When it comes to threats to a home’s foundation, few people realize the huge impact that soil can play. This is especially true for those who live in areas where so-called expansive soils are present. Expansive soils are capable of causing cracks and other structural issues in a foundation, thus greatly increasing the risk of damage inside your home as well as foundation trouble.

For that reason, it is important for homeowners to educate themselves about the nature of expansive soil. If you would like to learn more about what makes this type of soil so dangerous, as well as what you can do to cut down on the risks, read on. This article will provide a useful overview of expansive soil.

As its name would imply, expansive soil is ground soil that displays a marked tendency to undergo changes in its volume. As the volume of expansive soil increases, it exerts a greater and greater amount of pressure on your foundation, eventually leading to damage. Such volume increases are generally tied to periods of heavy rainfall.

To understand why this is the case,  it is important to know that expansive soils are distinguished by one key fact: they contain an especially high proportion of clay, specifically a category of clay known as smectite clays. Such clays are like sponges. When water is present, they are capable of soaking up – and retaining – an incredible amount.

This ability causes the volume of the soil to rapidly balloon. It has been estimated that expansive soils are capable of expanding their volume by as much as thirty percent when fully hydrated. As noted above, the result of such expansion can include such forms of damage as cracking, heaving and even outright collapse.

Yet expansive soils do not just cause damage when the weather happens to be wet. They are equally destructive during periods of extreme drought. In that case, as the soil grows drier and drier, it begins to shrink. Eventually, it may become so parched that it visibly pulls away from the foundation. In Houston, this can be seen throughout the dry summer months.

As you can imagine, this leaves the foundation unsupported, thus making them more susceptible to stress damage from the intense weight of your home. Worse still, these hollow pockets give water a convenient place to pool up the next time it does rain, meaning you will be at a much greater risk of leaks and other forms of water intrusion.

The good news is that there are a variety of different options when it comes to reducing the negative effects associated with expansive soil. The key here is to try and maintain an optimal – and even – degree of hydration in the soil around your home. Taking measures to increase drainage is the first thing you will need to consider, as this will reduce the amount of water that manages to penetrate into the soil around your home.

There are lots of ways to promote drainage. If the soil around your home is level – or even worse, if it slopes toward your house – you will want to hire a landscaper to help regrade it. The key here is to ensure that the soil slopes away from your home. You should also consider adding below-ground drainage structures like French drains and drywells. These will collect excess water, preventing it from being absorbed by the clay.

Take some time and check out our blog posts related to drainage for additional detail surrounding the impacts of water on your foundation.