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How to Fill Cracks in a Driveway

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Filling a driveway crack is 80 percent preparation and 20 percent product. Clean the crack out completely, key the edges on very narrow cracks, push backer rod into anything deeper than half an inch, then fill in two or three thin passes with a filler matched to the width — pourable for hairlines, trowelable for 1/4 to 1/2 inch, flexible polyurethane for anything that has reopened before. Work above 50°F on a dry slab with 24 hours of dry weather ahead. Materials run $30 to $80 for a typical driveway and the whole job is a morning.

First: Is This a Crack or a Symptom?

Some cracks are worth filling and some are telling you the driveway has a problem underneath. Filling the second kind is money and a morning spent on nothing.

What you seeWhat it meansDo this
Single straight crack, sides levelNormal shrinkage or thermal movementFill it
Crack at a control jointWorking exactly as designedFill with flexible sealant
Crack that reopens every winterSeasonal movementFlexible polyurethane only
Interlocking pattern over a wide areaBase failure — often called alligator crackingGet a contractor opinion
One side sits higher than the otherSubsidence or heave below the slabNot a filling job
Section rocks or sounds hollowVoid beneath the slabSlab jacking or replacement
Low-angle view of a person laying a stone paver into a sand base while building a garden path, in soft overcast light

Tools and Materials

Wide view of a person laying a stone paver into a sand base while building a garden path, in warm late-afternoon light

The Repair, Step by Step

  1. Kill any vegetation first. Grass and weeds growing in a crack have roots below it that will reopen the repair. Remove them and let the root zone dry out for a few days.
  2. Open and key narrow cracks. A crack you cannot get filler into is not a crack you can repair. Chase it with a cold chisel or a grinder wheel to roughly 1/4 inch wide, and undercut the edges slightly so the repair is wider at the bottom than the top. A keyed repair cannot lift out.
  3. Clean it out completely. Wire brush the walls, then vacuum. Every crumb of loose material left behind is a bond breaker between filler and concrete.
  4. Wash, degrease and dry. Oil is the classic adhesion killer on a driveway. Degrease stains, rinse, and then let the slab dry through — most fillers want a dry substrate, and a damp crack is the leading cause of a repair lifting in the first year.
  5. Backer rod anything deep. Push foam rod down until roughly half an inch of depth remains for filler. Depth is not strength; excess depth is shrinkage waiting to happen.
  6. Fill in passes. Two or three thin applications with cure time between them, rather than one deep pour that shrinks and dishes. Overfill very slightly on the last pass because most products settle a little.
  7. Match the texture. On broom-finish concrete, drag a dry brush across the filler as it starts to skin. Thirty seconds, and it is the difference between a repair you see from the sidewalk and one you do not.
  8. Let it cure fully — typically 24 to 72 hours depending on product, depth and temperature. Keep vehicles off for the full period. A repair driven over at hour six will print a tire pattern permanently.
  9. Seal the driveway afterward, once the filler has fully cured. This is the step that addresses the cause rather than the symptom — see driveway sealer picks, and check the sealer label for compatibility with a fresh repair.

Asphalt and Concrete Are Different Repairs

Concrete is rigid and mineral. It cracks from shrinkage, from thermal movement and from freeze-thaw damage, and it wants a cement-based or polyurethane filler. Concrete cracks tend to stay roughly the width they are unless something below is moving.

Asphalt is flexible and petroleum-bound. It cracks as it oxidizes and hardens with age, and its cracks visibly open in cold and close in heat, which is why an elastomeric filler that flexes is essential — a rigid cement product in an asphalt crack pops out within a season. Asphalt also gets potholes, which are a patching job with cold-patch material rather than a filling job.

One shared rule: never use sealcoat as a crack filler. Sealcoat is a coating, not a filler. It flows into a crack, cures thin, and reopens with the crack at the first freeze. Fill first, seal second, always.

Overhead view of a person laying a stone paver into a sand base while building a garden path, in warm late-afternoon light

The Mistakes That Cause Repairs to Fail

The Bottom Line

Clean it, key it, rod it, fill it in passes, texture it, cure it, then seal the whole driveway. Match the product to the crack width and to whether the crack moves. And be honest about the cracks that are telling you something about the base — a driveway with interlocking cracking across a wide area needs an opinion, not a tube of filler.

We never buy, test or physically handle the products we rank. Recommendations come from aggregated owner reviews, star ratings, review volume and expert consensus — see how we rank.

More from this hub: Landscaping & Hardscaping · Best concrete crack filler · Best driveway sealer · How to lay a paver patio · How we rank.

Straight Answers

Frequently Asked

What is the best way to fill a crack in a driveway?

Clean it out completely, key the edges if the crack is very narrow, insert backer rod in anything deeper than about half an inch, then fill with a product matched to the width. Hairline to 1/4 inch takes a pourable self-leveling filler. From 1/4 to 1/2 inch takes a trowelable pre-mixed patch. Anything that has reopened after a previous repair is moving seasonally and takes a flexible polyurethane sealant instead. Fill in two or three thin passes rather than one deep pour, because a single deep fill shrinks and dishes as it cures.

Can you fill driveway cracks yourself?

Yes — this is one of the most genuinely DIY jobs in home maintenance. Materials for a typical driveway run $30 to $80, the tools are a wire brush, a shop vac and a putty knife, and a morning covers most driveways. The skill is in preparation rather than application. What is not DIY is a driveway with interlocking cracks across a wide area, sections that rock underfoot, or vertical offset between the two sides of a crack. Those are symptoms of base failure below the slab, and filling the visible line changes nothing.

Should you fill driveway cracks before sealing?

Always, and in that order. Sealer is a coating only a few thousandths of an inch thick — it flows into a crack, does not span it, and reopens with it at the first cold snap. Fill first, let the filler cure fully to the manufacturer's stated time (typically 24 to 72 hours, longer in cool or damp weather), then seal over the top. Sealing an unfilled driveway produces the familiar result of a fresh black surface with the same cracks visible through it within weeks.

What temperature is right for filling driveway cracks?

Above 50°F and rising, with no rain forecast for at least 24 hours and ideally 48. The comfortable working range for most products is 55°F to 90°F. Avoid direct midday sun on a hot slab, because a filler that skins over before it wets the crack walls will not bond. The concrete or asphalt must also be dry through, not just dry on the surface — give it a couple of dry days after heavy rain. Cold and damp are responsible for most repairs that fail within the first year.

How long do driveway crack repairs last?

A well-prepared repair with the right product typically holds three to five years on a stable crack, and a flexible polyurethane repair on a moving crack often longer. A repair that fails within a season almost always failed on preparation — a dirty or damp crack, or a rigid product in a crack that opens and closes seasonally. Sealing the driveway afterward extends everything, because water getting into the surface and freezing is the mechanism that created the crack in the first place.