Homeowner Guide

Why Is My Driveway Cracking?

Almost every concrete driveway develops some cracking eventually — the question isn't whether a crack exists, it's what kind it is and whether it's actually a problem. Before assuming the worst, it helps to know what usually causes driveway cracks and which signs mean it's worth a real look.

What Usually Causes It

Most driveway cracking traces back to one of a few causes:

• Normal shrinkage cracking — concrete shrinks slightly as it cures, and hairline cracks from this process are common and rarely structural
• Freeze-thaw cycling — water gets into small cracks or pores, freezes, and expands, widening the crack over time; a real factor in Oregon's wetter, colder months
• Soil movement or poor base preparation — if the base under the slab wasn't compacted properly or the soil beneath it shifts, cracks can form as the slab settles unevenly
• Tree root intrusion — roots growing under a driveway edge can lift and crack the slab from below
• Heavy load stress — driveways rated for cars can crack under repeated heavy vehicle or equipment weight they weren't designed for

When It's Worth a Second Look

A single hairline crack that's the same width it's always been is usually cosmetic. What's worth paying attention to: cracks wider than about 1/4 inch, cracks where one side sits higher than the other (a sign of settling, not just surface cracking), multiple cracks radiating from the same area, or cracking that's visibly gotten worse over a season. Those patterns point to something happening underneath the slab, not just the surface — worth having someone look at before it spreads further.