How Much Does a Concrete Slab Foundation Cost?
A 1,200 sq ft concrete slab foundation with footings, a thickened edge and rebar costs $17,216 to $28,693 at national prices. Change the footprint or add your ZIP in the calculator for your own figure.
LIKELY INSTALLED PRICE
$22,954
Our installed range for this 30×40 ft, 6-inch slab: $17,216 – $28,693 ($14.35 – $23.91 per sq ft)
In plain terms: that's about the size of a workshop or pole-barn floor, and roughly 39% of the price is the crew's labor.
- DIY materials
- $9,086
- Concrete
- 22.22 yd³
- Bagged mix
- 1,100 80-lb bags
- Delivery
- 3 trucks
An estimate, not a bid. A contractor's price depends on your site, access and timing.
What changes the price
Where the money goes
- Materials$11,635
- Labor$7,494
- Overhead and profit (20%)$3,826
All 11 line items
| Item | Qty | Material | Labor | Total |
|---|---|---|---|---|
| Site setup, layout and cleanup | 1 job | $100 | $56 | $156 |
| Excavate and grade subgrade | 1,200 sqft | $0 | $1,332 | $1,332 |
| Forms, stakes and form release | 140 lf | $168 | $311 | $479 |
| Compacted crushed-stone base | 20.74 ton | $933 | $384 | $1,317 |
| 6-mil polyethylene vapor barrier | 1,200 sqft | $158 | $89 | $247 |
| #4 rebar, tied on chairs | 1,670 lf | $1,666 | $742 | $2,407 |
| Perimeter footing (12x24 in, formed and poured) | 140 lf | $3,080 | $1,813 | $4,893 |
| Thickened slab edge (12 in deep) | 140 lf | $1,260 | $622 | $1,882 |
| Ready-mix concrete, 3,500 psi, delivered | 23.33 yd3 | $4,059 | $518 | $4,577 |
| Place, screed and broom finish | 1,200 sqft | $60 | $1,554 | $1,614 |
| Sawn control joints | 100 lf | $150 | $74 | $224 |
| Subtotal × overhead and profit (20%) = midpoint | $22,954 | |||
National prices until you enter a ZIP.
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Compare a contractor's price with the range for these inputs.
What next
Get two or three quotes and compare them with $17,216 – $28,693. DIY: 1,100 bags or 23.33 yd³ of ready-mix.
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Turn this price into an estimate for your customer →Cost by thickness for 30x40 (1,200 sq ft)
4 in · patios, sheds
$15,984 – $26,639
14.81 yd³ · 734 bags · about $21,311
5 in · garages, driveways
$16,670 – $27,784
18.52 yd³ · 917 bags · about $22,227
6 in · shops, RV pads
$17,216 – $28,693
22.22 yd³ · 1,100 bags · about $22,954
What is a slab concrete foundation?
It's a floor slab and its footings poured as one piece, sitting directly on a compacted base. The edge is thickened to carry the walls. There's no crawl space or basement underneath.
Concrete footers under a slab foundation
Footers are the thick strips of concrete under the walls. Here they're priced per linear foot along the 140 linear ft of the edge. In cold regions they have to reach below the frost line, which a local contractor will size.
Rebar and reinforcement
This estimate uses 1,670 linear ft of rebar in the slab plus steel in the footings. An engineer's drawing may call for a tighter grid or post-tension cables. Either one changes the steel line.
Concrete slab vs raised foundation
A slab costs less and goes in faster than a crawl space or stem wall. A raised foundation gives access to plumbing and suits sloped or flood-prone lots. Your lot and climate usually decide it.
Cracks in a slab foundation
Hairline shrinkage cracks are common and mostly cosmetic. Wide, uneven or growing cracks point to soil movement and need an engineer, not a patch. Expansive clay soils make this more likely.
Why a contractor's bid will differ
This is an estimate from national data, not a bid. Soil reports, engineering, plumbing under the slab and inspections aren't in it. Ask foundation contractors to quote those separately.
DIY vs pro for this 30x40 pour
Materials alone come to $9,086, about 40% of the $22,954 midpoint contractor price. The difference is $13,869 of labor, equipment, delivery and contractor overhead across 11 line items. At 23.33 yd³ with waste the pour fills 3 mixer trucks, so ready-mix is the practical route even for a DIY pour.
Related slab sizes
Compare with the next sizes
Frequently asked questions
How much more is a foundation than a plain slab?
Footings, the thickened edge, a vapor barrier and heavier steel all add cost. Compare this figure with the same footprint on the slab calculator to see the gap.
How much concrete does a slab foundation take?
The floor alone is 22.22 yd³ at 6 inches. The footings add more, and the line items show both.
Can I build a concrete slab foundation myself?
Forming and steel are possible for a skilled owner. Inspections, the pour and the finish are usually best left to a crew.
Does a slab foundation need a vapor barrier?
Under any heated space, yes. It's one of the cheapest lines in the estimate and it keeps moisture out of flooring.
For contractors
Quoting concrete for customers?
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