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Know Your Foundation Options
by Jeremy Lang

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Every home—from the regal estate to the unassuming bungalow—has a foundation. Every home needs one. But in many instances, there is more than one foundation option from which to choose. When selecting your dream home, you need to decide which foundation is right for your region, your lifestyle—and your new home. What follows is a basic rundown of the eight most common types of home foundations. Standard basement This tends to be a regional option for home building, primarily in the Upper Midwest and around the Great Lakes. Because these areas are home to colder temperatures in the winter months, the frost line must be taken into consideration when building a foundation. Below the frost line, the temperature of the soil is constantly high enough to keep from freezing and thawing. But above that line, the soil "heaves" during the spring and fall, when temperatures rise above freezing during the daytime and dip below freezing at night. To prevent a home in this region from heaving during the freeze/thaw cycles, the foundation footings must extend below the frost line.

Usually having approximately the same square footage as the main floor, a standard (or "full") basement offers the advantage of adding living and storage space at a fraction of the per-square-foot price of upper floors. This is because a basement only involves adding minimal depth to the footings that were necessary for building a home with a crawlspace (instead of digging down four to five feet for the footings, dig down eight feet below the frost line and pour a concrete slab). One disadvantage to a standard basement, however, is that when putting a bedroom in, a window well must be added in order to install a window that is deep enough to exit in case of an emergency.

Daylight basement
For a sloping lot, whether front-to-back or front-corner-to-back-corner, this is the basement of choice. Simply put, a daylight basement is at ground level and opens to a side yard and/or the backyard. The big advantage is that this allows the basement to be an indoor-outdoor space, with the outdoors accessible through French or sliding glass doors. In a standard basement, there are probably fewer and definitely smaller windows, thus making it seem darker and perhaps a bit dingy. In a daylight basement, however, the result is a feeling of lightness and brightness not unlike the upper floors.

Partial basement
This is a basement where the lot dictates that the square footage be less than 75 percent of the main floor square footage. Areas with rocky or unstable soil conditions, or a sloping lot, often require a partial basement. If you want a full basement but can't dig on certain parts of your lot, you put in as much basement as you can.

Partial daylight basement
Just like a partial basement, the square footage is less than 75 percent of that of the main floor. Often this is found where the slope of a lot would only allow building a basement under part of the main floor, but the owner would like to have full-height windows and perhaps a door to the backyard.

Crawlspace
This type of foundation is an option where soil conditions or a high water table would not allow the construction of a full basement. Footings are extended down to the frost line, but not below it, as with a full basement. In cold conditions, a well-insulated crawlspace will result in a warmer main floor than would a concrete slab.

Slab
A slab can be poured right over the ground with little or no soil preparation, making it the least-expensive foundation option in home construction. This tends to be the option of choice in the Sun Belt, where soil conditions don't lead to frost problems. In Texas, slab foundations are common because a thick layer of bedrock often lurks just below the soil's surface; below the bedrock, the water table awaits!

Creating a slab foundation is a little bit like making a sheet cake: Put forms on the ground with steel reinforcing and pour concrete. Let concrete set before placing house on top. Cost-effectiveness is its biggest advantage, but it's also useful in areas that have insect problems, i.e. termites or ants. The downside is that with a slab foundation you don't get inexpensive living and storage space you do with any type of basement.

Pole (wood posts)
This is the foundation choice of necessity in coastal areas where homes are built either partially over water or in flood plains where water will rise periodically. The poles allow the main floor to be built high above the ground and thus keep the home out of harm's way, i.e. flood waters.

Pier (cement posts)
Again, this is the foundation option of necessity in some areas. Coastal areas with periodic flooding still apply, but the more likely type of lot to call for a pier foundation would be in mountainous or coastal areas where you would have to drill into the rock to place steel rods, around which you'd pour concrete. As with a slab foundation, cement posts offer the advantage of durability and insect-resistance.