Three options depending on how far it moved and whether it is still moving: carbon-fiber straps for modest bows under about 2 inches, steel I-beam bracing for larger or active bows, and exterior wall anchors that can pull the wall back over time where there is yard access. An engineer specifies which.
More detail
A bowing wall is responding to lateral pressure from saturated, expansive soil outside, so the fix has to resist that pressure and, ideally, relieve it. Carbon-fiber straps are epoxied vertically to the wall and anchored top and bottom; they are low-profile, paintable, and ideal for walls bowing modestly (generally under about 2 inches) that are not actively moving fast. They stop further inward movement but do not straighten the wall. Steel I-beam bracing uses vertical steel beams anchored to the slab and the floor joists, spaced per the engineer's plan; beams handle larger or still-active bows and, where the system allows adjustment, can recover some deflection gradually. Wall anchors work from outside: a steel plate is driven into stable yard soil beyond the pressure zone and connected by a rod to a plate inside the wall, and tightening the rod over seasons can actually straighten the wall, but only where there is 8 to 12 feet of open yard to reach undisturbed soil, which rules them out on tight urban lots. Per element, all three run roughly $500 to $1,000 installed (anchors $600 to $1,000). Critically, stabilizing the wall is only half the job. The driver is lateral soil and water pressure, so a lasting fix pairs the structural work with regrading, downspout extensions, and often a drainage system so the soil behind the wall stops loading up with water every spring. The engineer classifies the bow at the inspection by measuring deflection with a string line or level, then specifies the system and spacing.