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Types of Soil in Texas

While talking about foundation damage/repair, we always talk about high plasticity clay when referring to our soil in Texas. This is because of its properties of having a higher water-retention capacity and higher plasticity index than low plasticity clay, which for practical effects means that this capacity and its constant changes of moisture levels will cause expansion and contraction which can potentially become an issue that could develop into foundation damage.

This time however we would like to speak more in-depth about the actual types of soil found in our State; their respective characteristics and how they will interact with your home and foundation.

For starters there are over 1,300 different types of soil in our State. Each of them have specific sets of properties and uses, however for the effects of home foundation we will deal specifically with the five main different types of soils we deal with based on each different location.

But first what is soil? It is defined as the upper layer of earth in which plants grow. It typically consist of a mixture of organic remains, clay and rock particles and the effects of wind, water and reaction between salts also factor in.

Now the texture of soil is determined by the proportion of sand, silt and clay. And it is texture that determines all kinds of things like drainage, aeration, the amount of water the soil can hold, erosion potential as well as the nutrients it contains.

First we will talk about the soil at our home base: Fort Worth and Tarrant County. The soil found here is called Silt Loam and Clay.

Loam means that there’s roughly equal portions of sand, silt and clay. Therefore a sandy loam has a higher proportion of sand; silt loam has more silt in it and clay loam has more clay.

The clay soil in Fort Worth is mainly comprised of very fine particles of minerals with little organic material, so it makes it stickier and harder to drain. It is quite compacted so water tends to puddle, making proper drainage and irrigation system a high priority for homeowners in order to avoid any foundation damage. It’s expansive properties make clay soil a big risk to your foundation as it can put a significant pressure on your foundation in little time.

Next we move down to the San Antonio and Bexar county area, where we will find Gravelly Soil and Dark Alkaline Clay. Gravel is very small, irregular pieces of rock and stone. More rough and rocky than sand, smaller than stones. A gravelly soil will have a larger proportion of gravel, and white that at first glimpse might not sound so enticing, it has a great ability to drain well which is a benefit for foundation. Not only is it excellent with draiange, it also has a great load bearing capacity which makes it well-suited for construction. Proper compaction and soil stabilization techniques are still recommended however to maximize its potential for foundation support.

As for Dark Alkaline Clay the same precautions as Forth Worth’s clay soil apply when protecting your foundation.

Moving further we go to Austin/Travis county  where they have Alkaline Loams and Clay. The same characteristics of a traditional loam apply, the only difference is it is alkaline in nature which in reality has more an effect on what plants you’ll be having in your yard than it does with your foundation.

We move up to Houston and Harris County where you’ll find Loam and Sand. Loam Soil found in Houston is rich with nutrients and retains water well, but it still drains easily. It is well balanced in regards of soil, silt and sand composition, which results in a great balance of aeration, moisture and structure.

In contrast, sandy soil does not attract nor retains water all that well and its porous nature can be risky for your foundation as rain water can more easily flow down all the way to the foundation.

And finally the Dallas area with Dark Gray to Black Alkaline Clay, which again functions pretty much the same as the clay soil of Forth Worth, the main difference being the nutrients found in the clay, so the same precautions regarding foundations apply here.

With a clearer idea of the soils that can be found in broad terms in each area, you can have a clearer view of what precautions and services are needed to keep your foundation safe. And remember, if you suspect any possible damage or you just want to make sure your foundation is alright, don’t forget to call us!

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