Understanding your soil and drainage is the key to allowing us to help you maintain the desired equilibrium of your foundation. Soils within the prairie lands of Texas contain high percentage of clays and silt. Naturally, clay soils can substantially increase and decrease in volume with periods of over and under saturation. Unlike sand, a larger and more course particle, clay traps water allowing it to swell. Poor site drainage and maintenance has proved to jeopardize the integrity of residential and business foundations throughout not only San Antonio, but most of Texas, by means of erosion, slumping, heaving and subsidence.
Methods of removing excessive surface or sub-surface migratory water from under and around the structure can be obtained mechanically or chemically. Chemically altering the load bearing soils are accomplished typically in the development stages of the structure however a post construction method, to include mechanical means can be obtained at a premium. The more common and cost effective method of removing excessive surface and subsurface migratory water is done mechanically by re-grading portions of the existing soil, cutting a swale, adding surface Drains, Channel Drains, French Drains, Sump Pumps or Gutters to divert excessive water away from the structure. 
Equally important to controlling site drainage is maintaining an adequate moisture level within the clay based soils. On the other side of the “clay” coin is drought. During drought season with in the regions of expansive clays, the moisture level on the perimeter of the structure should be monitored for excessive shrinkage. If applicable, vegetation control and irrigation systems such as sprinklers, drip lines or soaker hoses can reduce negative volumetric change in the load bearing soils of the structure when drought conditions exist.
