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ARMORTHANE PROTECTING YOUR WORLD

PROTECTING YOUR WORLD

ARMORTHANE PROTECTING YOUR WORLD

Mudjacking vs
Polyjacking:
Which to Choose

What each method puts under your slab, what it costs, how long it lasts and when neither is the right fix. From the people who make ArmorFoam Lift concrete-lifting foam, with the math shown.
Concrete Lifting Quotes

Sunken slab? Get it lifted, not torn out.

Tell us what's sinking (walk, driveway, patio, garage or pool deck) and roughly how far it has dropped. We'll check whether an ArmorThane applicator near you offers foam concrete lifting and put you in touch for a written quote.

  • Sidewalks, driveways, patios and steps
  • Garage floors and pool decks
  • Lift height and hole locations on the quote
  • Contractors: ask about Lift 200/300 and rigs
Rather talk now? Call (417) 831-5090
Step 1 of 3
$4–$9
Mudjacking, per sq ft
Installed, HomeGuide, Nov 2025
$8–$25
Polyjacking, per sq ft
Installed, HomeGuide, Nov 2025
100–125 lb
Mudjack grout per cubic foot
vs 2.5 lb for ArmorFoam Lift 200
⅝ in.
Typical polyjacking hole
vs 1½–2 in. for mudjacking

A sunken sidewalk, driveway or patio slab can usually be lifted instead of torn out. The real decision is what goes underneath it: a heavy cement slurry pumped through a few big holes, or a light polyurethane foam injected through small ones.

Quick answer

Mudjacking pumps a cement-based slurry under the slab and costs about $4–$9 per sq ft. Polyjacking injects expanding polyurethane foam and costs about $8–$25 (HomeGuide, Nov 2025). Foam adds a small fraction of the weight (2.5 lb per cubic foot for ArmorFoam Lift 200 against 100–125 lb for grout), uses ⅝-in. holes instead of 1½–2 in., and takes traffic in about 30 minutes instead of a day or more. Mudjacking is cheaper, its grout is far stronger, and on firm soil it works. Neither one fixes the water or soil problem that sank the slab. Run the cost calculator or the method chooser.

Most pages on this topic are written by a company that sells one of the two methods, and it shows. One national foundation-repair company headlines why mudjacking is "considered a bad idea." A white paper published by a mudjacking contractor concludes that grout is the better overall solution. Both have a point, and both leave things out.

We make concrete-lifting foam (ArmorFoam Lift 200 and Lift 300) in Springfield, Missouri, so you'd expect us to say foam every time. We won't. Mudjacking is a legitimate repair with real advantages, and for a plain sidewalk on firm ground it's often the better buy per year of service. Below: the published numbers for both, the one peer-reviewed field comparison we could find, the strongest case each side makes, and four calculators that do the math for your slab.

What's in this guide
  1. 1What mudjacking and polyjacking are
  2. 2Mudjacking vs polyjacking, side by side
  3. 3What each costs (calculator)
  4. 4Does the weight matter? (fill calculator)
  5. 5How long each one lasts
  6. 6Which fits your slab? (method chooser)
  7. 7How much lift to ask for (slope check)
  8. 8What happens on lifting day
  9. 9Can you do it yourself?
  10. 10Safety and the environment
  11. 11ArmorFoam Lift 200 and Lift 300
  12. 12Mudjacking and polyjacking FAQ
The basics

What is mudjacking, and what is polyjacking?

Mudjacking (also called slabjacking) lifts a sunken concrete slab by pumping a cement-based slurry under it through drilled holes until it rises. Polyjacking (foam jacking, poly leveling) does the same job with a two-part polyurethane foam that expands under the slab. Same idea both ways: fill the void, push the slab up, patch the holes.

How mudjacking works

The crew drills holes through the slab, typically 1½–2 in. across (HomeGuide; Angi measures 1⅝ in.) and roughly 4 to 6 ft apart (Angi). A pump on a truck or trailer pushes slurry through a nozzle seated in each hole. The slurry fills the empty space first; once the void is full, pressure builds and the slab starts to rise. The operator moves from hole to hole, a little at a time, watching the slab come up. Then the holes are patched with cement and the slab rests. Angi says to allow about 24 hours before regular use and 24–72 hours for a full cure.

What's actually in the "mud"

There's no single recipe. Consumer guides describe a slurry of sand, soil, cement and water. The engineered version is a cementitious grout of portland cement, fly ash, fine sand, water and admixtures, according to a white paper by two New Jersey Institute of Technology (NJIT) engineering professors. Because it's a cement product, strength can be tuned: the same paper puts mudjacking grout typically under 1,000 psi, with more cement making it stronger. Some contractors pump a limestone mix instead, sold as stone slurry leveling. On HomeGuide's figures it prices between the other two, at about $6–$15 per sq ft.

How polyjacking works

Holes are much smaller, about ⅝ in. (HomeGuide). A port goes into each hole, and a pump that meters and heats two liquids (an isocyanate A-side and a polyol resin B-side) feeds a gun that mixes them at the port. The mix reacts, expands under the slab, fills voids and lifts. It cures fast. HomeGuide says about 15 minutes, Groundworks cites 90% rigidity within 30, and our ArmorFoam Lift product pages say the slab can be driven on in 30 minutes or less.

Lifting foam is not the spray foam that goes in walls. It's a denser, rigid, closed-cell product made for this job: ArmorFoam Lift 200 is 2.5 lb per cubic foot and Lift 300 is 3.75, both hydrophobic and water-blown.

Illustration of a lifting-foam injection gun on a pool deck slab, with yellow polyurethane foam filling the void underneath and arrows showing the slab rising
Foam goes in through a small port, fills the void and lifts the slab. Illustration: ArmorFoam Lift.
Head to head

Mudjacking vs polyjacking: side by side

Polyjacking wins on weight, hole size, speed and water resistance. Mudjacking wins on price, material strength and recyclability. Both lift a slab back to grade, and both fail the same way when water keeps washing soil out from under it. Here are the published numbers next to each other, with where each one comes from.

FactorMudjackingPolyjackingSource
Installed cost$4–$9 per sq ft ($3–$8 on Angi)$8–$25 per sq ft ($5–$25 on Angi)HomeGuide Nov 2025; Angi 2026
Minimum job$300–$700+; about $500 on Angi$300–$700+HomeGuide; Angi
Material weight100–125 lb/ft³2.5 lb/ft³ (Lift 200), 3.75 (Lift 300); 2–6 lb/ft³ across published productsNJIT paper; ArmorThane; Mr. Level
Material strengthTypically under 1,000 psi, adjustable with cement27–121 psi across one maker's 2.8–6 lb/ft³ line; NJIT cites 50–100NJIT paper; NCFI
Hole size1½–2 in. (1⅝ in. per Angi)About ⅝ in.HomeGuide; Angi
Hole spacing4–6 ft apartSet by the installerAngi
Back in useAbout 24 h; full cure 24–72 hCures in about 15 min; drive on within 30 minAngi; HomeGuide; ArmorThane
WaterMineral grout; doesn't stop the water that caused a washoutClosed-cell, hydrophobic (Lift 200/300); doesn't stop the water eitherArmorThane
Cold weatherUsable in colder temperaturesLift 200/300 can be injected in cold, damp or wet conditions; one other maker says not below 40°FNJIT paper; ArmorThane
Field control (one study)Faulting cut 1–2 mm; still moved slabs more than the 1.3 mm spec allowedFaulting cut 2–5 mm; moved slabs more than allowed, and the authors flagged foam for tighter process controlIowa State, 2016
End of lifeGrout crushes with the concrete for recyclingFoam has to be removed before the concrete is recycledNJIT paper
HazardsWet cement is caustic; drilling makes silica dustIsocyanates before cure; drilling makes silica dustNJIT; OSHA
DIYPossible with a rented grout pump, but hardNot realistic without a rigA1 Concrete Leveling; our view
Published lifespan claims5–10 years or more10–15 years or moreHomeGuide (claims, not studies)
Green marks the side with the advantage on that line, red the side at a disadvantage. The NJIT paper is by two NJIT engineering professors and is published by a mudjacking contractor; we quote it because it's the strongest documented case for grout.

Where polyjacking wins

  • Weight on weak soil. Filling a 2-in. void with grout adds 17–21 lb per square foot. With Lift 200 it's under half a pound. That matters most on soft fill, which is often what settled in the first place.
  • Holes. A 1⅝-in. hole has about 6.8 times the area of a ⅝-in. hole (our math). On stamped, colored or pool-deck concrete, smaller patches are easier to live with.
  • Speed. A driveway or garage can take a car within about 30 minutes, against a day or more with grout.
  • Water. Lifting foam is closed-cell and hydrophobic, and ours is made to be injected into damp or wet ground.
  • Tight spots and indoors. Our Lift product pages describe a portable resin pump instead of concrete mixers on site. That's easier in a garage, a basement or a fenced back yard.

Where mudjacking wins

  • Price. About half the cost per square foot on both HomeGuide's and Angi's ranges.
  • Strength. Grout typically runs under 1,000 psi and can be mixed stronger. One foam maker's lifting line runs from 27 psi at 2.8 lb/ft³ to 121 psi at 6 lb/ft³ (NCFI). Even 27 psi is about 3,900 lb per square foot, above the 3,000 psf the building code presumes for gravel, so strength rarely decides a driveway. But the gap is real.
  • A tunable mix. The contractor can change cement, sand and water for the job. Foam is a factory product with fixed properties.
  • Recycling. When the slab is finally replaced, grout crushes with the concrete. Foam has to be scraped off first (NJIT).
  • No isocyanates. Wet cement still needs gloves and eye protection, but there's no reactive chemistry on site.

Where it's a draw

Both need a slab that's still in one piece, or in a few big pieces. Both leave patched holes. Both fill voids as well as lift. Neither stops a downspout from dumping water under the slab or a clay soil from shrinking in the next drought, and neither is a structural foundation repair. If you take one thing from this page, take that: the method matters less than whether anyone fixes the reason the slab sank.

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How much does mudjacking cost vs polyjacking?

Mudjacking costs about $4–$9 per square foot and polyjacking about $8–$25 (HomeGuide, Nov 2025). Angi's 2026 figures are $3–$8 and $5–$25. On a 100 sq ft sidewalk that's roughly $400–$900 against $800–$2,500. Small jobs cost more per foot because most contractors carry a $300–$700 minimum charge.

Guides don't agree to the dollar. Our concrete leveling cost guide takes the median of six publishers and lands at about $3–$7 per sq ft for mudjacking. The calculator lets you switch between the two sources we quote here.

Cost comparison

What will lifting cost, and which method is cheaper per year?

Uses published per-square-foot ranges and your minimum charge. The lifespans default to the midpoints of HomeGuide's published claims; change them to whatever your quotes or warranties say.

Only the sunken part
Published: $300–$700+
$650
Mudjacking ($500–$900)
$1,650
Polyjacking ($800–$2,500)
$1,050
Tear out and replace ($600–$1,500)
2.5×
Foam price vs mudjacking
Mudjacking
$650
Stone slurry
$1,050
Polyjacking
$1,650
Replace the slab
$1,050

At middle HomeGuide (Nov 2025) prices for 100 sq ft: mudjacking $650 (about $87 per year over 7.5 years) and polyjacking $1,650 (about $132 per year over 12.5 years). Foam costs 2.5× as much here, so it has to last 2.5× as long to match on cost per year; the lifespans you entered are a 1.7× ratio. On these numbers mudjacking costs less per year. Foam still earns its price where weight, speed, water or hole size matter. Replacement is shown for comparison and doesn’t include fixing the soil either. Ask a certified applicator for a real quote.

How we calculated this: lifting cost = the larger of your minimum charge or area x rate; replacement = area x rate. Rates per sq ft (low / middle / high): HomeGuide mudjacking $4 / $6.50 / $9, polyjacking $8 / $16.50 / $25, stone slurry $6 / $10.50 / $15 (derived from its project table), replacement $6 / $10.50 / $15. Angi mudjacking $3 / $5.50 / $8 (Aug 2026) and polyjacking $5 / $15 / $25 (July 2026); Angi doesn't publish the other two, so they use HomeGuide's. Cost per year = cost ÷ the life you enter. Estimates only: void size, access and your local market move real quotes.

Published costs by project

Project (HomeGuide size)Mudjacking (HomeGuide)Mudjacking (Angi)Stone slurry (HomeGuide)Polyjacking (HomeGuide)
Steps (40 sq ft)$300–$700–$240–$600$320–$1,000
Sidewalk (100 sq ft)$400–$900$300–$900 (50–150 sq ft)$600–$1,500$800–$2,500
Patio or porch (150 sq ft)$600–$1,400$500–$1,500 (100–300 sq ft)$900–$2,300$1,200–$3,800
Garage floor (360 sq ft)$1,400–$3,200$700–$2,000 (150–400 sq ft)$2,200–$5,400$2,900–$9,000
Pool deck (400 sq ft)$1,600–$3,600$800–$2,500 (150–500 sq ft)$2,400–$6,000$3,200–$10,000
Driveway (450 sq ft)$1,800–$4,100$800–$2,400 (200–600 sq ft)$2,700–$6,800$3,600–$11,300
Basement floor (800 sq ft)$3,200–$7,200–$4,800–$12,000$6,400–$20,000
HomeGuide concrete leveling cost (Nov 2025) and Angi mudjacking cost (Aug 2026); Angi's project sizes are in parentheses. Tap a column heading to sort. The concrete leveling cost guide adds replacement, driveway and quote-checking detail.

Why small jobs cost more per square foot

Much of a lifting bill is showing up: the truck, the pump, drilling and cleanup cost nearly the same for one step as for a whole walk. Angi's size table shows it plainly: mudjacking a 50 sq ft slab works out to $12–$14 per sq ft, while 800 sq ft comes down to $3.50–$5. If you have two or three problem slabs, get them quoted as one visit.

Cost per year: the math most comparisons skip

Here's where we part ways with most foam sellers. At HomeGuide's midpoints, polyjacking costs about 2.5 times as much as mudjacking per square foot. HomeGuide's own lifespan claims (5–10 years or more for leveled concrete, 10–15 or more for foam) are a ratio of about 1.7. So on a plain sidewalk, on those numbers, mudjacking costs less per year of service.

The math flips when foam comes in at the low end of its range, when minimum charges make the two prices close, or when something besides price matters: a garage you need back tonight, soft fill that shouldn't carry more weight, a finished surface where big patches would show. That's the honest version of "foam is worth it." Sometimes it is, sometimes it isn't.

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Does the weight of mudjacking really matter?

Sometimes. Mudjack grout weighs 100–125 lb per cubic foot, 40 to 50 times more than ArmorFoam Lift 200 at 2.5 lb. Filling a 2-in. void with grout adds about 17–21 lb per square foot, a third or more of a 4-in. slab's own weight. On firm soil that's a small fraction of what the ground can carry. On soft or unprepared fill, it's extra load on the soil that already failed.

Fill & weight calculator

How much material goes under the slab, and what does it weigh?

Measure the sunken slab and how far it dropped at its low point. The calculator estimates the void, the grout and foam it takes, the load each adds, and how many mudjacking holes to expect.

Washout you can see or probe
8.3 ft³
Void to fill
833–1,042 lb
Mudjack grout
21 lb
Lifting foam at 2.5 lb/ft³ (free-rise)
+17–21%
Grout vs the slab's own weight
Slab alone, 4 in. (psf)
50
Slab + grout fill (psf)
58–60
Slab + foam fill (psf)
50

Void: 100 sq ft x 1 in. average depth = 8.3 ft³ (0.31 cubic yards). Grout adds 8.3–10.4 psf to the soil; foam adds 0.21 psf. That’s about 40–50 times the weight in grout.

Soil load

About 0.6–0.7% of presumptive bearing added by grout

The slab plus grout fill is 3.9–4.0% of the 1,500 psf IBC presumptive value; with foam, 3.3%. On firm soil like this the added weight is small. It matters more if the soil was loose or wet enough to settle in the first place.

Holes

Mudjacking: about 3–7 holes

On Angi’s 4–6 ft spacing. At 1⅝ in. each that’s 6.2–14.5 sq in. of drilled and patched concrete. A ⅝-in. foam hole is 0.31 sq in., 6.8 times smaller; the installer sets how many.

Before you get quotes

What to ask

  • Foam figures use free-rise density. Foam confined under a slab can end up denser, so treat foam pounds as a floor.

How we calculated this: void = length x width x (drop x shape factor + extra void) ÷ 12, with shape factors of 1 (even), ½ (one edge) and ¼ (one corner). Grout at 100–125 lb/ft³ (NJIT paper); foam at the product's free-rise density. Foam confined under a slab can end up denser than that, so treat the foam figure as a floor. Slab weight at 150 lb/ft³ for normal concrete. Mudjacking holes on a 4–6 ft grid (Angi). Soil values are IBC Table 1806.2 presumptive bearing values; they're code defaults for design, not a soil test.

The weight, against what the soil can carry

The International Building Code gives "presumptive" load-bearing values that designers can use without a soil test. Here's a 4-in. slab with a 2-in. void filled each way, against those values.

Soil (IBC Table 1806.2)Presumptive bearingSlab + 2 in. of grout (67–71 psf)Added by the grout aloneSlab + 2 in. of Lift 200 (50.4 psf)
Sandy gravel and gravel (GW, GP)3,000 psf2.2–2.4%0.6–0.7%1.7%
Sand, silty or clayey sand, silty or clayey gravel2,000 psf3.3–3.5%0.8–1.0%2.5%
Clay, sandy or silty clay, silt, sandy silt1,500 psf4.4–4.7%1.1–1.4%3.4%
Mud, organic silt or clay, peat, unprepared fillNone assumedThe code says these soils "shall not be assumed to have a presumptive load-bearing capacity" without data.
Our calculation: concrete at 150 lb/ft³ (a 4-in. slab is 50 psf), grout at 100–125 lb/ft³, Lift 200 at 2.5 lb/ft³. Presumptive values from IBC Table 1806.2 (2021 text). Vehicle and foot loads come on top and aren't shown.

The case that weight doesn't matter

The NJIT paper makes it directly: even a foot of grout adds only about 5% of the 1,500–3,000 psf that sands, silts and clays typically carry, which it calls negligible. On firm native soil our table agrees. A couple of inches of grout adds about 1% of the clay value. If your slab sank because a downspout washed out a pocket under one corner and the soil around it is sound, grout's weight isn't a good reason to pay double.

Where it does matter

Look at the bottom row. The code won't assign any bearing value to unprepared fill, organic soil or mud without testing, and that's exactly the soil under a lot of sunken slabs: loose backfill next to a newer house, a patio poured over topsoil, a walk over an old stump hole. Settlement is the soil telling you it's already compressing. Adding 17–21 lb per square foot, plus more at every re-lift, doesn't help. On that kind of ground we'd choose foam, and we'd still expect the slab to move again if the fill keeps consolidating.

One more nuance. Foam isn't weightless in practice. A big washout can swallow a lot of it, and the reaction gives off heat, so we'd fill big voids in stages rather than in one large shot. Probe the voids before anyone prices a foam job.

Durability

How long does mudjacking last compared with polyjacking?

Published consumer guides put professionally leveled concrete at 5–10 years or more and polyjacking at 10–15 years or more (HomeGuide). Angi says mudjacking can last many years, even decades. Those are estimates, not study results. How long either lasts depends mostly on the soil and water under the slab, not on what was pumped there.

What the research actually says

We looked for independent, long-term studies of residential slabs lifted each way and didn't find one. The closest is a peer-reviewed field comparison by Iowa State researchers (Vennapusa, Zhang and White, 2016), who stabilized sections of a deteriorating concrete pavement with injected foam and with cementitious grout, then tested them with a falling-weight deflectometer. Both methods significantly improved load transfer at joints and cracks. Foam reduced faulting by about 2–5 mm and grout by 1–2 mm, but both moved the slabs more than the 1.3 mm the spec allowed, and the authors called for tighter process control, "particularly with the injected-foam stabilization method."

That's a highway pavement, not a driveway, and it measured the result right after the work, not ten years later. What it does show is that both methods work when they're controlled, and that foam's speed cuts both ways: it lifts fast, so an operator has to watch it closely.

Why lifted slabs sink again

  • The water is still there. A downspout, a leaking line or runoff that washed soil out once will do it again, under grout or foam. Our foundation waterproofing guide covers grading and drainage around the house.
  • The fill is still settling. Loose backfill and organic soil keep compressing for years. Lifting the slab doesn't compact what's below the void.
  • The void wasn't filled. A slab that's lifted but not fully supported can crack or drop. A1 Concrete Leveling warns that a DIY lift likely won't last if the voids aren't filled.
  • Clay soil moves with the seasons. Clays shrink when they dry and swell when wet; a slab lifted in a wet spring can sit differently in a dry August.
  • The load changed. A walkway that becomes a parking pad, or a patio that gets a hot tub, is carrying something it wasn't built for.

Is mudjacking permanent? Is polyjacking?

Neither is permanent in any guaranteed sense, and a contractor who promises "lifetime" should show you exactly what the warranty covers: re-lifting? The same slab only? For how long, and what voids it? Our own lifting-foam page talks about foam lasting the life of the concrete with proper application. That's possible when the soil is sound and the water is handled. It isn't something any material can promise over a washout.

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Mudjacking or polyjacking: which fits your slab?

Choose mudjacking for a sound slab on firm soil when price matters most. Choose polyjacking when weight, hole size, speed or water matter, or when the slab is indoors. Replace the slab if it's broken into loose pieces. And if the house itself is settling, call a foundation contractor; lifting the walk won't fix a footing.

Method chooser

Which lifting method fits my slab?

Answer what you know. The chooser weighs price, weight, speed and appearance, and flags the cases where lifting isn't the right repair at all.

Doing it yourself?
Our lean: MudjackingGood fit for your priorities
Mudjacking
4 pts
Polyjacking
0 pts
Points for mudjacking

2 reasons

  • Mudjacking costs about half as much per sq ft ($4–$9 against $8–$25, HomeGuide).
  • A plain sidewalk on firm soil is the classic mudjacking job.
Points for polyjacking

Nothing specific here

Foam’s advantages (weight, small holes, speed) don’t line up with what you told us, so the cheaper method is a fair choice.

Before you book

Check these

  • Find out why it sank before anyone lifts it: downspouts, leaks, grading, loose fill. The fix is only as good as that answer.
  • Watch where the water goes in the next hard rain before you book the lift.

A screening tool, not an inspection. Scores weigh published cost, weight, cure-time and hole-size differences against the priorities you picked.

When to replace the slab instead

Lifting needs something to lift. If the slab is broken into loose pieces, crumbling or badly spalled, if tree roots have heaved it, or if you want to change its shape or grade a lot, replacement is the better money. HomeGuide puts replacement at $6–$15 per square foot and says mudjacking runs 30–50% less. That gap only matters if the slab is worth saving.

When it's a foundation problem, not a slab problem

Sinking walks and patios are usually a surface-soil problem. Stair-step cracks in brick, doors that stick, a wall pulling away from the chimney or a sloping floor inside are different: that's the structure moving, and the fix is usually piers or other foundation work, not slurry or foam under a patio. HomeGuide does list slabjacking for slab foundations, but on a house it's an engineer's call first. Our foundation repair guide walks through piers, wall anchors and crack injection.

Small lips: grind before you lift

A lip under ¼ in. is allowed to stay vertical under the ADA's accessibility standards, and one between ¼ and ½ in. only needs a bevel no steeper than 1:2. Grinding a small lip down, as A1 Concrete Leveling also suggests, is often the cheapest fix. Past ½ in., the ADA wants a ramp, and on a home walkway that's your cue to lift.

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How much lift should you ask for? Slope and trip-hazard check

Don't ask for "level." A slab next to the house should fall at least 2% away from it, about ¼ in. per foot, so water runs off; the building code asks for that on impervious surfaces within 10 ft of a foundation (IBC 1804.4). And a lip over ½ in. at a joint is a trip hazard by the ADA's measure. This check turns tape-measure readings into a lift target.

Slope & lip check

How much should the house edge come up?

Lay a straight board or string across the slab, from the edge nearest the house to the far edge, and level it. Measure how far each edge sits below it. Enter the difference: positive if the house edge is higher, negative if it's lower.

Negative = slopes toward the house
−0.42%
Slope now
2.4 in.
Fall needed at 2%
2.9 in.
Lift at the house edge
Trip hazard
Joint lip (ADA 303)

The slab tips toward the house by 0.5 in. over 10 ft, sending water at the foundation. To reach 2% it needs 2.4 in. of fall: ask to raise the house edge about 2.9 in. and hold the far edge where it is. A 0.75-in. lip is over the ADA’s ½ in. limit for an unramped change in level. Lift the low slab at least that much at the joint.

How we calculated this: slope now = height difference ÷ (run x 12) x 100; fall needed = run x 12 x target slope; lift at the house edge = fall needed minus the current difference, holding the far edge where it is. Lip thresholds from the 2010 ADA Standards, 303.2–303.4. The ADA governs public spaces, not your private walk, but its thresholds are a sensible benchmark for trips.

Why "level" is the wrong target

A slab lifted dead level against the house sends rain nowhere, and a slab that still tips toward the house sends it straight at the foundation. That's how a sunken patio becomes a wet basement. Ask your installer to hit a number: "raise the house edge 2 in. and hold the far edge," or "¼ in. per foot of fall away from the wall." Sidewalks and walkways have one more limit if you want them comfortable to walk: the ADA caps the running slope of a walking surface at 1:20 (5%) and the cross slope at 1:48 (about 2%).

Measure the lip the right way

Lay a straightedge on the higher slab so it overhangs the joint, then measure straight down to the lower slab. Measure at the worst point along the joint, since slabs usually tilt. A ½-in. lip is enough to catch a toe.

Step by step

What happens on lifting day

A residential lift can take as little as a few hours; Groundworks puts most jobs at less than a day. The crew checks what's under the slab, drills, pumps or injects in small increments while watching the slab rise, fills the remaining void, patches the holes and seals the joints. Foam jobs are back in service within about 30 minutes; grout needs a day or more.

  1. Look before drilling

    A good installer walks the slab, finds the low points, checks where water comes from and asks about utilities, irrigation and pool lines under the slab. On a foam job, probing the voids first matters: big washouts take a lot of foam, and we'd fill them in stages.

  2. Drill the holes

    1½–2 in. for mudjacking, about ⅝ in. for foam. Drilling concrete throws silica dust, and OSHA's construction standard expects handheld drills to use a shroud with dust collection and a HEPA vacuum to clean the holes.

  3. Pump or inject, a little at a time

    The operator fills the void first, then lifts in small increments from hole to hole while someone watches a level, laser or string line. Overlifting cracks slabs, and the Iowa State study shows how easily both methods move a slab more than intended.

  4. Fill the rest of the void

    Once the slab is at height, the remaining space under it gets filled so it's supported, not just propped up at a few points.

  5. Patch the holes

    Holes get a cement patch. It won't match old concrete exactly, which is one reason ⅝-in. foam holes are easier to live with than 2-in. mudjack holes.

  6. Seal joints and cracks

    Caulk the joints between slabs and along the house so water can't get back under. A1 Concrete Leveling ends its own process the same way.

  7. Use it again

    Foam: drive on it within about 30 minutes (ArmorFoam Lift). Grout: about 24 hours before regular use, 24–72 hours for a full cure (Angi).

After the lift: cracks, joints and sealing

Lifting closes the step at a crack; it doesn't heal the crack. Expect the old cracks and the patched holes to stay visible, and plan to keep the joints sealed. On driveways and garage aprons, a penetrating sealer or coating after the lift helps keep water and deicing salt out of the concrete; our concrete driveway sealer page compares the options.

Do it yourself?

Can you mudjack or polyjack yourself?

Mudjacking yourself is possible but hard. You need a hydraulic grout pump, a hammer or core drill, a slurry you can control and a way to watch the lift, per A1 Concrete Leveling's DIY guide. DIY polyjacking needs heated two-part equipment and isocyanate handling that doesn't fit a weekend. For a lip under ½ in., grinding is the realistic DIY fix.

A1's walkthrough runs seven steps: plan the lift, drill 2–2½ in. holes, mix the slurry, pump it, cut the slab where it's bound up, patch the holes and caulk the joints. It's honest about the risks: overlifting, cracking the slab and leaving voids, with the warning that a DIY job likely won't last long if the voids aren't filled. It also says DIY may cost nearly as much as hiring a pro, partly because grout pumps aren't easy to find.

Foam is harder to DIY than grout, not easier. Lifting foam comes as two reactive liquids that have to be metered, heated and mixed at the gun, and the A-side is an isocyanate. OSHA names occupational asthma and other lung problems as the main effects of hazardous isocyanate exposure. People do search for DIY polyjacking kits. We haven't tested any, so we can't tell you how much slab one will lift or how evenly.

Before you drill anythingFind out what's under the slab: irrigation lines, gas or electric service to a detached garage, pool plumbing, radiant heat. And fix the water first. A DIY lift over an active washout is money pumped into a hole.
The fine print

Is polyjacking safe, and is it bad for the environment?

Cured lifting foam is an inert plastic sitting under the slab; ArmorFoam Lift is made to cure fully to an inert polymer even in damp ground. The hazards are during installation. Uncured polyurethane chemistry contains isocyanates; OSHA says the main effects of hazardous exposure are occupational asthma and other lung problems, plus eye, nose, throat and skin irritation. Mudjacking has hazards of its own: wet cement is caustic, and drilling concrete makes silica dust with either method.

The environmental case against foam

The NJIT paper makes three points worth taking seriously. Foam is made from petroleum-derived chemicals. It has to be removed before a lifted slab can be crushed and recycled as aggregate, which makes landfilling more likely. And the foam reaction gives off heat: the paper cites a 2010 case in Vancouver where foam under slabs caught fire. The practical lesson for crews is the one above: explore the void, and fill big ones in stages rather than one large shot.

And the case for it

A foam lift moves very little material. In our fill calculator's default sidewalk, that's about 21 lb of Lift 200 against 833–1,042 lb of grout. Our Lift product pages describe a portable resin pump in place of concrete mixers, and ArmorFoam Lift is water-blown. Both lifting methods also avoid what the NJIT paper calls the "excess waste" of demolishing and replacing a slab, which is the real alternative most homeowners are weighing.

For crews: the two hazards to plan for

  • Silica. OSHA's construction silica standard (1926.1153) sets a permissible exposure limit of 50 µg/m³ over 8 hours. Its Table 1 entry for handheld and rotary hammer drills calls for a shroud or cowling with dust collection and a HEPA vacuum to clean holes, with no respirator required when that's followed.
  • Isocyanates. Follow the foam manufacturer's SDS for gloves, eye protection and respiratory protection, keep bystanders back during injection, and store and heat the chemicals within the maker's limits.
ArmorThane lifting foam

Polyjacking with ArmorFoam Lift 200 and Lift 300

We make two lifting foams. ArmorFoam Lift 200 is a two-component, closed-cell, water-blown, rigid slab-jacking foam at 2.5 lb per cubic foot, made for residential patio slabs, driveways and sidewalks, and for lifting concrete or asphalt. ArmorFoam Lift 300 is the heavier version, 3.75 lb per cubic foot, for commercial and industrial slabs and higher dead-weight loads. Both are hydrophobic, can be injected into cold, damp or wet ground, and can be driven on in 30 minutes or less.

Honest take: if your slab is a sidewalk on firm ground and budget is what matters, a good mudjacking contractor is a reasonable choice, and we'd tell you so. If you're dealing with soft fill, a washout, a garage you need back today or a finished surface where big patches would show, foam earns its price. Not every ArmorThane applicator does concrete lifting, so ask when you call. More on the method on our foam concrete lifting page and across the ArmorFoam product line.

Find a lifting applicator →Foam concrete lifting
Two 55-gallon drums of ArmorFoam Lift 200 concrete lifting foam, a black A-side drum and a blue B-side drum
ArmorFoam Lift 200, A-side and B-side drums.
2.5 lb/ft³

Lift 200

Residential slabs: patios, driveways, sidewalks, pool surrounds.

3.75 lb/ft³

Lift 300

Commercial and industrial slabs and higher dead-weight loads.

≤30 min

Back in service

Both may be driven on within 30 minutes or less after installation.

For contractors

Add polyjacking to your rig.

Published installed prices for foam lifting run about 2½ times mudjacking's per square foot (HomeGuide). If you already spray foam or coatings, ask us whether your rig can run Lift foam. We supply ArmorFoam Lift 200 and Lift 300, build custom rigs and train crews at your location. Not a franchise: no franchise fee, no royalties, and startup packages from $25,000.

Become an applicatorStart a foam business

See the equipment: custom mobile foam rigs → · why we're not a franchise →

Straight answers

Mudjacking and polyjacking FAQ

What is mudjacking?

Mudjacking, also called slabjacking, lifts a sunken concrete slab by pumping a cement-based slurry under it through holes about 1½–2 in. across. The slurry fills the void, pressure builds and the slab rises, and then the holes are patched. It's the older and cheaper of the two main lifting methods, at about $4–$9 per square foot (HomeGuide, Nov. 2025).

Is polyjacking better than mudjacking?

Polyjacking is lighter, uses smaller holes and gets the slab back in service faster, and closed-cell lifting foam doesn't soak up water. Mudjacking is cheaper and its grout is much stronger. For a sound slab on firm soil where price matters most, mudjacking is a fair choice. For soft fill, washouts, garages and finished surfaces, we'd pick foam. The method chooser weighs your case.

How much does mudjacking cost?

HomeGuide puts it at $4–$9 per square foot (Nov. 2025) and Angi at $3–$8, with a national average of $1,235 (Aug. 2026). Most contractors charge a $300–$700 minimum, so a single step costs far more per foot than a driveway. A 100 sq ft sidewalk runs about $400–$900.

How much does polyjacking cost?

About $8–$25 per square foot on HomeGuide's figures; Angi's range is $5–$25 (July 2026). That's about $800–$2,500 for a 100 sq ft sidewalk and $3,600–$11,300 for a 450 sq ft driveway (HomeGuide). The size of the void under the slab drives how much foam a job takes, so two slabs the same size can price very differently.

How long does mudjacking last? Is it permanent?

HomeGuide says professionally leveled concrete lasts 5–10 years or more, and Angi says mudjacking can last many years, even decades. Neither method is permanent in any guaranteed sense. If water keeps washing soil out or soft fill keeps compressing, the slab can drop again, so fixing the cause matters more than the material.

How long does polyjacking last?

HomeGuide says 10–15 years or longer. We couldn't find an independent long-term study of residential slabs showing that foam outlasts grout; the one peer-reviewed field comparison we found (Iowa State, 2016) measured pavement right after stabilization. The soil and drainage under the slab decide it.

Why is mudjacking considered bad?

Critics point to the weight (100–125 lb per cubic foot of grout), bigger holes, a day or more before use, and slabs that settle again. Some of that is fair. But a peer-reviewed field test found both methods improved slab support, and an NJIT paper shows grout's added weight is small next to what firm soil can carry. On sound soil, mudjacking is a legitimate repair.

Can you mudjack or polyjack concrete yourself?

Mudjacking is possible but hard: you need a hydraulic grout pump, a hammer or core drill, a workable slurry and a way to watch the lift, and A1 Concrete Leveling warns that a DIY lift likely won't last if the voids aren't fully filled. Polyjacking needs heated two-part equipment and isocyanate handling that doesn't fit a weekend. For a lip under ½ in., grinding it down is the realistic DIY fix.

How soon can I drive on a lifted slab?

After polyjacking, usually within about 30 minutes: our ArmorFoam Lift 200 and Lift 300 pages say 30 minutes or less, and HomeGuide says the foam cures in about 15. After mudjacking, plan on at least 24 hours before regular use, with full cure in 24–72 hours (Angi). Your installer's instructions govern.

Can you mudjack or polyjack a house foundation?

Slab foundations are sometimes lifted; HomeGuide lists a 1,500 sq ft foundation at $6,000–$13,500 for mudjacking and $12,000–$37,500 for foam. But cracking walls, sticking doors or a sinking footing are structural problems: get a structural engineer or foundation contractor, because piers carry a settling foundation down to competent soil. Our foundation repair overview covers the options.

Is polyjacking bad for the environment?

It's a petroleum-based plastic, and an NJIT paper notes the foam has to be removed before a lifted slab can be recycled as aggregate. On the other side, a foam job hauls a few dozen pounds of material instead of half a ton or more of grout, and ArmorFoam Lift is water-blown and cures to an inert polymer. Both methods avoid the demolition waste of a full tear-out.

Can you mudjack or polyjack in the winter?

Grout can be placed in colder weather (NJIT), and ArmorFoam Lift is made to be injected into cold, damp or wet conditions, though at least one other foam maker advises against use below 40°F. Frozen ground is the bigger issue. We'd wait until the soil under the slab has thawed, because a slab lifted on frozen ground can move again when it thaws.

Will lifting fix the cracks in my concrete?

No. Lifting closes the step at a joint or crack, but the crack stays. Seal joints and cracks afterward so water doesn't get back under the slab; A1 Concrete Leveling's process ends with caulking joints for the same reason. A slab broken into loose pieces is usually better replaced.

AT
ArmorThane Technical Team · Springfield, Missouri
Written from manufacturer data sheets, published cost guides, code text and 35+ years of making polyurethane systems. Last updated September 26, 2026.

Methodology and sources

Installed prices are published ranges from HomeGuide (Nov 2025) and Angi (July and Aug 2026), not a survey of our applicators. Material weights and strengths come from the NJIT white paper and ArmorThane product data; soil values from IBC Table 1806.2; slope and trip thresholds from IBC 1804.4 and the 2010 ADA Standards. Calculations are ours and are screening estimates, not a substitute for an on-site inspection.

  1. HomeGuide, mudjacking cost (Nov. 2025): homeguide.com/costs/mudjacking-cost
  2. HomeGuide, polyjacking cost: homeguide.com/costs/polyjacking-cost
  3. HomeGuide, concrete leveling cost (Nov. 2025): homeguide.com/costs/concrete-leveling-cost
  4. Angi, how much does mudjacking cost (Aug. 2026): angi.com/articles/how-much-does-mudjacking-cost.htm
  5. Angi, what is mudjacking (July 2026): angi.com/articles/what-is-mudjacking.htm
  6. Vennapusa, Zhang and White, pavement slab stabilization with cementitious grout vs injected polyurethane foam, J. Perform. Constr. Facil. (2016): doi.org/10.1061/(ASCE)CF.1943-5509.0000916
  7. Adams and Bandelt (NJIT), Advantages of Mud-Jacking Grout for Use in Slab Leveling (white paper, 2021, PDF): concretechiropractor.com/wp-content/uploads/2021/07/White_Paper_Rev_Ju
  8. IBC Table 1806.2, presumptive load-bearing values (UpCodes): up.codes/s/presumptive-load-bearing-values
  9. NCFI, dual-component geotechnical foams (density and compressive strength): ncfi.com/geotechnical-products/dual-component-systems
  10. IBC 1804.4, site grading (UpCodes): up.codes/s/site-grading
  11. U.S. Access Board, 2010 ADA Standards, sections 303 and 403: access-board.gov/ada/
  12. OSHA 29 CFR 1926.1153, respirable crystalline silica: osha.gov/laws-regs/regulations/standardnumber/1926/1926.1153
  13. OSHA, Isocyanates: osha.gov/isocyanates
  14. Groundworks, what is mudjacking (Aug. 2026): groundworks.com/resources/what-is-mudjacking/
  15. Mr. Level, polyjacking vs mudjacking (Oct. 2022): mrlevel.com/polyjacking-vs-mudjacking-what-it-is-and-which-is-the-bett
  16. A1 Concrete Leveling, DIY mudjacking (Aug. 2025): a1concrete.com/concrete-repair-learning-center/diy-mudjacking
  17. Wikipedia, properties of concrete (density): en.wikipedia.org/wiki/Properties_of_concrete
  18. ArmorThane, ArmorFoam Lift 200: armorthane.com/products/armorfoam-products/lift-200/
  19. ArmorThane, ArmorFoam Lift 300: armorthane.com/products/armorfoam-products/lift-300/
  20. ArmorThane, foam concrete lifting: armorthane.com/protective-coatings/foam-concrete-lifting/

latest news & bLOGS

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Lift it once, and fix the water.

ArmorThane applicators who do concrete lifting inject ArmorFoam Lift through ⅝-inch holes and put the lift height in writing. Contractors: we make Lift 200 and Lift 300, build the rigs and train your crew, with no franchise fee and no royalties.

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