Causes of Foundation Settlement in Greater St. Louis

What exactly is settlement?  Simply stated, settlement is the movement of your home when the soil it sits on can no longer support the weight of the home.  Even though the soil below your home may be fine at first, the soil moves and shifts over time.  There are three main changes in soil that cause settlement.

Drying and Shrinking of Soil

After several months of dryness, clay soil dries out and shrinks.  As the amount of soil around your home cracks and shrinks, it creates an empty space for your home to settle into.

Another big issue with dry soil is the growth and maturing of trees near your home.  The root system of a tree is often two times the size of the tree canopy, meaning a tree with branches that extend over your home most likely has roots that extend under your home.  These roots draw valuable moisture from the soil, causing the soil to dry out and your home to settle.

Wetting and Softening of Soil

During times of heavy rain or flood, clay soil absorbs the water and becomes very soft.  Soft soil can be very weak, causing your home to gradually sink down into it. 

Also, if your home has a poor drainage system, it can affect the soil below your home.  If water is allowed to stand next to your home, the soil will absorb the water, become weak, and cause your home to settle. 

Poorly Compacted Fill Soil

When building a new home, it is very common to remove the soil from hilltops and place it in valleys to create a flat and even plot of land.  If this fill soil is not compacted well, it will begin to compress under the weight of the new home, and therefore causing settlement.  A recent study showed that 15% of new homes have structural problems because of two causes: poor construction or homes built on poorly compacted fill soil.