Soil movement can cause extensive damage to a building, including cracking and heaving of slabs and hardscape, and separations of drywall and stucco. This damage can be caused by sudden events, such as earthquakes and landslides, or by slower processes caused by expansive soil triggering and in a hillside development called lateral fill extension or slope creep. Both expansive soil and inadequate grading and compaction can crack foundation systems and cause houses to longer be level and allowing a bowling ball to roll across the floor.
Building sites are graded before construction begins. Soil can either be removed (cut) or added (fill) at the time of grading. Correct compaction of the soil during the grading phase is critical. Problems we find include:
- Improper grading
- Inadequate compaction
- Inadequate foundation design for highly expansive soils
- Inadequate site drainage
- Inadequate area and retaining wall drains
- Inadequate depth of pilasters or other foundation system