Why Is My Driveway or Walkway Cracking?
Almost all concrete cracks eventually — the real question is whether a crack is cosmetic weathering or a sign that the ground underneath is genuinely moving.
- Time
- 30–60 min
- Cost
- $0–6,000
- Difficulty
- Moderate
- Risk
- Moderate Risk
01
Before you start
Diagnose first, then act.
02
Identify the most likely cause
Cause 1
Hairline Cracks From Weather and Normal Aging
Root cause
Concrete expands and contracts with temperature changes, and repeated freeze-thaw cycles in colder climates put ongoing stress on the surface. Thin hairline cracks are a normal, largely cosmetic result of this over years of exposure, not a sign of a structural problem.
30-second check
Measure the crack's width with a coin or ruler — hairline cracks are typically under 1/4 inch, and both sides of the crack should be level with each other with no step or height difference.
Tools & materials
Concrete crack filler or sealant (squeeze-tube or pourable), a wire brush, a caulking gun if using a cartridge-style filler.
Step-by-step
- 1 Clean the crack thoroughly with a wire brush to remove loose debris and dirt.
- 2 Apply concrete crack filler directly into the crack, following the product's instructions for depth and application.
- 3 Smooth the surface level with a putty knife while the filler is still workable.
- 4 Allow to cure fully per the product's timeline before driving or walking heavily on it.
- 5 Reapply sealant to the full driveway or walkway every 2–3 years as routine maintenance to prevent new cracks from forming as easily.
Cause 2
Expansion Joint Failure
Root cause
The flexible material in expansion joints (the intentional gaps between concrete sections) breaks down over time from sun and weather exposure, losing its ability to absorb the slab's natural movement — which can then show up as cracking near those joints instead of the joint flexing as intended.
30-second check
Look specifically at the expansion joints between concrete sections for crumbling, missing, or hardened filler material rather than a flexible seal.
Tools & materials
A flathead screwdriver or joint-cleaning tool, self-leveling polyurethane joint sealant, a caulking gun.
Step-by-step
- 1 Remove old, deteriorated joint filler with a screwdriver or joint-cleaning tool.
- 2 Clean out the joint thoroughly, removing debris and dust.
- 3 Apply new self-leveling polyurethane sealant into the joint, following the product's fill-depth instructions.
- 4 Allow to cure fully before use.
- 5 Repeat for all joints showing similar deterioration — they typically age at a similar rate.
Cause 3
Crumbling Edges or Surface Spalling
Root cause
Spalling — flaking or pitting at the surface — often results from de-icing salt exposure, poor original finishing, or trapped moisture freezing near the surface. Crumbling edges along a driveway are frequently from repeated vehicle weight concentrated right at the unsupported edge.
30-second check
Look for a rough, pitted, or flaking surface texture (spalling) rather than a clean crack, or check whether damage is concentrated specifically along an unsupported edge.
Tools & materials
A concrete patching compound or resurfacer, a trowel, a wire brush, safety glasses.
Step-by-step
- 1 Clean the damaged area thoroughly, removing all loose and crumbling material with a wire brush.
- 2 Dampen the area slightly per the patching product's instructions for better adhesion.
- 3 Apply concrete patching compound or resurfacer with a trowel, feathering the edges to blend with the surrounding surface.
- 4 Allow to cure fully before foot or vehicle traffic, following the product's specific timeline.
- 5 Consider reducing future salt use on this area, or switching to a concrete-safe de-icer, if salt exposure was the likely cause.
Cause 4
Wide Cracks, Uneven Slabs, or Sunken Sections
Root cause
Cracks wider than about 1/4 inch, or where one side of the crack sits noticeably higher or lower than the other, indicate the ground underneath has shifted — from erosion, poor original compaction, or a plumbing leak washing out the base material. Surface sealant won't address movement happening below the slab.
30-second check
The crack is wider than roughly 1/4 inch, one side is visibly higher than the other, or an entire slab section has noticeably sunk relative to its neighbors.
Why this one isn't DIY
What a professional actually does
A professional evaluates the underlying cause of movement, and depending on the diagnosis either lifts and levels the existing slab (mudjacking or polyurethane foam injection), replaces the affected section, or addresses a drainage or plumbing issue that's washing out the base material.
Recap
Decision matrix
A quick side-by-side once you know which cause applies to you. Time and cost reflect the job itself, not how long it takes a pro to arrive.
| Metric | DIY Approach | Pro Approach |
|---|---|---|
| Recommendation | Most people fix this themselves | If cracks are wide or slabs have shifted or sunk |
| Typical Cost | $2–80 | $300–5400 |
| Time Required | 15–60 min | 30–90 min |
| Tools Needed | Wire brush, concrete crack filler, caulking gun | Professional-grade tools & parts |
| Safety Risk | Moderate Risk | Handled by a licensed professional |
Deep dive
Learn more
The 1/4-Inch Rule of Thumb
A widely used, simple guideline: cracks under about 1/4 inch wide with both sides level are generally cosmetic and fine to seal yourself. Cracks wider than that, or with any noticeable height difference between the two sides, are worth having a professional look at before you invest in a DIY fix that a shifting foundation underneath will just crack again.
Why Sealing Cracks Early Actually Saves Money
An unsealed crack lets water seep in, which then freezes and expands during winter — widening the crack further each cold season. A $10 tube of crack filler applied while a crack is still hairline is genuinely one of the best-value maintenance tasks in the whole house, compared to what that same crack can turn into after a few untreated winters.
FAQ
Frequently asked questions
-
How do I know if a concrete crack is serious?
A simple guideline: cracks under about 1/4 inch wide, with both sides level, are usually cosmetic. Wider cracks, or any noticeable step where one side is higher than the other, point to ground movement underneath and are worth a professional assessment.
-
Can I seal a driveway crack myself?
Yes, for hairline cracks this is a genuinely simple and inexpensive DIY task — clean the crack, apply filler, and let it cure before use.
-
Why do driveway edges crumble more than the middle?
Edges lack the support of surrounding concrete on one side, so repeated vehicle weight right at that unsupported edge causes crumbling there faster than in the middle of the slab.
-
Is it normal for concrete to crack over time?
Yes — nearly all concrete develops some cracking eventually from temperature swings and freeze-thaw cycles. The question is whether it's cosmetic (thin, level) or structural (wide, uneven).
-
What causes a sunken section of driveway?
Usually erosion or settling of the ground underneath, sometimes from poor original compaction or a hidden plumbing leak washing out the base material. This needs a professional to lift and relevel, or to address the underlying cause.
-
How often should I reseal my driveway?
Every 2–3 years is a common recommendation for concrete, which helps prevent new cracks from forming as easily and extends the life of the slab overall.
Sources
Research & References
How this guide was researched
This guide was built by cross-referencing established concrete-repair references and contractor cost guides, with particular attention to the crack-width and level-difference criteria professionals use to distinguish cosmetic cracking from structural movement. full methodology for how we evaluate cost, time, and safety risk for every guide.
A quick disclaimer
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