When the interior walls of a basement begin to bulge inward or the concrete floor begins to show cracks, it is probably due to improper or adequate water control. The first signs of a bulging wall are loose mortar joints or cinder blocks that stick out farther and surrounding blocks. The hydraulic movement and pressure of groundwater and saturated soil cause this bulging. Cracks in the concrete floor of the basement indicate movement of the soil below it.
Porous soils, especially clay, do not maintain consistent moisture content. As the clay becomes moist, it expands, and as it dries, it shrinks. This expanding and shrinking can cause the house to shift and settle. This is sometimes not discovered until a contractor is repairing water damage.
The contractor may state that the bulging walls will need to be reinforced. There are several methods of doing this and you may want to consult a structural engineer to determine the best solution. While reinforcement beams and struts can be used, it may not be the best solution in a finished basement. Additionally, replacing the entire wall is costly and does not always adequately solve the problem.
Wall plate anchors, approved by many structural engineers and building code officials, can be a more economical and efficient method of all repair. Because of their design, wall plate anchors require a minimal amount of excavation, can be installed more quickly than other solutions and are more aesthetically pleasing. The plate can be covered with paneling or drywall, using furring strips to elevate a wall covering above any mounting hardware. Whatever method is used, water control still needs to be addressed.
Cracked floors might need to be repaired by a process called slab jacking. In this procedure, access holes are drilled into the concrete floor and loose or liquefied material is removed. Quick-hardening slurry is pumped into the hole, bringing the floor back to level. The holes are sealed and the mixture is allowed to dry before use.