Expansive soils are the second leading cause of property
damage in the United States
(second only to dry rot). The supporting posts for the deck at left have
because of seasonal soil expansion and contraction. The foundation post
at right has
been wracked by seasonal heave of foundation soils.
Highway cut on Pleasant Hill Road in Martinez, CA
in 1954, shortly after completion (at left).
Right view shows the same cut 32 years later, in 1986. Expansive soils
are subject to cyclic
creep due to seasonal absorption of moisture.