Mid-Soil Polyurethane Foam Injection or Slab Piers. Method Decided by the Void.

Concrete that's settled in Nebraska or Iowa didn't fail because the concrete failed. The slab dropped because the soil under it moved. Loess hydroconsolidated the first time it got wet, clay backfill shrank during a dry August, downspout discharge eroded the sub-slab fill, or a freeze-thaw cycle worked the joint loose enough to admit water that then carried fines out from under the pour. In every case the fix is supporting the soil column, not pouring a new slab on the same failing soil.

Epp Foundation Repair's concrete repair crews have lifted residential and light commercial slabs across the four-state territory since 1994 using mid-soil polyurethane foam injection or slab piers, never mudjacking. Method chosen by the void profile, the slab load, and the soil under it. Most surface-only polyurethane installers inject at the soil-slab interface, fill the immediate void, and walk away. Epp injects mid-depth in the soil column when the void profile demands it. 12 to 36 inches below the slab, depending on the depth of the disturbed soil. So the foam doesn't just fill the air space, it consolidates the loose fill that caused the settlement in the first place. That's the difference between a slab that holds for 18 months and a slab that holds for 15 years.

The inspection answers three questions before pricing. How deep is the void. A void confined to the top 4 inches under the slab is a clean polyurethane foam job. A void that runs 12 to 36 inches deep with loose, hydroconsolidated loess in between is mid-soil foam, drilled in two depth stages. A void with a clay heave below it that's pushing up faster than the slab dropped is a different conversation entirely. What load the slab carries. A driveway with daily vehicle traffic and a 6-inch slab carries 4 to 8 times the load of a garden-path sidewalk and needs deeper support. Anything supporting structural building load. Garage stem walls, porch piers. Gets a slab pier conversation, not foam. What's under the void. Loess responds to foam injection because the foam consolidates the soil as it expands. Clay backfill that's already saturated doesn't compress further; foam either floats on it or runs sideways. Soil identification on the first visit decides whether the method is foam or piers; mudjacking is never on the table. ## Mid-Soil Polyurethane Foam Injection. The Default for Residential Work

Residential driveways, sidewalks, patios, pool decks, garage floors, and stoops in Nebraska and Iowa default to polyurethane foam because the soil profile is right for it. Two-part expanding polyurethane injected through 5/8-inch ports at 3 to 6 foot spacing expands 15 to 25 times its liquid volume in about 15 seconds, fills the void, consolidates the loose soil around the injection point, and cures hard enough to support the slab within 15 minutes. A typical 12-by-20 foot driveway section lifts in 30 to 90 minutes including patch and cleanup. The slab is back in service the same day. The mid-soil distinction matters in this territory. Loess soils across eastern Nebraska, western Iowa, and northern Kansas are particularly prone to hydroconsolidation. The silt-sized particles collapse the first time they get fully saturated, dropping the soil column by 6 to 18 percent of its depth. A surface-only foam injection that fills the immediate void leaves the loose loess below it untouched, and that loess collapses again the next time water reaches it. Mid-soil injection consolidates the loess as the foam expands, so the soil column gets denser and stays denser.

Mudjacking is the older method for lifting concrete: a cement, sand, and water slurry pumped through 1.5 to 2 inch ports. It is heavier than foam (around 100 pounds per cubic foot versus 4 to 6 pounds per cubic foot for foam), which is why some contractors still reach for it on very large voids where per-square-foot material cost is the deciding factor. Epp Foundation Repair does not perform mudjacking. The larger injection holes show more in the finished slab, the slurry needs a 24 to 48 hour cure before the slab can carry full load, and the added weight can push against a foundation wall where extra load isn't wanted. When a void is large enough that a heavier fill would help, Epp reaches for deeper mid-soil foam injection or, when the load is structural, slab piers, not mudjacking.

Settled garage stem walls, settled porch slabs that support roof load, settled basement floors that have dropped enough to crack the slab structurally. These are slab pier territory, not foam territory. Slab piers drive a 3-inch steel pier to bearing stratum or refusal (typically 10 to 30 feet deep in this territory), then engage the slab via a bracket. The slab is then lifted to grade on the pier system, which transfers load to deep bearing soil and bypasses the failing surface soil entirely. Right tool only when the load profile justifies it.

Inspection and void mapping. Slab measured for differential settlement with a rotary laser or level. Typical readings note the high point, the low point, and the lift target. Drilling test holes at the suspected low point confirms void depth and soil profile. Reference marks placed at the slab edges so lift can be monitored to a hundredth of an inch during injection. Drilling and port placement. 5/8-inch holes drilled through the slab at 3 to 6 foot spacing across the lift area. Spacing tightens to 2 to 3 feet near edges, corners, and isolated heavy load points. Standard residential driveway uses 6 to 15 ports total. Holes are clean, dry, and ready for injection within 30 minutes of starting. Foam injection with rotary laser monitoring. Two-part polyurethane injected through each port in turn, starting at the lowest point and working toward the highest. Rotary laser tracks lift in real time at the slab edge. The installer stops injecting at a given port the moment the laser reads target elevation, switches to the next port, and continues. The slab lifts in roughly the order it dropped, which prevents stress fractures in the concrete during lift. Cure and load test. Foam reaches 90 percent of final strength within 15 minutes. Slab is walked, driven on, and inspected for residual differential within an hour of finishing. Any settlement that didn't lift to target gets a second injection pass at the affected port. The slab is back in full service the same day. Patch and cleanup. 5/8-inch holes patched with hydraulic cement or color-matched concrete patch. Flush to the slab surface, set within 30 minutes. Slab cleaned, foam over-spray (if any) removed, and the homeowner walks the work with the installer before sign-off. Written warranty documents lift area, target elevation achieved, and materials used.

The honest part of this page. Lifting works when the slab is salvageable and the soil is fixable. Three scenarios where lifting is the wrong scope and pouring new concrete is the right scope. The slab is cracked beyond repair. A driveway section with 5 or more structural cracks, a sidewalk with crumbling edges, or a pool deck with surface spalling at 40 percent or more of the area is end-of-life concrete. Lifting it back to grade leaves the cracking, and the lifted-but-cracked slab fails again within 2 to 4 years. Replacing the section is the right scope at that point. Epp removes the failed concrete, corrects the ground that caused the failure, and pours new on properly prepared base. The slab is doing structural work it wasn't designed for. A residential garage slab supporting an addition's foundation load is wrong scope for foam; it needs a slab pier or a properly engineered foundation. The cosmetic damage is the actual complaint. Surface staining, paint failure, salt spalling. These are mason or decorative concrete contractor scope, not foundation contractor scope. Epp will say so on the inspection. Also wrong scope. Lifting a slab without addressing the drainage cause. If the void was created by a downspout discharging at the slab edge for ten years, lifting the slab without extending the downspout or re-grading the drainage is buying a 12 to 24 month repair instead of a 15 year repair. Epp identifies the drainage source and tells the homeowner what needs to change. Re-grading and downspout extension are landscape and gutter contractor scope respectively. Epp doesn't perform them but will quote the lift contingent on the source being addressed.

Eastern Nebraska and western Iowa loess across the Missouri River valley hydroconsolidates the first time it saturates. Typically when the original construction trenched, refilled, and pavement was poured before the soil had a chance to settle naturally. Settlement appears in years 3 to 8 after construction and concentrates at corners, edges, and downspout discharge points. Polyurethane foam is the right tool here because the mid-soil injection consolidates the remaining loose loess as it lifts. Kansas and Missouri expansive clay drives a different problem. Heave in wet seasons, shrinkage in dry seasons, with seasonal differential of 3/4 inch to 1-1/2 inches at the slab edge over a typical year. Foam works on the shrinkage settlement but doesn't address the heave; in expansive clay territory the inspection accounts for which direction the slab actually needs to be supported. Across the four-state region, 50-plus freeze-thaw cycles each winter open joints and admit water that erodes sub-slab fill over a 5 to 15 year horizon. By the time the homeowner notices the settlement, the void has been forming for a decade. Drainage source identification is part of every Epp inspection because lifting without addressing the drainage means lifting again.

Epp lifts, levels, and stabilizes salvageable slabs, and pours new concrete where a section has reached end of life. Three adjacent scopes Epp does not perform. Re-grading landscape or extending downspouts. Drainage source corrections are landscape contractor and gutter contractor scope respectively. Epp identifies the source and quotes the lift contingent on it being addressed. Cosmetic resurfacing, paint, or stain repair. Mason and decorative concrete contractor scope. Slab replacement to fix surface damage. If the homeowner's actual complaint is paint, staining, or scaling rather than settlement, Epp says so on the inspection and points to the right trade.

Concrete lifting and leveling from Epp Foundation Repair runs across these anchored components. Inspection and quote: no-cost on-site visit, Customized Repair Estimate within 48 hours, void mapping and method recommendation included. Customized Repair Estimate after on-site inspection reflects your scope. Epp Foundation Repair is BBB A+ accredited and a two-time BBB Integrity Award winner (2011 and 2016). Recognition tied directly to declining to quote a lift when the slab is end-of-life and pouring a new section instead, identifying drainage sources before quoting the work, and choosing method by void profile rather than by what's most profitable to install.