Most concrete slab foundations acquire cracks during curing of the concrete or with heaving of highly expansive clay below the slab as it acquires moisture after construction is completed. Many of these types of cracks have little or no effect on the performance of the foundation. The term "Cracked Slab" is a colloquialism used by real estate agents or persons familiar with abnormal foundation differential settlement. Cracks usually develop in the floors and grade beams of buildings having an abnormal degree of differential settlement. The cracks in concrete are normal and could be a symptom of differential settlement and not the problem.