20x20 Concrete Slab Cost in 2026
A 20x20 concrete slab costs $3,200 to $6,400 in Greater New Orleans in 2026, with most jobs falling between $8 and $16 per square foot depending on ground prep, finish, and site access. That range covers a standard 4-inch slab on compacted base with rebar reinforcement and broom finish. The sections below break down exactly what moves a 400 square foot slab from the low end to the high end of that range.
Key facts
- A 20x20 concrete slab (400 sq ft) costs $3,200 to $6,400 in Greater New Orleans in 2026
- Per square foot rates range from $8 to $16 depending on finish, access, and ground conditions
- Standard spec is 4 inches of 3,500 PSI concrete over 4 to 6 inches of compacted limestone base
- Demolition of an existing slab adds $2 to $6 per square foot to total project cost
- Control joints are cut every 8 to 10 feet within 12 hours of the pour
| Slab size | Square footage | Typical range (2026) | Per square foot |
|---|---|---|---|
| 10x10 | 100 sq ft | $1,000 to $1,800 | $10 to $18 |
| 12x12 | 144 sq ft | $1,300 to $2,300 | $9 to $16 |
| 15x15 | 225 sq ft | $1,800 to $3,400 | $8 to $15 |
| 20x20 | 400 sq ft | $3,200 to $6,400 | $8 to $16 |
| 20x30 | 600 sq ft | $4,800 to $9,000 | $8 to $15 |
| 24x24 | 576 sq ft | $4,600 to $8,600 | $8 to $15 |
| 30x30 | 900 sq ft | $6,800 to $12,600 | $7.50 to $14 |
| 40x60 | 2,400 sq ft | $16,800 to $31,200 | $7 to $13 |
A 20x20 concrete slab is 400 square feet and runs $3,200 to $6,400 in the Greater New Orleans market in 2026. Per square foot cost drops slightly on larger slabs because mobilization, forming, and finishing spread across more area. The table above reflects our pricing experience across south Louisiana residential and light commercial work.
What Determines the Price of a 20x20 Concrete Slab?
Five factors move a 20x20 slab from $3,200 to $6,400, and each one is quantifiable before the pour.
How Much Does Demolition Add to the Cost?
Removing an existing slab adds $2 to $6 per square foot to the project. A 400 square foot demolition runs $800 to $2,400 depending on thickness and rebar content. A basic 4-inch unreinforced pad sits at the low end. A 6-inch reinforced slab with wire mesh or rebar requires saw cutting, heavier equipment, and more haul-off, pushing the cost toward the high end. Concrete disposal runs $45 to $75 per ton in Jefferson and Orleans parishes, and a 400 square foot slab at 4 inches thick generates roughly 8 to 10 tons of debris.
How Does Subgrade Condition Affect the Price?
Subgrade prep adds $1 to $4 per square foot depending on the existing soil. South shore sites in Metairie, Kenner, and New Orleans East sit on soft alluvial clay with a water table 18 to 36 inches below grade. That clay requires over-excavation and 6 inches or more of compacted limestone to create a stable bearing surface. A north shore site in Slidell or Mandeville typically has sandy soil with natural drainage, where 4 inches of compacted base is adequate. The difference on a 400 square foot slab is $400 to $1,600 in subgrade work alone.
How Does Site Access Change the Cost?
Restricted access adds $0.50 to $2 per square foot. A concrete pump truck costs $400 to $800 per pour. A backyard slab with no truck access requires a pump, while a driveway slab poured directly from the chute does not. Tight side-yard access where materials travel by wheelbarrow also adds labor hours.
How Does Reinforcement Affect the Total?
Reinforcement adds $0.75 to $2.50 per square foot. Fiber mesh mixed into the concrete costs $0.75 to $1.25 per square foot. Number 3 rebar on 18-inch centers costs $1.50 to $2.50 per square foot but provides structural continuity that fiber cannot match. A 400 square foot slab with rebar reinforcement adds $600 to $1,000 over a fiber-only pour.
What Does a 20x20 Concrete Slab Cost by Size Comparison?
Cost scales with square footage, but not linearly. Smaller slabs carry a higher per square foot rate because setup, forming, and mobilization are fixed costs. Three common sizes illustrate the math:
- 10x10 slab: 100 sq ft at $10 to $18 per sq ft = $1,000 to $1,800
- 20x20 slab: 400 sq ft at $8 to $16 per sq ft = $3,200 to $6,400
- 30x30 slab: 900 sq ft at $7.50 to $14 per sq ft = $6,800 to $12,600
The per square foot rate drops by $1 to $3 between a 100 square foot slab and a 900 square foot slab because the concrete truck, pump, crew mobilization, and forming labor are nearly the same fixed cost regardless of area.
What Does a 20x20 Concrete Slab Cost by Finish Type?
Finish selection adds $0 to $8 per square foot over the base broom finish price. Each finish carries a different labor intensity and material cost.
| Finish | Per sq ft premium | Total for 400 sq ft |
|---|---|---|
| Broom finish (standard) | $0 (included) | $3,200 to $6,400 |
| Smooth trowel finish | $0.50 to $1.50 | $3,400 to $7,000 |
| Exposed aggregate | $2 to $4 | $4,000 to $8,000 |
| Stamped concrete | $4 to $8 | $4,800 to $9,600 |
| Colored concrete (integral) | $1 to $2.50 | $3,600 to $7,400 |
Stamped concrete requires release agent, stamping mats, and a second finishing pass before the concrete reaches initial set, which limits crew productivity to roughly 200 to 400 square feet per day. Broom finish crews pour and finish 800 to 1,200 square feet per day on a straightforward site. That labor difference is the primary cost driver between finishes.
What Is Included in a Contractor's Price for a 20x20 Slab?
A complete contractor quote for a 20x20 slab covers seven items. Anything missing from the list below is either an add-on charge or a sign the scope is incomplete.
Typically included in a full-scope bid:
- Excavation to 8 to 10 inches below finished grade
- 4 to 6 inches of compacted limestone base material
- Perimeter forming with staked 2x4 or steel forms
- 4 inches of 3,500 PSI concrete
- Fiber mesh or rebar reinforcement
- Control joints cut every 8 to 10 feet within 12 hours
- Broom finish and form stripping
Typically not included unless specified:
- Demolition and haul-off of an existing slab ($800 to $2,400 for 400 sq ft)
- Permit fees ($75 to $250 depending on parish)
- Grading or drainage correction ($500 to $2,000)
- Vapor barrier (6-mil poly, $0.50 to $1 per sq ft)
- Sealer application ($1.50 to $3 per sq ft)
- Stamped, colored, or exposed aggregate finish upgrades
How Do You Tell if a Concrete Slab Quote Is Fair?
A fair quote for a 20x20 slab in Greater New Orleans falls between $8 and $16 per square foot for standard broom finish work in 2026. A bid below $6 per square foot on a south shore site raises three specific concerns.
A below-market bid often means one of the following: the slab thickness is 3 inches instead of 4 inches, the base layer is skipped or reduced to 2 inches, reinforcement is omitted, or control joints are not included. Each of those shortcuts creates a slab that cracks or settles within 2 to 5 years on south Louisiana clay soils.
Three checkable items in any quote: slab thickness (4 inches minimum for residential), base depth (4 to 6 inches of compacted stone), and reinforcement type (fiber mesh at minimum, rebar for driveways and loaded slabs). A quote that does not specify these three items is incomplete, not competitive. A site visit is what produces an actual number for a specific property.
Where Do New Orleans Concrete Slab Prices Sit Against the National Range?
Greater New Orleans concrete slab prices run 10% to 25% above the national average of $6 to $12 per square foot. Three factors drive the premium. First, soft alluvial clay across Jefferson Parish and Orleans Parish requires deeper base preparation than the 4 inches standard in stable-soil markets, adding $1 to $3 per square foot in material and compaction labor. Second, concrete plant locations and delivery logistics in the metro area add $8 to $15 per cubic yard in delivery surcharges compared to suburban Sun Belt markets. Third, the regional labor market for concrete finishers supports $22 to $30 per hour crew rates, reflecting steady residential and commercial demand across the metro.
A 20x20 slab that costs $2,400 to $4,800 in a stable-soil market with lower labor costs runs $3,200 to $6,400 in Greater New Orleans because the ground requires more preparation and the labor market reflects a different cost structure.
Common questions
- How much does a 20x20 concrete slab cost in 2026?
- A 20x20 concrete slab costs $3,200 to $6,400 in Greater New Orleans in 2026. That range covers 400 square feet at $8 to $16 per square foot, including 4 inches of 3,500 PSI concrete over compacted limestone base with reinforcement and broom finish. Site access, subgrade condition, and finish upgrades move the price within that range.
- How many yards of concrete do I need for a 20x20 slab?
- A 20x20 slab at 4 inches thick requires approximately 2.5 cubic yards of concrete. Most suppliers require a minimum order of 3 to 4 cubic yards per delivery, or charge a short-load fee of $40 to $75 per cubic yard under the minimum. A concrete contractor typically orders 3 cubic yards to account for waste and slight grade variations.
- How thick should a 20x20 concrete slab be?
- A 20x20 concrete slab for residential use requires a minimum thickness of 4 inches. A slab supporting vehicle traffic, such as a parking pad, requires 5 to 6 inches with number 4 rebar on 12-inch centers. Standard residential patio and shed slabs use 4 inches of 3,500 PSI concrete with fiber mesh or number 3 rebar on 18-inch centers.
- Does a 20x20 concrete slab need a permit in New Orleans?
- Most parishes in Greater New Orleans require a permit for a concrete slab over 200 square feet. A 20x20 slab at 400 square feet exceeds that threshold in Jefferson Parish and Orleans Parish. Permit fees run $75 to $250 depending on the parish. Contact the parish permits office directly to confirm current requirements and setback rules for a specific property.
- How long does a 20x20 concrete slab take to pour and cure?
- A 20x20 concrete slab takes 1 day to pour and finish. Foot traffic is safe after 24 to 48 hours. Vehicle traffic requires a minimum of 7 days. Full structural cure takes 28 days. Control joints are cut within 12 hours of the pour to control cracking. Forms are stripped at 24 hours on most residential pours.
- Is stamped concrete worth the extra cost on a 20x20 slab?
- Stamped concrete adds $4 to $8 per square foot over broom finish, bringing a 20x20 slab to $4,800 to $9,600 total. The upgrade provides a decorative pattern that replicates stone, brick, or tile at 40% to 60% less than the cost of natural pavers. Stamped concrete requires resealing every 2 to 3 years at $1.50 to $3 per square foot to maintain color and surface protection.
Last updated August 5, 2026
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