An empty space can open beneath a road, a building, or a pipeline without any warning on the surface. Left alone, it grows, and the ground above it eventually gives way.
Solutions for this Service
Sinkholes
Void Formation
Soil Loss
Abandoned Utility Voids
Related Industries
Transportation
Municipal Infrastructure
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An empty space can open beneath a road, a building, or a pipeline without any warning on the surface. Left alone, it grows, and the ground above it eventually gives way. Void Filling injects an expanding polymer directly into the gap to fill it and support the soil above. Engineers, facility owners, and public agencies use it when a structure needs the ground beneath it made solid again, without digging it up.
Underground voids don't stay hidden. Here's what they lead to if they're not filled.
Sinkholes forming under roads, parking lots, or building slabs with little or no warning
Pavement dips, cracks, or sudden collapse over eroded or washed-out soil
Structural settlement where a foundation loses the support it was built on
Ongoing soil loss around aging pipes, culverts, and utility lines that keeps the problem growing
A void usually shows itself in small ways before it becomes an emergency. Watch for these.
A dip or depression in pavement that wasn't there before
Cracks radiating outward from one point on a slab or roadway
A hollow sound when the ground is tapped or driven over
Water pooling in one spot after rain, even on flat ground
A pipe or culvert joint that has visibly separated
Soil settling or disappearing near a drain, manhole, or utility line
Why agencies and engineers choose Void Filling over excavation.
Reaches voids at depth without digging them open. URETEK 486 Star® polymer is injected through holes as small as 5/8 inch, so the void gets filled without exposing the pipe, slab, or roadway above it.
Reduces the safety risk of open excavation. Trenchless injection means crews aren't working inside an open pit next to live traffic or unstable soil, which is the main safety hazard with traditional dig-and-replace repair.
Keeps the road, lot, or facility open. Because there's no excavation, the surface above stays in use during and after the work. This matters most on active roadways, airport aprons, and public rights-of-way that can't be closed for weeks.
Works overnight or on short notice. Crews can mobilize nights, weekends, or holidays in a self-contained unit, and injected polymer cures to 99% of its strength in minutes, not days.
The polymer expands to fill irregular voids completely, not just the space it's poured into. URETEK 486 Star® is a two-part polyurethane that expands up to 20 times its original volume once injected, so it pushes into the full shape of the void, including narrow channels a rigid fill material would miss.
Void Filling is the right call when there's an identified, empty or eroded space beneath a structure, road, or utility, and the goal is to fill that space and stop further soil loss. It's built for sinkholes, washed-out soil pockets around culverts and pipes, and voids left behind by old utility lines or decayed underground structures. It's not the right tool for soil that's simply weak but not hollow, or for a foundation that's already settled unevenly; for those, Soil Stabilization, Compaction Grouting, or Settlement Control is the better starting point.
Void Filling is often paired with Curtain Grouting when water intrusion caused the void in the first place, since sealing the water path stops the void from reforming after it's filled.
1
Evaluate
A URETEK project manager studies the void, not a salesperson, and reviews soil conditions on site before proposing a plan.
2
Deploy
Crews mobilize on the schedule the site needs, including nights, weekends, or holidays, in a self-contained unit.
3
Drill
Small holes, as narrow as 5/8 inch, are drilled in a pattern designed around the void's size and location.
4
Inject
URETEK 486 Star® polymer is injected into the void, expanding up to 20 times its original volume to fill the space completely.
5
Clean Up
There's no excavation to backfill and no trench to restore, so cleanup is minimal.
6
Validate
The client confirms the void is filled and the surface is stable before the crew leaves.
URETEK has filled underground voids for state departments of transportation and municipal clients nationwide, from highway sinkholes to bridge abutments.
URETEK 486 Star® cures to 99% of its final strength within minutes of injection, so it isn't a slow-setting material that shifts as it hardens. Public Works and Federal projects carry a two-year warranty, and every job is evaluated by a project manager first, not sold on a standard package regardless of what's actually under the ground.
The injection pattern is designed around the void's mapped size and location before drilling starts, and the polymer's expansion, up to 20 times its original volume, pushes it into the full shape of the space rather than settling in the center. The final step in the process is validation, where fill coverage is confirmed on site before the job is closed out.
In most cases, yes. On the San Jose bridge abutment project, filling the void this way cost less than a third of what full excavation and replacement would have run, mainly because there's no digging, no trench restoration, and no lane or site closure to pay for.
Yes. Because the polymer is injected through small holes instead of an open excavation, the surface above stays usable during the work. On the I-95 Rhode Island project, the repair was completed with no lane closures during high-traffic periods.
Crews can mobilize on short notice, including nights, weekends, and holidays, which is why URETEK is often called in for emergency sinkhole repairs on active highways, like the I-15 Utah sinkhole that shut down a state highway until it was filled.
Get a void assessed and filled before it becomes a collapse. URETEK crews respond fast, including emergencies.
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