How Do You Repair Cracks in a Concrete Driveway?
Fill cracks up to 1/8 inch with liquid polyurethane sealant, pack cracks 1/4 to 1/2 inch with backer rod first, and get a professional assessment for anything over 1/2 inch or with vertical displacement. Crack repair is the most important maintenance action for a concrete driveway, because an open crack lets in water that damages the base and widens the crack through freeze-thaw cycling.
Hairline Cracks (Under 1/4 Inch): Seal Promptly
A hairline crack (under 1/8 inch wide) in concrete is cosmetically minor but functionally important: it is a direct water infiltration path to the base. Sealing material: a liquid polyurethane or silicone caulk-based crack sealer applied with a squeeze bottle (costs: $8 to $20 per tube). Application: clean the crack of loose material and dirt with a wire brush and compressed air, let the crack dry, then fill the sealer slightly above the surface (it will shrink slightly as it cures). Hairline crack repair is a DIY task that takes 30 to 60 minutes for a standard driveway. Service life of the sealant: 3 to 5 years before reapplication is needed. (For more on this, see DIY Driveway Repair: What You Can Do Yourself.)
Medium Cracks (1/4 to 1/2 Inch): Fill with Backer Rod and Caulk
A crack 1/4 to 1/2 inch wide: fill with foam backer rod (a cylindrical foam strip pressed into the crack as a bottom support: $0.30 to $0.50 per linear foot) before applying a polyurethane crack sealant. The backer rod prevents the sealant from sinking into a deep crack and ensures the sealant maintains the correct shape to flex with the crack movement without failing. Without backer rod in a deep crack: the sealant is pulled in two directions (top surface and depth) and tears prematurely.
Wide or Structural Cracks (Over 1/2 Inch): Professional Assessment
A crack wider than 1/2 inch or a crack with vertical displacement (one side higher than the other): may indicate base movement rather than just surface cracking. Have a concrete or driveway contractor assess the crack before attempting to fill it — a crack in a heaving or settling slab will reopen immediately after filling because the underlying movement has not been addressed. Surface filling alone is appropriate for stable cracks; a moving crack requires addressing the base cause (mudjacking if settling, drainage correction if water-driven) before the surface can be permanently repaired.
Working With a Contractor on This Project
Getting the right outcome on any home services project starts before the work begins. A few consistent practices make the difference between a smooth project and a frustrating one.
Get at least two or three quotes. A single quote gives you no basis for comparison. Two or three quotes reveal the market rate for the work, expose scope differences between bidders, and let you assess contractor communication quality before any commitment is made. The lowest bid is not automatically the best value if the scope is thin or the materials are underspecified.
Ask for licenses and insurance before work starts. Verify current general liability insurance and, for any work involving workers on your property, workers compensation coverage. Licensing requirements vary by state and trade; confirm the specific requirements in your jurisdiction. A licensed contractor who carries appropriate insurance protects both parties if something goes wrong during the project. (For more on this, see Driveway Repair Questions to Ask Before Hiring.)
Get the scope in writing. A written proposal that specifies materials, labor scope, timeline, what is included (permits, cleanup, disposal), and warranty terms is the foundation of a professional engagement. Verbal agreements on any of these points invite misunderstanding. For any project over $500, written scope is non-negotiable.
Clarify the payment schedule upfront. A reasonable payment schedule ties major payments to project milestones: a deposit at signing, a payment at material delivery or project start, and a final payment at completion after a walkthrough confirms satisfaction. A contractor who requires full payment upfront before work begins is a red flag in any trade.
Making a Confident Decision
The information in this article is designed to help you ask better questions of the professionals you work with, evaluate their answers with more confidence, and understand the decisions involved in this type of home services project. It is not a substitute for professional assessment of your specific home.
Every home is different. Roof slopes, local weather, tree exposure, soil conditions, and existing system condition all affect what the right solution is for your specific situation. The general principles here apply broadly, but a professional who assesses your home in person will give you guidance that accounts for the details that general articles cannot.
When you are ready to move forward, getting at least two or three quotes from licensed, insured, local contractors is the most important practical step. It lets you compare approaches, assess contractor quality, and confirm that the solution proposed matches your specific situation and budget.
Ranges here are national ballpark figures, not quotes. Actual pricing varies by region, home condition, materials, and contractor. How we source cost data.