (this is just from personal experience) a house with a full head height basement of 8’-9’ tall. Forms are more readily available, they displace more weight, they are built under most frost lines (more in the North than the South obviously), make more money for the contractor, and they can be built into easier. It’s much easier to fit a water heater, an oil tank, washer and dryers, piping and plumbing in a normal sized basement than a crawl space. But there are times when a crawl space might be warranted.
Reasons to build a Crawl Space
Ledge is typically an answer one would hear if they considered constructing a crawl space. Ledge is sometimes impossible to move without massive demolition. Ledge also tends to lend itself to a high density of rocks in the ground around the crawl space.
Another reason that a crawl space would be constructed over a regular head height basement is cost. People building or designing their first home sometimes would rather spend the money on other amenities in the design and rather cut costs on the foundation. One way to do that is to limit the head height of the space and create a crawl space.
There are limitations to building crawl spaces. Circulation is typically poor. Mold and moisture build ups are common place and get rather complicated to remediate (click here to read more about mold remediation options). Most crawl spaces don’t get concrete floors which opens up the bottom of your flooring crossbeams to direct contact with moisture and or water from the ground and from the foundation walls if leaks occur. (click here to read more about moisture control options for your crawl space.)
Because of space limitations crawl spaces tend to displace many of the amenities that we’ve come to associate with basements such as washer and dryers, heating, central air, well water pumps, oil or gas tanks, and other things.
This article is continued at: http://ezinearticles.com/?Solving-Issues-With-Crawl-Spaces—Crawl-Spaces-Pt-2&id=1385784