Expansive Soil And Your Foundation: Answers To Two Common Questions

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Believe it or not, one of the most common causes of foundation cracks is the soil around a home. Even if your foundation appears okay, if you have so-called expansive soil, you may be at risk of serious--and costly--foundation cracks. If you would like to learn more about this threat, read on. This article will answer two of the most common questions about expansive soil.

What exactly is expansive soil?

To begin with, it is helpful to understand what expansive soil is. A soil is referred to as expansive when it contains a large proportion of clay; clay is especially water-absorbent. That means that the volume of expansive soil can easily experience fluctuations of up to 30%. In other words, when the soil is full of water it will exert a much greater degree of pressure on your foundation, eventually leading to cracks and other problems.

Just as expansive soil expands when saturated, it is also prone to excessive shrinking when dry. This causes the soil to pull away from your foundation, thus leading to inadequate support. Also, as the soil goes through cycles of saturation and shrinkage, it can cause deep cracks to form below the surface. These cracks make it easier for water--another likely cause of foundation cracks--to come into contact with the walls of your foundation.

What can I do to prevent the ill effects of expansive soil?

If you are living in a region with expansive soil, it is vital to take measures to regulate the moisture content of your soil. By maintaining a consistent moisture level, you will reduce the amount of expansion and shrinkage, thus reducing the amount of strain on your foundation.

Regulating a soil's moisture is most difficult in the summer months, when most water is absorbed by the top layer of soil. This leads to drying and shrinkage of deeper soil. Luckily, a soil auger can be used to drill holes that will increase the depth of water penetration and keep the lower layers of soil from shrinking. Here's how: 

Begin drilling holes approximately two feet from the perimeter of your home, with each hole spaced two feet from either of its neighbors. Likewise, the holes should be about two feet deep. Once the holes are drilled, fill them with crushed gravel. This improves the structural stability of the holes, while also making it easy for water to penetrate to the bottom. During hot, dry weather, water the holes regularly using either a hose or an appropriately located sprinkler.

To learn more about the topsoil in your area, contact a company like AAROC Aggregates Soil.