Foundation Cracks: When Should You Worry?
Almost every home develops some kind of foundation crack eventually. The real question isn't whether you have a crack — it's whether the specific crack you're looking at is something to monitor or something to act on.
Generally Less Concerning
- Thin, vertical hairline cracks in poured concrete — often related to normal curing
- Small cracks that have stayed the same size for years
- Cracks with no associated leaking, bowing, or door/window issues
Worth a Closer Look
- Horizontal cracks, which often indicate soil pressure against the wall
- Stair-step cracks in block foundations along mortar joints
- Cracks wider than about a quarter inch
- A crack that's visibly growing over weeks or months
- Any crack that's actively leaking water
- Cracks appearing alongside sticking doors, uneven floors, or visible wall bowing
Why the Direction of a Crack Matters
Vertical cracks usually form as concrete settles slightly during curing — a largely cosmetic process. Horizontal cracks tend to form when soil pressure pushes against a wall from the side, which is a structural concern rather than a cosmetic one. That's why the same size crack can mean very different things depending on its orientation.
A Simple Way to Track a Crack
If you're unsure whether a crack is growing, mark each end with a pencil and the date, and check back in a month. Measurable growth over a short period is a stronger signal than the crack's current size alone.
When to Call a Professional
If a crack falls into the 'worth a closer look' category, or you're simply unsure, a professional inspection removes the guesswork and gives you a clear answer about what's actually happening.