Can Cracked Concrete Be Lifted? What You Need to Know

One of the most frequent questions property owners ask when dealing with uneven driveways, walkways, or interior slab floors is: “Can you lift concrete if it is already cracked?”

The short answer is yes, cracked concrete can frequently be lifted. However, whether your cracked slab is a candidate for polyurethane foam lifting depends on the type, severity, and number of pieces the concrete has broken into.

This guide explains how polyurethane foam lifting works on cracked slabs, what happens to existing cracks during the process, how to distinguish slab settlement from structural foundation failure, and when complete replacement is necessary.

Direct Answer: Can Cracked Concrete Be Lifted?

• Yes, if the slab is in large sections: If a driveway panel or patio slab has snapped into 2, 3, or 4 distinct, intact pieces, technicians can drill individual micro-injection ports into each section and independently raise them until they line up flush with each other.
• No, if the concrete is shattered: If a slab resembles a broken jigsaw puzzle with dozens of micro-fractures or crumbling edges, expanding foam cannot bind the loose fragments back together. In these cases, full concrete replacement is required.

What Happens to Existing Cracks After Concrete Lifting?

A critical misconception property owners have is assuming that lifting a sunken slab will make the existing crack lines disappear.

Will existing cracks go away?

No. Lifting concrete aligns the broken sections, but it does not erase the crack line.

1. Flush Realignment: Polyurethane foam injection raises the sunken side of the crack until both sides are perfectly level, eliminating the vertical lip and trip hazard.
2. Crack Line Visibility: The physical break line in the concrete will remain visible.
3. Post-Lift Sealing: Once the slab is locked at grade, technicians fill open crack lines with flexible, waterproof joint sealant to prevent surface water from penetrating beneath the slab.

For a detailed walkthrough of the complete installation and patching process, see our guide on how polyurethane concrete lifting works.

11 Types of Concrete Cracks & Their Root Causes

Understanding why your concrete cracked in the first place is essential for choosing the correct repair method. Cracks fall into three broad behavioral categories:

Category 1: Settlement Cracks (Ideal for Lifting)

1. Soil Erosion / Washout Cracks

• Cause: Rainwater from roof downspouts or leaking plumbing washes away crushed gravel and sub-grade soil.
• Appearance: Long cracks running parallel to slab edges or across corners.
• Lifting Suitability: Excellent candidate. High-density foam fills subterranean washouts, compacts base soils, and levels the slab. Read more on our void filling and soil stabilization page.

2. Poor Soil Compaction Cracks

• Cause: Uncompacted backfill dirt around garage foundations or utility trenches naturally settles under gravity over 2 to 5 years.
• Appearance: Wide, sloping cracks where one side drops significantly lower than the other.
• Lifting Suitability: Excellent candidate.

3. Overload / Heavy Vehicle Cracks

• Cause: Parking heavy RVs, dump trucks, or trailers on standard 4-inch residential slabs sitting over uncompacted soil voids.
• Appearance: Diagonal cracks extending outward from vehicle tire positions.
• Lifting Suitability: Good candidate, provided high-density 4.0 lb foam is used to support heavy wheel loads.

Category 2: Shrinkage & Curing Cracks (Cosmetic / Non-Structural)

4. Plastic Shrinkage Cracks

• Cause: Occurs within hours of pouring when surface water evaporates faster than the concrete cures, causing micro-tension.
• Appearance: Shallow, fine hairline cracks on the surface that do not extend through the full depth of the slab.
• Lifting Suitability: Can be lifted if the slab subsequently settles, though the crack itself is purely cosmetic.

5. Drying Shrinkage Cracks

• Cause: As fresh concrete hardens over 28 days, moisture loss causes the slab to contract slightly.
• Appearance: Clean, straight cracks through the slab (if control joints were not cut deeply enough).
• Lifting Suitability: Ideal candidate for lifting.

6. Thermal Expansion / Contraction Cracks

• Cause: Temperature swings (such as Calgary Chinook winds swinging from -20°C to +10°C) cause concrete to expand and contract.
• Appearance: Hairline breaks along control joints or near fixed structures.
• Lifting Suitability: Good candidate if panels drop out of alignment.

Category 3: Heaving, Structural & Environmental Cracks

7. Freeze-Thaw Frost Heave Cracks

• Cause: Water trapped beneath slabs freezes in Calgary winters, expanding by ~9% and pushing the concrete upward (heaving). When the Chinook arrives, the ice thaws rapidly, leaving uneven settlement behind.
• Appearance: Irregular upward arching or jagged multi-directional cracking.
• Lifting Suitability: Moderate candidate. Foam lifting can level the slab after thaw, provided perimeter drainage is corrected. Discover root environmental causes in why concrete sinks in Calgary.

8. Tree Root Intrusion Cracks

• Cause: Growing tree roots exert massive mechanical pressure, lifting concrete panels from below.
• Appearance: Raised, humped crack lines directly over tree root paths.
• Lifting Suitability: Not suitable for lifting. Tree roots must be cut or removed before the slab can sit flat.

9. Concrete Matrix Delamination / Spalling

• Cause: Deicing salts, chemical corrosion, or poor finishing cause the top 1/2 inch of concrete to flake away into loose gravel.
• Appearance: Pitted, flaking, or crumbling surface matrix.
• Lifting Suitability: Poor candidate. If the top surface is crumbling, concrete replacement is recommended.

10. Rebar Corrosion / Expansion Cracks

• Cause: Moisture penetrating to internal steel rebar causes rust. As steel rusts, it expands up to 400%, spalling the concrete from within.
• Appearance: Rust-stained cracks running directly along rebar grid lines.
• Lifting Suitability: Not suitable. The internal structural matrix has failed.

11. Structural Foundation Footing Cracks

• Cause: Settlement of deep concrete foundation footings beneath load-bearing home walls.
• Appearance: Diagonal stepped cracks in exterior brickwork or basement foundation walls.
• Lifting Suitability: Requires engineering inspection and deep steel piering, not standard slab-on-grade foam lifting.

Structural vs. Non-Structural Cracks: Key Differences

Important Distinction: Cracked Floor Tiles vs. Foundation Failure

Homeowners frequently panic when they discover cracked ceramic or porcelain tiles on a basement floor or slab-on-grade room, assuming their house foundation is collapsing.

Floor Slab Movement vs. Structural Foundation Settlement

• Slab Movement (Common): Interior basement floors and garage slabs are almost always non-structural concrete slabs on grade. They are poured independently of the perimeter house foundation footings. When soil under a basement floor dries or settles, the thin floor slab drops slightly, causing rigid tile grout and tiles to crack.
• Structural Foundation Settlement (Serious): Foundation footings sit deep below frost lines and support exterior load-bearing walls.

Cracked floor tiles rarely mean your house foundation is failing. In most cases, it simply indicates minor settlement of the thin interior concrete floor slab—a issue that can often be stabilized using low-pressure polyurethane foam injection beneath the interior slab.

When Should a Structural Engineer Inspect the Property?

While most driveway, sidewalk, and patio cracks are straightforward slab settlement issues, you should consult a licensed structural engineer before proceeding if you observe any of the following warning signs:

1. Diagonal Stepped Cracks in Brick / Mortar: Stair-step cracks running up exterior brick veneer or foundation walls.
2. Sticking Doors and Windows: Windows and exterior doors on upper floors binding or sticking in their frames.
3. Basement Wall Bowing: Interior foundation walls bowing inward by more than 1 inch.
4. Significant Gap at Foundation Connection: A gap opening between an addition and the primary house structure.

Why Post-Lift Crack Sealing Is Essential

Lifting a cracked slab fixes the elevation and fills underground voids, but sealing open crack lines is vital to protect your investment.

Benefits of Crack Sealing

• Prevents Water Intrusion: Stops rainwater and snowmelt from channeling beneath the slab and eroding the base soil again.
• Blocks Freeze-Thaw Damage: Prevents water from trapping inside cracks and freezing during Calgary winter Chinook cycles.
• Stops Weed Growth: Prevents grass, weeds, and roots from invading crack lines.
• Extends Repair Lifespan: Protects both the concrete matrix and the underlying foam base for decades.

Learn more about long-term durability expectations in our guide to how long concrete lifting lasts.

Decision Summary: Can Your Cracked Concrete Be Lifted?

1. Evaluate Slab Fragment Count: Count the number of broken sections.

Is the slab in 1 to 4 large pieces, or shattered into dozens of tiny fragments?

• 1–4 Large Pieces: Suitable for Lifting.
• Shattered Fragments: Requires Replacement.

Check Surface Matrix Health: Inspect surface condition for scaling, flaking, or crumbling.

Is the top surface finish sound and solid, or crumbling into loose gravel?

• Solid Finish: Suitable for Lifting.
• Crumbling / Spalling: Requires Replacement.

3. Identify Settlement Cause: Verify cause of settlement (washouts vs tree roots).

Did the slab drop due to soil erosion or uncompacted fill?

• Soil Erosion / Washout: Ideal for Polyurethane Foam Lifting.
• Active Tree Roots: Tree roots must be cut/removed before repair.

4. Schedule Lift & Joint Sealing: Plan for post-lift crack sealing and joint maintenance.

Technicians raise the cracked panels flush and level, followed by applying flexible waterproof joint sealant across all open breaks.

Ready to Level Your Cracked Concrete?

Don’t let cracked, uneven concrete lower your home’s curb appeal or create dangerous trip hazards. High-density polyurethane foam offers a fast, clean, and permanent solution for cracked slabs.

• Process Breakdown: Learn how polyurethane concrete lifting works.
• Method Comparison: Review all options in our concrete lifting methods guide.
• Cost Expectations: Check budget factors in our Calgary concrete lifting cost guide.
• Foam vs. Slurry: Read our head-to-head comparison of mudjacking vs. polyurethane foam.