Probable Cause(s) of Movement Foundation Movement

Various factors can influence the differential movement of slab foundations. The mechanism of the typical causes for slab distress is best summarized as follows:

• The maintenance of the foundations perimeter moisture.
• The amount of water/moisture in the soil prior to placement of the concrete.
• The grading of the perimeter soils up to 10 feet away from the foundation.
• The presence of shallow groundwater seepage (bog).
• The past or present influence of large vegetation and/or trees.
• The presence of fill soils and the various amount of cut and fill across the lot.
• Soil creep.
• Structural design of the slab for the assumed soil conditions.
• The construction execution in the field.
• The antecedent weather conditions prior to pouring the concrete.
• Extreme weather patterns causing soil consolidation.

Upon years of observation and research the most significant soil-structure interaction mechanism causally related to
differential slab movement is due to soil moisture withdrawn from nearby root systems of trees extracting moisture from
the soils beneath the foundation.