Three ways foundation soils can create settlement:
- Wetting and softening of soil
- Drying and sinking soil
- Poorly compacted fill soil
You may think that your home is on “solid ground,” but the ground beneath your home is made up of different layers of soil. Each layer has its own properties, and they can change over time. These features have a major impact on the foundations of the structures on which they’re built.
Foundation settlement is the movement your foundation experiences when the soil can no longer support the weight of your home. Three of the most common reasons for foundation settlement are drying and shrinking of soil, wetting and softening of soil, and poorly compacted fill soil.
Here are 3 ways settlement can occur:
1. Wetting and softening of soil
Clay soils are prone to moisture issues. Clay retains water and becomes soft, causing the home to sink into it.
During a heavy rainfall or large snow melt, large amounts of water enter the soil around your home. Sometimes, large amounts of water in a short amount of time can cause the soil to wash away. This leaves empty spaces that cannot support the weight of your home, and that’s when the home settles. This could also happen after a water main break or a cracked plumbing line.
2. Drying and sinking soil
While too much rain can cause foundation problems, the lack of rain can cause its own issues. When long periods of drought or extremely hot weather, clay soil dries out. As it dries, it shrinks, which creates voids that your home can settle into.
Also, if you have trees near your home, the roots can extend underground toward your home’s foundation. The roots draw moisture from the soil, causing it to shrink.
3. Poorly compacted fill soil
In order to level a site where a foundation will be formed, builders sometimes bring in loose soil from another location to fill depressed or hollow areas.
This newly moved “fill” soil is much looser and lighter than the dense, hard-packed undisturbed soils at the site.
The fill soil brought in by the builder has to be compacted thoroughly before a foundation is built on top of it. If the soil is not compacted well, it may begin to compress under the weight of your new home, creating settlement problems that can damage your foundation.
That means that entire neighborhoods can be prone to foundation settlement.
The different characteristics of the layers beneath your home can create need for a major structural repair down the line. Understanding what causes foundation settlement and the warning signs of foundation settlement helps you to understand the importance of getting it fixed right away.