Why Concrete Cracks and How to Prevent It?

Concrete is one of the most durable and widely used materials in construction. From sidewalks and driveways to patios and foundations, concrete plays a vital role in building strong and lasting structures. But even with all its strength, you’ve probably noticed that concrete sometimes cracks. While this might seem normal, it’s important to understand why it happens and how to prevent it.

If you’ve ever spotted cracks forming in your driveway or patio, you’re not alone. Cracking is one of the most common issues with concrete, and in most cases, it can be avoided with the right care and installation methods. In this article, we’ll break down the causes behind concrete cracks and share practical tips on how to prevent them—so your surfaces stay smooth, strong, and long-lasting.

Understanding Why Concrete Cracks

Concrete may seem rock-solid, but it’s not invincible. It’s a mix of cement, water, sand, and gravel. When these materials combine, a chemical reaction called hydration occurs, causing the mixture to harden. During this process, concrete changes slightly in volume—expanding and contracting based on temperature, moisture, and other conditions.

When those changes are uneven or extreme, cracks can form. Let’s take a closer look at the most common reasons concrete cracks.

1. Shrinkage During Drying

Shrinkage is the number one reason concrete cracks. After concrete is poured, the water inside begins to evaporate as it dries. As it loses moisture, the concrete slightly reduces in volume. Since the surface often dries faster than the deeper layers, tension builds up.

When that tension becomes too strong, the concrete cracks—usually appearing as thin, surface-level lines called “shrinkage cracks.”

How to prevent shrinkage cracks:

• Use the correct water-to-cement ratio. Too much water weakens concrete and increases shrinkage.

• Keep the surface moist while curing. Covering it with plastic or using a curing compound helps slow down drying.

• Add control joints to direct where cracks form so they don’t appear randomly.

2. Rapid Temperature Changes

Concrete expands when it’s hot and contracts when it’s cold. If temperature shifts happen too fast, internal stress can cause cracking. For instance, a hot sunny day followed by a cold night can make the surface contract faster than the interior, leading to thermal stress cracks.

How to prevent temperature cracks:

• Install expansion joints to give concrete room to move.

• Avoid pouring concrete during extreme temperature conditions.

• Use proper curing methods to maintain temperature balance.

3. Poor Subgrade Preparation

The subgrade—or the soil base under the concrete—plays a major role in its stability. If the base isn’t compacted evenly or contains soft spots, the concrete can sink or settle unevenly, leading to cracks.

How to prevent subgrade cracks:

• Ensure the soil base is compacted and level before pouring.

• Avoid using clay or loose soil as a base.

• Add a layer of crushed stone or gravel for better stability and drainage.

4. Overloading the Slab

Every concrete slab has a weight limit. Placing heavy vehicles or equipment on thin concrete can cause it to crack, especially if the load isn’t evenly distributed. Driveways and garage floors often face this issue when they’re not designed for high loads.

How to prevent overloading cracks:

• Design slabs with the right thickness for their purpose.

• Use reinforced steel or rebar in areas that will bear heavy loads.

• Avoid driving or parking oversized vehicles on residential concrete.

5. Improper Curing

Curing is the process of allowing concrete to retain enough moisture and strength after pouring. If concrete dries too fast or doesn’t cure evenly, the surface becomes weak and prone to cracking. Many homeowners skip proper curing, not realizing how crucial it is for long-term durability.

How to prevent curing cracks:

• Keep the concrete surface damp for at least seven days.

• Cover it with plastic sheets or use a curing compound to reduce evaporation.

• Avoid pouring during windy or very hot conditions to slow down drying.

6. Tree Roots and Ground Movement

If trees are planted too close to concrete surfaces, their growing roots can push the slab upward, causing visible cracks and uneven surfaces. Similarly, soil movement due to freezing, thawing, or poor drainage can also create stress under the slab.

How to prevent cracks from tree roots or ground shifts:

• Avoid planting large trees too close to driveways, patios, or sidewalks.

• Use root barriers to direct roots downward instead of outward.

• Make sure the area has proper drainage to prevent soil expansion.

7. Using Low-Quality Concrete Mix

Concrete strength depends on the quality of materials and the precision of the mix. Cheap or poorly mixed concrete often lacks the durability to withstand stress, which leads to early cracking.

How to prevent quality-related cracks:

• Use high-quality materials and follow the right mix ratio.

• Hire a professional concrete contractor for installation.

• Avoid adding extra water during mixing—it weakens the structure.

The Role of Control Joints in Preventing Cracks

Control joints are intentional lines or grooves cut into the surface of concrete. They act as a “planned” weak point, allowing cracks to form in straight lines instead of randomly across the surface.

Best practices for control joints:

• Place joints at regular intervals—typically every 8 to 12 feet for sidewalks and driveways.

• Cut joints about one-quarter the depth of the slab.

• Use a saw or hand tool to create clean, straight lines soon after finishing.

Properly placed control joints can greatly extend the life of your concrete and reduce unwanted cracking.

The Importance of Proper Drainage

Water is concrete’s worst enemy when it comes to cracking. Poor drainage allows water to pool under or around concrete, softening the soil and causing uneven support. Over time, this leads to settling cracks and surface damage.

Tips for preventing drainage-related cracks:

• Slope concrete surfaces away from your home or structure.

• Install drainage channels or gravel trenches to guide water away.

• Regularly inspect and clean gutters and downspouts.

Weather and Regional Factors

In areas like Bellevue, Nebraska, the weather can fluctuate dramatically between seasons. Freeze-thaw cycles are particularly damaging to concrete. When water seeps into small pores or cracks, it freezes and expands, putting pressure on the slab and widening the cracks.

To minimize freeze-thaw damage:

• Seal concrete surfaces with a high-quality sealer to block water.

• Apply sealant every one to two years for best results.

• Ensure proper slope and drainage to keep water from pooling.

How Bellevue Concrete Pros Can Help

At Bellevue Concrete Pros, we understand that every concrete project is unique. Our team focuses on long-term durability, from site preparation to finishing and sealing. Located at 4916 Robin Dr, Bellevue, NE 68157, we’ve helped countless homeowners and businesses prevent concrete cracking through proper installation and maintenance.

Our experienced concrete contractor team follows industry-best practices:

• We carefully assess soil conditions before pouring.

• We use high-quality concrete mixes tailored for Nebraska’s climate.

• We add expansion and control joints strategically.

• We handle curing with precision to ensure maximum strength.

• We recommend sealing and maintenance plans for lasting protection.

Working with professionals ensures that your concrete not only looks great but also lasts for years without cracks or damage.

How to Repair Existing Cracks

Even with the best precautions, small cracks can still appear over time. The key is to address them early before they expand or allow water to seep in.

Steps to repair small concrete cracks:

1. Clean the crack: Remove dirt, debris, and loose concrete.

2. Apply filler or sealant: Use a concrete crack filler or epoxy to seal the gap.

3. Smooth the surface: Use a trowel for a clean finish.

4. Seal the area: Apply a protective sealer to prevent future moisture damage.

For deeper or structural cracks, it’s best to call a professional. DIY repairs can work for minor issues, but significant cracks may require reinforcement or slab replacement.

Preventive Maintenance Tips

Regular maintenance can go a long way toward preventing cracks and extending the lifespan of your concrete. Here are some simple practices to follow:

• Clean regularly: Dirt and debris can trap moisture that weakens the surface.

• Seal annually: A quality sealer prevents moisture penetration.

• Avoid harsh chemicals: De-icing salts can damage concrete during winter.

• Watch for water pooling: Fix drainage issues early.

• Inspect frequently: Catch small cracks before they worsen.

By taking these steps, you can avoid costly repairs and keep your surfaces strong for decades.

Final Thoughts

Concrete is built to last, but like any material, it needs proper care. Cracks may be common, but they’re not inevitable. By understanding the main causes—shrinkage, temperature changes, poor base preparation, and improper curing—you can take control and prevent damage before it happens.

The secret lies in quality installation, smart design, and consistent maintenance. Whether it’s a new driveway, patio, or foundation, working with experienced professionals makes all the difference.

At Bellevue Concrete Pros, we’re committed to delivering concrete work that not only looks good but also stands the test of time. Our trusted concrete contractor team in Bellevue, Nebraska, is here to guide you through every step—from planning and pouring to protection and maintenance.

If you’re dealing with cracks or planning a new project, don’t wait until the problem grows. Contact Bellevue Concrete Pros at 4916 Robin Dr, Bellevue, NE 68157, and let’s build something that lasts.