Sinking Concrete Slab Repair | PolyLevel™ Concrete Leveling- fixing cracked concrete patio ,A sinking, cracked concrete slab can be a symptom of a more serious problem. A sinking slab (also known as sinking concrete) is always worth fixing, whether it’s located in your basement, garage, driveway or patio.How to Repair Concrete Cracks | how-tos | DIYRepairing cracks in concrete is an easy project any DIYer can do. Not only does it make the concrete look better but it extends the life of the concrete by keeping out the elements.