Why are houses in the American South built without underground basements?
Among the reasons are:
- Cost - Basements cost extra and many people cannot afford to have built if/when they are building a new home.
- High water table – Many areas of the South, particularly along the Gulf Coast and the major rivers, have relatively high water table. Building a basement in such an environment either wouldn’t be possible (the basement walls and foundation would sink) or it would be inordinately expensive to do so (extensive drainage and pumping systems would be required.)
- The structure cannot accommodate one – Obviously mobile homes and many types of manufactured homes cannot, due to their design, accommodate a basement. This type of home is quite prevalent throughout the South due its low cost and the lower overall wages of the people who live in the region.
Tornadoes are actually relatively uncommon in what’s referred to as the “Deep South.” They are more prevalent in “border areas” like Oklahoma, Missouri, Arkansas, Texas and Tennessee. Areas like Louisiana, Mississippi, Alabama, South Carolina and Georgia have tornadoes; but they are relatively rare events that make basements a “nicety” but not necessarily a necessity.
The first thing to understand is that the original purpose of basementswas not to provide storm shelter, storage, or living area, although of course they are used for all of these. Thefunction of a basement is to lower the foundation to a point below the frost line to prevent frost heaving, an upwards swelling of soil during freezing conditions caused by an increasing presence of ice as it grows towards the surface, upwards from the depth in the soil where freezing temperatures have penetrated into the soil. If frost-susceptible soils located where they will affect foundations can be removed and replaced by coarser material, frost heaving will not occur.
Therefore, especially with older building methods, basements were vital up North. Down South, we don’t have much problem with frozen ground.
Having worked many years in land development and building, I can verify thatthe cost of building a basement is a lot higher than the perceived increase of value. So if, in a development, we’re building some houses with basements and some without, most people are shocked at the price difference and even if they’d prefer a basement they would rather have a larger, nicer home for their investment.
Here in North Georgia, we tend to have extremely rocky soil. Digging a hole in dirt is one thing, blasting a hole through rock is a whole different ballgame, and again, greatly increases the cost. We pretty much only build basements where the terrain requires it- so homes built in hills will have a “half basement”, usually with windows and a garage. Obviously I can’t speak for the entire region, but I’ve actually never once seen a full below ground basement here in Georgia.
Basements will continue to cost more than a slab foundation throughout the life of the home. With a high water table and generally wet climate found in much of the South, basements will almost inevitably develop water problems, leading to mold issues. Once mold gets in the vents it can spread throughout the house. Again, with a hot and wet climate, mold is a major concern. Mold infestation can lead to your entire home and all your belongings being labeled as toxic, we’ve all heard the stories of somebody’s cousin who called their insurance company about a little mold damage, and suddenly their home and all the belongings are labeled as toxic, they have to abandon everything.
In our area, there’s also the fact that while we get a lot of tornadoes, due to our hilly terrain they tend to be much smaller than the ones in the northern plains states. We don’t get miles wide tornadoes. I’ve had tornadoes go right through my backyard and another time right down the middle of my street, and the worst damage was they pulled off a few shingles and knock the HVAC unit off its base. In nearly 40 years, while I’ve seen a lot of damage from tornadoes, I’ve only personally known one person killed by one, and no serious injuries. Home decor
Where they do the most damage is trailer parks, and nowhere that I know of builds basements under trailers. Tornadoes touch down most often in “transition zones” – areas where a dramatic change in landscape takes place. In other words, where tall buildings end and farmlands begin, or where a forest stops and the plains start. Trailer parks tend to be built on the outskirts of town, which is often at the transition zone, thus making them more likely to be hit. And if a tornado hits a mobile home, the flimsy materials and lack of any concrete foundation means it’s doomed.
In my neighborhood, about one out of every ten homes has a half-basement. When the storm sirens sound, we gather our go-bags and all go gather at those houses. I have a key to my neighbor’s basement in case they aren’t home when I need it.
TL;DR version- Northerners need basements so the frozen ground doesn’t crinkle their house. Down South, basements are stupidly expensive, if you’re worried about storms it’s a heckuva lot cheaper to just buy a storm shelter.