He found that by the middle of this century, some areas under the Loop may heave upward by as much as 12 millimeters (0.47 inch) or settle by as much as eight millimeters (0.31 inch), depending on the soil makeup of the area involved. Though these may sound like small displacements, Rotta Loria says they could cause cracks in the foundations and walls of some buildings. This could lead to water damage or cause buildings to tilt. Over recent decades, this hidden factor could have contributed to some of the ongoing challenges and costs of maintaining these structures, he says.