10x12 Concrete Slab Materials List: Concrete, Base and Rebar
A 10 × 12 ft slab poured 4 inches thick needs 1.63 cubic yards of concrete (74 bags of 80 lb, with 10% extra), 2.5 tons of gravel for the base, 9 twenty-foot rebar bars and 168 ft² of vapor barrier. The slab materials calculator works out the whole list for any size.
Part of the project planner: Planning a concrete patio, slab or driveway.
The materials list
| What to buy | How much | How we worked it out |
|---|---|---|
| Concrete | 1.63 yd³ (or 74 bags of 80 lb) | Concrete calculator: 120 ft² at 4 in thick, 10% extra. Ready-mix is ordered in quarter yards |
| Compacted gravel base | 2.5 tons of crushed stone | Gravel calculator: 4 in deep, plus 20% because loose stone compacts |
| Vapor barrier | 168 ft² of 10-mil poly | The slab plus a foot all round, lapped 6 in and taped |
| Rebar, #3 (3/8 in) | 9 bars of 20 ft (or 3 sheets of mesh) | Rebar calculator: a grid across the slab |
| Rebar chairs | About 8 | One for every 4 × 4 ft, to hold the steel mid-depth |
| Form boards | 6 boards of 8 ft (2×6) | The 44 ft perimeter |
| Stakes | About 18 | One every 2 to 3 feet, plus the corners |
| Control joints | 10 ft to cut or tool | Cut within 24 hours of the pour, a quarter of the slab depth |
| Isolation joint strip | 44 ft | Where the slab meets a wall, footing or column |
| Sealer | 1 gallon | About 250 ft² a gallon, applied once the concrete has cured for a month |
Thickness changes the order
Same 10 × 12 ft slab with a 4 inch base:
| Thickness | Concrete with 10% waste | 80 lb bags | Base stone | Rebar |
|---|---|---|---|---|
| 4 in | 1.63 yd³ | 74 | 2.5 tons | 9 bars |
| 5 in | 2.04 yd³ | 92 | 2.5 tons | 9 bars |
| 6 in | 2.44 yd³ | 110 | 2.5 tons | 9 bars |
The thickness trade-offs are in how thick should a concrete slab be, and the answer page for this size is how much concrete for a 10 × 12 slab, with bags and weight at five thicknesses.
Bags or ready-mix?
At 74 bags, hand-mixing is tiring and the batches must all be placed before they set. Ready-mix is the sensible choice above about 1 cubic yard; ask for the short-load fee. See how many bags of concrete you need for the bag charts.
Common mistakes to avoid
Poor compaction of the base, concrete placed too wet and joints cut late cause most cracks: read common mistakes when pouring a slab. For a larger floor see the garage slab materials list. Estimates only: check local code and your supplier before ordering.
Frequently asked questions
How much concrete do I need for a 10x12 slab?
A 10 × 12 ft slab 4 inches thick needs 1.63 cubic yards with 10% waste, which is 74 bags of 80 lb mix, or a small ready-mix order.
How much gravel goes under a 10x12 slab?
A 4 inch compacted base takes about 2.5 tons of crushed stone, which includes 20% extra because loose stone compacts.
How much rebar does a 10x12 slab need?
A grid at the calculator's default spacing takes 9 bars of 20 ft, or 3 sheets of 5 × 10 ft wire mesh. Support it on chairs so it sits in the middle of the slab.
How thick should a 10x12 slab be?
Four inches for a patio, walkway or light shed floor, five to six inches for a workshop or anything that carries a vehicle.
Can I mix 10x12 slab concrete myself?
You can, but 74 bags is a lot to mix before the first batch starts to set. Most people order ready-mix or rent a mixer and a helper.
More guides
Tools & materials for this project
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.