A slab lift guide 24 covering licenses and first jobs

Last updated 2026-08-21

What is slab lift?

Slab lift raises a sunken concrete slab by pumping material underneath it until the panel comes back toward level. Crews drill a pattern of holes, inject grout or expanding polyurethane, watch the lift with a level or laser, then patch the holes. That is the whole method.

You are not building new concrete. You are filling voids and putting support back under what is already there. Driveways, garage floors, sidewalks, patios, pool decks, and warehouse slabs are the usual private jobs. Highway crews do a heavier cousin called slab stabilization on pavement panels.

Two materials dominate. Cementitious grout (people still say mudjacking or slabjacking) is a slurry pumped under the panel. Polyurethane foam is a two-part mix that expands and sets fast. Foam usually means smaller holes and less added weight. Grout is heavy, slower, and often cheaper per unit volume. I would pick foam on interior floors and on soils that cannot take more load. I would still use grout on some exterior flatwork if the price and the soils fit.

Do not treat lift as a personality brand. It is a structural patch. If water is still washing soil out, if tree roots are still heaving the panel, or if the slab is broken into loose pieces, you are selling theater. Tear-out and replace is the honest job then.

Highway preservation texts treat underslab grouting as void filling and support restoration, not as a crack cure. The Concrete Pavement Preservation Guide (FHWA HIF-14-004) frames slab stabilization that way ^[12]. House slabs follow the same physics, just with nicer landscaping in the way.

A clean lift still leaves the original concrete in place. Hairline cracks may close a bit. They will not vanish. Tell the owner that before you bid, or you will eat a callback.

The name on the invoice can say slab lift, slabjacking, polyjacking, or foam injection. Owners do not care about the trademark. They care whether the door swings and whether the puddle at the garage goes away.

How do you start slab lift?

You start slab lift by building a contractor shop that can legally drill, inject, and warrant concrete work. Buying a foam gun and printing door hangers is not a start. Form an entity, get an EIN if you will hire or if a bank or carrier wants one, confirm the license class with the state or city board, bind insurance that names slab jacking or polyurethane injection, and write your silica and hazard-communication programs before the first hole ^[8][2][1].

I would not skip the board call. Classes differ. Some states park this under concrete. Some park it under a specialty or repair class. Some cities add a local card on top. Confirm the class, the test, and the current fee with that board. I will not invent a fee or a wait time. Those change, and a wrong number here is worse than no number.

SBA puts the entity choice in plain English: "The business structure you choose influences everything from day-to-day operations, to taxes, to how much of your personal assets are at risk." ^[9] Sole prop is simple and leaves your house exposed. An LLC costs more paper and is what I would file if this is real work, not a one-off favor.

IRS Publication 334 is the small-business tax guide you actually use for records, vehicle costs, and materials ^[7]. Keep invoices and mix logs like you expect an audit, because foam drums and grout tickets are easy to lose. The EIN application is online and free on the IRS site when you need one for payroll, a business bank account, or a carrier ^[8].

If a helper shows up more than once, read WHD Fact Sheet 13 before you call that person a contractor ^[11]. The label on the check does not decide the employment test. I have watched shops try to 1099 a full-time hose person. That is how you buy back wages later.

Buy practice time before you buy chrome. A hammer drill, bits, a laser, PPE, and a proportioner or grout pump you were trained on will make money. A wrapped dump trailer will not. Compare this path with nearby trades if you are still choosing slab lift vs nearby career.

Then do three ugly slabs for cost. Friends, your own pad, a throwaway section. Learn how fast foam moves and how little warning a slab gives before it cracks. After that, bid small exterior jobs with access you can see from the street.

The first 90 days are mostly paper, training, and ugly practice. That is normal. Anyone selling you a turnkey income figure is selling a story.

Is slab lift the same as mudjacking or foam injection?

Yes, with a naming mess. Slab lift is the job. Mudjacking, slabjacking, and foam injection are ways to do it. People also say polyjacking or polyurethane slab lifting. Same idea: material goes under the slab, the slab comes up.

Mudjacking uses a cementitious slurry pumped through larger holes sized for that mix and pump. Foam uses smaller holes because the liquid finds voids and then expands. I am not pinning a single hole diameter as a national rule. Crews pick diameter from the equipment and the spec in front of them.

Weight is the real difference. Grout adds mass. That can be useful when you want the slab to sit down and stay. It is a problem on weak fill or on a patio where you do not want more dead load. Foam is light after cure. It fills and lifts without stacking extra weight the way a cement slurry does.

Cure time differs too. Foam can take foot traffic faster. Grout needs more babysitting. Neither one waterproofs a leaking slab edge by itself. You still fix the water.

If a salesperson says their foam is a new category that is not slab lift, they are selling fog. Read the SDS. If it is two-part isocyanate and polyol, it is polyurethane work ^[6].

Approach	What you inject	Typical fit	Poor fit
Mudjacking (grout)	Cementitious slurry	Heavy exterior slabs with room for larger holes	Weak fill that cannot take more weight
Polyurethane foam	Two-part expanding resin	Interiors, tight access, weight-sensitive soils	Owners who will not accept chemical handling rules
Tear-out and replace	New concrete	Shattered slabs, wrong elevation, new finish wanted	Sound slabs where a lift would meet the spec

For a side-by-side of methods, see slab lift guide 12 and slab lift guide 18.

What license do you need to do slab lift work?

You need whatever contractor license or registration your state and city require for concrete repair or specialty concrete, and you confirm that class with the board before you advertise. There is no federal slab lift card.

California is a useful example because the board publishes class text. The CSLB Description of Classifications puts mass, pavement, and flat concrete work under the C-8 Concrete Contractor class ^[10]. That does not mean every foam injection job in every state is a C-8 analog. It means one large state treats flat concrete as a defined trade. Your state may use a general contractor license, a specialty license, or a municipal registration only.

Public sidewalks add another layer. Many cities want a right-of-way permit and specific restoration rules when you drill city concrete. HOA driveways add a third layer that is contractual, not statutory. I would read the permit page before I bid a corner sidewalk. City inspectors do not care that your foam is pretty.

I would not take interior commercial work or post-tension podiums on a handyman card. Post-tension cables and embedded utilities turn a drill pattern into a damage claim. If the board says the work is inside a licensed class, get the class. Testing is cheaper than a stop-work order.

Never list a license number you do not hold. Never imply a manufacturer cert is a state license. Those certs can be useful training. They are not a substitute for the statute.

If you plan to work across state lines, read each state's reciprocity rules yourself. I would start with one state and one metro until the paper is boring. Hard states pile license, local business tax, and picky sidewalk specs on the same job. See The hardest states for slab lift work (and why they hurt).

What OSHA and EPA rules hit a slab lift crew?

Drilling concrete makes respirable crystalline silica. Injecting polyurethane can release isocyanates. Those two facts drive most of the compliance stack on a slab lift truck.

OSHA sets the respirable crystalline silica PEL at 50 μg/m3 as an 8-hour TWA in 29 CFR 1926.1153 ^[1]. The same standard sets an action level of 25 μg/m3 as an 8-hour TWA ^[1]. The rule says: "The employer shall ensure that no employee is exposed to an airborne concentration of respirable crystalline silica in excess of 50 μg/m3, calculated as an 8-hour TWA." ^[1] You either follow Table 1 (for listed tasks like handheld drills with dust control) or you measure and stay under the PEL. I would put water or a vac shroud on the drill from day one. Dry drilling a driveway like you are in a hurry is how you buy a citation and a bad chest.

OSHA Table Z-1 lists a ceiling limit of 0.02 ppm for methylene bisphenyl isocyanate (MDI) ^[4]. Foam A-side is an isocyanate family chemical. NIOSH Alert 96-111 exists because diisocyanate exposure has caused asthma and deaths ^[6]. Once someone is sensitized, later exposures get uglier, not easier. That is why exposure control is not a nice-to-have.

If respirators are required, 29 CFR 1910.134 wants a written program, medical evaluation, and fit testing ^[3]. Hazard communication under 1910.1200 wants SDS access, labeled containers, and training ^[2]. Construction PPE rules in 1926.95 still apply to eyes, hands, and skin ^[14].

I would treat unused mixed foam and solvent wipes as a waste stream you actually characterize, not as household trash. Read the SDS disposal line. Do not invent a dumpster habit.

This is not optional paperwork you grow into. It is the cost of the first hole.

What equipment should you buy first?

Buy diagnosis and dust control first. A rotary hammer, the right bits, a laser or digital level, a moisture meter, a camera for under-slab clues if you have a port, PPE, and a vac or water system for silica. Then buy the injection plant you were trained on.

I would not finance a brand-new truck-mounted foam rig with no booked work. Portable two-component units exist. Used grout pumps exist. Training from the material supplier matters more than the color of the trailer. If you cannot hold a ratio, foam becomes an expensive void that did not lift.

On a used foam plant I would inspect heaters, hoses, the proportioner, and whether the seller will hand you current SDS and a parts list. Mystery resin from a reseller with no paperwork is a waste of money. So is a full vehicle wrap in year one unless you already have a route.

You need a way to move drums or grout bags without wrecking your back. You need cones and a hose ramp because driveways are also roads. You need patch material that matches the slab better than a volcano of gray mud. Manufacturer training days are worth the trip. YouTube is not a proportioner class.

For more gear comparisons in this series, slab lift guide 30 is the next stop.

How do you bid a slab lift job without guessing?

You bid after you know why the slab dropped, how thick it is, whether it is one panel or rubble, where the water is coming from, and what is under it. Square footage alone is a lazy number. Hole count, hose run, furniture or vehicle move, interior vs exterior, and whether you must match decorative concrete all change the day.

I price material with a waste factor because foam goes into voids you cannot see. I price a no-lift clause. If the slab is locked, cracked through, or sitting on a tree root, I walk or I bid replacement. Replacement is not a failure. It is the right scope.

Write the bid so the owner sees what is included: holes, lift to a stated tolerance, patch, cleanup, and what is excluded (drainage, plumbing, color match, hairline cosmetics). Take photos before you touch the slab. A verbal "we'll get it close" is how you donate a Saturday.

If you want a fill-in mix and bid-per-square-foot sheet instead of a blank notebook, SlabLiftPath sells a $149 one-time Mix + Bid-per-Sqft Kit. You do not need it to use anything else on this page.

Watch access. A backyard slab through a gate that will not fit the cart is a different job than a driveway. Watch weather. Grout and foam both have temperature windows. Read the data sheet, not a forum.

A related bid walkthrough lives in slab lift guide 36.

What insurance do slab lift operators carry?

You carry general liability that actually describes concrete raising or polyurethane injection, hired and non-owned or commercial auto, and workers compensation if you have employees or if the jobsite requires it. Many carriers also want a contractors pollution or chemical endorsement once foam drums show up. Confirm forms with a licensed agent who has written concrete repair. I will not invent a premium.

Inland marine or tools coverage is optional until you own a plant you cannot replace from cash. I would buy it once the proportioner costs more than your deductible comfort. Ask the agent what happens if a hose dumps A-side on a finished floor. If the answer is vague, keep shopping.

Certificate requests from GCs will name additional insured and waiver of subrogation. Build that into overhead. Do not start a commercial slab for a handshake. Umbrella coverage starts to make sense when you leave residential driveways and walk onto campuses or loading docks.

Homeowner policies are not your GL. Tell the owner to call their own carrier if they want to know about coverage on the dwelling side. You are not their broker.

Pollution coverage gets declined when shops rinse guns into a storm drain. Do not do that. The SDS and the city both care.

What paper do you keep on every slab lift job?

Keep a job file that would make sense to a claims adjuster two years later. Before photos, after photos, a sketch of hole pattern, start and finish elevations, material product name and lot, amount used, weather, who was on site, and the signed scope.

Keep SDS for every chemical on the truck, plus the written hazard-communication and silica plans ^[2][1]. Keep fit-test and medical records where 1910.134 says to keep them ^[3]. Keep mix tickets. If a helper later claims they were never trained on the A-side, that file is the shop.

IRS Publication 334 expects records that support income and expenses ^[7]. That means invoices, drum receipts, card slips, and mileage if you deduct it. A shoebox works until it does not. I would scan the pile weekly. Foam suppliers do not enjoy reprinting six-month-old tickets.

Warranties should say what you lifted, to what tolerance, and what voids the promise (new water, new fill failure, owner overload, earthquakes). Unlimited lifetime stickers are marketing. I would not print one.

If you work public concrete, keep the permit and the city inspection tag in the same folder. Lost permits turn into stop-work theater.

When should you replace the slab instead of lifting it?

Replace the slab when it is already broken into pieces that will not act as one plate, when thickness is a joke, when post-tension or radiant heat makes drilling reckless, or when the owner wants a new finish anyway. Lift cannot turn rubble into a slab.

Also replace when the grade is so wrong that a lift would create a trip hazard at a door or a drainage trap against the foundation. You can grind or saw after a lift. You cannot invent concrete that is not there.

If a plumbing leak caused the void, fix the leak first. Lifting a slab onto an active leak is a callback with a smell. Dye tests and a plumber cost less than a redo.

I walk away from interior slabs where I cannot confirm utilities. One hit on a conduit or a PEX line wipes the job profit and then some. A cheap scanner is not magic, but it is better than hope.

Owners push lift because it is faster and usually cheaper than tear-out. That is fine when the concrete is sound. It is a bad upsell when you hear hollow fragments underfoot. Say no.

More replacement-versus-lift notes sit in slab lift guide 42.

Which states make slab lift work harder?

States get hard when a state contractor license, a city license, a right-of-way permit, and a picky inspection all stack on a small residential driveway. Some states also treat specialty concrete as a tested class. Some treat it as general contracting over a dollar threshold. Confirm the threshold with the board. I will not post a stale dollar trigger.

Sales tax on labor vs materials differs. So does workers comp for a one-person shop. So does whether foam chemicals trigger extra fire-code storage rules in a rented warehouse. I would read those pages before I sign a lease on a unit with no ventilation.

I would read the contractor board, the SOS entity page, the city business tax page, and the DOT or streets permit page for any metro you want to work. Four sites. An hour. Cheaper than a redo.

Crossing a state line with drums may also raise hazmat questions. Read the SDS transport section and the current PHMSA rules before you assume a pickup load is just freight. When unsure, ask the supplier and the regulator, not a Facebook group.

The comparison piece on hard states is here: The hardest states for slab lift work (and why they hurt).

What does a first year in slab lift actually look like?

Slow, lumpy, and very paper-heavy if you do it right. You will spend more days on licenses, insurance, and practice slabs than social media implies. Winter kills exterior work in a lot of the country. Interior commercial work is a different sales cycle and a different insurance conversation.

Nobody has a clean national dataset on first-year slab lift profit. The closest honest numbers you can hold are wage series in nearby concrete occupations, and those are wages, not owner profit. I am not going to fake a revenue target. Anyone who quotes a national average ticket is guessing.

NAICS 238110 is the poured concrete contractor class many flatwork shops use ^[13]. Specialty injection-only shops sometimes land in another specialty trade code. Confirm the code with your CPA and then stay consistent on tax and insurance forms.

I would keep overhead tiny until repeat GCs or a real residential pipeline shows up. One van. One plant. One helper only when the hole count demands it. Track material per square foot so your next bid matches reality, not hope.

SlabLiftPath is an independent publisher, not a law firm and not a service company. For the kit and a single start page, go to /start.

Frequently asked questions

What is slab lift?

Slab lift is raising a sunken concrete slab by pumping grout or expanding polyurethane underneath it, then patching the injection holes. The old concrete stays in place. It is a void-fill and lift, not a new pour. If the slab is already rubble, replacement is the honest scope.

How do you start slab lift?

Start as a contractor shop. Form an entity, get an EIN if you need one, confirm the license class with your state or city board, bind insurance that names the work, and write silica plus hazard-communication programs before you drill. Then train on a real plant and practice on slabs you can afford to mark up. Confirm every fee locally.

Do I need a contractor license for residential driveway lifts?

Often yes, but the class is a state and city question, not a national one. Some boards park the work under concrete. Some use a specialty class or a local registration. California publishes a C-8 concrete class that includes flatwork, which is only one state's model. Call the board that would fine you, and do not advertise until that answer is in writing.

Is polyurethane foam the same chemistry as spray foam insulation?

It is the same chemical family. Two-part polyurethane uses an isocyanate side and a polyol side. NIOSH's diisocyanate alert still matters even if your nozzle is under a driveway, not in an attic. Read your product SDS. Do not treat driveway foam as a toy resin.

What is the OSHA silica limit when drilling lift holes?

OSHA sets the respirable crystalline silica PEL at 50 μg/m3 as an 8-hour TWA in 29 CFR 1926.1153. The action level in that same standard is 25 μg/m3 as an 8-hour TWA. Use Table 1 dust controls on handheld drills or measure. Dry drilling without controls is a bad habit.

What is the OSHA limit for MDI on a foam crew?

OSHA Table Z-1 lists a ceiling limit of 0.02 ppm for methylene bisphenyl isocyanate (MDI). A ceiling is not an 8-hour average you can dilute with lunch. If the SDS and the task require respirators, 29 CFR 1910.134 also wants a written program, medical evaluation, and fit testing.

Can I run slab lift on a handyman registration?

Only if your state and city actually allow this scope on that card, which many do not once you leave tiny patch work. Interior commercial slabs, public sidewalks, and post-tension decks are a poor fit for a handyman sticker. Confirm the class before you print yard signs. A manufacturer training card is not a license.

Do I need a CDL to haul foam drums?

Maybe. CDL and placarding turn on vehicle weight and whether the load meets hazmat rules, not on the word slab lift. Read the SDS transport section, the drum labels, and your state DMV rules for the actual truck you will drive. I will not invent a weight cutoff here. Confirm it before you load drums.

How long will a lifted slab stay level?

Nobody has a clean national survival curve. A lift lasts as long as the support you restored and the water problem you actually fixed. If the leak, the poor fill, or the drainage is still there, the slab can drop again. Warrant the workmanship and the lift tolerance. Do not print a fantasy lifetime sticker.

Can you lift a post-tension slab?

Sometimes, and it is a bad first-year job. Tendons are not where hope says they are. I would not drill until a plan, as-built, or a competent scan is in hand and the owner accepts the risk in writing. One nicked tendon is a structural claim. Walk if the documents are missing.

What NAICS code do slab lift shops use?

Many concrete flatwork shops use NAICS 238110, Poured Concrete Foundation and Structure Contractors. Injection-only specialty shops sometimes use another specialty trade code. Pick the box that matches the work you actually sell, then keep tax, insurance, and census forms consistent. Ask the CPA before you lock it in.

Does manufacturer foam training replace a state license?

No. Supplier training can teach ratio, temperature, and safety for that product. It does not satisfy a contractor practice act. Boards fine unlicensed contracting. Keep the training cert in the job file beside the state card, and do not advertise the cert as if it were the license.

What records does IRS expect from a first-year shop?

IRS Publication 334 expects records that support income and expenses: invoices, material receipts, vehicle costs, and how you split personal and shop use. Drum tickets and card slips count. A shoebox is a start. A weekly scan habit is better. Keep the same file you would hand an auditor.

Should I start with foam or mudjacking?

Start with the material you can buy training, SDS support, and insurance for in your market. Foam fits interiors and weight-sensitive soils. Grout still fits some exterior slabs if the soils can take the mass. I would not buy both plants in month one. Master one system on cheap practice slabs first.

Sources

1. OSHA, 29 CFR 1926.1153 Respirable crystalline silica: Silica PEL is 50 μg/m3 as an 8-hour TWA and the action level is 25 μg/m3 as an 8-hour TWA, with Table 1 task controls for listed drilling work.
2. OSHA, 29 CFR 1910.1200 Hazard communication: Employers must maintain SDS access, container labels, and worker training for hazardous chemicals.
3. OSHA, 29 CFR 1910.134 Respiratory protection: When respirators are required, a written program, medical evaluation, and fit testing are required.
4. OSHA, 29 CFR 1910.1000 Table Z-1: Methylene bisphenyl isocyanate (MDI) has a ceiling limit of 0.02 ppm.
5. NIOSH Alert 96-111, Preventing Asthma and Death from Diisocyanate Exposure: Occupational diisocyanate exposure is linked to asthma and has caused deaths, which is why exposure control is required.
6. IRS Publication 334, Tax Guide for Small Business: Small businesses must keep records that support income and deductible expenses, including materials and vehicle costs.
7. IRS, Apply for an Employer Identification Number (EIN) Online: Businesses can apply online for an EIN when they need one for hiring, banking, or tax filing.
8. U.S. Small Business Administration, Choose a business structure: Business structure affects day-to-day operations, taxes, and how much personal property is at risk.
9. California CSLB, Description of Classifications (C-8 Concrete): CSLB's C-8 Concrete Contractor classification includes mass, pavement, flat, and other specified concrete work.
10. U.S. DOL WHD Fact Sheet 13, Employment Relationship under the FLSA: Whether a helper is an employee is an economic-reality test, not whatever label is printed on the check.
11. FHWA, Concrete Pavement Preservation Guide, 2nd ed. (HIF-14-004): Slab stabilization is treated as void filling and restoration of support under existing concrete panels, not as a universal crack repair.
12. U.S. Census Bureau, NAICS 238110 Poured Concrete Foundation and Structure Contractors: NAICS 238110 is the poured concrete foundation and structure contractor classification used by many concrete shops.
13. OSHA, 29 CFR 1926.95 Criteria for personal protective equipment: Construction employers must provide and require PPE when hazards can cause injury to the eyes, face, head, or body.