Your driveway did not sink overnight, and it will not stop sinking on its own. Sunken slab repair covers everything from diagnosing why your concrete settled to lifting it back to level with mudjacking or polyurethane foam. For Des Moines homeowners, the cause almost always traces back to what is happening in the soil underneath: expansive clay, washed-out fill, or poor compaction from the original build. This guide explains the root causes behind sinking concrete, walks you through the repair process step by step, and shows you what to expect on cost, timeline, and insurance. By the end, you will know why your slab dropped and what the right fix looks like.

What You'll Find in This Guide

Prefer to have a pro handle it? Sunken slab repair is one call away.

Why Slabs Sink: The Soil Story Under Your Concrete

Concrete does not sink because the slab failed. It sinks because the ground beneath it moved. In central Iowa, three soil problems cause almost every sunken driveway, patio, and walkway we see.

Expansive Clay and the Freeze-Thaw Cycle

Much of the Des Moines metro sits on expansive clay soil. This clay swells when it absorbs water and shrinks when it dries out. As a result, the ground under your slab rises and falls with the seasons. Iowa winters make it worse. Water in the soil freezes, expands, and heaves the slab upward. Then spring thaw arrives, the soil collapses back down, and the slab settles into the gap. Repeat that cycle for ten or fifteen years, and you get a driveway that has dropped two inches at the garage apron. You can explore the soil composition on your own lot through the USDA's Web Soil Survey, which maps clay content across Polk, Dallas, and Warren counties.

Poor Compaction in Newer Subdivisions

If your home sits in a subdivision built in the last twenty years, poorly compacted fill soil is the most likely culprit. Builders grade lots by moving large volumes of soil, and that fill needs proper compaction before anyone pours concrete over it. In practice, crews often rush this step. Loose fill can take five to ten years to fully settle under its own weight. That is why so many homeowners in newer Des Moines developments notice sinking slabs right around the time their builder warranty expires. The concrete itself is fine. The ground it was poured on simply was not ready to hold it.

Erosion and Drainage Problems

Water is the third villain, and often the sneakiest. A downspout dumping next to your patio, a negative grade sloping toward the house, or a leaking irrigation line can all wash soil out from under a slab. Over time, this erosion creates a void under the concrete slab. The slab bridges that empty space for a while. Eventually, it cracks and drops into the gap. If one corner of your slab sank faster than the rest, look for a water source nearby. You will usually find one.

How Sunken Slab Repair Actually Works

Once you understand why your slab sank, the repair path becomes much clearer. However, most homeowners have never hired a concrete leveling company before. Here is what the process looks like from first call to finished slab.

Diagnosis Comes Before Any Quote

A legitimate repair starts with an on-site inspection, not a phone estimate. We measure how far the slab has dropped, check whether the concrete is sound enough to lift, and look for the cause. That last part matters. Lifting a slab without fixing the drainage problem that sank it just schedules the same repair for five years from now. Beyond that, the inspection determines which lifting method fits your situation. If the quotes you receive read like a foreign language, our plain-English glossary of sunken slab repair terms translates the jargon before you sign anything.

Mudjacking vs. Polyurethane Foam

Both methods work the same basic way. The crew drills small holes through the slab, pumps material underneath, and the pressure lifts the concrete back to level. The difference is the material. Mudjacking uses a cement-based slurry, which is heavier, cheaper, and well suited to large slabs like driveways. Polyurethane foam is lighter, cures in minutes rather than days, and needs smaller drill holes. Foam costs more per job, but it puts less weight on already-weak soil. Neither method is universally better. The right choice depends on your slab's condition, the load it carries, and how fast you need it back in service. We walk through exactly how we make that call on our sunken slab repair service page for Des Moines.

What the Day of Repair Looks Like

Most residential lifts finish in a few hours. The crew drills the injection holes, lifts the slab in small increments while checking level, then patches the holes with matching concrete. With foam, you can drive on the slab the same day. With mudjacking, plan on keeping vehicles off for 24 to 48 hours while the slurry cures. Either way, you avoid the demolition, hauling, forming, and multi-day cure that full replacement requires. That said, some slabs are too far gone to lift. Severely crumbled or shattered concrete needs replacement, and an honest contractor will tell you that upfront.

Cost, Insurance Claims, and When to Act

The two questions every homeowner asks first: what will this cost, and will insurance cover it? Both deserve straight answers.

What Sunken Slab Repair Costs

Leveling almost always beats replacement on price. According to HomeAdvisor, mudjacking runs $3 to $6 per square foot and costs 25% to 50% less than replacing the slab entirely. For a typical project, Angi puts the national average between $661 and $1,871, with most homeowners paying around $1,232. Small jobs still carry a floor, though. Angi notes that minimum charges of around $500 apply even when the affected area is under 100 square feet. Your actual price depends on slab size, drop depth, and method. For a full breakdown of every cost driver, read our sunken slab repair cost guide. One more number worth knowing: Angi reports that concrete leveling projects can recoup 70% to 90% of their cost in added home value. Few home repairs return that much.

The Insurance Question

Here is the hard truth. Standard homeowner's insurance almost never covers slab settling caused by soil movement, erosion, or poor compaction. Insurers classify gradual settling as a maintenance issue, and most policies exclude earth movement outright. However, there are exceptions. If a sudden covered event caused the sinking, such as a burst plumbing line washing out the soil under your slab, the resulting damage may qualify for a claim. Before you file, document everything. Take dated photos, get a written diagnosis identifying the cause, and read your policy's earth movement exclusion carefully. Filing a claim that gets denied still goes on your record. With this in mind, get the diagnosis first and talk to your agent second.

Why Waiting Makes It Worse

Sunken concrete never improves on its own. Each freeze-thaw cycle widens cracks and lets more water reach the soil below. As a result, a half-inch drop this year becomes a two-inch drop in three years. The repair cost grows with it, because deeper voids need more material and badly cracked slabs may lose the option to lift at all. Trip hazards add liability risk on walkways and steps. If your slab has visibly dropped, this fall is better than next spring, and this spring is better than after another winter.

Ready to Get Started?

If your driveway, patio, or walkway has sunk, the fix is usually faster and cheaper than you expect. Des Moines Concrete Leveling Pros will inspect your slab, explain the cause in plain language, and tell you honestly whether mudjacking, foam, or replacement is the right call. Reach out today for a no-pressure assessment from a local crew that knows central Iowa soil.