Skip to Main Content
FRS Logo Truck

Understanding Soil Layers

The earth has different soil layers which support life and various human activities, including construction.

Get a Free Estimate

From geography class, you already know that the earth is made up of different layers of sedimentation; it’s not just one big mass of rock or soil. These layers were formed over hundreds and thousands of years due to wind, water, ice, decomposition of plants and animals, and more recently, human activity. These layers contain diverse material, both organic and inorganic. 

Some soil layers are suitable for construction while others instigate problems such as foundation settlement. You need to know which soil layers you’re dealing with when building a structure. Here, we will delve into the various types of soil layers and show you how they were formed. 

What is a Soil Layer?                                                                    

Soil is divided into different layers, which from top to bottom, form a landscape. The earth is made up of a variety of landscapes, some are fertile and made up of nutrient-rich soils while others expose underlying rocks made up of regolith and bedrock. Each layer of soil is different in age, texture, makeup, and other characteristics. Layers stabilize and grow stronger with time. 

Different Types of Soil Layers 

Let’s look at the five types of soil layers and what’s behind them. 

Fill Soil 

Whenever builders find out that the underlying soil is unstable or weak, they’ll bring in other soils that are stable and fill in the area around the foundation in with it. Such soil is known as fill soil and consists of sand, clay, and rocks. As well as providing foundational support, fill soil is used in construction projects and landscaping. This soil can help level up the ground on which the foundation is built and improve soil drainage. 

Glacial Deposits 

Receding glaciers often move various materials such as clay sediments, gravel, and rock debris along the land surface. All these materials can pile up and form a soil layer that is beneficial for construction. Some of it will end up in water bodies like lakes. 

Erosion Soil 

The name of this soil gives us a big clue as to its makeup. Ice, fast-moving water, and wind can all dislodge the loose topsoil and deposit it elsewhere. Over time, erosion can lead to soil degradation which results in the loss of organisms and vital minerals that help keep the soil compact. 

In addition, erosion can also weaken your home’s foundation and this can lead to structural damage and collapse. The remnant soil isn’t strong enough for construction or suitable for farming. To stop soil erosion, you can plant grass on your lawn or yard and stabilize the slope around your home. 

Wind Deposits 

When wind sweeps across the landscape, it abrades the soil surface and carries with it silt or clay particles. These soil particles pile up over time and form loess. Wind deposits are usually fertile and good for crop farming. 


Underneath the unconsolidated surface materials lies a solid, intact layer that’s known as bedrock or R-Horizon. This layer is made up of unweathered rocks that have been cemented and compacted by the weight of the layers above it. Rocks in this layer are somewhat gray and can lie up to hundreds of feet below the topsoil. Basalt, limestone, granite are all found in this layer. 

Bedrock is the most stable of all soil layers and is weather resistant. In areas where the underlying soil is expansive, foundation contractors usually drive underpinning or piering solutions down to the bedrock to stabilize the foundation. 

Is your foundation built on top of loose or unstable soils? It needs to be stabilized before it caves in under the weight of your home. Contact Foundation Recovery Systems today for a free inspection and repair estimate, and find out how we can strengthen your foundation or stabilize it.

Foundation Recovery Systems Service Map

Our Service Areas

Des Moines Location

2401 SE Creekview Dr.
Ankeny, IA 50021

Kansas City Location

7280 NW 87th Terrace, Suite C-210
Kansas City, MO 64153
(816) 774-1539

Lee's Summit Location

211 SE State Route 150
Lee's Summit, MO 64082
(816) 774-1539

Moberly Location

1401 US-24
Moberly, MO 65270
(660) 202-8662

Springfield Location
1820 N Barnes Ave
Springfield, MO 65803
(417) 612-8286
St. Louis Location

1625 Larkin Williams rd.
Fenton, MO 63026
(314) 207-9995