Your slab moved — but which way it moved, and when, decides the fix. Frost heave pushes concrete UP in winter and lets go in spring. Settlement lets it sink DOWN as soil support disappears, and it never comes back up. They look alike in March. Here is how to tell them apart, what each one costs you, and which one concrete lifting actually fixes.
Frost heave and settlement are two completely different physics that happen to produce the same complaint: "my concrete isn't level anymore." Understanding the difference matters because the fixes are opposites — and paying for the wrong one is pure waste.
Frost heave is the ground expanding. Water in the soil freezes, and as it does, it grows ice lenses — thin sheets of ice that thicken by wicking up more water from below, jacking the soil (and everything sitting on it) upward a fraction of an inch at a time. Over a Salt Lake winter, that can raise a slab an inch or more. Then spring comes, the ground thaws, the ice lenses melt, and the slab drops back down. The whole cycle reverses. The slab ends up roughly where it started — minus whatever damage the trip did.
Settlement is the ground giving up. The soil under the slab consolidates under weight, washes out as water moves through it, or was never compacted properly when the home was built — and the slab drops into the resulting void. Nothing reverses it. It does not bounce back in spring. It only gets worse, because every year the void grows and the next freeze-thaw cycle works the joint a little more. (The full mechanics are in why concrete sinks and why Utah concrete settles.)
Here is the expensive mistake in one sentence: concrete lifting fixes settlement, not heave. Lifting fills voids and restores grade to a slab that dropped and stayed dropped. A heaving slab has no void to fill — it is sitting on expanded frozen ground, and in spring it will drop back down with your money. If you cannot tell which one you have, the five tests below will sort it out.
You do not need equipment for any of these. A ruler, a phone camera, and one winter of patience will do it.
Heave has a season. In the Salt Lake Valley it typically appears from December through March, peaks in February, and fades by May. Settlement has no season — it is there in July, it is there in October, and it never improves. The single most useful question you can ask yourself: did this show up in winter and disappear by Memorial Day? If yes, that was heave. If the lip is still there in August, you have settlement — possibly with some heave layered on top, which is common here.
Lay a ruler across the offending joint and photograph it with the date — once in February, once in May. Heave: the lip shrinks or vanishes between the two photos. Settlement: the lip is unchanged or bigger. This is the definitive home test, and it costs nothing. Bring both photos to any estimate visit; a contractor who sees dated proof of seasonal movement will give you a fundamentally different (and more honest) recommendation than one working from "it's been like this a while."
Heave and settlement tend to draw different shapes. Heave often lifts the middle of a slab or a broad area — the ground freezing most where water collects — and it can affect several adjacent slabs in a rolling, uneven way. Settlement usually drops one side, one corner, or one slab relative to its neighbor, creating a sharp lip at the joint; it follows water erosion paths, backfill zones along the foundation, and utility trenches. A sharp, localized lip that never changes is settlement's signature. A broad winter hump is heave's.
Both need water, but they use it differently. Heave needs water sitting under the slab in freezing weather — look for low spots, shaded north-facing sections that freeze deeper and longer, and areas near downspouts. Settlement follows water moving through the soil — downspout discharge points, sprinkler overspray zones, the drip line off the roof. If the movement tracks a drainage path, suspect settlement. If it tracks the coldest, wettest patch of ground, suspect heave.
Has this slab been lifted before? A slab that was lifted two years ago and has dropped again in the same spot is telling you the soil is the problem (see soil stabilization) — that is settlement, recurring. But a slab that rises every January and falls every May, year after year, is heave on a loop. And a slab doing both — seasonal bounce on top of a slowly growing permanent lip — is the classic Utah combination. Treat them as two separate problems with two separate fixes.
Describe what you are seeing and when it started — winter-only or year-round. We will give you a straight read on whether lifting is even the right fix, before anyone quotes you a price.
Utah is unusually good at producing both phenomena, which is why this confusion is so common here. The frost line in the Salt Lake Valley runs roughly 30 inches deep — plenty deep enough to get under a 4-inch residential slab and work on the soil beneath it. We get dozens of freeze-thaw cycles per winter, not one long freeze, and every cycle is another round of ice-lens growth and release.
Then there is the soil. The west side of the valley sits on Lake Bonneville lakebed deposits — fine clays and silts. Fine-grained soils are the most frost-susceptible soils there are, because their tiny pores wick water upward to feed growing ice lenses the way a candle wick feeds a flame. Those same clays are also expansive, swelling when wet and shrinking when dry. So a west-side driveway can heave in February on ice lenses, then settle in May as spring snowmelt and irrigation water wash fines out from underneath. Same slab, both physics, three months apart.
The east benches run sandier and gravelly, which drains better and heaves less — but sandy soil washes out fast under a broken irrigation line or a misdirected downspout, so the benches trade heave for settlement. Valley-wide, newer subdivisions add a third ingredient: graded, recompacted hillside where compaction quality varies lot by lot (more on Utah's settling soils). Know your soil and you are halfway to the right diagnosis.
This is the part people get wrong: "it goes back down in spring, so no harm done." There is harm. When one section of slab lifts an inch while its neighbor stays put, the joint between them absorbs the movement — sealant tears, edges chip and spall. Worse, a slab that lifts at one end and not the other is being bent like a beam, and concrete is terrible in bending: it cracks across the middle. A few winters of heave-and-release fatigue a slab the way bending a paperclip fatigues metal.
Heave also does practical damage: a heaved walkway section becomes a trip hazard all winter; a driveway apron that heaves against the garage floor can bind or scrape; heaved slabs "walk" — migrating slightly with each cycle until joints open up. The lift reverses. The cracked, spalled, separated slab does not. Prevention is the only real fix, and prevention means water management: extend downspouts well away from slabs, regrade so water sheets away from the concrete, and keep irrigation from soaking the ground under flatwork through fall. (Start with downspout and drainage fixes — it is the highest-leverage work you can do.)
Settlement is a void problem: somewhere under your slab there is empty space where soil used to be, and the slab has dropped into it. Concrete lifting — mudjacking or polyurethane foam — exists for exactly this: the contractor drills small holes, pumps material into the void, and the expanding fill raises the slab back to grade while supporting it from below. It is a permanent repair of a permanent problem, and most residential jobs land between $500 and $3,000 (see the cost guide).
But lifting a heaving slab accomplishes nothing, because there is no void — the ground is expanded, not missing. Pump foam under a slab sitting on frozen, heaved soil and you have simply added expensive material to a slab that will drop in spring. Worse, some homeowners get sold a winter lift for a heave problem, watch it "fail" by May, and conclude concrete lifting is a scam — when the actual failure was the diagnosis. This is why the calendar test matters: if the slab is currently heaved, wait. Lift in late spring or summer, when you are lifting the true, permanent settlement and nothing else.
| Frost heave | Settlement | |
|---|---|---|
| Direction | Up — ground expands under the slab | Down — slab drops into a void |
| Timing | Winter (Dec–Mar), peaks in February | Year-round, never improves |
| Reverses? | Yes, every spring — but the damage stays | No — only gets worse |
| Typical pattern | Broad lift, middle of slab, multiple slabs rolling | Sharp lip at a joint, one side or corner dropped |
| Root cause | Water under slab + freezing temperatures | Voids: washout, consolidation, poor compaction |
| Fix | Drainage — remove the water before it freezes | Fill the void and lift the slab |
| Does lifting help? | No — there is no void to fill | Yes — this is what lifting is for |
| Urgency | Moderate — prevent the next cycle's damage | Moderate — it compounds; water pooling accelerates it |
If it is heave: fix the water. Extend downspouts at least several feet from the slab, regrade the soil so surface water sheets away from the concrete, and stop irrigating the strip next to the driveway in late fall. These are weekend projects with hand tools, and they do more for a heaving slab than any contractor can. If the slab is already cracked or spalled from past heave cycles, that damage is permanent — at that point the question becomes lift the settled portions vs. replace the ruined sections.
If it is settlement: probe, lift, and fix the water source in that order. A lifting contractor should confirm voids before quoting (see how concrete lifting works), and the estimate should address what caused the sinking — because lifting without fixing the cause is a temporary repair at a permanent price. Most residential lifts run $500–$3,000, and foam is typically usable the same day (cure times).
If it is both — and in the Salt Lake Valley, it often is: do the drainage work first, wait out heave season, then lift the permanent settlement in late spring or summer. That order means you pay once, for the real problem, at the moment the slab is telling the truth about where it sits.
Yes — and that is the part people underestimate. The heave itself reverses every spring: the slab drops back down as the ground thaws. But the damage it does on the way up does not reverse. When one section of slab lifts while the next one stays put, the joint between them takes the stress — sealant tears, edges chip, and the slab can crack across its middle like a beam loaded at one end. A few winters of that and you have a cracked, spalled slab sitting back at grade. The lift was temporary; the damage is forever. This is why the fix for heave is drainage, not lifting — you have to take the water out from under the slab before the frost can weaponize it.
Almost certainly not — and an honest contractor will tell you so. Concrete lifting fixes settlement, which is permanent. Frost heave is seasonal: the ground freezes, expands, and lets go in spring. If you pay to lift a heaving slab in January, you will watch your money drop back to grade by May. What you actually want is to find out where the water under that slab is coming from — a low spot, a downspout, a shaded north-facing section that freezes deeper — and fix the water. If the slab ALSO has permanent settlement underneath the seasonal movement (common in Utah, where the same slab can heave in February and settle in May), lift the permanent part in late spring or summer, after heave season is over. See concrete lifting in winter for the seasonal timing.
The ruler-and-calendar method. Pick the joint or lip that bothers you, lay a ruler across it, and photograph it with the date — do this once in mid-winter (February is peak heave season in the Salt Lake Valley) and once in late spring (May). If the lip shrank or disappeared between the two photos, that was frost heave. If it stayed the same or grew, that is settlement. It costs nothing, takes two minutes, and it is more reliable than any guess. Bring both photos to your estimate visit — a contractor who sees dated proof of seasonal movement will diagnose differently than one working from a verbal description.
No — and be skeptical of anyone who implies it does. Polyurethane foam is waterproof, which is a genuine advantage: it will not wash out or break down the way a cement slurry can. But frost heave is the SOIL expanding, not the fill material failing. When the ground under your slab freezes and grows ice lenses, it lifts everything above it — slab, foam, slurry, all of it. The foam rides up with the slab and comes back down in spring, same as anything else. Foam's real freeze-thaw advantage is durability of the repair itself, not immunity from heaving. Compare the methods honestly in mudjacking vs. foam.
Reasonably, with a caveat. Mudjacking slurry is cement-based, so it is not as inherently freeze-thaw resistant as polyurethane foam — repeated freeze-thaw is harder on it over the years. That said, a properly placed mudjacking lift in the Salt Lake Valley typically holds 5–10 years (see how long concrete lifting lasts), and the bigger variable is almost always water management, not the material. A mudjacked slab with good drainage outlasts a foam-lifted slab sitting in a puddle. Method choice matters less than fixing why the slab moved in the first place.
Almost certainly not. Lifting warranties cover the contractor's work — the lift settling back down — not acts of nature. Frost heave is explicitly the ground doing what ground does in Utah winters, and no contractor can warranty the weather. Read the exclusions section of any warranty before you sign; "frost heave," "expansive soils," and "acts of God" are standard carve-outs. Our warranty guide breaks down what typical coverage actually includes. The practical takeaway: if your slab heaves seasonally, a warranty would not have helped you anyway — the fix is drainage, which is a different project.
Late spring or summer, after the ground has fully thawed and the seasonal heave has released. Lifting in mid-winter means lifting a slab that is sitting artificially high on frozen ground — when spring comes, your expensive lift sinks with the thaw, and you have paid to move a slab twice. A good contractor in the Salt Lake Valley will tell you to wait if they see active heave. The one exception: if a heaved slab is an immediate trip hazard, a temporary grind or shim can get you through winter safely, with the real lift scheduled for May or June.