The T. family residence was built in 1985 with the original 18-foot wide driveway slab still in place. Over time, the area of the driveway nearest the garage had settled 5 inches down and towards the garage. This concrete slab settlement created trip hazards when walking in and out of the garage, and made it awkward when the homeowner entered or exited the garage with her vehicle. In addition, the slope of the driveway slab was directing water toward the home rather than away from it, promoting further slab settlement and potentially future basement water problems and foundation damage. The homeowner considered removal and replacement of the concrete slab panels or mud jacking to raise the slabs. Replacing the concrete was determined to be too costly and disruptive for the homeowner. Mud jacking was not chosen for several reasons including: the additional weight it places on the already problematic soil, the cure time required, the potential of wash out over time, and the fact that mudjacking would not be a long-term permanent solution. Because of these concerns, the homeowner found herself seeking an alternative to traditional concrete repair methods.
Thrasher proposed a polyurethane injection system, PolyLevel, to provide an economical, quick and effective solution for lifting the homeowner's concrete driveway slab. PolyLevel is a two-part polyurethane material that expands into a rigid foam used to fill voids and lift and stabilize concrete slabs. Once injected through small, penny-sized drilled “ports”, a chemical process converts the product into a strong, rapidly-setting foam material. In its foam state, PolyLevel is relatively lightweight, weighing two to six pounds per cubic-foot (pcf). Other void-filling or lifting materials can weigh upwards of 120 pcf, adding a significant burden to the supporting base material beneath the concrete, and potentially contributing to further settlement issues. For this project, Thrasher installed 61 pounds of PolyLevel and lifted the concrete slab to within a quarter-inch of its original position. The entire project was completed in 3 hours and with PolyLevel's quick cure time, the homeowner was able to drive on the slab 20 minutes after installation. PolyLevel is an environmentally friendly, clean, efficient, long-lasting and economical alternative to traditional concrete repair options.