When building in clay soil, you have a few things to worry about. Most important, you will need to adjust for the actions of the soil. You don’t want to have your foundation and basement walls cracked during the first year due to moisture changes. As moisture in the soil changes expansive soil will move. During wetter seasons clay grows, during dry seasons clay shrinks. This can be seen in the soil itself if you watch the ground you will notice the cracks and shrunken appearance the ground has, especially in areas that may have had a pond or a creek.
When you build a basement, you want to build on solid ground, or as solid of ground as possible. If you are working in an area that is made up of clay or other expansive soils, you may want to consider stabilizing the ground with lime. Treating the ground with lime gives a much more stable surface to work with.
First, you will need to remove not only the earth in the area that you wish to use as your basement but you need to dig below this area and put in trenches for the lime to be poured into. Trenches should be dug around the perimeter of the foundation and in columns spaced throughout the foundation approximately 3 feet apart. These trenches will turn into a solid base for your home. Removal of several inches of soil is important. This gives you the space you need to build your foundation that you are going to place your home on.
After removing the earth in the trenches, you need to fill those trenches with a lime slurry made of crushed lime and water. This mixture will be thick. Naturally, we aren’t talking about the fruit lime. Instead we are talking about limestone. The slurry is a mixture of crushed lime and twenty to sixty percent water (measured by weight) that can be mixed inside the trenches.
Once the lime slurry dries, you will have a solid rock base to place your foundation on. This will keep moisture from causing ground expansion that will crack your foundation. This can save billions of dollars annually in structural damage that occurs to buildings due to natural fluctuations in ground moisture.