Elaborate, finished basements have become a staple of American culture. In what was formerly used solely as a storage space for utilities, the basement now serves as a fully furnished space for living and recreation.
However, if you live in an area where basements are an integral part of homes, you might be surprised to find out that many houses in the USA do not include them. If basements have so much utility nowadays, why aren’t they being built in certain areas?
The first thing to consider is a region’s frost line, and how it determines how deep a foundation must be built into the ground. The frost line, or frost depth, is the maximum depth that groundwater will typically freeze in the soil. Building codes require a house’s foundation to be placed below the frost line to prevent frost heaving, which can damage the foundation as the soil swells upwards due to an increase in volume.
In areas with colder climates, such as the Northern states, the frost line tends to be at least four feet beneath the ground. It is also commonplace for houses in colder areas to have central heating systems, and a basement serves as an excellent storage space in this regard. Excavating an additional four feet to build a standard-height basement is therefore very practical.
In warmer climates, however, the frost line often doesn’t exceed 20 inches, especially in Southern and Coastal states. With the frost line being closer to the surface, establishing a deep foundation is not necessary, and warmer states rarely need dedicated heating systems. Therefore, there is less of an incentive to build basements in these areas.
But let’s say that you still want to enjoy the advantages of a basement, even though you live in a warmer climate. Basements can technically be built anywhere, but you could face a number of obstacles if you want one built in an area where they are not as common.
In many Southern states, the water table is very close to the surface, which compromises the long-term sustainability of a basement. A high concentration of swamps, lakes, and rivers means there’s going to be a lot of moisture in Southern soils. Building an eight-foot basement in an area with a high water table will make the basement extremely susceptible to flooding damage, and could even make the entire house float! Utilizing a relief well can resolve this issue, but it is a very expensive option, and problems can arise if the well’s pump breaks.
Also, building a basement can be dangerous in states with high concentrations of clay in the soil, such as Texas, Oklahoma, and Arkansas. Clay soils expand and contract as they collect and release moisture. As the seasons change, the amount of moisture in the soil changes accordingly. If the proper precautions are not taken, a basement can sink when the soil contracts, or it can be pushed upwards by expanding soil, causing damage to the basement’s walls. As a solution, builders will compact the soil to make the ground more stable, and might even add trenches filled with lime mixture beneath the foundation to control moisture levels. However, this process adds about a month to construction time, so most people decide to forego adding a basement altogether.
Cost is also an important factor in determining whether or not a basement is built. In regions where property value is high, such as the Northern states, adding a basement can be very cost-effective. Land in Southern states is generally cheaper than that of Northern states, so it is easier and less expensive to build detached storage spaces above ground. Furthermore, many Southern homes are built on top of slab foundations. These foundations are cheaper, but basements cannot be built under them.
In contrast, houses in states such as California are extremely expensive, and adding basements will only drive the cost through the roof. Basements built in California are often below sea level, so extra measures must be taken to prevent flooding and other water-related issues. Most contractors working in California try to reduce expenses wherever possible, and excluding basements from homes fulfills this goal. Basements in Californian homes are thus a luxury.
It is clear that while basements are becoming more of a luxury, they are unnecessary or impractical in certain areas of the USA. If you are finding a number of homes in the South and West Coast that are without basements, costliness and geographical restrictions are likely to blame.
With DriBot, we are all about protecting basements and homes from water damage. As a company based in Indiana, our DriBot team members recognize basements as a common part of midwest home construction, but as we've just discussed, there are some areas in the USA where basements are extremely rare.