Best Concrete Lifting Method for Sunken Slabs (2026)

Sunken concrete doesn't fix itself, and guessing at a repair method usually means paying twice. This guide ranks the concrete lifting methods used on Alberta driveways, sidewalks, and garage floors in 2026, and tells you which one actually matches a sunken slab versus a slab that needs full replacement.

Why this matters

A sunken slab is a symptom, not the problem. The soil underneath has washed out, compacted unevenly, or frozen and thawed one too many times — common across Calgary, Okotoks, High River, and Lethbridge where freeze-thaw cycles hit concrete hard every winter. Pick the wrong repair method and the slab sinks again within a season or two, and you've paid for a fix that didn't fix anything.

The method matters more than the contractor's sales pitch. Aztec Spray Systems works on sunken driveways, sidewalks, patios, garage floors, and pool decks across southern Alberta, and the method that gets picked depends on slab size, soil condition, and how much weight the surface needs to carry once it's back level.

How this list was ranked

The methods below are ranked on four factors: how long the fix lasts, how fast you can use the surface again, how much material disturbance it causes to landscaping and soil, and how well it performs specifically on sunken slabs versus slabs with only cosmetic surface flaws. Methods built for minor cosmetic leveling — not true lifting — are flagged and ranked lower even when they're cheaper up front. This isn't a generic concrete-repair roundup; it's built around the sunken-slab use case specifically, which rules out a few popular DIY options fast.

The ranked methods

1. Polyurethane foam injection — the modern standard

Polyurethane foam injection uses small holes, roughly 5/8 inch in diameter, drilled through the slab to pump expanding structural foam beneath it. The foam expands within seconds, fills voids, and lifts the slab back to grade. Cure time runs 1 to 2 hours, meaning a driveway or sidewalk can carry traffic again the same day.

The foam weighs a fraction of traditional fill material, so it doesn't add load stress to already-weak soil underneath — a real advantage on the sandy, freeze-thaw-prone ground found around Okotoks and High River. Holes are small enough to patch invisibly, and the process works on sunken driveways, garage slabs, and thin sidewalk panels alike.

Verdict: Buy. This is the method to specify by name when a sunken slab needs lifting in 2026, especially on residential driveways and walkways.

2. Mudjacking (mortar slurry injection) — the budget option for big slabs

Mudjacking pumps a cement, sand, and limestone slurry mixture under the slab through larger drilled holes, typically 1 to 2 inches wide. It's been the standard lifting method for decades and still works, particularly on large commercial areas like parking lots where the cost per square foot matters more than speed.

The tradeoff is weight and time. The slurry mixture is heavy, which can compress already-soft soil further, and it needs 24 to 48 hours to cure before the surface takes load again. Holes are larger and patch less cleanly than foam injection.

Verdict: Consider. Reasonable on large commercial pours like concrete lifting for commercial parking lots where downtime is acceptable, weaker fit for a residential driveway you need back in service the same afternoon.

3. Self-leveling compound — cosmetic fix only

Self-leveling compound is poured over the surface to smooth out minor dips and unevenness, usually less than a quarter inch deep. It's fast, cheap, and fine for interior garage floors with shallow surface irregularities.

It does not lift a slab. If the concrete has actually sunk — meaning the whole panel has dropped relative to the slab next to it — self-leveling compound sits on top of the problem and does nothing about the void underneath.

Verdict: Skip for true sunken-slab repair. Fine only for cosmetic surface leveling on garage floor slabs with minor unevenness, not settlement.

4. Slabjacking — same process, different name

Slabjacking is essentially the older industry term for mudjacking — the mortar slurry method described above, sometimes marketed under a different name. Some contractors use "slabjacking" to describe any pressure-grouting lift, foam or mortar.

Ask exactly what material goes under the slab before signing anything. If the quote says "slabjacking" with no material specified, get clarity — it changes the cure time and the weight added to the soil.

Verdict: Consider, but only after confirming which material is actually being pumped.

5. Full slab replacement — the reset button

When a slab has sunk more than 2 to 3 inches, cracked into separate pieces, or the base material underneath has fully washed out, lifting doesn't hold. Replacement means breaking out the old concrete, rebuilding the base, and pouring new.

It costs more and takes days rather than hours, but it's the only real fix once the existing slab is structurally compromised. This applies most often to older patios and pool decks and sidewalks and walkways that have shifted for years without repair.

Verdict: Buy — but only once lifting has been ruled out by inspection, not as a first move.

Comparison table

Where to hire the work

Getting the right method specified matters more than getting the lowest bid. Three rules before hiring anyone for a sunken slab in 2026:

• Ask what material goes under the slab, by name. "Concrete lifting" and "mudjacking" and "foam injection" are not interchangeable, and the quote should say which one.
• Confirm licensing and insurance for the region. A contractor working driveways in Calgary, Okotoks, High River, or Lethbridge should carry coverage specific to Alberta freeze-thaw conditions.
• Get the cure time and traffic timeline in writing. A driveway you can't use for two days is a different project than one you can drive on by dinner.

FAQ

One last thing

The injection hole size is the tell. If a contractor's foam injection quote mentions holes wider than about 5/8 inch, ask why — oversized holes usually mean the crew is used to mudjacking equipment and hasn't switched material, not that the job needs it.

Related guides

• Concrete lifting for Okotoks properties
• Concrete lifting for commercial parking lots
• Concrete lifting for Lethbridge properties

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