Cracks in foundations occur for various reasons, some normal and some bad. A crack in a foundation can be caused by simple settling, pressure from surrounding materials or a problem in the structure of the building. Because not all foundation cracks are bad, it is important not to overreact when cracks are found, so an assessment of the size and location of the cracks can be made.
Concrete often cracks during the curing process, so cracks are not necessarily a problem in and of themselves. One of the more important things to take note of when investigating whether your foundation cracks are bad is how big the cracks are. A crack of less than 1/8 inch long that does not grow in length or width is nothing to worry about.
Concrete Block Foundations
A vertical crack in a poured concrete block foundation indicates movement. If the crack is wider at the top than the bottom, either the sides of the foundation are slipping or the center of the foundation is rising. A crack that is larger at the bottom than the top is an indication of the center of the foundation sagging or the ends rising. Either way, calling a structural engineer to examine the foundation is a necessity.
Brick on Concrete Foundations
Bricks laid directly onto concrete foundations will often cause an angular crack in the first 1 to 1 1/2 feet of the concrete foundation, usually in the corner of the concrete. This is due to pressure on the concrete when the bricks expand during settling and is not an indication of any structural problems.
Concrete Slab Foundations
Concrete slab foundations commonly crack all the way through due to concrete shrinkage and settling, or as an indication of poor-quality soil below the foundation. Any cracks in concrete slab foundations should therefore be monitored. If they do not grow in length or width, this is often an indication that the cracks formed during settling and can be ignored. If in doubt, however, consult a structural engineer for a thorough assessment.
- Photo Credit Hemera Technologies/AbleStock.com/Getty Images