The foundation is cracked, should I be concerned?
Foundation cracking is very common and is often a topic of concern for buyer’s. Not every crack is necessarily a major issue. Poured foundations will typically develop shrinkage cracks as the concrete cures. These will often form on a long wall or from the corner of basement window openings. This type of crack will always be vertical and usually less than 1/8″ in width This type of crack is likely not a structural concern; however, it should still be monitored for additional movement. There are devices such as the “CrackMON” (http://www.builderswebsource.com/tools/crackmonitor/crackmon.htm) which can be adhered to the foundation wall to detect movement.
Water intrusion can be an issue with this or any foundation crack. To reduce the chances of water intrusion into the basement, the crack should be sealed, gutters checked regularly and the downspouts should be extended at least 5′ away from the foundation. You should also ensure that the grading of the yard has sufficient slope away from the foundation (typically 1/4″ per foot for 10′) to direct water runoff away from the foundation. In extreme water intrusion cases, a basement waterproofing contractor should be consulted.
When is a foundation crack considered a structural concern? If any of the conditions described below are observed, it is recommended to consult a professional structural engineer for further evaluation.
- A vertical crack that is 1/4″ or greater in width usually indicates that structural movement has occurred and may still continue.
- Any vertical or horizontal displacement in the wall from one side of the crack to the other is also indicative of structural movement.
- Horizontal cracking is a sign of possible expansive soil pressure against the foundation. Poor grading will contribute to this type of movement as water runoff will be directed toward the foundation and can push the wall inward during freeze/thaw cycles. Horizontal cracking can also occur during back filling of soil against the foundation during construction. Bowing of the wall is often visible in extreme cases. This type of crack is more likely to be found on a block wall foundation.