Most houses have cracks of some kind, however a hairline fracture in the slab is normally of no structural significance, however cracking in the foundation wall is more important.While a stair-step crack is less important than a vertical crack either one with an opening of 1/8″ to 1/4″ may be cause for concern, of course smaller cracks may also be a concern depending on the circumstances.
The key to load bearing wall cracks is to insure that there is no further movement. To do this you should fill in the crack and then over a period of 6 to 12 months check for reappearances or separation between the filling and the wall.
If there’s is additional movement then it would be advised that you call a specialist. It may be anything from a simple matter regarding the property or something as expensive as underpinning the foundation.
Remember, cracks frequently appear around windows and door frames which are places of inherent weakness.
This tip brought to you by one of the many great home inspectors I use.