What Is Void Filling?
When the soil beneath your concrete shifts, settles, or washes out, it leaves empty spaces called voids. These gaps weak slab support and lead to cracking, sinking, or even full collapse. Void filling injects high-density polyurethane foam into those empty areas, restoring stability and stopping further movement — fast.
Whether you’re dealing with a driveway, warehouse, roadway, or stamped concrete patio, filling voids now can prevent major repairs later.
Why Do Voids Form Under Concrete?
Voids don’t appear overnight — they form slowly beneath the surface due to environmental and structural factors. Once a void forms, washing away the soil below, the slab above loses support and begins to settle or crack.
Common causes include:
Water erosion from poor drainage, placement of downspouts, leaking pipes, or runoff
Poor soil compaction during construction
Decaying buried organic material like tree roots or debris
Freeze-thaw cycles that push and pull the soil beneath the slab
Left untreated, these hidden voids lead to further collapse and cracking of your concrete.
Looking for more commercial concrete solutions? RaiseRite also offers expert services for warehouse floors, factory floors, interior slab leveling, loading docks & ramps, strip malls, airports, schools, municipal concrete repair, and more. Explore our full commercial services to see how we can help.
Why Wisconsin Trusts RaiseRite
- 50+ Years of Experience (Est. 1974)
- 100,000+ Projects Completed
- 5-Year Warranty
- Family-Owned & Operated (3 Generations)
- Fast, Same-Day Results
- Renewable Foam (40% recycled content)
- Virtual Estimates Available – Just snap, upload, and get a quote
We’re not a franchise. We’re your neighbors. And we care about doing the job right.
What Are the Signs You Need Void Filling?
Most voids form quietly under the surface — but there are warning signs to look for:
- Hollow sounds when walking or tapping on a slab
- Cracks forming suddenly in previously solid concrete
- Water pooling where it used to drain
- Slabs that feel unstable or bounce under weight
- Visible separation between concrete and surrounding structures
- Known drainage or soil problems near the slab
Spotting these signs early can prevent bigger structural issues later.
Our Fix: Quick, Clean Concrete Leveling with Foam
Step 1) Injection holes are strategically drilled around the areas where the concrete is sunken and requires lifting.
Step 2) Once everything is prepped, and the hose and material are in place, the polyurethane foam is injected through the holes. It expands to fill the space underneath the concrete slab, using the slab itself to drive the foam into the crevices, thereby lifting the concrete back to its original position.
Step 3) Once the concrete is stabilized and lifted to the proper position, the injection holes are filled with new cement, allowing you to use your surface immediately.
Polyurethane concrete raising uses a foam material that is injected under the slab. When the components of the material are mixed, a reaction causes the material to expand. This expanded foam fill any voids beneath the slab and raises the concrete. This material will never lose density, is permanent and weighs only about 2 pounds per cubic foot.
Frequently Asked Questions
You might hear a hollow sound when tapping or walking across the slab. Cracking, sinking, or bouncing concrete can also indicate hidden voids.
Yes — if a void becomes large enough, and the slab has no support underneath, it can eventually crack or cave in under the weight.
Yes — the polyurethane foam we use is permanent, water-resistant, and won’t shrink or break down over time.
No — we provide void filling for both residential and commercial properties.
Yes — if the slab is still level but unsupported, we can inject foam underneath it to stabilize without changing the height.
The foam sets in minutes. In most cases, the area is ready for use the immediately.
Still have questions? Check out our full FAQ page for more answers.
What Our Customers Have to Say
Why Choose RaiseRite
Serving Wisconsin since 1974
Over 50 years of experience lifting and leveling concrete across Wisconsin and beyond.
100,000+ Jobs Completed
We’ve helped more families and businesses fix their concrete than anyone else in the state.
$20M+ Saved vs. Replacement
Our concrete lifting service has saved customers millions by avoiding tear-outs and full replacements.
5-Year Warranty
We stand behind every concrete leveling job with a real warranty — no fine print, just peace of mind.
Family-Owned & Operated
Three generations working together to deliver honest work and long-lasting results.
We Train the Industry
Contractors across the country come to us to learn — when you hire RaiseRite, you get the team that sets the standard.
We Manufacture the Tools
We build the same polyurethane foam and equipment used by top pros across the industry.
Residential, Commercial & Municipal Work
From homes to highways, we handle projects of all sizes — safely and professionally.
Proudly Based in Wisconsin
We’re a local team using American-made tools and doing the job right, every time.
