Every spring after the frost comes out of the ground in the GTA, the calls start. A garage slab sits two inches lower at the door. The walkway by the side of the house has tipped toward the foundation. The pool deck has a step where there should be a smooth transition. The first question is almost always the same: can you lift it back up, or do we need to tear it out and pour new?
The answer in 2026 sits between two methods that get used almost interchangeably in marketing copy but that work very differently in practice. Polyjacking, also called polyurethane foam injection or polylifting, is the newer approach. Mudjacking, also called slabjacking or pressure grouting, is the older one. Both can lift sunken concrete back to the right elevation. Neither one fixes a slab that should never have been lifted. The cost difference between them is real and the long-run durability difference is even bigger.
This is a contractor-side walkthrough of how we think about polyjacking and mudjacking calls in the GTA for spring 2026, with the cost ranges we currently see in our market, the diagnostic checks that tell us when lifting is the wrong call, and the questions to ask before signing a quote.
Why concrete sinks in GTA neighbourhoods
Concrete does not actually sink. The ground under it sinks, and the slab follows. That distinction matters because the right repair depends entirely on why the ground moved. In the GTA we see four common patterns and they each demand a different response.
The first pattern is subbase erosion. Water gets under the slab through a crack, an unsealed expansion joint, or runoff pooling against an edge, and it carries away fines from the granular base. Over a few seasons the slab loses uniform support and tilts toward the void. This is the classic case for lifting. The slab itself is fine. The base needs to be re-supported.
The second pattern is compaction failure. The original install was on poorly compacted fill, organic soil, or a recently disturbed trench from a service line. The base was not built to carry a slab in the first place. Over time the soil consolidates under the load and the slab settles unevenly. Lifting works here too, as long as the lift material is rigid enough to act as the new base going forward.
The third pattern is frost heave, and this one is the most misunderstood. Frost heave is not settlement at all. It is the opposite. Ice lenses form below the slab during freezing weather and push the slab upward. When the lens melts in spring the slab drops back down, often unevenly, and a new crack appears at the edge. Frost-heaved slabs cannot be repaired by lifting because the underlying drainage and frost-susceptibility problems will repeat the cycle next winter.
The fourth pattern is structural failure of the slab itself. The base might be fine but the concrete has cracked into pieces that no longer move together. Lifting a slab in this condition often makes the cracks worse and produces a finish that looks lifted but trips homeowners and trips cleaning equipment. This is a tear-out call, not a lifting call.
The diagnostic order matters. Before any quote on lifting, the contractor should be telling you which of those four patterns is driving the problem on your property. If the answer is hand-waved, the quote is not yet trustworthy.
Mudjacking versus polyjacking: how the two methods actually differ
Both methods solve the same problem in the same general way. Drill access holes through the slab, inject a fluid material under the slab, displace voids and lift the concrete to the target elevation, patch the holes. The differences sit in the materials and in how those materials behave once they are in the ground.
Mudjacking uses a slurry of cement, sand, and water (the older recipe) or a limestone slurry sometimes called limecrete (the newer recipe). The injection holes are roughly one to two inches across. Cure time runs twenty-four to seventy-two hours before the slab can carry full weight again. The cured material weighs roughly one hundred to one hundred and fifty pounds per cubic foot. Done well, mudjacking can hold for many years. Done poorly, the slurry can wash out under continued water exposure and the slab settles again.
Polyjacking uses two-part polyurethane resin that expands into a closed-cell foam after injection. The injection holes are roughly five-eighths of an inch. The cure happens within fifteen minutes and the slab is back in service the same hour. The cured foam weighs roughly two to four pounds per cubic foot. The foam is closed-cell and waterproof, so erosion does not eat it the way water can eat slurry. Polyurethane resin runs roughly thirty to fifty dollars per cubic foot in raw material cost compared to pennies per cubic foot for slurry, which is the largest single reason polyjacking quotes come in higher.
The weight difference matters more than most homeowners realise. If the original sinking happened on weak or organic soil, adding one hundred pounds per cubic foot of slurry under the slab adds load onto soil that already could not carry the slab. Polyurethane foam adds almost nothing in additional load. On weak soil polyjacking is generally the more durable repair. On strong soil with simple void erosion either method can hold for a long time and the cost calculus matters more than the engineering.
The hole size and cure time differences also matter on visible surfaces. A polyjacked driveway has small grout-patched holes that are barely visible at five feet. A mudjacked driveway has larger patches that often remain visible against the original concrete colour. On a stamped or coloured slab the polyjacking finish is almost always preferred for the cosmetics alone.
Real GTA cost bands, spring 2026
Quotes in the GTA in spring 2026 sit close to North American averages but with some local variation. These are the bands we see currently from reputable lifters in our market.
Mudjacking on a typical driveway, sidewalk, or porch slab runs three to seven dollars per square foot of slab being lifted. A standard two-car driveway section of around four hundred square feet that needs partial lifting along one panel is usually a fifteen-hundred to twenty-five-hundred dollar job. A small front walkway or porch slab is often a six-hundred to fifteen-hundred dollar job. Larger projects with more access difficulty or multi-panel work climb from there.
Polyjacking on the same slabs runs five to eighteen dollars per square foot of lift area, with the higher end of that range applying to thinner slabs over weak soil where the lifter is using more material to spread load through the foam. The same partial-lift two-car driveway section comes in roughly twenty-five-hundred to forty-five-hundred dollars. Small walkway and porch jobs are typically eight-hundred to two-thousand dollars. Pool decks and large patio slabs scale up because the surface area is larger and the lift pattern is more complex.
There are a few GTA-specific premiums to know about. Lifting a slab tight against the foundation costs more because the lifter has to work around the existing structure and the access geometry is harder. Lifting a slab that has trapped water under it requires the lifter to drain or accept the foam displacing the water, which adds either time or risk. Stamped or stained concrete carries a finish-protection premium because patch work has to match the existing pattern and colour. Lifting a section of city sidewalk requires Toronto Public Works permission and a permit, even if it sits on a private property easement, and that paperwork adds a few hundred dollars and several weeks to the timeline.
There is a fourth band worth flagging because it shows up in marketing material more than in real quotes. Some firms advertise nine-ninety-nine starter pricing or three-dollar-per-foot teaser bands. Those numbers describe the cheapest possible job on the smallest possible surface with no access challenges and no real-world conditions. Treat them as floor-of-the-floor numbers, not as quotes.
For broader GTA driveway and concrete scope context, our Ontario Driveway and Interlock Guide 2026 covers the full materials decision for new pours and replacements, and the GTA Driveway Sealing Spring 2026 write-up covers the maintenance side that often delays the need for lifting in the first place.
When concrete lifting works, and when you should replace
The single most useful test we use on the first site visit is the forty to fifty percent rule. If the cost of lifting plus any related repairs exceeds forty to fifty percent of the cost of full tear-out and replacement, replacement is usually the smarter long-run move. Polyjacking is expensive enough that this threshold can flip the math against lifting on smaller slabs.
Beyond the cost rule, lifting is the right call when the slab itself is structurally intact, the cracks are minor and not running across the lift zone, the cause of sinking is identifiable and addressable, and there is no active water source under the slab that will continue to undercut the new fill.
Replacement is the right call when the slab has multi-directional structural cracks, when water continues to pool under the slab because of grading or drainage problems, when the slab has lost large pieces along edges, when the surface is delaminated such as old stamped concrete with a failing top layer, or when the cause of sinking is a service-line trench that needs to be reopened anyway for unrelated work.
The replacement decision often comes with a side bonus. Tearing out gives you the chance to fix the underlying drainage that drove the original sinking, to set a deeper base for the new pour, to add a wider expansion joint pattern, and to reset the slab elevation to match a planned future addition or grade change. If your house is heading into a larger exterior renovation in the next year or two, replacing rather than lifting can be the cheaper aggregate move.
Frost heave is not a settlement problem
This deserves its own section because it is the most common misdiagnosis we see on phone-call descriptions before site visit. The slab is unlevel. The homeowner thinks it sank. The lifter is called. The lifter quotes mudjacking or polyjacking based on what the homeowner described. The job goes forward. Next winter the slab moves again, in the opposite direction, and now there is a new crack and the whole problem repeats.
Frost heave on a concrete slab in the GTA is driven by water in frost-susceptible soil under the slab freezing and forming ice lenses. The lenses push the slab up. When the lenses melt the slab drops back, often unevenly because the underlying soil has been disturbed. The fix is not lifting. The fix is one or both of two things. Either the soil under the slab needs to be replaced down to a frost-resistant depth with clean granular fill, which is generally only economic on a tear-out and repour, or the drainage around and under the slab needs to be rebuilt to keep water from accumulating in the freeze zone, which sometimes is possible without removing the slab and sometimes is not.
The diagnostic that distinguishes settlement from frost heave is direction over time. A settling slab moves down monotonically and stops when the underlying support stabilises. A frost-heaving slab moves up in winter and back down in spring with a slight net offset that grows year over year. If the homeowner has photos from previous springs showing the slab in different positions, that history is worth more than any visual inspection.
The cold-weather complication
Polyjacking is more temperature-sensitive than most homeowners expect. The two-part resin reacts and expands through a chemical process that releases heat and depends on a minimum starting temperature. Below roughly five degrees Celsius the reaction slows enough that some of the foam stays liquid in the void instead of expanding properly, and the lift fails to hold or fails to reach target elevation.
Reputable GTA polyjackers stop new polyjacking installs once daytime ground temperatures drop below that threshold, which in our market typically means the season runs roughly mid-March through late November depending on the year. There are heated injection systems that extend the season but they cost more and not every operator runs them.
Mudjacking is also temperature-sensitive but in a different way. The slurry needs the cured material to be above freezing for the cement set, and a freeze cycle in the first few days after a lift can damage the material. Mudjacking pushed late into November or early December often comes with a no-warranty caveat for that reason.
For homeowners who notice the problem in winter, the practical answer is usually to wait. Quoting in February for a March or April lift is normal practice. Pushing a job into a marginal weather window to get it done before a holiday is how warranty problems start.
Spring 2026 contractor red flags
A few patterns we see in our market that should slow down a homeowner about to sign a quote.
The first red flag is no diagnostic. A reputable lifter spends fifteen to thirty minutes on the first site visit poking, probing, and asking about water and drainage history before quoting. A quote that comes back from a phone call alone, with no walk-through and no diagnostic conversation, often misses the cause of sinking entirely. The job might still get done well, but the chances of a repeat in two or three years go up sharply.
The second red flag is a quote that does not name the cause. The proposal should identify whether the contractor thinks this is subbase erosion, compaction failure, frost heave, or structural slab failure, and that diagnosis should change the recommendation. A proposal that just says concrete leveling without naming the cause is usually either a templated quote or a quote that hides a frost heave call as a settlement call.
The third red flag is a single-method shop. Some GTA lifters only do polyjacking. Some only do mudjacking. Both approaches can hold up for a long time on the right project, but a single-method shop has every incentive to recommend their method even when the other one would be a better fit. A second opinion from an alternate-method shop is cheap insurance.
The fourth red flag is a no-warranty or short-warranty quote on a polyjacking job. Reputable polyurethane lifters in the GTA offer five to ten year warranties on the lift work as standard. A polyjacking quote with no warranty or with a one-year-only warranty is often a quote from a lifter using a thinner foam or a less stable resin chemistry, both of which are durability red flags in this climate.
The fifth red flag is upfront full payment. Lifting jobs in the GTA are typically priced with a deposit at booking and the balance on completion. Full payment up front is non-standard and is often associated with operators who are running thin on cash and on warranty support.
DIY versus calling a contractor
There are foam concrete leveling kits sold at hardware retailers and online. They use a smaller two-part polyurethane cartridge and a hand-pump applicator. For very small lifts on small areas (a single porch slab, a patio paver, a settled section under a downspout) they can produce a passable result for a few hundred dollars in materials.
Where they fail is on real driveway and walkway lifts. The foam volume in the consumer kits is a fraction of what a full driveway slab needs, the injection pressure is much lower than a contractor pump, the operator has no real-time elevation monitoring, and the lift control is by feel rather than by precision gauge. A homeowner can lift a small slab a fraction of an inch with a kit. Lifting a driveway panel an inch and a half back to the original elevation across a fifteen-by-twenty-foot pour is not a kit job. The kit will run out of foam, the lift will stall partway, and the result is often worse than the starting condition.
For the small jobs where DIY makes sense, treat the kits as patch repairs rather than as proper level set. For anything bigger, the cost of a professional lift is small enough relative to replacement that the contractor route is almost always the better value.
How concrete lifting fits the rest of the exterior package
Concrete lifting often comes up as part of a broader exterior decision rather than as a standalone job. If the driveway is being resealed this year (see GTA Driveway Sealing Spring 2026 for the maintenance side), a sunken section is worth lifting before the seal goes on so the seal does not pool in the low spot. If the driveway is being torn out and replaced (see GTA Asphalt Driveway Install Spring 2026 for the install decision), a separate lift on a connected walkway might still be the right call if the walkway is structurally fine. If a porch or step is being repaired alongside foundation work, lifting and replacement should both be on the table and the foundation work is the controlling decision.
The order matters too. Drainage corrections always come first. Concrete lifting comes after drainage. New pours come after both. Skipping the drainage step and lifting directly produces lifts that fail in two to three years on the same site that drove the original sinking.
Bottom line by use case
For a single sunken section of driveway, walkway, or porch on otherwise good concrete with no frost-heave history, polyjacking is usually the right call in the GTA in 2026. The premium over mudjacking buys speed, smaller patches, and longer durability against future water infiltration. Budget two-thousand to four-thousand dollars for a typical job.
For a multi-section driveway with structural cracks or visible frost-heave history, replacement is usually the right call. Budget seven-thousand to fifteen-thousand for a full two-car driveway tear-out and pour, depending on size and finish. The lift would not hold even if it could be done.
For a porch or small walkway slab on weak soil, polyjacking is almost always preferred over mudjacking because of the soil-load issue. Budget eight-hundred to two-thousand.
For a pool deck with multiple lift points, get two quotes from different lifters using different methods before signing. The price gap on these jobs can be three or four thousand dollars between an experienced polyjacker and a less specialised operator, and the warranty difference is usually larger than the price difference.
For a stamped or coloured slab, polyjacking is the only call that preserves the visible finish. Mudjacking patches are visible and the patch colour rarely matches the original.
For a slab that should never have been there in the first place (sitting on organic soil, draining toward the foundation, in a frost-prone low spot), the answer is replacement plus drainage correction. No amount of lifting will save a slab that the site is fighting against.
A note on $RENO
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If you have a sunken slab on your property and want a real-world cost band before the contractor walks the site, post a photo and a few notes about water history (where the downspouts drain, how long the slab has been there, when the sinking started). Two or three eyes on a photo before the quote saves a lot of one-method-only diagnostic mismatches.