There are a tremendous amount of variations within the soil of Texas. According to the Natural Resources Conservation Service, there are over 1,300 different soil types in Texas.
All 1,300 kinds affect the foundation of homes in different ways. To help simplify this, the 1,300 different types of soil are grouped into 9 sections by taxonomy. The following Texas soil types are in taxonomic order.
Histosols and Spodosols
These two are the lowest concentration of soils in Texas. They are in the southeastern part of the state.
Histosols are wet and dense with organic matter. This makes it terrible soil to build a foundation on, but it does make for lush vegetation. It is not uncommon to find histosols in forests, bogs, swamps, and densely wooded areas.
Spodosols are also fertile and dense with organic matter but are a bit dryer. The soil is high in acidity, which makes it hard to grow crops unless treated with fertilizer and lime. What makes this soil type so unique is that its primary location is on tundras. Spodosol soil is good for building foundations, though.
These are soils that have a large amount of montmorillonite, or expansive clay that creates large cracks during dry seasons. Vertisol can be found in Eastern and Southern Texas.
You can identify vertisols in the wild through their deep cracks as well as their color. The color ranges from a dark black to red or grey. Because vertisol has clay, it expands and contracts. This circulates the earth, creating a “self-mulching” soil in the ground. Its unstable nature makes it hard for trees to grow. That’s why vertisols are found in grasslands or woodlands. However, it does create excellent conditions for cotton to grow.
The challenge with vertisol and foundation is the growth factor. Any foundation built in vertisol must have some wiggle room. This allows the foundation to move along with the earth. If the foundation is too tight, it could cause problems for the home.
A perfect example of vertisol is the state soil, Houston Black. Houston Black can be found from the Red River all the way to San Antonio and a little bit beyond.
This is a dry and inhospitable order of soil that supports more minerals than plant life. Aridisols are located more in the desert than anything. This type of soil resides in the far western area of Texas.
Aridisols do not hold onto water well. They are practically impermeable to any moisture, which is why little vegetation grows on its topsoil.
Because the soil is rich in minerals such as sodium, gypsum, calcium, and carbonate, the area fortifies into a solid piece of soil.
For your foundation, this could be good. Low water solubility means little chance for any foundation to be invaded by water or vegetation. It also decreases the chance of settling.
This brand of soil is highly weathered and has low fertility rates. These soils are found in humid areas and have been stripped of their minerals and nutrients.
The color of ultisol can range from a deep red to a yellowish-brown. This is due to the varying amounts of iron oxide present within the soil. Ultisol soils can be found in the eastern part of the state close to Louisiana. You can find ready examples of the soil in the Timberlands of East Texas.
Ultisol has no shrink-swell property. This makes it perfect to build a foundation on top of.
This soil is rich in nutrients and is fertile for vegetation. You will often find mollisol used for agricultural means on fields or slight hills.
Mollisols are a deep brown color. This is due to fresh organic matter being added every year and sticking to the top. The soil is rich in calcium and magnesium, adding to the rich minerals found in the soil.
The rich soil from mollisols makes up a large part of the land in Texas. You will find the largest concentration of mollisols on the plains.
Mollisol soil should be used for agricultural growth. While you can build on top of mollisol, you may have to prevent any vegetative growth around the home.
This order of soil is rich in clay and very fertile. Agriculture flourishes in alfisol soil, as alfisols are slow to lose nutrients.
Alfisols can be found in most of Texas, including the Rio Grande Plain in the northwestern part of Texas.
You can identify an alfisol by looking for a gray to gray-brown color. The more brown the alfisol has, the more clay content it possesses.
Because alfisols are friendly for farming, it could invite strong greens to grow around the foundation. This could require repairs for your home.
Inceptisol is a newer type of soil that has been able to build on itself, but not much else. Inceptisol does not contain much clay or many minerals. Slopes and fresh areas of geographic formation hold inceptisol. It is also the most abundant soil on the entire planet, taking up about 22% of all land areas. You can find it in sporadic areas of northern and the deep southern tips of Texas.
Inceptisol is easily eroded and waterlogged. It is very water-absorbent, which means inceptisol is easy to degrade.
Foundations should have no interaction with inceptisol. To build on inceptisol is to basically build on a river bed, which would almost instantly sink.
Entisol is a brand new soil that has been created due to leftover deposits from moisture flow. You can often find new entisol in the wake of hurricanes, floods, or landslides.
Entisols are located in a small part of western Texas, close to the aridisols. Entisols are also located on the coast of Texas. This soil type is common. Because weather constantly circulates any soil deposits, new entisol is created during any storm.
It also holds onto water. Do not build foundation on entisol, as the soil has not settled and is permeable to all weather.