Replacing your existing driveway can be costly, troublesome, and expensive. The problem with replacing sinking concrete is that the concrete is not the issue, it’s the soil or tree roots surrounding the area. After replacing the driveway within a couple of years or less you may end up with the same problems. A faster, cleaner, and cheaper alternative to replacement is to have your driveway lifted by using polyurethane injections.
The process is simple. A dime size hole is drilled in the concrete at strategic locations and polyurethane foam is injected under the slab. This foam spreads to fill voids and then expands to lift the concrete. Once the concrete is lifted, the holes are patched with a cement patching material. The process typically takes from four to eight hours depending on the size of the driveway and the amount of lift it will require.
The foam, while expanding, will push up on the concrete and down on the soil. If the soil is weak it will continue to push down and compact the soil until it is strong enough to lift the weight of the concrete. The foam will remain under the concrete until the concrete is removed. Prevention of water intrusion is critical so the soil under the foam does not erode. Homeowners should attempt to point down spouts away from the edges or joints of the driveway.