Many houses have one or more concrete foundation cracks. Vertical cracks in the foundation visible in the basement or crawlspace are typically not structural defects.  However multiple vertical cracks or any horizontal cracking in a single wall can indicate a serious foundation issue. Multiple vertical cracks or horizontal cracks in a concrete foundation wall are always a concern and should be evaluated by a foundation specialist.

Foundation cracks that are wider than 1/8″ can also indicate a serious defect whether they appear vertically or horizontally in the wall. Larger cracks should always be referred to a professional for evaluation and repair.

With load bearing foundation wall cracks, it is important to ensure there is no additional movement occurring. You can do this by filling small cracks with concrete patching compound. The area should be monitored over a period of 6 to 12 months. If crack reappearance or separation between the filling and the wall does occur, a foundation specialist should be consulted for repair options. Correction can involve injecting a sealant to prevent water or pest entry to something as expensive as underpinning the foundation if structural movement is occurring.

Remember, cracks frequently appear around windows and door frames which are areas of inherit weakness.