Skip to Main Content
CFI Trainer in front of class

Soil Layers

Soil layers play a significant role in the construction work. Learn about the different soil types and their characteristics before starting the foundation.

Schedule Free Inspection

Soil Layers 

When starting your construction work, what’s going to be beneath your foundation matters a lot. Many homeowners will imagine the ground is good enough to hold the building together. But that’s where many go wrong. The ground won’t support your building properly if underlying soil has issues. 

Soil layers are very important in building a strong foundation. You must understand the type of soil you have down there and whether it’s perfect for the kind of structure you’re planning to put up. We will outline different types of soil layers and their characteristics as far as construction work is concerned. Let’s start by defining soil layers. 

Expansive soils with grass

What Are Soil Layers 

Your home’s foundation rests in different soil layers. Each of these layers comes in different thicknesses with characteristics to fit different kinds of structures. Some layers are perfect for buildings, while others are a no-go zone. 

Soil layers are deposits that have formed over a long time. Some factors that facilitate the layer deposits include wind, water, glaciers, and human activities such as construction. The layers gain strength and capacity with time. Beneath the layers are bedrocks that keep it even stronger and stable. 

Different Types of Soil Layers 

Fill Soil 

With a lot of construction work going on, soil for foundations is becoming scarce. Sometimes, builders are forced to bring in soil from other locations to cover up hollows and depressions in the ground. The soil taken from a different area is called fill soil. 

Fill soil supplies a sturdy base for construction work. It consists of a mixture of rocks, clay, and sand which provide more stable construction material. It’s mostly used for large construction projects and landscaping. It’s used to level up the ground around the foundation area and fix water drainage issues. 

Fill soil also secures the ground and retains walls. 

Bedrock or Rock 

Bedrock or simply rock soil comes in limestone, sandstone, and a variety of other rock types. They are a layer of rock formed underneath the surface of another soil layer. Bedrock soil is excellent building soil thanks to its bearing capacity, which is perfect for holding large buildings. 

Compared to clay, which can expand and shrink with weather changes, bedrock is more stable and resistant to weather changes. Constructions far above bedrock are unlikely to crack or shift. But builders need to level the soil before starting the construction work. 

Glacial Deposits 

Glacial deposits also make important soil layers for construction. Glacial deposits form from minute clay particles and large boulders found in the areas invaded by glacial mass. These deposits are known as drift. They consist of crushed rock fragments picked up along ice paths. When the ice reaches the final movement stages, the glacier stagnates and decays. The sediments get deposited on the land surface. Some deposits are picked by running water and later deposited as lake deposits. 

The deposits consist of sand, gravel, clay, and more. They range in size, including coarse particles. It’s important to determine the type of soil formed due to glacial deposits before beginning the construction process. 

Erosion Soil 

Flowing water, ice, and wind constantly disrupt soil profiles by removing the topsoil. These processes cause soil deterioration. The erosion process removes soil from horizons, causing weathering. This also causes the loss of nutrients, particles, and organisms that hold soil layers together. 

The removal of soil is very detrimental, especially when it damages structures by weakening their foundation. Sometimes, erosion happens so slowly that you don’t even notice it. 

The ground left behind after a massive erosion of soil is not good for construction. It lacks nutrients and organisms that hold soil particles together to ensure their strength. The soil deposited in a new place after erosion is also not good for construction work. Eroded soil is weak and won’t hold a structure. 

But there are different ways builders can prevent soil erosion from destroying a foundation or interfering with construction work. One of the ways includes slope stabilization and proper landscaping. 

Other Types of Soil Layers 

There are other types of soil layers that builders should consider before beginning any construction. The topsoil layer is the most recognized one because it holds structures together. It has the deepest concentration of organic matter, making it the best soil layer. 

Topsoil also consists of different sub-layers. The first is the organic matter which consists of leaves and decomposing material. They break down over time, forming organic matter. There’s also surface soil which consists of decomposed organic material. There’s subsoil that consists of clay and other consolidating soils. Finally, there’s parent rock, which is usually deeper than other layers and strong enough to hold building foundations. 

Builders must consider all these soil layers before beginning any work. Not paying attention to the soil below the base can give rise to some structural issues you never want to encounter. Nature doesn’t always cooperate and events like soil erosion are always possible. Due diligence is paramount. 

If you home was not built on the right soil, it can easily show signs of failure like cracks and settlement. 

For help with permanently repairing and stabilizing your foundation, contact the experts at JES Foundation Repair for a free foundation inspection and repair quote

Publish Date:

Last Modified Date:

Service Areas


8361 Town Center Ct
Nottingham, MD 21236


311 Central Rd.
Suite 2-02
Fredericksburg, VA 22401


2569 Quality Ct
Virginia Beach, VA 23454


7940 Gainsford Ct.
Bristow, VA 20136


309 Quarles Rd
Ashland, VA 23005


2033 Cook Dr.
Salem, VA 24153


456 Old Courthouse Rd
Appomattox, VA 24522


45 W Boscawen St,
Winchester, VA 22601