Concrete Void Filling
Restore support beneath concrete before settlement gets worse.
Metro Wide fills empty spaces beneath concrete with expanding polyurethane foam across the Kansas City metro. Void filling helps stabilize slabs affected by erosion, washout, or lost base material—with or without a significant lift.
Support Matters
A slab can look level and still have empty space underneath.
Concrete performs best when it has consistent support. Water moving along a slab edge, leaking downspouts, poor original compaction, and soil consolidation can leave a cavity beneath the surface. The slab may bridge that space temporarily, but normal loads can contribute to cracking or future settlement.
Polyfoam void filling places lightweight material directly beneath the slab. The foam expands through the unsupported area, hardens, and restores contact without adding the weight of a cement-based fill. When movement is also needed, the same process can be carefully continued to lift the concrete.
The Void-Filling Process
Place material below the concrete—not just around the edges.
- 01
Evaluate
We inspect the slab, visible washout, settlement pattern, water sources, and access to the unsupported area.
- 02
Inject
Polyfoam enters through a pattern of small ports and expands beneath the concrete to reach open space.
- 03
Monitor
We control placement to restore support and limit unintended movement, then patch the ports and clean up.
Void Filling FAQ
What to know about unsupported concrete.
Does void filling always lift the slab?
No. The primary goal may be to fill unsupported space while minimizing slab movement. The plan depends on current elevation and the result the property needs.
What causes concrete voids?
Common causes include erosion, poor compaction, plumbing or drainage leaks, shrinking or consolidating soil, and water entering along joints or slab edges.
Is fixing the water source part of the service?
Polyfoam can fill the void, but gutters, grading, drains, or plumbing may need separate correction so the conditions that caused the washout do not continue.
Where We Fill Voids
Support for many common concrete slabs.
We evaluate voids beneath driveways, sidewalks, patios, garage floors, steps, landings, and other accessible concrete. Site conditions, slab construction, and the source of the lost support determine whether polyfoam is the right approach.
If the slab has already moved, visit our pages for driveway leveling, patio leveling, or garage floor leveling.
Void-Filling Estimate
Show us the slab edge, washout, and nearby drainage.
Photos of the surrounding grade and full slab help us see what may be contributing to the lost support.
