In prior posts I spoke a little about expansive soils, and the damage it can cause to concrete slabs and footings. Expansive soil is basically another name for clay soils. The expansivity of the soil depends on how "pure" the clay is. If the clay is mixed with sand, for example, it is less expansive. Geotechnical engineers classify the expansiveness of soil based on the percentage of clay in the soil.
Damage can occur when water is introduced or when the soil dries out. The cycle of wetting and drying can exert great pressure on a structure, resulting in damage. What can be done to prevent this cycle? Here are a few suggestions:
1. Create an apron around the structure where very little water is introduced to the environment. This means very little landscaping near the structure, or landscaping that is very drought tolerant and needs little water;
2. Install drains and cut off walls to prevent the introduction of water near a structure. Cut off walls are often designed to be constructed below grade and to prevent the flow of subsurface water near a structure.
The key is to prevent the expansion and contraction of the soil near a structure. Developers often plant lush landscaping that requires a large amount of water to stay green. When thing dry out during a drought or in the Summer, the soil contracts, and damage can result.
Call me at 1-866-870-2020 to discuss any questions you might have regarding defects to your home or building. I have been representing building owners in construction and soil defect cases for 25 years.