Sinking Concrete
You can see here that there is now a void underneath the concrete slab causing it to sink down and cause the patio to be uneven.
Trip hazards
Not only is this unsightly, but the location of this crack around a pool adds to the danger of tripping and falling.
Back to Level
Once the PolyLevel is injected, the expansion of the polyuethane allows for a precise lift and stabilization of the slab.
Looking Good!
Further advantages of PolyLevel is that the material is waterproof and will not wash out beneath the slab in the future - ideal for around swimming pools!