Conditions where outdoor concrete has already begun to sink is not uncommon in District of Columbia and is often the result of shifting, a weak soil base or erosion. It causes driveways, sidewalks, walkways, concrete steps or patio areas to become tripping hazards and can affect property value.
District of Columbia soil has a variety of soil types, ranging in density and load-bearing capacities. When the weight above the soil exceeds the soil below, the soil will compact and settle. Clay and silt can also cause soil to compact when it becomes dry. Regardless of the reason, once soil becomes compact, heavy concrete above the soil will sink and crack. It's a gravity thing!
While it is a very noticeable problem, with the right contractor, it can have a very simple solution.
Previously, sinking concrete was repaired by a technique called "mud jacking" that uses a thick slurry to fill in the gap underneath the sunken concrete. While effective, it is not the most efficient way to solve the problem, and adds more weight above the compacting soil.
Today, select contractors in District of Columbia are trained and certified to provide a better alternative to mud jacking. PolyLevel is a less intrusive, lighter weight solution that doesn't add more weight to the problem.