Last updated 2026-08-21
TL;DR
Slab lift is injecting grout or expanding polyurethane under a settled slab so the existing concrete rises back toward level. No federal slab lift license exists. You start by forming an entity, getting a free IRS EIN, confirming your state contractor class, and standing up silica and HazCom rules before you drill. Confirm every fee and classification with the board that licenses your county. Highway work is a different paper stack.
What is slab lift?
Slab lift raises a settled concrete slab by injecting grout or expanding foam under it until the slab moves back toward level. You keep the existing concrete. You fill voids, restore bearing, and try to match the elevation next door. It is a specialty trade, not a national license.
People use the phrase for driveways, sidewalks, garage slabs, warehouse floors, and some pavement. The material changes. The idea does not. Pressure plus fill moves a plate of concrete that already exists.
Replacement is a different job. Saw, haul, rebar, pour, cure. That is concrete construction. Slab lift is injection under a finished surface. If the slab is shattered into loose pieces, lift is usually the wrong call. You cannot float rubble back into a driveway.
Two fills show up on invoices. Cementitious slurry (mudjacking) uses a pump and a mix of soil, sand, cement, or commercial grout. Polyurethane foam uses a two-part chemical that expands and hardens. Both can work. Both can fail if the soils keep moving. USGS mapping of swelling clays is the reminder that moisture change under a slab is not something you foam away and forget [15].
Highway slab jacking sits under agency specs and traffic control. That is not your first residential driveway. Do not quote a DOT undersealing note to a homeowner, and do not use a homeowner mix design on a bridge approach.
If someone sells you slab lift as a patented secret, walk. The physics are public. The paper path is local.
How do you start slab lift?
You start slab lift by forming a legal business, checking your state contractor board for the right classification, buying insurance a GC will accept, and putting silica and chemical rules in place before the first hole. No federal slab lift card exists. Confirm every fee and class with the board that licenses your county.
Form an entity first. The IRS is blunt about why: "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] Get an EIN online. An IRS Employer Identification Number has a $0 online filing fee, per the IRS EIN application page [8]. Open a bank account that is not your personal checking.
Then the board. California often parks this work under the C-8 Concrete classification [13]. Florida defines contractor in statute 489.105, and that definition is wider than forum posts pretend [12]. Arizona and Colorado do not copy each other. Read the slab lift board in california notes, then the slab lift board in florida page, then your own state. Confirm. Boards change class language.
SBA's start sequence is boring and correct. Plan, legal structure, tax IDs, licenses, then finance [10]. Skip the motivational overlay.
Do not buy a new foam rig before you have a place to store chemicals out of heat and a customer who will pay. Drill a practice slab. Photograph elevations. Learn what an over-lift looks like when you cannot put the concrete back down.
Census NAICS 238110 (poured concrete foundation and structure contractors) is the box many concrete specialty shops land in. 238990 catches odd specialty trades. Pick the code with your accountant. It affects how some insurers file you [11].
Is slab lift the same as mudjacking or foam injection?
Mudjacking is one kind of slab lift. Foam injection is another. People arguing that only their brand name counts as real slab lift are selling kits, not describing the trade.
Mudjacking pumps a heavier slurry through larger holes, often 1 to 2 inches. Foam usually goes through smaller ports, often about the size of a nickel. Hole size is a field choice, not a moral one. I have seen both leave a driveway usable the same day. I have seen both leave a hump you have to grind.
Weight is the honest difference. Slurry is heavy. Foam is light. On a poorly supported subgrade, extra dead load is a real argument. On a slab that needs mass and a cheap fill, slurry still earns its keep. Nobody has a clean national failure-rate study that ends the argument. Vendor white papers do not count.
If a salesperson says foam waterproofs the soil, ask for the test method and the independent lab. I want the lift, the void fill, and a drainage fix. I do not want a chemistry lecture in the driveway.
Replacement still wins when the slab is broken into disconnected pieces, or the elevation change is past what injection can control without cracking. Say that out loud before you take the deposit.
What license do you need to lift concrete slabs?
You need whatever contractor classification your state and city assign to concrete repair or general contracting, unless you fall under a written exemption. No nationwide slab lift license exists. Confirm the class, dollar thresholds, and exam with your board before you advertise.
California's Contractors State License Board describes the C-8 Concrete class for people who form, pour, finish, and repair concrete [13]. Business and Professions Code 7026 is the definition of a contractor you actually read, not a blog paraphrase [14]. Florida's chapter 489 is the parallel stack, and 489.105 is the definitions section [12].
Some states let you take small jobs under a dollar cap without a license. Those caps move. I will not print a number your board can change next quarter. Call them. Get the answer in writing.
Cities add business tax certificates and permit rules. A driveway in a historic district is not the same paper as a warehouse in an unincorporated county.
If you work across state lines, you do not port a license like a phone number. Read slab lift board in arizona and slab lift board in colorado as examples of how two neighbors still do not match. slab lift board in connecticut is another reminder that New England does not copy the Sun Belt.
Advertising as licensed and insured when you are not is how you meet a state investigator. It is also how a homeowner's claim gets ugly.
What paper do you actually need in year one?
Year-one paper is entity documents, an EIN, the contractor license or a documented exemption, insurance certificates, SDS sheets, a silica plan if you drill, and job records with elevations. That stack matters more than a logo. Confirm licenses with the board and policies with your agent.
Here is the working table I wish someone had handed me.
| Paper | Why you hold it | Who confirms it |
|---|---|---|
| Entity filing | Contracts and banking | State secretary of state |
| EIN | Taxes, payroll, accounts | IRS EIN application [8] |
| Contractor license or exemption letter | Legal right to contract | State contractor board |
| General liability COI | Jobsite access | Your insurer, then the GC |
| SDS and HazCom file | Chemical right-to-know | Manufacturer plus OSHA 1910.1200 [2] |
| Silica written program | Drilling concrete | OSHA 1926.1153 [1] |
| Before and after elevations | Proof of what you did | Your notes and photos |
Workers' compensation is not optional once you have employees. State rules differ. Sole proprietors sometimes exclude themselves. Ask the state fund, not a forum.
I keep a job folder with the signed scope, the elevation sketch, hole map, material lot numbers, and photos. When a slab moves again in a wet spring, that folder is how you tell shrink-swell from a bad injection.
Permits are local. Some cities want a building permit to lift a garage floor. Some do not care about a sidewalk. Guessing is how you redo work.
What chemicals and safety rules apply to foam slab lift?
Foam slab lift uses isocyanates. Drilling any concrete can release respirable crystalline silica. OSHA and NIOSH already wrote the rules. You follow them. You do not invent a construction exception because the driveway is outside.
OSHA sets the construction silica PEL at 50 μg/m3 as an 8-hour TWA in 29 CFR 1926.1153. The rule text is not vague: "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] The action level is 25 μg/m3. OSHA's silica fact sheet walks through Table 1 control methods if you want the short version [4].
If you use a drill on concrete, you need wet methods or a vac with a HEPA setup that actually fits the tool. A broom is not a control method.
Two-part polyurethane brings MDI and related isocyanates. NIOSH's alert on diisocyanates exists because these chemicals can cause asthma and worse [5]. The NIOSH Pocket Guide entry for MDI lists a recommended exposure limit of 0.05 mg/m3 [6]. EPA keeps a public risk-management page on MDI and related compounds under TSCA [7]. Read the SDS. Store drums out of heat. Do not spray in a closed garage with no air.
PPE is not a brand preference. OSHA 1926.95 requires PPE wherever hazards are present that engineering controls have not removed [3]. Gloves that match the SDS, eye protection, and respiratory protection when the SDS or the exposure assessment says so.
HazCom is 1910.1200. Labels, SDS, training. If your helper cannot find the SDS, you do not have a program [2].
A branded empty binder is a waste of money. Buy the right cartridges and a real vac.
How much does it cost to start a slab lift crew?
There is no honest single startup number for slab lift. Foam proportioners, grout pumps, compressors, generators, and used rigs trade in ranges that move with the used market. Treat any national start-for-this-price post as advertising. Get two current quotes and look at used prices the week you buy.
Start on the grout side only if you already understand mix and you have a cheap pump you can service. Start on foam only if you have chemical storage that stays in the temperature window on the SDS and a supplier who will take your call on a Sunday.
A new enclosed trailer wrap, matching hoodies, and a drone before you have 20 jobs is a waste of money. Buying both foam and grout plants in month one so you can offer everything is another.
Working capital matters more than chrome. You will buy chemicals or grout materials before the check clears. You will crack a slab and have to make it right. Keep cash.
Training costs real days. Pour a sacrificial pad or buy a broken slab and lift it. Measure. Cut it open. Look at the fill pattern. That day teaches more than a vendor certificate no board recognizes.
Insurance down payment, license exam prep, basic tools, a decent rotary hammer, and elevation gear add up. I will not invent a package price. Price those line items locally.
If cash is tight, subcontract your first few lifts to a crew that already owns a rig and watch. Paying a day rate to learn beats financing a plant you cannot feed.
How do you bid slab lift work without guessing?
You bid slab lift by measuring the area, estimating void depth, counting access and holes, pricing material with waste, and adding time for lift, clean, and a return visit. Price per square foot is a shorthand, not a brain. Confirm material yield with your supplier lot, not a brochure.
Walk the slab. Sound it with a hammer. Mark hollow areas. Measure elevation differences at joints and against fixed points (house foundation, cleanout, intact panel). If you cannot explain the low spot, you cannot price the fill.
Foam is sold by the pound or by the set. Grout is sold by the yard or the bag. Conversion to per square foot happens after you guess thickness. That guess is where people go broke. I would rather quote a site visit and a range than lock a per-square-foot number on a slab I sounded for four minutes.
Access changes labor. A backyard slab through a gate is not a driveway. Interior warehouse work at night is not a sidewalk.
Return visits belong in the bid. Some slabs take a second shot after the first lift relieves a hidden void. If you pretend every job is one and done, you will eat the second trip.
If you want mix notes and a bid-per-sqft sheet already laid out, SlabLiftPath sells a $149 one-time Mix + Bid-per-Sqft Kit at /start. You can also do the same math in a notebook. I care that you measure twice.
Do not bid structural foundation repair as slab lift. Piers, grade beams, and wall rotation are another trade. Send that to an engineer.
What equipment does a first slab lift job actually take?
A first slab lift job takes a way to drill ports, a way to inject fill, elevation control, PPE, and a plan to clean the surface. That is the short list. Everything else is comfort or marketing.
For grout: mixer, pump, hoses, packers or simple ports, and a crew that will not blow a line. For foam: proportioner, feed that matches the machine, heated hoses if your climate needs them, gun, and chemical that is still in date.
Drills: a rotary hammer you can get parts for. Extra bits. Water or vac for silica. A generator if the house circuit is a joke.
Elevation: a rotary laser is nice. A water level still works on a driveway and does not reboot. I would not start without something that reads to a small fraction of an inch. Eyeballing a garage floor is how you make a roll toward the house.
Hand tools, plastic, tape, a grinder for the rare high spot you created, and a way to flush or cap ports so the homeowner does not stare at open holes.
Skip the custom truck in year one. A plain van and a trailer that can carry drums legally is enough. Check GVWR. Overloaded trailers are how you meet state troopers.
Read slab lift board in georgia and slab lift board in alabama if those are your states, because some boards care about the work, not the brand of pump. slab lift board in idaho is the same idea in a different climate.
Where do soils and drainage make lifts fail?
Lifts fail when water keeps cutting soil out, when expansive clay keeps shrinking and swelling, or when you raised a slab that was never a single plate. Fix water first when you can. Say no when the slab is rubble.
Downspouts dumping at a garage corner will reopen a void. I would rather lose a job than foam under an active washout and promise a lifetime level floor. Point that gutter out in writing.
Expansive clays change volume with moisture. USGS published a swelling-clays map of the conterminous United States as IMAP 1940, and that map is still the public starting point for where volume-change clays are common [15]. A dry summer then a wet fall will move slabs in those soils whether you injected or not. Tell the owner that before they pay.
Tree roots and leaking laterals are the other two regular villains. I am not a plumber. I will not pretend foam seals a broken clay pipe.
If the panel is isolated and rocking, lift can still work. If it is alligatored into a puzzle, replacement is cleaner. Have that spine on the sales call.
Interior slabs with moisture coming through the surface may need a vapor conversation that is not your foam gun. Do not overclaim.
Do you need insurance before you lift a slab?
Yes, you need liability insurance before you lift someone else's slab, and you need workers' comp once the law in your state says you do. A COI is how a property manager lets you on site. Confirm limits with the client and exclusions with your agent. I will not invent a premium.
General liability is the policy GCs ask for. Additional insured endorsements are normal on commercial work. Read whether your policy treats polyurethane as a pollution event. Some do. That surprise shows up after a claim, which is the wrong day.
Auto and the trailer matter. A drum that dumps on a highway is not a tools claim in every policy.
Bonds show up on public work. Do not bid a city sidewalk package until you know the bond cost.
Homeowner policies sometimes cover sudden collapse and almost never cover settlement. Do not coach a customer to file a false claim. That is their insurer and their honesty, not your close.
What records should you keep after every lift?
Keep the signed scope, a simple sketch with elevations, a hole map, material lot numbers, photos before and after, and the COI you sent. Keep them longer than the warranty you wrote. Those records are how you defend a good job and how you learn from a bad one.
I photograph the joint against a fixed point with a tape in the frame. Phone photos without a reference are arguments.
If you promised a return visit, write the date window. If you excluded drainage work, write that too. Scope creep is how a sidewalk bid becomes an unpaid redesign of the yard.
Training records for silica and HazCom belong in the shop file, not in your head [1][2][4]. If an inspector asks who taught the helper to run the vac, you want a date and a name, not a shrug.
SlabLiftPath is an independent publisher, not a law firm and not a service company. Nothing here is a license approval or a timing promise. Confirm the live rule with your board before you print a card.
Frequently asked questions
What is slab lift?
Slab lift is raising a settled concrete slab by injecting grout or expanding polyurethane under it so the existing concrete moves back toward level. You are filling voids and restoring bearing, not pouring a new slab. If the concrete is broken into loose pieces, replacement is usually the cleaner job.
How do you start slab lift?
Form an entity, get a free IRS EIN, then call your state contractor board and confirm the class and any dollar exemption. Stand up general liability, HazCom, and a silica plan before you drill. Practice on a sacrificial slab. Confirm every fee with the board. No federal slab lift license exists.
Do I need a contractor license for residential slab lift?
Often yes, unless your state publishes a written exemption under a dollar cap. California commonly treats concrete repair under C-8. Florida defines contractor in statute 489.105. Caps and class names change. Confirm with your board before you advertise. A city business tax certificate can still apply on top.
Is foam slab lift better than mudjacking?
Not always. Foam is lighter and usually uses smaller holes. Cementitious slurry is heavier and often cheaper per unit of fill. Both can level a slab and both fail if water keeps cutting soil out. Nobody has a clean national failure-rate study that ends the vendor argument. Pick the fill that matches the soils and the budget.
How long does a slab lift last?
It lasts as long as the soils stay put and water stops cutting voids. On a well-drained, stable subgrade, a good lift can hold for years. On expansive clay or next to a downspout, the same slab can move again after the next wet season. Lifetime promises are sales copy. Write a clear warranty and exclude active drainage problems.
Can I run slab lift out of a garage as a side job?
You can store hand tools in a garage. You should not store isocyanate drums in a hot residential garage, and you still need whatever license, insurance, and zoning your city requires. Side job is not a legal category. Confirm home-occupation rules, chemical storage on the SDS, and board licensing before you take money.
What insurance do slab lift contractors usually carry?
General liability is the policy that gets you on most residential and GC sites. Add workers' comp when you have employees or when the state says you must. Ask your agent whether foam is treated as a pollution event. Auto and trailer coverage matter once you haul drums. I will not invent a premium. Get a quote.
How many injection holes does a driveway need?
Enough to reach the hollow areas you sounded, and not one more for show. Spacing depends on slab thickness, void pattern, and whether you are using slurry or foam. There is no honest universal hole count. Hammer-sound the panel, mark the lows, and drill to the work, not to a marketing diagram.
Can you lift a slab that is already cracked?
Sometimes. A single crack across an otherwise intact panel can still move as a unit. Alligator cracking into loose pieces usually means replacement. Tell the owner that lift will not weld the concrete back together. Cracks that are already there will still be there after the lift, even if the elevation is better.
Do I need an engineer to lift a sidewalk?
Most residential sidewalks and driveways do not need an engineer stamp for a simple lift. Structural slabs, racked garage columns, rotating foundation walls, and anything a building official flags are different. When load path is in doubt, stop and get an engineer. Do not sell piering work as slab lift.
Is leftover polyurethane foam hazardous waste?
Cured foam and leftover liquid are not the same thing. Follow the SDS and your state hazardous-waste rules for unused A and B components. Do not dump liquid in the dirt behind the shop. Empty drums and waste determinations are a local environmental question. Confirm with the manufacturer SDS and your state environmental agency.
Does homeowners insurance pay for slab lift?
Usually not for ordinary settlement. Many homeowner policies exclude earth movement and settlement and may cover sudden collapse from a named peril. Do not coach a customer to stretch a claim. Have them call their carrier. Bid the work on its own. Their deductible and exclusions are their contract, not yours.
What elevation tolerance should I promise?
Promise what you can measure and live with on a callback. A fraction of an inch against a fixed joint is honest on many driveways. Dead flat across a 40-year garage slab often is not. Write the target in the scope. Photograph a tape at the joint. Eyeball warranties start fights.
Can I start slab lift without buying a foam rig?
Yes. Start with grout if you can service a pump, or subcontract the injection and watch a few jobs. A foam proportioner is optional until you have storage, chemical supply, and paid work. Buying a plant you cannot feed is how people go broke in month four. Learn elevations first.
Sources
- 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.
- OSHA 29 CFR 1910.1200 Hazard Communication: Employers must have labels, SDS access, and HazCom training for chemical hazards.
- OSHA 29 CFR 1926.95 Criteria for personal protective equipment: PPE is required where hazards are present that engineering controls have not eliminated.
- OSHA fact sheet OSHA 3681, Crystalline Silica Rule for Construction: OSHA publishes Table 1-style control methods and a short construction silica overview.
- NIOSH Publication 96-111, Preventing Asthma and Death from Diisocyanate Exposure: NIOSH documents asthma and serious health effects from occupational diisocyanate exposure.
- NIOSH Pocket Guide to Chemical Hazards, MDI: NIOSH REL for MDI is 0.05 mg/m3 (TWA).
- EPA, Risk Management for Methylene Diphenyl Diisocyanate (MDI) and Related Compounds: EPA maintains a public TSCA risk-management page for MDI and related compounds.
- IRS, Apply for an Employer Identification Number (EIN) Online: An EIN can be applied for online at no cost.
- IRS, Business Structures: Choice of business structure affects operations, taxes, and personal asset risk.
- U.S. Small Business Administration, 10 steps to start your business: SBA sequences starting a business through planning, structure, tax IDs, and licenses.
- U.S. Census Bureau, NAICS 238110 Poured Concrete Foundation and Structure Contractors: NAICS 238110 is the 2022 classification for poured concrete foundation and structure contractors.
- Florida Statutes § 489.105 (2023): Florida statute 489.105 defines contractor and related construction licensing terms.
- CSLB, Description of Classifications (C-8 Concrete): California CSLB describes the C-8 Concrete contractor classification in its official classifications publication.
- California Business and Professions Code § 7026: BPC 7026 defines who is a contractor under California license law.