Moisture Barrier Wall

Abstract

A foundation system is disclosed that is used when building a structure on expansive soils. The foundation system includes a vertical wall that prevents moisture from migrating beyond the vertical wall into the zone of influence under the foundation. The prevention of the moisture migration into the zone of influence precludes damage to the foundation and structure caused by expansive soils.

What is claimed is: 
     
         1 . A device for preventing moisture from migrating into a structure's zone of influence in expansive soil, the device comprising in combination:
 a structure, and   a vertical wall located below the structure and located at least partially underground, the vertical wall placed contemporaneously with or prior to construction of the structure;   the vertical wall configured to form a vertical skirt around the expansive soil underneath the structure;   the vertical wall comprising at least some structural connection to a perimeter of the structure; and   the vertical wall configured underneath the perimeter of the structure so that an outside face of the vertical wall and an outside face of the structure form a single vertical plane.   
     
     
         2 . The device of  claim 1 , further comprising a liner on the outside face of the vertical wall. 
     
     
         3 . The device of  claim 1 , the vertical skirt extending at least 18 inches below the soil surface. 
     
     
         4 . The device of  claim 1 , the vertical wall comprising concrete. 
     
     
         5 . The device of  claim 1 , wherein the structure is a concrete slab. 
     
     
         6 . The device of  claim 1 , the vertical wall comprising grout or a slurry mix.