How Much Does a Concrete Slab Cost in California in 2026?
Plan on roughly $9 to $18 per square foot for a concrete slab in California in 2026. Published figures for Sacramento and the Central Valley sit lower. A standard 4 inch slab there runs about $9 to $14 per square foot. National cost guides put the country as a whole at $6 to $12, with about $8 as the average.
Against real sizes, a 10 by 10 shed pad lands in the hundreds. A 20 by 20 garage slab lands around $3,600 to $5,600 at Valley rates. Those are market numbers, not our price list. Here is what the guides publish, and what moves the number on a concrete slab or pad.
What does a concrete slab cost per square foot?
National cost guides published for 2026 put a standard residential slab at $6 to $12 per square foot installed. The average they quote is close to $8 for a 4 inch pour. A national trade guide lists a plain slab at $6.50 to $10.50 per square foot.
One national calculator updated in May 2026 runs higher, at $10.33 to $12.65. Its number covers forms, steel and finishing. Excavation, base rock and compaction sit outside it.
California sits above all of those. National guides that break the country into regions put the state at $12 to $18 per square foot. A California cost guide splits the state by region.
That guide puts the Bay Area and Los Angeles at $13 to $18 per square foot. Sacramento and the Central Valley come in closer to $9 to $14.
The concrete itself is a small part of that. On one guide’s 400 square foot example, the concrete is about $850 of a $2,000 to $3,400 job. The rest is labor, prep and forms. The same California guide lists Central Valley ready mix at $165 to $195 per cubic yard.
What does a slab cost by size?
Here is what national cost guides publish for common sizes in 2026. The last column applies the published Central Valley range to the same square footage.
| Slab | Square feet | National guide range | At Valley rates of $9 to $14 |
|---|---|---|---|
| 10 by 10 shed pad | 100 | $600 to $1,200 | $900 to $1,400 |
| 12 by 12 workshop pad | 144 | $860 to $1,730 | $1,300 to $2,020 |
| 20 by 20 garage or ADU slab | 400 | $2,400 to $4,800 | $3,600 to $5,600 |
| 24 by 24 two car garage | 576 | $3,500 to $7,000 | $5,180 to $8,060 |
| 30 by 30 shop floor | 900 | $5,400 to $10,800 | $8,100 to $12,600 |
| 30 by 40 barn or shop slab | 1,200 | $6,000 to $14,400 | $10,800 to $16,800 |
RV pads price on their own scale, poured thicker with steel through the pad. A guide built around RV parking publishes these 2026 ranges.
| RV pad | Square feet | Published range |
|---|---|---|
| 10 by 40 | 400 | $1,800 to $3,600 |
| 12 by 45 | 540 | $3,200 to $4,900 |
| 14 by 65 | 910 | $6,400 to $8,200 |
Small equipment pads break the pattern. An HVAC or generator pad is only a few square feet. The trip out and the forming cost more than the concrete does. Those price as a small job rather than by the foot.
What moves the price up or down?
Thickness and use. Going to 5 or 6 inches adds concrete and steel over a 4 inch pad. Cost guides put each extra inch at about $0.50 to $1.25 per square foot. Shop floors, RV pads and equipment pads on commercial and industrial sites usually get the thicker pour.
Rebar or mesh. Wire mesh runs about $0.20 to $0.50 per square foot in published guides. Rebar on 18 inch centers runs $1.40 to $2.50 per square foot installed. Heavier bar on tighter spacing runs more again.
Base and grading. The dirt work hides inside the quote and it is real money. Guides list gravel base at $0.80 to $1.50 per square foot, and excavation or grading at $1.50 to $5.00. Valley soil runs from sandy loam to clay, with hardpan in spots.
Vapor barrier. A sheet under the slab is cheap, about $0.10 to $0.50 per square foot in the guides. It matters when the slab sits inside a building or under flooring.
Thickened edges. A pad that carries a wall or a heavy load gets a deeper edge. Guides list edge thickening at about $1.00 to $1.75 per square foot.
Access and tear out. If the truck cannot reach the forms, the concrete moves by buggy, pump or wheelbarrow. That is labor. Pulling out a cracked old slab first adds demolition and haul off.
Summer scheduling. Modesto summers run long and dry, with many days over 100 degrees. Hot concrete stiffens fast, so the crew has less time to finish the surface. Pours get started early and the slab gets kept damp while it cures.
Does a concrete slab need a permit?
That depends on what sits on top of it. Private flatwork like a patio slab or a plain back yard pad usually needs no building permit in Modesto. The City of Modesto’s Building Safety Division lists an exemption for small sheds. Permits are not required for one story detached storage sheds 120 square feet or less.
A slab that carries a building is a different job. A garage, an ADU or a room addition is structural. Those get a permit, engineered plans and inspections before the pour. Outside city limits, Stanislaus County’s Building Permits Division handles it, so confirm before you order concrete.
Is a pad the same thing as a foundation?
The two are different jobs and the price shows it. A pad is a flat slab sitting on compacted base. A shed pad, an RV pad, a sport court or a machine base is that.
A slab on grade foundation has footings built into it. The edges and the load bearing lines are thickened and heavily reinforced. Walls and a roof land on them, so an engineer sizes the steel and the concrete.
The published ranges reflect the extra work. The same California guide puts a monolithic slab foundation at $6 to $14 per square foot. A stem wall slab runs $10 to $16. A 1,500 square foot house foundation lands at $9,000 to $21,000.
A garage, an ADU or an addition needs more than a pad. The pour includes footings and stem walls under the walls. That work follows the engineer’s drawings and we pour to those plans. Our post on how a stem wall compares with a slab on grade covers both systems.
What should you do with these numbers?
Treat them as a sanity check. A real number comes from the site. Size, thickness, steel, base and access all feed into it. So does anything that has to come out first.
Concrete Solutions pours concrete slabs and pads in Modesto and about 65 miles out across the Central Valley. Tell us what will sit on the pad. We measure the site and hand you a written price, at no charge. Call or text (209) 606-9904.