Concrete foundations are of two types - poured concrete and concrete block. Poured concrete is a modern manner of laying foundations, while concrete blocks are more traditional. Concrete blocks are preferred for their visual appeal and strength. Yet, as time passes, there may be degradation of concrete.

The prime cause of cracks in concrete foundation is seepage of water. Such cracks caused due to leakage of water are thin and hairline. They may widen over time, but they are present only in those areas where the seepage occurs. In order to repair leakage cracks, it is necessary first to investigate the source and the point from which the leakage originates.

There may be other reasons for concrete foundations to crumble. Soil may lose its moisture content in summer. There may be underground roots which may wither and die. Such natural causes make the soil shrink and hence the foundation may move. Though this movement is gradual, overtime it will cause cracks to occur. These cracks will be large gaping ones, running across the entire length of the foundation. They may even be in the form of tiny holes in certain places.

Whatever be the reason, cracks in the foundation are very perilous if ignored. Repair must be done as soon as possible. Difficulties involved in the repair process are influenced by how big the cracks are.

For tiny moisture created cracks, the repair is relatively simple and can be done by almost anyone. These cracks must first be brushed clean with a wire brush. A jet of water may be passed to remove any loose concrete particles within the crack. The crack is then allowed to dry completely and filled with concrete caulk. If the crack is large, then it is packed with patching materials that are specifically available for concrete. These patching materials must be wet when applied. They are limestone based, and they expand as they dry, filling up the crack completely. The finishing touch is to apply a sealant to the repaired crack.

But if the crack is sinister and not the do-it-yourself kind, then it is most prudent to shell out a few dollars and hire some good repairmen. Such cracks occur due to rods which may have rusted inside and snapped or because of deterioration of the materials present within the concrete. Some leakage cracks when ignored can also reach dangerous levels. Such cracks are more found in poured concrete.

Contractors treat the concrete foundation with urethane injections to extract the embedded water. They may even excavate the area around the foundation and replace the faulty tile or construct a provision for the water to lose contact with the foundation.