How slab lift works and how operators start year one

Last updated 2026-08-20

What is slab lift?

Slab lift raises a sunken concrete slab by pumping material into the empty or weak space under it. Crews use expanding polyurethane foam or a cement slurry people still call mudjacking. The slab can be a driveway, sidewalk, patio, garage floor, or a warehouse panel. You are not replacing the concrete. You are moving it.

The method is simple to say and easy to botch. You drill a hole pattern. You inject in short shots. You watch a level or a laser. You stop before the slab crowns or cracks. Foam expands and sets in minutes. Slurry is heavier, slower, and cheaper per cubic foot. I use foam on interior floors and on soil that already failed under the dead load of the slab. I use slurry when the panel is thick, the owner wants the low number, and the subgrade can take more weight.

This is not piering and it is not a new foundation. If the house footing is dropping, lifting the porch slab does not fix the house. Say that on the first visit. You will turn down work. That is the job.

Typical foam holes run about 5/8 inch. Slurry holes are often 1 to 2 inches. You patch every hole. The owner will stare at those patches longer than they stare at your level reading.

Drilling concrete makes respirable dust. OSHA's construction silica rule does not care that your crew is small. OSHA sets the respirable crystalline silica PEL for construction at 50 μg/m3 as an 8-hour TWA under 29 CFR 1926.1153 ^[1]. Cut, grind, or drill the slab and you are in that world.

How do you start slab lift?

You start slab lift by proving you can legally sell the work, then setting up a boring business, then learning a controlled lift on small, ugly jobs. There is no federal slab lift license. States and cities disagree about whether this is concrete contracting, a specialty, or unlicensed work under a local dollar cap.

Read your contractor statute before you print door hangers. In California, Business and Professions Code section 7026 pulls in people who undertake or offer to construct, alter, or repair structures for compensation, and the rest of that chapter is the license machine ^[9]. Florida writes a similar net. Florida Statute 489.105 defines a contractor, except as exempted in that part, as the person who, for compensation, undertakes to, submits a bid to, or does construct, repair, or alter work on a building or structure ^[10]. North Carolina's G.S. 87-1 defines a general contractor with a project-cost threshold. Confirm the current dollar figure and any specialty path with the North Carolina Licensing Board for General Contractors. Do not trust a Facebook group for that number ^[11].

Form an LLC or stay a sole proprietor. Get an EIN if you will hire or open a real business account. The IRS page is plain: "Applying for an EIN is a free service offered by the Internal Revenue Service." Use the official application, not a reseller ^[6]. Follow a basic startup sequence (entity, tax ID, accounts, insurance) even if you already know how to run a pump. The SBA 10-step guide is generic and still better than starting on a handshake ^[7].

If you are choosing this trade against another local option, read slab lift vs nearby career after you finish the license check.

What happens on a typical slab lift job?

A normal residential call starts with a walk-around, not a drill. You look at crack maps, joint lines, drainage, downspouts, and whether the slab is one pour or a mess of patches. You bounce a 6-foot level across the low corner. You ask how long it has been sinking. A slab that dropped after a water-line break is a different job than a slab on fat clay that moves every dry August.

You write the lift target in inches, not vibes. A 1.5 inch lift on a 12 by 20 driveway is a real job. A promise to make a shattered slab like new is not. Mark utilities. Call 811 before you punch holes near the house. Then drill your pattern, usually starting at the low point and working toward the hinge line.

Inject, wait, measure. Foam wants short triggers. Hold the trigger like a car-wash wand and you will crown the slab and create a trip edge the owner will hate. Slurry wants a steady pump and a watchful eye on adjacent panels, because pressure migrates. When the elevation holds, you cut ports, patch, and clean the film. You do not leave gray dust on the owner's shrubs.

Take photos before and after with the same level in the frame. That file is your warranty defense. For more on how crews compare methods after the first walk-around, slab lift guide 18 is a useful next read.

Do you need a contractor license for slab lift work?

Maybe. It depends on the state, the city, the contract amount, and whether you touch anything structural. I treat it as licensed contracting until a board or a statute tells me otherwise in writing.

California's CSLB Description of Classifications lists C-8 Concrete for people who form, pour, place, finish, and install concrete work, including specified pavement and flatwork. Slab lift is repair of existing flatwork. Confirm with CSLB whether C-8, a C-61 specialty, or another class is the one they want for injection lifting. Classification guidance changes. Call them ^[12].

Florida uses certified and registered contractor categories under Chapter 489. Read 489.105 for the definitions ^[10]. Some small jobs fall under exemptions. I will not list those dollar caps here because legislatures move them. Pull the current statute and confirm with the board. California's 7026 net is the same warning in a different code ^[9].

Plenty of states have no statewide concrete license. Your city may still want a business tax receipt, a contractor registration, or a permit to work in the right of way if the sidewalk is theirs. Right-of-way work is where new operators get surprised.

Never tell a customer you are fully licensed nationwide. That phrase is a myth. If a lead mill uses it, walk away.

What equipment do you actually need to start?

You need a way to drill, a way to inject, a way to measure, and a way to patch. That is the whole list on day one.

For foam, the expensive piece is a proportioner (heated hoses, correct ratio, purge discipline). Used entry rigs show up in a wide band. I have seen complete trailer packages quoted from the mid five figures into six figures depending on output, heaters, and whether the seller is dumping a tired pump. I do not have a clean national survey of rig prices. If a salesperson gives you one number as the industry standard, they are selling.

For slurry, a piston or hydraulic mud pump, a mixer, and a hose reel cost less than a foam plant in most quotes I have heard, and the mess is worse. You also need water and a place to dump leftover grout that is not the owner's lawn.

Shared tools: hammer drill or core rig, generator, laser or digital level, PPE, shop vac, and a real concrete patch. Rent the foam rig for the first handful of sold jobs if you can. Buying a plant before you have repeatable bids is how people fund their competitor's used-equipment ad in six months.

A paper bid kit is cheaper than a wrong plant. If you want a one-time mix and bid-per-sqft worksheet set, SlabLiftPath sells a $149 Mix + Bid-per-Sqft Kit. You do not need it to understand the work.

Compare gear paths in slab lift guide 24 when you are ready to spend.

How should you handle foam chemicals and silica dust?

Two hazards sit on almost every slab lift. Silica from drilling, and isocyanates if you run polyurethane.

OSHA's construction silica standard 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." That sentence is the PEL ^[1]. The same standard sets an action level at 25 μg/m3 as an 8-hour TWA. Table 1 lists specified controls for many tasks. Follow Table 1 as written and you get a defined compliance path. Freelance your dust control and you own the exposure assessment.

Respiratory protection, when required, sits under 29 CFR 1910.134. That rule wants a written program, medical evaluation, fit testing, and training. A dust mask from the gas station is not a program ^[2].

Polyurethane slab-lift foam is a two-part system. Part A is commonly an isocyanate. NIOSH's pocket guide for 4,4'-methylenediphenyl diisocyanate lists a recommended exposure limit of 0.05 mg/m3 as a TWA and treats the chemical as an irritant and a sensitizer ^[4]. EPA keeps a risk-management page for MDI and related diisocyanates under TSCA. Read it before you treat foam like insulation caulk ^[5]. OSHA's hazard communication standard requires you to keep safety data sheets and train anyone who may be exposed ^[3].

Gloves, eye protection, and long sleeves are not heroic. They are how you still have skin in year five. I would not run foam in a closed garage without ventilation and the right respirator cartridge. If that slows the job, good.

What insurance and tax paper comes first?

File the entity. Get the EIN if you need it ^[6]. Open a bank account that is not your rent account. IRS Publication 583 walks through basic federal tax records for a new business. It is not exciting. It will save you a winter ^[8].

General liability is the policy owners, GCs, and property managers will ask for. Ask the broker for per-occurrence and aggregate limits that match the contracts you want, and get the additional-insured endorsement language in writing. Inland marine covers the rig on the trailer. Commercial auto covers the truck that people pretend is just personal. Workers' compensation applies when you have employees, and in some states it applies to owner-officers too. Confirm with your state fund or a broker who actually writes construction.

I will not quote a premium. Two crews in the same zip code get different numbers after one claim.

Disturb one acre or more of land and EPA's 2022 Construction General Permit can apply. Almost no patio lift hits that acreage. A huge yard program or a paved lot might. Know the 1-acre trigger so you do not discover it on a commercial bid ^[13].

Sales tax on the material, on the service, or on both is a state question. Your department of revenue, not a forum, answers it.

More paper comparisons live in slab lift guide 30.

How do you price slab lift in year one?

Price the void and the risk, not a national square-foot myth. Foam is sold by the pound or by a board-foot equivalent. Slurry is sold by the cubic foot or the sack. Owners want a per-square-foot number because that is how every lead form is written.

A driveway with a 2-inch void is not the same job as a driveway with a 1/4-inch dish. Bid both at the same sq ft rate and you will love one and hate the other. Measure elevation. Probe if you can. Then bid the material you expect to place, plus drill and patch labor, plus a contingency for the void you cannot see.

I keep a floor price for showing up with a foam rig, even on a tiny stoop. Mobilization is real. People who skip it work weekends to break even.

Nobody runs a federal price index for residential slab lift. Published home-service averages bounce by city and by whether the quote is foam or mud. Treat any single national average as marketing. Your number has to cover chemical, labor, fuel, insurance, and the callback you will eat when a panel was already cracked through.

Year one, write every bid the same way. Same fields. Same photos. That habit is worth more than a fancy app. See slab lift guide 36 for side-by-side bid thinking.

Is foam or mudjacking better for a first-year crew?

Foam wins on weight, speed, and interior cleanliness. Slurry wins on material cost and on crews who already think in grout. Both can lift a slab. Both can crack a slab. Both can fail if water is still running under the panel.

I would not start with both plants. Pick one, get ten clean jobs, then decide. If your market is HOA driveways and garage floors, foam is the easier sell. If your market is farm pads and cheap municipal walks, slurry still eats.

Holes are smaller with foam, which owners notice. Slurry patches are bigger and more visible. Foam can lift faster than you can think if the ratio is hot and the void is connected. That is the beginner injury to the slab, not to your hand.

A simple comparison:

Method	Common hole size	What you pump	Weight on soil	Where I'd start
Polyurethane foam	about 5/8 in	two-part foam	low	interiors, light soils
Slurry (mudjacking)	1 to 2 in	cement mix	high	thick exterior slabs

If you want more method comparisons, slab lift guide 42 continues that thread.

Where do new slab lift operators lose money?

They buy the max rig, then starve it. They promise a structural fix. They ignore drainage, so the same slab drops again and they warranty a water problem they never owned. They underdrill, then flood one hole until the slab hinges. They forget 811 and punch a gas line. That last one can end the company.

Callbacks kill year one. Write a warranty that covers your lift, not the soil, not new leaks, not tree roots, not the crack that was already through the slab. Take the before photos. If the owner refuses drainage work, write that refusal on the ticket.

Another leak is unpaid change orders when the void is bigger than the probe suggested. Stop. Show the extra material. Get a signature. Foam disappearing into a French drain or a collapsed sewer is not a small overrun.

Labor is the other hole. A two-person crew that drills an entire driveway before injecting anything looks busy and wastes time if the first shots show a different void pattern. Drill a zone, lift a zone.

Read slab lift guide 48 if you want more failure modes next to other paths.

What should you confirm with your state board before you bid?

Before you bid, call the contractor board (or the city) with a plain description: you inject foam or grout under existing concrete slabs to raise them, and you do not pour new foundations. Ask which license class, if any, they want. Ask about dollar thresholds. Ask whether a handyman exemption exists and whether advertising as a company kills that exemption. Then get the answer in writing if you can.

Confirm bonding if the class needs it. Confirm continuing education if you already hold a related license. Confirm whether employees need their own cards. I will not give you a processing time. Boards run at their own speed, and anyone who guarantees a date is guessing.

Work across a state line and you repeat the call. Reciprocity is not a personality trait. It is a written rule or it is nothing.

Keep the statute bookmarked. California BPC 7026, Florida Chapter 489, North Carolina G.S. 87-1, and your own state's chapter are the texts that matter, not a national blog ^[9][10][11].

Also confirm utility locate rules, sidewalk permits, and HOA application windows. Those are not licenses and they still stop jobs.

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

A clean first year is 20 to 40 small jobs you documented, no injured lungs, no bounced checks, and a license file you can find. It is not a wrapped truck.

Stay in a tight radius. Learn one soil. Learn one foam or one slurry. Raise your floor price when your calendar fills. Fire the customer who wants a house lifted with patio foam.

Keep SDS binders in the truck. Keep silica controls boring and consistent. Keep tax deposits boring and consistent ^[8]. Hire someone and 1910.134 and 1910.1200 become your weekly life, not a poster ^[2][3].

SlabLiftPath is an independent publisher, not a law firm and not a service company. Use this as a reference, then confirm fees, classes, and forms with the board that actually issues the card. If you want the worksheet kit after that, it is at /start.

For neighboring writeups, slab lift guide 54 is a reasonable next click.

Frequently asked questions

What is slab lift?

Slab lift is raising a sunken concrete slab by injecting polyurethane foam or a cement slurry under it. You drill a hole pattern, pump in short shots, and watch a level until the panel comes back toward grade. It is a repair of existing flatwork, not a new pour and not a foundation pier system. Owners still need drainage and soil that can hold the slab after you leave.

How do you start slab lift?

Confirm with your state board or city whether the work needs a contractor license. Form an entity, get a free EIN from the IRS if you need one, buy general liability, and learn one injection method on small jobs. Rent a rig before you buy one. There is no national license and no official national price list.

Is slab lift the same as mudjacking?

Mudjacking is one kind of slab lift. It uses a cement slurry pumped through larger holes, usually 1 to 2 inches. Polyurethane slab lift uses expanding foam through smaller holes, often about 5/8 inch. Both raise concrete. Foam adds less weight. Slurry is usually cheaper per cubic foot and messier. Pick one method for year one.

Do you need a license to start slab lift?

Often yes, sometimes no. California, Florida, and North Carolina all pull repair work into contractor statutes, with different classes and exemptions. Other states leave it to cities. Describe the work in plain language and confirm the class, any dollar threshold, and advertising rules with the board. Do not use a nationwide license claim.

How much does a foam rig cost?

Complete trailer packages get quoted from the mid five figures into six figures, depending on output, heaters, and whether the unit is used. Nobody publishes a clean national survey I trust. Rent for the first sold jobs if you can. Buying the biggest plant before you have repeatable bids is a common way to run out of cash.

Is polyurethane slab lift foam dangerous to breathe?

The A-side is commonly an isocyanate. NIOSH lists a 0.05 mg/m3 TWA recommended limit for MDI and treats it as an irritant and sensitizer. Use the SDS, ventilate, and wear the respirator your program actually covers. Do not shoot foam in a closed garage like it is craft glue. Training under OSHA's hazard communication rule is part of the job.

Can slab lift fix a sinking house foundation?

No. Slab lift moves a concrete panel. It does not replace footings, piers, or a failing foundation wall. If the house is dropping, send that work to a foundation contractor. Lifting a porch or patio while the footing keeps moving is how you buy a callback you cannot fix with more foam.

Do you need an EIN to start a slab lift business?

You need one if you hire employees, and many banks want one for a business account. Sole proprietors with no staff can sometimes use a Social Security number, but an EIN keeps that number off vendor forms. The IRS does not charge a fee to apply online. Skip websites that sell the same filing back to you.

What OSHA rules apply if you only have two people?

Crew size does not waive the rules. Drilling concrete brings 29 CFR 1926.1153 (silica PEL 50 μg/m3). Foam chemicals bring hazard communication under 1910.1200. If a respirator is required, 1910.134 wants a written program, medical evaluation, and fit testing. A two-person shop still needs SDS sheets in the truck.

How do you bid slab lift per square foot?

Use sq ft only as a customer language, not as your real cost model. Measure the void depth, estimate material, then add drill, patch, mobilization, and a contingency. A 2-inch void is not the same job as a 1/4-inch dish. Keep a show-up floor price so tiny stoops do not wreck the day.

How many holes do you drill in a driveway?

Enough to control the lift, not a decorating pattern. Spacing depends on thickness, void continuity, and whether you are on foam or slurry. Start at the low point and work toward the hinge. Drill a zone, inject that zone, then decide if you need more holes. Overdrilling a thin slab just gives you more patches to hide.

Should you start with foam or mudjacking?

Start with one plant, not both. Foam is cleaner and lighter, which helps on interiors and HOA driveways. Slurry is cheaper on material and still makes sense on thick exterior pads. I would rather see ten clean jobs on one method than a garage full of unused hose. Add the second method after your bids stay consistent.

Does a city sidewalk need extra permits?

Often yes, even when the house driveway does not. Right-of-way, ADA grade, and traffic control sit with the city, not with your contractor class. Ask public works before you drill a walk that touches the street. HOA design review is a separate delay. Neither one is a license, and either one can stop the job.

What warranty should a new operator write?

Warrant your lift, not the soil and not future water. Exclude existing through-cracks, new plumbing leaks, tree roots, and drainage the owner refused to fix. Put the refused drainage work on the ticket. Take before photos with a level in the frame. A vague lifetime promise is how year-one crews work for free.

Sources

1. OSHA 29 CFR 1926.1153 Respirable crystalline silica: Construction silica PEL is 50 μg/m3 as an 8-hour TWA; action level is 25 μg/m3.
2. OSHA 29 CFR 1910.134 Respiratory protection: Required respirator use needs a written program, medical evaluation, fit testing, and training.
3. OSHA 29 CFR 1910.1200 Hazard communication: Employers must keep safety data sheets and train workers on chemical hazards.
4. NIOSH Pocket Guide 4,4'-Methylenediphenyl diisocyanate: NIOSH REL for MDI is 0.05 mg/m3 as a TWA.
5. EPA TSCA risk management for MDI and related diisocyanates: EPA maintains a TSCA risk-management page for MDI and related diisocyanates.
6. IRS Apply for an Employer Identification Number (EIN) online: Applying for an EIN is a free service offered by the Internal Revenue Service.
7. U.S. Small Business Administration 10 steps to start your business: SBA publishes a 10-step federal checklist covering structure, tax ID, and startup setup.
8. IRS Publication 583 Starting a Business and Keeping Records: Publication 583 is the IRS starter guide for federal tax records of a new business.
9. California Business and Professions Code section 7026: California defines a contractor to include people who undertake or offer to construct, alter, or repair for compensation.
10. Florida Statute 489.105 (2023) contractor definitions: Florida defines a contractor as a person who, for compensation, undertakes or bids to construct, repair, or alter a building or structure, except as exempted.
11. North Carolina General Statute 87-1: North Carolina defines a general contractor using a project-cost threshold that must be confirmed in the current statute.
12. CSLB Description of Classifications (C-8 Concrete): CSLB describes the C-8 Concrete classification as forming, pouring, placing, finishing, and installing specified concrete and flatwork.
13. EPA 2022 Construction General Permit (CGP): EPA's 2022 CGP covers construction stormwater discharges from disturbances of one acre or more (or part of a larger common plan).