Every building material has its primary weakness. Wood rots, metal corrodes and concrete cracks. Concrete also is prone to surface damage, such as flaking or chipping. On the upside, concrete is so massive and durable that sound structures with cracks and surface damage usually can be repaired to like-new condition, unlike rotted wood and corroded metal. The secret to a successful concrete repair is using the right repair product. There are different repair materials for small vs. large cracks; horizontal vs. vertical structures; shallow vs. deep holes; and localized vs. widespread damage