July 12, 2010
Virginia residents, pets and plants are not the only ones feeling the brutal effects of this heat wave and abnormally dry period, so are some area homes. Exterior bricks and interior walls are suddenly cracking and area homeowners are wondering why.
The reason for this type of structural damage is expansive soils.
Common throughout the commonwealth, expansive soils are characterized by the presence of swelling clay minerals. When they get wet, the clay minerals absorb water and exert uplift or pressure on a home’s foundation causing walls to crack, doors to jam, chimneys to separate and floors to warp. Conversely, as these soils dry, they also shrink, leaving large voids in the soil and causing the cracks they created during the swelling phase to open up as the pressure is released.
According to W. Lee Daniels, a Professor of Soil Science at Virginia Tech and a Virginia Certified Professional Soil Scientist, “Expansive soils are even more destructive during pronounced wet and dry seasons. In Virginia, the last worst cycle of shrink, swell soil occurred in 2002 during a period of deep drought. This type of cycle often repeats itself every 8-10 years.”
Although we are not officially in a drought, the U.S. Drought Monitor indicates that most of Virginia is currently “abnormally dry.”
“Unfortunately the damages that expansive soils cause to a home do not get better over time, and in many cases, they actually get worse,” says Jesse Waltz, professional engineer and President of JES, a leading foundation repair company in the area. “Homeowners may see cracks close-up after a heavy rain and get a false impression that the problem has gone away. However, this is not the case at all. Continuous cycles of wet and dry periods just cause repetitive stress on the home.”
Fortunately, a home experiencing settlement issues due to expansive soils can be permanently stabilized. When left untreated, not only does the structure become more and more unstable and unsafe, but the value of the home declines too.