Basement wall bowing inward — San Francisco, California

A basement wall that bows inward is one of the most serious structural problems a house can have. Lateral soil pressure — made worse by clay soil, poor drainage, or hydrostatic pressure from a high water table — pushes against the wall until it begins to deflect. The deflection often starts as a horizontal crack along the midpoint of the wall and progresses to a visible inward curve. If left unaddressed, the wall can eventually collapse. A foundation specialist assesses the severity (typically measured in inches of deflection), then recommends carbon-fiber reinforcement straps for minor bowing (<2 inches), steel I-beam braces for moderate deflection, or wall anchors drilled through the wall into stable soil for more advanced cases. Costs range from $4,000–$15,000+ depending on method and wall length.