What Causes Concrete to Crack?
Understanding what causes cracks helps you choose the right repair solution.
1. Shrinkage
Concrete shrinks as it dries. If it dries too quickly, it can form hairline cracks. These are usually surface-level but should still be sealed to block moisture.
2. Settlement
Soil under your slab may shift over time. This movement causes uneven settling and cracking. When this happens, you may need foundation underpinning to stabilize the structure.
3. Temperature Changes
Concrete expands in hot weather and contracts in cold weather. Without expansion joints, these movements can cause stress cracks.
4. Moisture Problems
Poor drainage allows water to collect under your slab, leading to cracks. Proper grading and exterior drainage solutions help prevent this.
Types of Cracks You Might See
Hairline Cracks
Thin and shallow, these usually appear after curing. They are mostly cosmetic but should be filled to avoid water damage.
Surface Cracks
These cracks are wider and often appear in driveways due to traffic or temperature changes.
Structural Cracks
These cracks run deep and may affect walls or foundations. They often need wall stabilization or foundation underpinning.
Tools and Materials for Repairing Concrete
Before you start any repair concrete cracks project, make sure you have:
- Wire brush or chisel
- Shop vacuum or broom
- Concrete crack filler or patching mix
- Concrete bonding adhesive
- Trowel or putty knife
- Caulk gun (for liquid filler)
- Gloves and goggles
For deeper cracks, use epoxy injection kits, hydraulic cement, or polyurethane sealant.
Step-by-Step: How to Repair Cracks in Concrete
1. Clean the Crack
Use a brush or chisel to remove debris, dust, or old filler. Vacuum the crack for a clean surface.
2. Prepare the Area
For larger cracks, slightly widen the bottom edge with a chisel. This shape helps the new material lock in place.
3. Apply Bonding Adhesive
Coat the inside of the crack with bonding adhesive. It helps the new patch stick to the old surface.
4. Fill the Crack
- Small cracks (less than ¼ inch): Fill with liquid concrete crack filler using a caulk gun. Smooth it with a putty knife.
- Larger cracks (more than ¼ inch): Mix a patching compound. Use a trowel to fill and level the area.
5. Let It Cure
Allow the area to dry for 24 to 48 hours. Keep traffic away until it is fully cured.
6. Seal the Surface
Apply a concrete sealer to protect against moisture and stains. Sealing also helps prevent new cracks.
Concrete Driveway Crack Repair
Driveways take a lot of stress from weather, traffic, and heavy loads. For concrete driveway crack repair, follow these extra tips:
- Check the depth: Cracks deeper than two inches may need professional attention.
- Use flexible sealant: Driveways expand and contract, so choose a flexible filler that can move with the concrete.
- Resurface if needed: When cracks cover large areas, a resurfacing mix can restore the entire driveway’s appearance.
If your driveway cracks come from shifting soil, our foundation underpinning team in Evansville can help stabilize your base.
Concrete Floor Crack Repair
Indoor and garage floors often show cracks from settling or moisture buildup. Here’s how to handle concrete floor crack repair:
- Dry the surface completely: Moisture prevents filler from bonding.
- Use epoxy filler: Epoxy works well for floor slabs that bear weight.
- Sand smooth once dry: This ensures a clean finish for coatings or paint.
If cracks form near walls or corners, that could signal foundation movement or moisture issues. Our waterproofing team can fix the root cause and protect the area long-term.
Mistakes to Avoid When Repairing Concrete
Even simple how you repair a crack in concrete projects can go wrong without care. Avoid these errors:
- Not cleaning the surface before patching.
- Using the wrong filler for large cracks.
- Ignoring drainage or moisture problems.
- Forgetting to seal the repair after curing.
How to Prevent New Cracks
Repairing is important, but prevention saves more time and money.
- Keep gutters clear and direct water away from your foundation.
- Maintain proper yard grading.
- Seal your concrete every few years.
- Address small cracks as soon as they appear.
Our skilled underpinning contractors can check your foundation if cracks keep coming back or if walls begin to lean.
When to Seek Professional Help
You should contact a professional if:
- Cracks are wider than ½ inch.
- You see water leaking through the concrete.
- Doors or windows begin to stick.
- Floors or walls shift unevenly.
These signs may indicate deeper structural movement. Our Evansville team can inspect the issue and suggest lasting repair options.
Conclusion
Concrete will always move slightly over time, but with the right care and repair, you can keep your surfaces strong for years. Whether you need concrete crack repair for a small driveway line or major concrete floor crack repair, the steps above will help you restore safety and strength. If your concrete keeps cracking, it’s time to address the source with proper foundation underpinning or drainage corrections to prevent more damage.
How Midwest Structural Solutions, LLC Can Help
Since 2003, Midwest Structural Solutions, LLC has helped homeowners and property managers in Evansville, IN maintain durable, stable structures. We handle everything from concrete crack repair and waterproofing to foundation underpinning and wall stabilization. With more than 10 years of hands-on experience, our skilled team delivers reliable results that last. Call us at (812) 305-0781 today to schedule your inspection and restore your concrete’s strength and appearance.