The angle, width, and location of a foundation crack tell a clear story about what the soil around your home is doing. Use this guide to read the pattern on your wall and know when to call a local specialist for an on-site evaluation.
Each crack direction points to a specific force—curing shrinkage, footing settlement, or lateral earth pressure.
Climbing in a jagged step pattern along mortar joints in concrete block or brick foundations, stair-step cracks indicate that one section or corner of the footing is settling into softer soil. If the crack is wider at the top than the bottom, the corner is dropping and may need push piers or helical piers.
Running side-to-side near the middle of a basement wall, horizontal cracks are a serious structural warning sign. They happen when wet clay soil, hydrostatic water pressure, or winter frost heave pushes the wall inward. Local contractors stabilize bowing walls using carbon fiber straps or steel earth anchors.
Narrow, straight vertical cracks in poured concrete walls usually come from natural shrinkage as the concrete cured. While rarely a threat to structural stability, they create a direct path for groundwater seepage and are sealed from the inside using pressurized polyurethane foam injection.
A diagonal crack in a poured concrete wall that tapers from wide at the top to narrow at the bottom—or radiates from a basement window corner—signals differential settlement along the footing and should be measured with a laser level.
To check whether a crack is actively moving, draw a light pencil mark across the narrowest tip of the crack and write the date beside it. Also lay a straightedge against the wall to see if one side of the crack sits proud of the other (shearing) or if the center of the wall bows inward.
When a crack is wider than one-quarter inch, growing past pencil marks, or accompanied by inward bowing or sticking upstairs doors, surface caulk will not hold. Compare structural stabilization and crack injection methods on our South Bend foundation repair page, or book a foundation inspection in South Bend so a licensed local contractor can inspect the wall and provide a written estimate.
Stair-step cracks follow mortar joints in concrete block or brick walls and typically indicate differential footing settlement or lateral soil movement at a corner.
Uniform hairline vertical cracks in poured concrete are usually caused by curing shrinkage rather than structural failure, though they often leak during wet weather and can be sealed via polyurethane foam injection.
Find out whether your crack needs simple polyurethane sealing or structural stabilization.