Hidden Voids Beneath Concrete Create Serious Structural Risks
Voids beneath concrete slabs are a common but often unseen problem. As soil washes out or compacts over time, empty spaces form beneath concrete, leaving it unsupported. These voids can lead to sudden settling, cracking, and even slab failure if left unaddressed.
Void filling restores support beneath the concrete—stabilizing the slab and helping prevent future settlement without removing or replacing the concrete.
The Problem: Voids Beneath Concrete Slabs
Voids form when soil beneath concrete is displaced due to water erosion, poor compaction, leaking utilities, or natural soil movement. Once support is lost, concrete slabs are left spanning empty space.
Voids beneath concrete can:
- Cause slabs to sink or crack unexpectedly
- Create trip hazards and uneven surfaces
- Lead to hollow-sounding concrete
- Allow continued soil erosion and washout
- Increase the risk of slab failure over time
Because voids aren’t always visible, the damage can worsen before it’s noticed.
Common Signs You May Have Voids Under Concrete
Not sure if void filling is needed? Common warning signs include:
- Hollow sounds when tapping on concrete
- Cracks forming without obvious surface damage
- Settling or sinking slabs
- Gaps appearing near slab edges or foundations
- Water washing soil away from beneath concrete
If the concrete itself is still intact, void filling is often the right solution.
Why This Problem Shouldn’t Be Ignored
Voids beneath concrete do not fix themselves. Over time, unsupported slabs are more likely to crack, settle, or fail—often suddenly. What starts as a hidden issue can quickly become a costly repair or safety concern.
Addressing voids early helps stabilize the slab, stop ongoing erosion, and prevent more extensive damage.
The Best Fix: Void Filling Instead of Replacement
Many property owners are told sinking or hollow concrete must be replaced—but that’s often unnecessary.
Void filling restores support beneath the slab instead of removing it. This approach:
- Addresses the root cause beneath the concrete
- Costs less than full replacement in many cases
- Avoids demolition and major disruption
- Preserves the existing slab
Replacing concrete without filling underlying voids often leads to repeat settlement. Stabilizing the soil below is the key to long-term performance.
Our Fix: Mudjacking Concrete Leveling
Restoration Concrete LLC levels concrete using mudjacking, a proven method that restores support beneath settled slabs. A cement-based slurry is pumped under the concrete to fill voids, stabilize the base, and lift the surface back toward a safe, level position—without tearing out or replacing the concrete.
- Small access holes are drilled through the concrete
- A cement-based slurry is pumped beneath the slab
- The concrete is carefully lifted and stabilized
- Access holes are patched after lifting
Most concrete leveling projects are completed in a short timeframe, and once the material has properly set, many surfaces can be returned to use the same day.
The Benefits of Void Filling
- Fast repairs with little disruption
- Completed within hours with minimal downtime
- Lifts and supports the concrete you already have
- Adds long-term stability beneath the slab
- Can cost up to half as much as replacing the concrete
Why Property Owners Choose Restoration Concrete LLC
Choosing the right contractor matters when dealing with hidden structural issues. Property owners choose Restoration Concrete LLC because we offer:
- Clear evaluations and honest recommendations
- Proven mudjacking void filling solutions
- Clean, controlled application with minimal disruption
Long-term stabilization—not temporary fixes- A 5-year warranty on applicable void filling services
Long-term stabilization—not temporary fixesWe focus on fixing problems at their source—below the concrete—so issues don’t return.
Reach out to Restoration Concrete LLC to discuss your void filling needs and find out if soil stabilization is the right solution for your property.
Void Filling & Soil Stabilization FAQs
What is void filling?
Void filling is a process used to stabilize empty spaces beneath concrete slabs. These voids form when soil erodes, washes out, or settles, leaving gaps under the concrete. Filling those spaces restores support and helps prevent sinking, cracking, or further movement.
What causes voids to form under concrete?
Voids typically form due to water movement beneath the slab. Poor drainage, leaking pipes, downspouts discharging near concrete, freeze–thaw cycles, and natural soil erosion can all wash soil away over time, leaving unsupported areas beneath the concrete.
Why are voids under concrete a problem?
Voids reduce support beneath the slab, which increases the risk of sinking, cracking, or sudden failure. Even if the concrete looks fine on the surface, unsupported areas can lead to uneven slabs, trip hazards, drainage issues, and higher repair costs if left untreated.
How does void filling work?
Void filling is performed by pumping a cement-based slurry beneath the concrete to fill empty spaces and restore lost support. The material flows into voids created by soil settlement or washout, helping stabilize the area and reduce future movement beneath the slab.
This process supports long-term concrete stabilization by addressing the underlying support issue below the surface.
You can learn more about the injection method on our
Concrete Leveling Process page.
Is void filling the same as concrete leveling?
Not exactly. Void filling focuses on stabilizing empty spaces beneath the slab, while concrete leveling lifts and repositions sunken concrete. In many cases, void filling is performed alongside concrete leveling to both stabilize and lift the slab when needed.
When is void filling recommended?
Void filling is often recommended when hollow sounds are detected beneath concrete, when early settlement is noticed, or when preventing further sinking is the goal. It’s commonly used as a preventative solution before major movement occurs.
Can void filling be done without lifting the concrete?
Yes. In some situations, the goal is to stabilize the slab without lifting it. Void filling can be used to fill empty spaces and support the slab at its current elevation when lifting is not required.
What types of concrete benefit from void filling?
Void filling is commonly used under driveways, sidewalks, walkways, patios, garage floors, warehouse floors, parking lots, and other residential or commercial concrete slabs.
How long does void filling take?
Most void filling projects are completed in just a few hours. The exact time depends on the size of the slab and the extent of the voids beneath it.
When can the concrete be used after void filling?
Once the cement-based material has properly set, many surfaces can be returned to use the same day, helping minimize downtime for homes and businesses.
Will the mudjacking material wash out or break down over time?
Mudjacking uses a cement-based material that hardens into a solid, load-bearing support beneath the concrete. When properly installed, it is designed to remain stable under the slab and resist normal soil movement.
As with any concrete repair, long-term performance depends on factors like drainage, soil conditions, and water management around the slab. Addressing water issues helps ensure the repair lasts.
Are the injection holes noticeable after void filling?
The access holes are small and are patched after the work is completed. While they may be visible up close, they are far less noticeable than uneven slabs or cracked concrete.
How long does void filling last?
When installed correctly and paired with proper drainage, void filling provides long-lasting support. Our work is backed by a 5-year warranty, offering added confidence in the repair.
How do I know if void filling is the right solution?
If concrete sounds hollow, shows early signs of settlement, or has known drainage issues nearby, void filling may be the right fix. Evaluating the cause of soil loss and the condition of the slab helps determine whether stabilization is needed.
Is void filling more affordable than replacing concrete?
In most cases, yes. Void filling typically costs less than replacement because it avoids demolition, hauling, and extended downtime—while helping prevent more serious concrete damage.
Areas We Serve
Restoration Concrete LLC proudly serves homeowners, businesses, and property managers throughout Northeast Indiana and nearby Ohio communities. Based in Harlan, we provide concrete leveling and lifting services within approximately 60 miles, allowing us to respond quickly while delivering consistent, high-quality work.
Our Primary Service Area Includes:
- Fort Wayne
- Auburn
- Columbia City
- Warsaw
- Wabash
- North Manchester
- Huntington
- Kendallville
- Albion
- Avilla
- Ligonier
- LaGrange
- Decatur
- Angola
- Van Wert
- New Haven
- Huntertown
- Leo-Cedarville
- Grabill
- Woodburn
- Harlan
- Bluffton
- Roanoke
- Butler
- Defiance
- Hicksville
- Garrett
- Monroeville
- Ossian
- Churubusco
We also serve surrounding towns and communities throughout Allen County and DeKalb County.
If you’re unsure whether your property falls within our service area, feel free to reach out. We’re always happy to let you know if concrete leveling is available for your location.
About Us
Restoration Concrete LLC is a locally owned concrete lifting and leveling company serving Fort Wayne, IN and surrounding communities. We help homeowners and businesses fix uneven, sinking concrete that creates trip hazards, drainage problems, and safety concerns—without tearing out and replacing slabs.
Using proven mudjacking (slabjacking) methods, we raise and stabilize concrete for 50–75% less than replacement. Most projects take just a couple of hours, and surfaces are often ready for use immediately. From driveways and sidewalks to patios, garage floors, and warehouse slabs, we focus on fast, clean solutions that work. Contact us today to schedule your free quote and get your concrete safely level again.
Address: 10428 Thimlar Rd, Harlan, IN 46743
