As concrete cures, it is common for small cracks to appear in foundation walls. These cracks are very common, and they’re not a sign of a major foundation problem.
Shrinkage cracks tend to be very small “hairline” cracks that are usually 1/16″ wide or less. They generally occur near the center of a span and maintain a consistent width for the length of the crack.
A Word Of Warning: Be careful not to assume that a crack in your foundation is merely a shrinkage crack! If you see cracks in your foundation walls, monitor them regularly. If the cracks widen enough that you can fit a dime in them, or one end of the crack grows wider than the other, you should consult a foundation contractor right away.