Yes, you can fix small concrete driveway cracks yourself if the slab isn’t displaced. You’ll typically use a flexible polyurethane concrete sealant rather than a rigid patch. This kind of repair buys you time by keeping out water and dirt.
If hairlines suddenly look bigger after a storm or pressure-wash, you can address them before getting a full replacement quote. But you do need to know when DIY makes sense. Confirm it’s a “line, not a step,” then size the crack so you know whether you need backer rod or sand. Match the sealant to the surface: self-leveling for flat areas and non-sag for slopes or edges. Wilmington-area humidity and frequent rain can ruin adhesion, so a clean, lasting fill usually comes down to prep and dryness more than the brand name on the tube.
Decide if it’s a safe DIY crack
You can usually DIY a crack that’s mostly a line, not a step for concrete driveway crack repair: roughly 1/8–1/2 inch wide and no edges lifting (a common DIY threshold noted in Sakrete’s cracked concrete repair guide). Measure width with a tape (or drill bits as a quick gauge) and check depth. Guessing is a bad plan, even if you grabbed supplies from the Home Depot or Lowe’s project aisle; once the void is deeper than about 3/8–1/2 inch, you’ll often need a backer (sand or backer rod) before you seal (a step also recommended in Sakrete’s concrete crack repair instructions).
Sealing doesn’t stop movement, and that’s what separates a repairable crack from a replacement decision. If the crack is widening over months, has a raised lip you can catch with a shoe or tire, or you see heaving/settlement, treat it as a base or slab issue and pause the DIY filler plan.
If the crack keeps widening or starts to feel like a raised “step,” that’s often a sign the slab or base is moving and simple filling won’t solve the root cause. Read more in our article: Driveway Replace Vs Repair
What to use for small cracks
A rigid patch can look perfect on day one, then split with the next temperature swing and leak again.
If you’re repairing a typical driveway crack in the 1/8–1/2 inch range, start with a flexible polyurethane concrete sealant as an exterior concrete crack sealant rather than a rigid patch (see Concrete Network’s driveway repair guidance on why patches aren’t automatically the best choice). That “harder” look is often misleading. It’s a bandage on a moving joint, and it can debond as the slab keeps shifting, so you just kick the can down the road with a blotchy stripe that still lets water work underneath.
Sealing driveway cracks is mostly about keeping water from getting into the base, which helps slow down future widening and spalling around the crack. Read more in our article: Seal Driveway Cracks
| Crack / condition | What to buy / use |
|---|---|
| Hairline to ~3/8 inch deep (shallow, clean crack) | Concrete crack filler can work; polyurethane sealant usually lasts longer |
| Up to ~1/2 inch wide/deep or seems to move seasonally | Polyurethane sealant |
| Horizontal, flat crack | Self-leveling polyurethane |
| Sloped sections or any vertical edge (apron, curb edge) | Non-sag polyurethane |
| Deeper than ~3/8–1/2 inch | Closed-cell backer rod first (or clean sand for irregular voids), then sealant |
Quick DIY Steps (Coastal NC Reality)
A Wilmington homeowner seals a crack right after a light rain, and a week later the bead has lifted in strips like a bad sticker. The fix was never the tube, it was the timing and the surface prep.
In Wilmington-area humidity, rushing this like a simple caulk job often leads to a repair that doesn’t hold. Even This Old House would tell you moisture control decides whether the repair lasts. A damp slab from dew or recent rain will weaken the bond, so the bead can lift or pop out after the next storm.
Pressure washing can open up hairlines and leave moisture in the pores, so sealing too soon after cleaning is a common reason crack filler fails to bond. Read more in our article: Pressure Wash Driveway Sealing
Pick a 24–48 hour dry window, then:
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Clean: dig out weeds and grit; blow out dust (shop vac or leaf blower).
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Dry: let the crack air out; don’t seal if water keeps beading up.
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Shape (if needed): knock off loose edges; don’t smear over crumbling concrete.
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Back + fill: add backer rod or sand for deep gaps, then apply polyurethane in short runs.
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Cure: keep cars off until it skins over and fully cures per the label (how long does concrete crack filler take to cure).
Small cracks only get worse once water starts working into them. Our driveway crack repair crew in Wilmington seals them up before they spread further.
