Because water is the number one cause of Cincinnati foundation problems. Saturated clay loses strength and settles, swells and bows walls, and freeze-thaw heaves footings. Stabilizing the structure without controlling the water that caused the failure is a short-term fix. The two repairs go together.
More detail
Almost every foundation failure we see in Greater Cincinnati traces back to water doing something to the soil. When clay soil gets saturated it loses bearing capacity and the footing settles; when expansive clay takes on water it swells and pushes basement walls inward; when water in the soil freezes it expands and heaves shallow footings every winter; and when downspouts dump at the foundation or the grade slopes toward the house, all of those processes accelerate. So when a contractor stabilizes a settled foundation on piers or braces a bowing wall but ignores the water source, the structural symptom is fixed while the underlying driver keeps working. That is why a durable repair pairs the structural fix with water control: extending downspouts away from the foundation, regrading so the surface drains away from the house, and in many cases installing or restoring an interior or exterior drainage and waterproofing system so the soil around and behind the foundation stops loading up with water. This is also why foundation and waterproofing cross-sell so naturally; they are two halves of the same problem. We flag the water source during the inspection, explain what is driving the failure, and scope the drainage work alongside the structural work so the repair actually holds for the long term rather than recurring the next wet spring. A repair that addresses only the structure and not the water is one a homeowner should question.