Concrete Cracks & Gaps2026-11-05T11:06:58-06:00

Concrete Cracks & Gaps in Sioux Falls, SD: What They Mean & How to Fix Them

Cracking and separation in driveways, sidewalks, patios, porches and other concrete surfaces is common, but it shouldn't be ignored. While some cracks are just a byproduct of normal concrete curing, others point to soil beneath the slab that has settled, shifted, or eroded. As that support disappears, the concrete can crack, separate or become uneven. In a free inspection, Blackburn Foundation Repair identifies what's driving the damage and recommends the right solution.

Symptoms

Warning Signs Your Cracks Need a Professional

Concrete cracks range widely, from small hairline cracks to growing gaps between slabs. Although some are simply a product of normal aging, the warning signs below often indicate the concrete is still moving because the supporting soil has shifted or settled.

Causes

Why Do Concrete Cracks & Gaps Happen?

Concrete naturally develops small cracks over time, but not all cracks have the same cause. Some come from the normal curing process or years of exposure to the elements. Others form because the soil beneath the slab has shifted, settled or eroded, allowing the concrete to move. Pinpointing the cause of the damage is the key to choosing the right repair. While small surface cracks may be harmless, widening cracks, growing gaps or uneven concrete often point to underlying problems that should be professionally evaluated.

  • Soils That Expand and Shrink

    Changes in soil moisture can cause the ground beneath concrete to expand during wet periods and shrink during dry conditions. As the soil moves, the concrete loses consistent support, increasing the likelihood of cracks, gaps and settlement.

    Many regions contain clay-rich soils that naturally expand when they absorb moisture and contract as they dry. This constant cycle places stress on concrete slabs, causing them to shift over time. Even minor soil movement can lead to widening cracks or uneven surfaces when it goes unaddressed.

  • Loose or Poorly Compacted Soil

    Concrete performs best with properly compacted soil underneath it. If the ground wasn’t adequately prepared before the slab was poured, it may settle over time, leaving sections of concrete without the support they need.

    Poor compaction shows up often beneath driveways, sidewalks, patios and porches, especially where fill soil was added during construction. As that loose soil compresses, the slab can crack, sink or separate from neighboring concrete.

  • Washout and Erosion Beneath Slabs

    Soil erosion happens when water slowly carries away the soil supporting a concrete slab. As that support disappears, the concrete may settle, crack or separate from nearby slabs.

    Inadequate drainage, leaking downspouts, heavy rainfall or water traveling under the slab can lead to soil erosion. As these voids grow, the concrete begins to settle into the empty space, leading to cracks, uneven slabs and widening gaps.

  • Freeze-Thaw Cycles

    Water that seeps into cracks or the surrounding soil expands when it freezes and contracts as it thaws, putting additional stress on the concrete.

    Ongoing freeze-thaw cycles can cause existing cracks to spread and add to soil movement under the slab. Over time, this seasonal expansion and contraction can accelerate settlement and make concrete damage more noticeable.

  • Heavy Loads on Concrete

    Frequent heavy loads can push concrete beyond what it was designed to handle, particularly when the soil beneath it has already weakened.

    Driveways that see large trucks, RVs or commercial vehicles often crack or settle sooner than lightly used surfaces. If unstable soil sits beneath the slab, the additional weight can hasten movement and worsen existing damage.

  • Natural Concrete Curing and Aging

    Hairline cracks are a typical part of concrete curing and aging. That said, cracks that continue to widen, open into gaps or turn uneven often signal movement beneath the slab rather than normal wear.

    Not every crack means there’s a structural problem. However, widening cracks, growing gaps or uneven concrete often suggest the slab is moving rather than simply aging. A professional inspection can determine whether the damage is cosmetic or caused by underlying settlement.

What Happens When Concrete Cracks Are Ignored

  • Stage 1

    Water Finds Its Way In

    Small cracks may appear cosmetic at first; however, they give water a path to the soil beneath the slab. As moisture washes away supporting soil or causes it to expand and contract, the concrete can continue to shift.

  • Stage 2

    Uneven Concrete & Trip Hazards Develop

    As the supporting soil keeps settling or washing away, sections of concrete can become uneven or pull apart from one another. What began as a simple crack can turn into a trip hazard, collect standing water and make driveways, sidewalks, patios or porches harder to use safely.

  • Stage 3

    Repairs Become More Extensive

    Overlooking ongoing slab movement can cause larger cracks, further settlement and more expensive repairs. Catching the problem early often allows the concrete to be stabilized and restored before more extensive damage—or even replacement—becomes necessary.

The Way Blackburn Foundation Repair Restores Cracked Concrete

Two concrete cracks seldom require the same repair. During a free inspection, Blackburn Foundation Repair identifies what's causing the damage before recommending a solution. If the slab has settled, PolyLevel® is first used to lift and stabilize the concrete. Once the slab is fully supported, NexusPro® seals the cracks and joints to help prevent water intrusion and protect the repair.

  • NexusPro® Joint & Crack Sealant

    NexusPro® seals concrete cracks and joints to help stop water from reaching the soil beneath the slab. Unlike many over-the-counter fillers, it stays flexible as concrete expands and contracts with the seasons for a longer-lasting seal.

  • PolyLevel®

    If the cracks came from slab settlement, PolyLevel® lifts and stabilizes the concrete before it’s sealed. Addressing the underlying cause helps create a longer-lasting repair.

How It Works

Blackburn Foundation Repair's Process for Repairing Concrete

Benefits

Why Homeowners Trust Blackburn Foundation Repair

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What To Expect

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Frequently Asked Questions

Is DIY concrete crack filler a permanent fix? 2026-10-02T11:53:11-05:00

Hardware store crack fillers can improve the appearance of concrete and help keep water out, but they don’t address the underlying cause of many cracks. When the slab is settling because the soil beneath it has shifted or washed away, the concrete can continue moving even after the crack is filled. A professional inspection can determine whether sealing alone is enough or if the slab should first be stabilized with PolyLevel® before the crack is repaired. 

How much does concrete crack repair cost? 2026-10-02T11:52:42-05:00

The price depends on a few factors, including slab size, the extent of settlement, the number of cracks and the repairs needed. Because every property is different, the best way to receive an accurate estimate is through a free professional inspection. Blackburn Foundation Repair will inspect the condition of your concrete and recommend the most effective repair for your situation. 

What’s the lifespan of a concrete crack repair? 2026-10-02T11:52:13-05:00

Long-term results depend on addressing the underlying cause of the damage. When settled concrete is stabilized with PolyLevel® and the cracks are sealed with NexusPro®, the repair is designed for lasting performance. At your inspection, Blackburn Foundation Repair will recommend the best solution for your property’s specific conditions. 

What does PolyLevel® do for cracked concrete? 2026-10-02T11:51:46-05:00

PolyLevel® is a high-density polyurethane foam placed beneath settled concrete through small, penny-sized injection holes. As the foam expands, it fills voids in the soil and gently lifts the slab back toward its original position while providing long-term support. If settlement caused the cracks, stabilizing the slab helps address the underlying problem before the cracks are sealed. 

Will concrete cracks continue to get worse? 2026-10-02T11:51:19-05:00

They can. Once cracks let water reach the soil beneath the slab, erosion and settlement can continue, pushing the concrete to shift further. Over time, small cracks can grow larger, gaps may widen and uneven concrete can create trip hazards. Handling the underlying cause early can help stop additional damage. 

When should I be concerned about cracks in my driveway or sidewalk? 2026-10-02T11:50:53-05:00

Thin hairline cracks are often just a normal part of concrete aging. However, when cracks continue to widen, gaps appear between slabs, one section becomes higher than the next or the concrete starts sinking, it’s a good idea to schedule an inspection. Signs like these often mean soil movement is ongoing and can worsen if left untreated. 

Can cracked concrete be repaired instead of replaced? 2026-10-02T11:50:26-05:00

Yes. Many cracked concrete slabs can be repaired without the cost and disruption of replacement. If the slab is structurally sound, it can often be lifted and stabilized with PolyLevel®, then sealed with NexusPro® to help reduce water intrusion and protect the repair. Full replacement is typically required only when the concrete is too damaged to restore. 

Do concrete cracks mean I have foundation problems? 2026-10-02T11:49:41-05:00

Usually not. The majority of cracks in driveways, sidewalks, patios and other exterior concrete slabs are caused by soil movement beneath the slab—not foundation damage. That said, if you’re seeing settlement across your property or cracks in both your concrete and your foundation, scheduling a professional inspection to identify the cause is a good idea. 

What causes cracks and gaps in concrete? 2026-10-02T11:49:10-05:00

Concrete can crack for a number of reasons, including normal curing, age, heavy loads and seasonal weather changes. That said, many widening cracks and gaps appear because the soil under the concrete settles, shifts or erodes over time. Once the slab loses support, it can crack, separate or settle unevenly. A professional inspection can determine whether the damage is purely cosmetic or the result of underlying soil movement. 

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