However, over time, even the best-laid concrete can develop cracks. These cracks may start small, but if left untreated, they can lead to more significant structural issues.
In this article, we’ll explore the most common causes of concrete cracks, the types of cracks you may encounter, and the best methods for concrete crack repair—whether you’re a DIY enthusiast or planning to hire a professional.
What Causes Concrete Cracks?
Understanding why concrete cracks is the first step toward effective repair. The most common causes include:
Shrinkage
As concrete dries and cures, it naturally shrinks. If this process happens too quickly or unevenly, it can result in fine surface cracks. These are common and usually not structurally serious.
Settlement
When the soil beneath a concrete slab shifts or settles, it can cause the slab to move and crack. This is often due to poor compaction during construction or erosion caused by water drainage issues.
Temperature Changes
Concrete expands in heat and contracts in cold. Repeated cycles of expansion and contraction can put stress on the slab, leading to cracking over time.
Overloading
Excessive weight—such as heavy vehicles parked on a driveway not designed for them—can also create stress that causes the concrete to crack.
Improper Installation
If the concrete was not mixed properly, poured correctly, or lacked sufficient reinforcement, it becomes more vulnerable to cracking over time.
Types of Concrete Cracks
The type of crack helps determine the best repair method:
Hairline Cracks
These are very thin, surface-level cracks caused by shrinkage or minor movement. While usually cosmetic, sealing them can prevent water from seeping in and causing more damage.
Vertical and Diagonal Cracks
Often found in walls and foundations, these may be due to settlement or shifting. Some are harmless, while others may indicate structural issues.
Horizontal Cracks
Typically more serious, especially in foundation walls. They may be caused by external pressure from soil or water and often require professional evaluation.
Structural Cracks
Wide or deep cracks, especially those that continue to grow, can indicate foundational movement or failure and usually require expert intervention.
DIY Concrete Crack Repair Methods
If you’re dealing with small or non-structural cracks, you may be able to handle the repair yourself. Here are some popular DIY solutions:
Concrete Crack Sealant
This is a flexible, water-resistant compound applied with a caulking gun. It’s ideal for filling small surface cracks in driveways, sidewalks, and patios.
Epoxy Injections
Used for more serious cracks, especially in walls or structural elements. Epoxy bonds the two sides of the crack together and restores strength.
Polyurethane Foam
Great for cracks that leak water, such as in basements. The foam expands to fill the gap and blocks moisture.
Patching Compounds
For larger gaps or chipped areas, pre-mixed concrete patching compounds can be applied with a trowel to restore a smooth surface.
When to Call a Professional
While DIY methods are effective for many small cracks, you should contact a professional if:
- Cracks are wider than ½ inch
- You notice water seepage through the crack
- The crack is growing over time
- The area around the crack feels uneven or unstable
- You see horizontal cracks in foundation walls
A licensed contractor can evaluate the issue and use more advanced repair techniques, like slab jacking, underpinning, or full wall stabilization, if necessary.
Cost of Concrete Crack Repair
The cost depends on the type and size of the crack and whether you're doing it yourself or hiring a contractor:
| Repair Type | Average Cost (USD) |
|---|---|
| DIY Sealant or Epoxy Kit | $10 – $100 |
| Professional Crack Repair | $300 – $1,000 |
| Foundation Wall Repair | $1,000 – $4,000+ |
| Slab Jacking (Leveling) | $500 – $2,500+ |
Early repair usually costs less and prevents more expensive structural damage later.
Preventing Future Cracks
To minimize the chance of new cracks forming, follow these best practices:
- Ensure proper drainage around concrete areas
- Avoid overloading slabs with heavy equipment
- Use control joints to manage shrinkage
- Seal the concrete surface regularly to protect it from moisture and chemicals
- Hire experienced professionals for concrete installation to ensure proper reinforcement and curing
Conclusion
Concrete crack repair is an essential part of home maintenance that protects your investment and prevents long-term structural issues. From hairline surface cracks to larger foundation concerns, addressing the problem early can save you time and money.
Whether you're planning a simple DIY fix or need a professional inspection, understanding the cause and type of crack will help you make the right decision. Stay proactive, and your concrete will remain strong, safe, and functional for years to come.
