A long crack running through the floor of a high-traffic medical supply warehouse in Memphis signaled a problem below the slab. With forklift traffic and heavy racked storage running daily, and the building staying operational throughout, the team needed to know what was happening underground before choosing a repair method.

Initial Assessment

Ground penetrating radar (GPR) scans identified voided areas roughly 10 to 20 inches below the slab, confirming the crack wasn't just surface wear. Soil had shifted or washed out beneath the concrete, leaving sections of the slab unsupported. Removing and replacing the affected concrete would have meant disrupting warehouse traffic, adding downtime, and extending the repair window well beyond what the facility could accommodate on a live operating schedule.

Proposed Solution

Mid-South Concrete Lifting selected AP Lift 475, a two-component, high-density structural polyurethane, to fill the voids beneath the slab without removing any concrete. The product's expansion behavior, reacting to fill irregular void shapes rather than settling flat, made it a fit for reaching uneven cavities and re-establishing contact with the underside of the slab. This approach kept the facility in service throughout the repair.

Procedures

• Located the crack and mapped suspected void zones
• Staggered injection points along both sides of the crack
• Covered approximately 450 linear feet
• Drilled injection holes through the slab
• Injected polyurethane to fill the voids
• Monitored slab response throughout injection

Results

• Completed the project in two days
• Minimized disruption to warehouse operations
• Filled voids without slab replacement
• Improved support beneath forklift traffic areas

What This Means for Similar Projects

Void fill worked here because the slab itself was in good enough condition to stay in service and the underlying issue was a void rather than a structural failure in the concrete. That won't hold true on every job. Deteriorated or delaminated concrete, active water intrusion, poor bearing soil, or a drainage source that's still feeding the erosion can all change which repair approach actually makes sense. GPR or another subsurface assessment is generally the step that determines that, not the crack itself.

As a general point of reference, industrywide, full removal and replacement of an industrial slab tends to run well above void fill injection on a cost basis once demolition, disposal, and downtime are factored in. That gap varies by region, access, traffic control requirements, and the extent of the voiding, so it's not a number to lean on without a site-specific estimate.

The Role of a Technical Partner

This job was completed by Mid-South Concrete Lifting, a contractor experienced in polyurethane slab lifting and void fill work. On projects like this, Alchatek's role is providing the product knowledge and technical backup that help a contractor match the right polyurethane system to the void size, load, and site conditions, and staying available for tech support once the crew is on-site.

If you're weighing void fill, slab lift, or another repair method for a project you're looking at, Alchatek's tech support team can walk through the site conditions with you before you commit to an approach.

Want more information on geotech products?

For contractors, winning more work often comes down to more than simply offering the right service. The way value is communicated, questions are asked, and recommendations are presented can have a major impact on whether a prospect moves forward. On August 27 at 12:00 PM Eastern, sales consultant Gene McNaughton will lead a contractor-focused Sales Excellence webinar designed to help contractors sharpen those conversations and improve their ability to close more opportunities.

During the 45-minute live session, Gene will share four practical strategies contractors can use to strengthen their sales approach, build more confidence with prospects, and improve close rates. The session is designed to be immediately useful, with ideas that can be applied to real-world sales conversations rather than broad theory. Attendees will also have the opportunity to participate in a live Q&A and ask questions about the specific sales challenges they face.

Whether you are looking to improve your own sales performance or give your team a stronger framework for turning more opportunities into signed work, this webinar is built to provide actionable takeaways.

Space is limited to 30–50 attendees, so early registration is encouraged.

For DOT maintenance teams, municipalities, public works departments, bridge maintenance engineers, and the contractors who perform concrete lifting, void filling, and soil stabilization work — what an unstable approach slab really costs, and why the bump is rarely the actual problem.

A bridge approach slab does not fail all at once. It shows up as a bump, then a dip, then a crack along the joint where the slab meets the deck. Crews patch it, grind it smooth, and move on. A few months later, the same spot is back on the list.

That cycle is why this problem is easy to underestimate. Each patch looks cheap on its own. It's the repeated mobilizations, the lane closures, and the eventual heavier repair that add up. Most of that cost has nothing to do with the asphalt on top. It's driven by what's happening in the soil underneath.

The Real Cost Driver Isn't the Patch

A single patch is inexpensive. What's expensive is the pattern: mobilizing a crew, setting traffic control, closing a lane, and grinding or filling the same joint — repeatedly, at the same location, because the cause was never addressed. Traffic control and mobilization alone often cost more than the patch material itself, and that overhead repeats with every visit.

Left long enough, the condition can progress from the slab into the structure itself. At that point, repair moves into abutment or wing wall territory, where structural work runs $500–$1,200 per square foot.

Actual costs vary by region, traffic control requirements, agency specifications, slab condition, drainage, soil conditions, access, and severity.

This gradual progression is the point: money spent patching the same location, over and over, without resolving the underlying condition — until it's no longer just a slab problem.

The Bump Is the Symptom. The Void Is the Problem.

An approach slab bridges two systems that behave very differently. The bridge itself sits on a foundation — an abutment, piles, drilled shafts, footings bearing on stable material. The approach slab sits on compacted fill and native soil. Those two systems settle at different rates, and that difference is where the trouble starts.

Common causes include:

• Fill settlement — backfill behind the abutment consolidates over time, especially if it wasn't compacted to spec.
• Erosion and soil loss — water finds a path under the slab or through a failed joint and carries fines out, leaving a void.
• Failed drainage — deck drains or approach drainage that no longer function concentrate water exactly where it does the most damage.
• Voids beneath the slab — once soil is lost, the slab spans open space instead of bearing on support, and traffic loading accelerates the cracking.

None of this is visible from the driving surface. What's visible is the bump — the downstream symptom of a support problem that started below grade.

Why Repeated Patching Doesn't Fix It

Asphalt patching and grinding improve ride quality fast, which is why they're usually the first response. But if there's a void or ongoing erosion beneath the slab, the patch sits on the same unsupported base that caused the original settlement. Traffic keeps flexing the slab over the void, the patch cracks again, and the crew returns on a schedule that tends to compress rather than stretch out.

Where Polyurethane Injection Fits

When the cause is loss of support — a void, settled fill, or eroded soil — polyurethane injection addresses that condition directly, without full slab removal. Small-diameter ports are drilled through the slab or pavement, and high-density polyurethane resin is pumped beneath it. The material expands to fill the void, densify loose soil, and in appropriate cases lift the slab enough to close the joint differential.

If a soil boring or dynamic cone penetrometer (DCP) test indicates weaker soils at greater depth, those layers can be targeted first with polyurethane injected several feet into the ground using Alchatek's Deep Lock® process — addressing the soil density issue driving the settlement before the slab itself is lifted.

This isn't a fit for every situation. It addresses void and soil support — not a structurally deficient slab, a failed expansion joint, or drainage that's actively delivering water to the site. Site conditions, soil type, drainage, and the extent of the void all factor into whether injection is appropriate.

Why Contractors and Agencies Work With Alchatek

Alchatek manufactures high-strength polyurethane systems for void filling, soil stabilization, and concrete lifting on roadway, bridge, and transportation infrastructure. For contractors working under DOT or municipal specifications, that means products engineered for wet conditions, rapid cure, and traffic-ready turnaround, backed by technical support from a team familiar with public infrastructure estimating and application questions.

The right approach depends on the cause of the settlement, the soil conditions, and the condition of the slab — not a one-size-fits-all fix.

Related Reading

• 5 Warning Signs a Structure May Need Slab Lifting or Stabilization
• A Trusted Polyurethane Soil Stabilization Resource for Engineers
• AP Fill 700 – Polyurethane for Pipe Repair

Talk to a Specialist

If an approach slab on your system is showing repeated settlement, the first step is understanding what's happening beneath it. Call an Alchatek specialist at (404) 618-0438, or find a trained contractor near you.

The structural repair range in this article is confirmed via Alchatek's Cost Reference Library. Actual costs vary by site conditions, region, traffic control requirements, agency requirements, slab condition, drainage, soil conditions, access, and severity of settlement.

Want more information on soil stabilization?

Learn More About Coastal Structure Failure

Landon Feese | Applications Engineer
Online PDH Session — August 26 | 12:00 PM ET

• Diagnosing soil loss behind seawalls, bulkheads, and retaining walls
• Comparing repair methods by cost, downtime, and site access
• Fit criteria and limits for chemical grouting in the tidal zone

Includes coastal project examples and measured outcomes. 50-minute session plus live Q&A.

Reserve Your Seat →

The Wall Isn't What Fails First

Every tide that moves past a seawall or bulkhead takes a little more soil with it than it brought in. That process runs for years before anyone notices, because the wall itself usually holds its shape long after the ground behind it has hollowed out.

By the time a panel cracks, a cap shifts, or a section of walkway drops, the structure isn't announcing a new problem. It's reporting one that's already been running unseen since long before the first inspection flagged it.

That gap between when a coastal structure starts failing and when it looks like it's failing is where budgets get blown. Engineers and contractors who can read the early signs are working with a fraction of the cost, and a fraction of the disruption, of the crew who gets the call after a section of shoreline has already opened up.

What This Session Covers

Landon Feese, Applications Engineer at Alchatek, will walk through how to read the early signs of soil loss behind coastal structures and how to evaluate the repair options once it's confirmed.

The session is built around three practical questions engineers and contractors face on nearly every coastal job:

How do you confirm soil loss behind a wall you can't see behind? Landon will cover the diagnostic approach for evaluating voids and undermining behind seawalls, bulkheads, and retaining walls, including what separates a cosmetic crack from a structural warning sign.

How do the repair options actually compare? Once soil loss is confirmed, the choice usually comes down to excavation and replacement, mechanical anchoring, or chemical grouting. The session breaks these down by real cost, downtime, and how much site access each one demands, so you can make that call before it becomes an emergency decision.

Where does chemical grouting work, and where doesn't it? Tidal zones are unforgiving on materials and methods. Landon will lay out the fit criteria and limits for using chemical grouting in this environment, including where it's the right call and where it isn't.

Who Should Attend

This session is built for engineers, marine contractors, and municipal staff responsible for evaluating or maintaining seawalls, bulkheads, and waterfront retaining structures. If you've ever had to explain to a property owner or a board why a wall that "looked fine" needed emergency repair, this session is for you.

Master the Application. Win the Work. Get Paid.

If Paid in Full By EOD Autust 31 – $645
If Paid in Full September 1 or Later – $845
$50 Discount- Each Additional Participant

Day 1: The Deep Lock® Application Process

Master the technical foundation that allows you to confidently diagnose, design, and deliver Deep Lock® projects safely and correctly.

On Day 1, you’ll gain expert instruction on site evaluation, material selection, rig setup, and injection strategy from Alchatek's Andy Powell and Colt Hullander — two seasoned industry veterans with decades of combined field experience. This is not just theory — you’ll learn the exact processes and decision-making frameworks that ensure predictable results, controlled risk, and successful project execution in both residential and commercial applications.

• How Deep Lock® works and when to specify it

• Site evaluation & diagnostics

• Material selection, rig setup, and safety essentials

• Injection patterns, pressure/flow control, and QA

• Step-by-step walkthroughs of real job scenarios

Day 2: The Deep Lock® Sales Process

Learn how to win more Deep Lock® deals — with more margin and at higher average sales prices.

On Day 2, you’ll gain proven sales frameworks from Gene McNaughton, Sales Expert and author, who built Geobear USA from the ground up and generated over $4 million in Deep Lock® residential and commercial sales. This session goes beyond theory — you’ll learn the exact strategies, positioning, and closing techniques used to consistently secure high-value projects.

• How to find Deep Lock® opportunities

• Site evaluation & client qualification

• Estimating, scopes, and pricing essentials

• Proposal presentation, negotiation, and contracting

• Step-by-step walkthroughs of the lead to payment cycle

(Hotel rates available soon. Info sent upon registration. Daily transport from hotel to event provided.)

HOA Sidewalk Compliance Without Replacement

A large retirement community faced HOA, resident, and county pressure after newly poured sidewalks exceeded cross-slope limits. With more than 900 sidewalk sections at risk of tear-out, the project had to be handled in phases while keeping resident access, county inspections, and neighborhood disruption under control.

Initial Assessment

Many of the slabs exceeded the target slope tolerance of roughly 3.5%. Replacement would have damaged yards, blocked walking routes, delayed inspections, and created major disruption for residents.

Proposed Solution

Lift-It-Rite used AP Lift 430 to lift and re-pitch selected slabs without tearing them out. The material allowed controlled lifting, fast return to service, and precise grade correction in high-use walking areas.

Procedures

1. Measured slab grades

2. Saw-cut bound sections

3. Drilled injection holes

4. Injected controlled foam bursts

5. Monitored slope with digital levels

6. Ground transitions as needed

Results

• Restored sidewalk grades without full replacement

• Completed phase one seven weeks ahead of schedule

• Kept walkways usable with minimal disruption

• Passed county inspections

• Delivered estimated 50% to 75% savings versus tear-out and replacement

Want more information on slab lifting?

For warehouse and plant operators, facility managers, and the contractors who serve them — what a settled concrete slab really costs to fix, why it keeps getting worse, and why lifting beats tearing it out.

A settled concrete slab does not fail all at once. It drops a fraction of an inch at a time — a low spot by a dock door, a dip in a forklift aisle, a rack line slowly going out of plumb. By the time it is obvious enough to schedule a repair, the slab is no longer the only cost. The cost of a settled concrete slab in a warehouse is measured in equipment wear, damaged product, slowed operations, and liability, and every one of those climbs while the floor sits.

What Causes a Settled Concrete Slab

The slab itself is rarely the problem. What fails is the ground underneath it. Soil that was never compacted properly keeps consolidating under load. Water from a leaking line, poor drainage, or a high water table washes fines out of the subgrade and leaves voids. And a warehouse floor carries punishing, repetitive loads — loaded forklifts, pallet jacks, and tightly packed racking cycling over the same lanes day after day — that drive settlement faster than any other floor in the building.

Once a void opens beneath the slab, the concrete is spanning empty space. It flexes under each pass, cracks, and drops further into the gap. The settlement does not stabilize on its own; the loads that caused it are still there every shift, so the low spot deepens and spreads. A dip that was a nuisance becomes a transition a forklift has to slow for, then an edge that chips and spalls, then a section that cracks through.

Not all of this takes years, and not all of it starts with the soil. A brand-new facility can have an uneven floor before it ever takes on inventory. As a fresh slab cures, the top surface dries and shrinks faster than the bottom, which pulls the edges and corners of each panel upward — a phenomenon called slab curl. Curled edges are no longer fully supported by the subgrade, so they rock under a passing forklift, hammering the joints and breaking down the edges. The same rocking happens over any void: the slab pivots on the unsupported spot like a see-saw, and every pass drives it further out of level. Filling the gap beneath a curled or rocking slab re-supports it and stops the movement.

Cost of Inaction vs. Repairing It Right

The slab repair is the smallest number in this whole conversation. The expensive paths are doing nothing and tearing the floor out.

Read those first two rows carefully. The replacement figure is for the concrete alone — the real cost is that price plus demolition, disposal, and the days or weeks the footprint sits offline. Lifting is an all-in number, and the work is measured in hours. For a just-in-time operation, the downtime difference alone is often larger than the entire repair invoice.

Why Contractors Use Alchatek for This

Stopping the problem means filling the voids and raising the slab without adding weight to soil that already failed — which is exactly what structural polyurethane lifting foam does. Alchatek's AP Lift foams are injected as a liquid through small holes drilled in the slab, then expand to fill the voids underneath and lift the concrete back to grade in a controlled, measurable way. For heavily loaded warehouse and dock slabs, and for stopping movement from slab curl, a higher-density product such as AP Lift 475 carries the load. Where the underlying soil itself has failed, that subgrade can be stabilized as part of the same scope before the lift.

The advantages that matter on a working floor:

• Minimal disruption — small jobsite footprint allows for repairing slab without interrupting operations.
• Minimal downtime — traffic-ready in minutes, not days.
• No added weight on weak soil — the foam is a fraction of the weight of the slurry used in old-style mudjacking, so it does not re-load the ground that gave way.
• Precision — the slab is raised in stages and checked to grade, so transitions come back smooth instead of overcorrected.

The positioning Alchatek brings its contractors is the one running through this whole article: you are not selling a few pails of foam, you are selling the operator their floor back — level, load-ready, and back in service the same shift.

Continue Reading

• Case Study: Warehouse Slab Leveling
• Sinking Concrete Slabs: Causes and Solutions
• Foam Concrete Lifting: A Durable Solution for Sunken Slabs

Get the Floor Back to Grade

The cheapest time to lift a settled concrete slab is before the voids spread and the racking goes out of plumb. Talk to an Alchatek specialist at (404) 618-0438, or find a trained contractor near you.

Cost ranges in this article are industry averages drawn from published 2025–2026 concrete-leveling and slab-replacement cost guides. Figures represent typical repair and replacement pricing; actual costs vary by site conditions, region, slab thickness, load, and severity.

Want more information on lifting slabs with polyurethane?

Master the Application. Win the Work. Get Paid.

If Paid in Full By EOD August 31 – $645
If Paid in Full September 1 or Later – $845
$50 Discount- Each Additional Participant

Day 1: The Deep Lock® Application Process

Master the technical foundation that allows you to confidently diagnose, design, and deliver Deep Lock® projects safely and correctly.

On Day 1, you’ll gain expert instruction on site evaluation, material selection, rig setup, and injection strategy from Alchatek's Andy Powell and Colt Hullander — two seasoned industry veterans with decades of combined field experience. This is not just theory — you’ll learn the exact processes and decision-making frameworks that ensure predictable results, controlled risk, and successful project execution in both residential and commercial applications.

• How Deep Lock® works and when to specify it

• Site evaluation & diagnostics

• Material selection, rig setup, and safety essentials

• Injection patterns, pressure/flow control, and QA

• Step-by-step walkthroughs of real job scenarios

Day 2: The Deep Lock® Sales Process

Learn how to win more Deep Lock® deals — with more margin and at higher average sales prices.

On Day 2, you’ll gain proven sales frameworks from Gene McNaughton, Sales Expert and author, who built Geobear USA from the ground up and generated over $4 million in Deep Lock® residential and commercial sales. This session goes beyond theory — you’ll learn the exact strategies, positioning, and closing techniques used to consistently secure high-value projects.

• How to find Deep Lock® opportunities

• Site evaluation & client qualification

• Estimating, scopes, and pricing essentials

• Proposal presentation, negotiation, and contracting

• Step-by-step walkthroughs of the lead to payment cycle

(Hotel rates available soon. Info sent upon registration. Daily transport from hotel to event provided.)

About the Webinar

Price pressure is one of the biggest challenges contractors face. When prospects compare bids, it can feel like the only way to win more work is to lower your number. But competing on price is a dangerous habit. It cuts into profit, weakens your positioning, and trains customers to see your service as a commodity instead of a valuable solution.

In this upcoming webinar, Win More Jobs Without Cutting Your Price: The 7-Step Sales Blueprint Every Contractor Should Know, Gene McNaughton will walk contractors through a practical sales framework for improving the way they compete for work. This 45-minute session is designed to help contractors strengthen their sales process, have better conversations with prospects, and build more confidence when presenting the value of their solution.

The webinar takes place July 30 at 12 Noon Eastern and includes live Q&A. Space is limited, so contractors who want to improve their close rate, protect their pricing, and win more jobs without racing to the bottom should reserve their seat today.

About Gene McNaughton

Gene is a nationally recognized sales trainer, author, and business growth expert who has spent more than two decades helping companies improve how they sell, communicate value, and win more business.

As the creator of The Sales EDGE, Gene has trained thousands of professionals on how to stand out in competitive markets by mastering the conversations that drive buying decisions.

A cracked granite pier supporting an active freight rail line moved approximately ¼ inch every time a train crossed. With the Hudson River below and rail service still running, continued movement created a serious structural and operational risk. 

Initial Assessment

The planned carbon fiber wrap required a stable substrate before epoxy work could proceed. Active pier movement prevented warranty approval, while existing grout bags, riprap, and rail operations blocked excavation or underpinning options.

Proposed Solution

DeBrino Caulking Associates selected AP Lift 430 with the Deep Lock process to stabilize soils beneath the pier while trains stayed active. The polyurethane foam was chosen for deep injection, fast reaction, void filling, and support below difficult access zones.

Procedures

1. Laid out offset injection pattern around pier base

2. Rock-drilled through grout bags and obstruction zones

3. Installed 36 injection pipes: 18 to -10 ft and 18 to -5 ft

4. Injected 35 lbs at deep points and 25 lbs at shallow points

5. Pumped approximately 150 gal total

6. Monitored crack movement during train loading

7. Stopped injection when lift indicated full contact

Results

• Reduced crack movement to a minimum

• Stabilized the pier for epoxy repair and carbon fiber wrap

• Kept freight rail active during stabilization

• Avoided excavation and underpinning disruption

• Completed stabilization in two injection visits

Want more information on Deep Lock®?