Sinkhole activity is the result of a dynamic geologic process. The soil upon which nearly all structures in Florida are built rests upon a layer of limestone that is vulnerable to dissolving ground water. This is the result of a low concentration of acid in the water that dissolves the calcium carbonate in the lime rock. As the water table rises and falls, the subsurface limestone erodes and forms voids and caves beneath the surface. As the limestone deteriorates, the soil moves or "ravels" into the voids, exerting additional pressure upon the limestone layer. When the limestone layer collapses, a surface depression may develop on the surface, resulting in subtle to catastrophic damage to existing structures. Damage Caused by Sinkhole Activity Because the size of sinkholes can be very small (i.e. 5-10 feet in diameter) or several hundred feet across, the damage associated with sinkholes varies greatly. The discovery of sinkhole activity may be immediate, causing dramatic damage to the surface. More often, however, the damage appears gradually over the course of a few weeks to several years. This more common, subtle damage usually manifests itself as follows: Damage to Foundations - As the subsurface loses its ability to support the structure, cracks appear with varying widths beyond ordinary settlement. In commercial buildings, damage may begin near manholes or around large equipment, due to the foundation's inability to support added weight. Damage to Walls - Wall cracks appear in a "stair step" pattern. The walls may also appear to separate from each other, creating gaps between sheet rock or between wall joints. For example, a small apartment complex, may begin separating between the individual structures. Functional Impairment - Property owners may discover difficulty closing windows or doors as the structure loses its integrity. Swimming pools nearby may begin losing water at a faster rate and roofs may leak where no such problem existed before. Misconceptions About Sinkholes