Concrete flatwork FAQ: scope, cost, and specs

Last updated: October 28, 2026

This concrete flatwork FAQ answers what our crews hear on almost every pour. What does flatwork cover? What does it cost? How thick should the slab be, and which cracks are normal? Flatwork is roughly 80 percent of the concrete a homeowner ever buys, so most people ask once. Standard flatwork runs $5.32 to $15.61 a square foot. Guess at that number, and a budget goes sideways before the first truck shows up.

What flatwork covers

Flatwork is the concrete you walk and drive on, and it’s most of what a buyer ever orders.

What is concrete flatwork?

Concrete flatwork is any concrete poured flat on the ground, either level or at a set slope. Driveways, patios, sidewalks, garage aprons, slabs, and building pads all count. If you walk or drive on it and it sits flat on the ground, it’s flatwork. The word sets these ground-level pours apart from upright work like walls and footings. One set of rules covers all of it, from a 100 square foot stoop to a 20,000 square foot warehouse floor. Our concrete flatwork guide has the full breakdown.

What projects fall under concrete flatwork?

The common flatwork jobs:

• Driveways, for homes and businesses
• Patios, stoops, and porches
• Sidewalks and walkways
• Garage, shop, and interior slabs
• Equipment and RV pads
• Warehouse, retail, and distribution center floors

Home flatwork is the bulk of what a homeowner buys. Commercial flatwork, the spec-grade end, has its own commercial flatwork page.

What is the difference between residential and commercial flatwork?

The spec. A home crew pours to a thickness and a finish. A commercial slab answers to a structural spec with measured flatness limits. It gets heavier steel sized for racks and forklifts, and a paper trail that follows it from the packed ground to the final profiler readout. From the curb the two can look the same, because a gray slab is a gray slab. Underneath, the load, the flatness numbers, and how the slab takes its finish set them apart. Only one of them gets checked with a Dipstick profiler before anybody signs off on it.

Cost and value

How much does concrete flatwork cost per square foot?

Standard broom-finish concrete flatwork runs $5.32 to $15.61 a square foot installed. Sidewalks sit near the low end. Patios run $5.30 to $17.72, and stamped or exposed-aggregate finishes push toward the top of those ranges. Commercial spec-grade slabs start at $6.19 a square foot, depending on thickness and the flatness target. Where you land comes down to thickness, reinforcement, finish, tear-out, and how many square feet there are to spread the fixed trip cost over. Our concrete cost guide breaks down every line.

Why does flatwork pricing vary so much?

Five things move almost every price across that $5.32 to $15.61 band. Thickness sets how much ready-mix you buy. Reinforcement, the rebar or mesh, decides if the slab holds together when the ground shifts. Finish sets how many labor hours the top takes, and it swings the widest of the five. A broom-finish patio and a stamped patio the same size have the same slab underneath. The whole price gap is surface labor and decorative material, not concrete. Tear-out, site access, and total square footage move the rest.

Is a thicker slab worth the extra cost?

Usually, yes. Going from 4 inches to 5 or 6 costs more per square foot, because the deeper pour takes 25 to 50 percent more ready-mix. But slab strength grows with the square of the thickness, not in a straight line. So a small jump in inches buys a big jump in the load it can carry. A 4-inch driveway under a loaded one-ton truck cracks where a 5-inch slab holds. The quote tool prices each thickness, so you can see the difference before you pick. Nobody goes back and adds an inch after the truck leaves. You get one shot at it.

Slab thickness and mix design

What rolls across the slab sets the recipe, not the size of the pour.

How thick should a concrete driveway be?

A home driveway for cars and light trucks needs 4 inches of concrete over a packed base. Heavier loads need more. For RVs, work trucks, or anything over 8,000 pounds, step up to 5 or 6 inches, and add a #4 rebar grid while you’re at it. Patios and sidewalks that only carry people on foot are fine at 4 inches under ACI 332. That’s the home building code that sets 4 inches as the floor for slabs on the ground.

What concrete mix do you use for flatwork?

The mix follows the load. Strength is rated in psi, or pounds per square inch. Home walkways run fine on a 3,000 to 3,500 psi mix. Driveways that carry cars want 4,000 to 4,500 psi. Commercial slabs use at least a 4,000 psi mix with three-quarter-inch stone. For slabs that will be polished or coated, we keep the water-to-cement ratio below 0.45, so the top hardens well later. Watch the water at the truck. Adding water on site makes the mix easier to place, and it’s the most common way a strong spec turns into a weak slab.

Do you need a vapor barrier under a slab?

A vapor barrier belongs under any slab in a heated or cooled space, or under a floor covering. It’s a 10 to 15 mil plastic sheet that stops ground moisture from moving up through the concrete. That moisture is what causes coating failures, efflorescence (a white, powdery crust), and that musty smell in a finished garage. Outdoor driveways and open patios usually skip it, because the top breathes and dries in the open air. So the call turns on what goes on top of the slab and whether walls close in the space.

On a slab that’s already poured, nobody can see the barrier from the top. The sheet is under the concrete, the crew that laid it left years ago, and the paperwork almost never survives the build. So we read the floor instead of the file. These all point the same way:

• White powder on the surface
• Dark patches that get darker after a wet week
• A musty smell in a closed garage
• An old coating that peeled off in sheets

Taping a square of plastic down overnight is a hint, not a verdict. So when the floor shows one of those signs, we run a moisture test on the concrete itself. That reading decides what goes on top.

Pouring, finishing, and curing

The pour everyone watches is the short part. The base and the cure decide how it turns out, and the rest of the build has to work around both.

What happens during a flatwork pour?

A flatwork pour runs six stages, always in this order:

1. Prepare and pack the ground under the slab (the subgrade).
2. Lay the base and set the steel.
3. Place the concrete.
4. Finish the top.
5. Saw the joints.
6. Cure the slab.

Everybody watches the troweling, because it’s the part that looks like the finished floor. It isn’t the part that decides anything. The base and the first week of curing decide if the slab lasts. The finishing pass is the last 10 minutes of a job that’s mostly dirt work, crushed rock, steel, and timing. A broom finish over soft, unpacked ground cracks and settles inside two winters, no matter how clean the top looked on day one.

How long does concrete flatwork take to cure?

Concrete reaches roughly 70 percent of its design strength in 7 days. It gets close to full strength near 28 days. You can walk on most flatwork after 24 to 48 hours and drive light cars and trucks on it after 7 days. But the chemistry only finishes if the slab stays wet through that first week. Keep it wet for 7 days, or spray on a cure-and-seal coat right after finishing. Either way, the top comes out 30 to 50 percent stronger and harder to wear down than a slab left to air-dry in the sun.

What finish options are available for flatwork?

The finish sets both the look and the grip, and it has to match where the slab lives. The common choices:

• Broom finish: a broom dragged across the smoothed top, for grip on outdoor driveways, patios, and sidewalks.
• Exposed aggregate: the top paste washes off to show the stone, for a patio with high grip.
• Stamped concrete: textured mats pressed into the wet slab to look like stone, brick, or plank.
• Steel-trowel: a smooth indoor finish, the starting point for polish or a coating.

Match the finish to the use. A smooth trowel finish outdoors turns into a skating rink in the rain. And a broom finish indoors fights the clean look a polished or coated floor wants.

Joints and crack control

Concrete cracks. Good flatwork decides where.

Why does new concrete crack?

Some cracking is just how concrete behaves, and it isn’t a sign anybody did the job wrong. The slab shrinks as it cures. Control joints get cut to steer that shrinking into straight lines instead of random cracks. So a hairline crack at or running into a joint is working as designed, the same as a zipper doing its job. The cracks that mean real trouble look different:

• Wider than a quarter inch
• Offset, with one side sitting higher than the other
• Curving in a way that ignores the joints

Those almost always trace back to the base. Think poor packing, no drainage, or expansive clay (clay that swells when it’s wet) lifting the slab.

Where do control joints go and when are they cut?

Space control joints 2 to 3 times the slab thickness, in feet. A 4-inch slab gets joints every 8 to 12 feet, and a 6-inch slab every 12 to 18 feet. The saw cuts one quarter of the way through the slab. Timing is the part rushed crews get wrong. Saw cuts go in within 6 to 12 hours of finishing. That’s early enough to control the crack before the shrinking pulls hard, and late enough that the saw doesn’t chip (ravel) the edges. Commercial pours follow the column-line grid per ACI 302.1R. On a big pour, the saw starts while finishing is still going at the far end.

Flatness and commercial specs

Commercial floors live or die on measured numbers, not on what looks flat.

What flatness specs can you hit on commercial flatwork?

Standard commercial flatwork meets FF 35 at least, under ACI 117, and we can go higher when you ask. FF is a floor flatness number, and FL measures how level the floor is. Higher is better on both. Floors that will be polished or coated pour to FF 50 or higher, checked with a Dipstick profiler at 72 hours. High-tolerance jobs like VNA (very narrow aisle) warehouses and automated storage can reach FF 50/FL 30 or above. That takes extra screeding and re-straightening. On commercial work the FF and FL numbers are the spec, not a suggestion. A slab hits its number or it doesn’t, and the profiler readout says which.

Why does the pour spec matter for the finish?

The pour spec decides whether the finish works. On a polished or coated floor, that goes further than most buyers think, because the slab is the floor. There’s no covering to pull up and swap when you change your mind. So “we can always change the flooring later” stops being true the day the concrete goes in. A slab poured for carpet or tile never got a flatness target worth measuring. It likely got an acrylic cure film sprayed on it, too. Both get fixed later on somebody’s dime. A slab 10 points under its FF target takes 2 to 3 extra grinding passes. And the cure film has to be ground off before a coating will stick to anything.

New concrete doesn’t settle it either. A brand-new pour can be clean and look flat and still have been placed for a floor covering nobody is going to put down. That’s the most common way a fresh slab turns into a grinding bill. Our Pour-4-Polish spec exists to close that gap. It’s why we ask what’s going on top before the first truck arrives, not after the concrete sets.

Can our other trades keep working while you are on the floor?

Usually yes, as long as the floor itself stays ours. Grinding and polishing throw dust and run loud, so anyone who needs quiet or clean air works another zone that day. Freshly poured concrete is off limits to everybody until it can take weight. Coating is the strict case. Once primer or a base coat goes down, that section belongs to our crew until it cures. A bootprint in a wet coat means a redo, not a touch-up, and the redo costs the schedule more than the wait ever would. In a building that stays open, we work in sections so the place keeps running while one area is closed. On a new build, we’d rather have a clean floor for two days than share it for five. Send us the trades you can’t move, and we’ll plan around them.

How do we protect the floor for the rest of the build?

Cover it, and cover it with something that breathes. Use hardboard or heavy protective paper. Tape the seams to each other, never to the floor, because tape on a coated or polished floor can pull up color or leave a mark when it comes off. That cover carries a finished slab through the punch list. Sheet plastic laid flat is the common mistake. It traps moisture against the concrete and can leave a haze or a stain that has to be ground off later.

After that, it’s housekeeping. Keep steel wheels, pipe cutting, and drywall mud off the cover. Don’t park anything heavy on one bare spot. Wipe spills the day they land, not the week somebody notices them. The floor goes in late for good reason, but there’s always one more punch item. So put the cover in the schedule instead of piecing it together from leftover cardboard the morning the painters show up.

Can you coordinate with our GC on a commercial build?

Yes. About half of our commercial work comes through GC partnerships. It helps to know we show up at two points in your schedule, not one. The slab pour goes in early with the structural work, while the site is still open enough to get trucks and screeds onto the pad. The finish work is a late trade. It waits until the building is dried in, the roof is on, and the wet trades overhead are done. Then it goes in ahead of trim, base, and final fixtures, so nothing gets dripped, cut, or dragged across a finished floor.

Before the pour you get a submittal package. It holds the mix design, a joint layout drawing, the steel plan, and the FF/FL targets. We carry our own insurance and keep daily logs. We also meet the paperwork rules on commercial jobs, like safety plans and workmanship warranty certificates for the finished work. ACI 302.1R calls for a planning meeting before a large pour. It catches more problems on paper than on the slab, and we push for one on any pour over 5,000 square feet. Crews are typically three to six weeks booked, so the useful time to call is when the sequence firms up, not the week the slab is ready for us.

Getting started with Bel Covo

Can you pour the slab and finish it in one job?

Yes, and it’s almost always the cheaper path. One scope for the pour and the finish cuts a second trip charge. It cuts the risk of lining up two contractors. And it ends the finger-pointing when a rough top or a missing vapor barrier turns into the finisher’s problem. Our Pour-4-Polish process pours the slab to spec and takes it to the finished surface under one workmanship warranty on the work. So the slab is built from the start for whatever finish you pick.

Do you offer a warranty on concrete flatwork?

Yes. Bel Covo backs flatwork with a workmanship warranty on the work itself. It covers our pour and our finish. It doesn’t cover slab movement we trace to a base or drainage problem and flag before the job. The terms show up in the quote, in writing, so you know what’s covered before any concrete goes down. Have any contractor you’re looking at, us included, walk you through the warranty terms line by line before you sign.

How do I get a quote for concrete flatwork?

Get your price in about 2 minutes with the online quote tool, or send a few photos and the measurements. A real quote needs five facts: square footage, thickness, reinforcement, finish, and whether anything has to come out first. We send back a range built on real installed jobs, with no callback wait and no pressure. When one spec covers the pour and the finish, one quote covers both. Measure it once, and we’ll tell you what it really takes.