How Do Foundations Settle?

When a home is being built, contractors will compact the soil that the foundation will be made upon. This is done to make sure that the soil is as dense as it can be and capable of supporting the weight of an entire house. While the soil is capable of doing just that the first few years after the home has been built, it will eventually experience erosion. Soil erosion describes the way soil shifts and moves as it is exposed to water and other elements capable of displacing it. For soil in St. Louis, MO, the soil is granular enough that even just the weight of the house can eventually cause it to shift about.

As the soil under the house moves, the house begins to settle on top of the uneven soil layer. Depending on how the soil eroded in the first place, the house will either sink straight down or, it will sink on one side. Tilting settling can lead to differential settling, which is when a home settles to the side as the foundation tears away from the rest of the house. This kind of settling is what causes the most obvious problem signs, such as basement flooding and jammed doors. It’s caused by the foundation no longer being able to take the uneven distribution of weight as the house shifts.

Groundwater also plays a major role in foundation settling. As the water table rises when it rains, the soil gets displaced and loosens up. A proper foundation drainage system does more than just keep water out of your foundation: it can also help prevent foundation settling. The key to preventing foundation problems is to limit its exposure to erosive elements like water. There may not be much you can do about the weight of the house, but you can control the amount of groundwater that’s around your foundation.