He pressed his thumb against the wall to the left of the crack. Solid. He pressed to the right. Solid.
| Crack Characteristic | Likely Cause | Urgency | | :--- | :--- | :--- | | Hairline (<1/16"), straight, stable | Cosmetic / settlement | Low – monitor & patch | | 1/8" wide, stable | Moderate settlement / lintel sag | Medium – repair with mesh tape | | >1/4" wide, growing, tapered | Foundation movement or rusting lintel | | | Accompanied by sticking windows/doors | Structural movement | High – get professional inspection | vertical crack above window