How Much Concrete for a 15x22 Slab?
How much concrete for a 15x22 slab depends on thickness. The slab covers 15 × 22 = 330 square feet, and at 4 inches thick that is about 4.07 cubic yards, or 4.48 yards with a 10 percent allowance. Mixed from bags, it is roughly 184 bags of 80 lb mix.
Concrete calculator →The math for a 15x22 slab
- Area: 15 ft × 22 ft = 330 sq ft.
- Thickness in feet: 4 in ÷ 12 = 0.333 ft.
- Volume: 330 × 0.333 = 110.0 cubic feet.
- Cubic yards: 110.0 ÷ 27 = 4.07 yd³.
- With 10% extra: 4.48 yd³.
The concrete calculator runs the same steps for any size and thickness.
Related: How Much Concrete for a 12x20 Slab?
Concrete for a 15x22 slab by thickness
| Thickness | Cubic feet | Cubic yards | Yards +10% | 80 lb bags | 60 lb bags |
|---|---|---|---|---|---|
| 4 in | 110.0 | 4.07 | 4.48 | 184 | 245 |
| 5 in | 137.5 | 5.09 | 5.60 | 230 | 306 |
| 6 in | 165.0 | 6.11 | 6.72 | 275 | 367 |
Bag counts assume about 0.60 cubic feet per 80 lb bag and 0.45 per 60 lb bag, rounded up.
Choosing the thickness
Four inches is the usual thickness for patios, walks and shed floors. Slabs that carry cars or a heavy hot tub are often poured at 5 to 6 inches, and edges are sometimes thickened where loads concentrate.
Related: How Much Concrete for a 12x24 Slab?
Ordering ready-mix
Concrete is ordered by the cubic yard, and a yard is 27 cubic feet. Ready-mix plants usually sell in quarter- or half-yard steps, so round up to the next step rather than down. Running short in the middle of a pour leaves a cold joint, which is a weak seam in the slab.
Getting the ground ready
Uneven ground is the main reason pours run short. Every half inch of extra depth across the slab adds concrete you did not plan for. Screed the base flat, check it with a string line and set the forms to finished height before the truck arrives.
Joints, mesh and rebar
Plan the joints before the pour. Panels close to square crack less than long, narrow ones, and joint spacing around 10 feet is typical for a 4-inch slab. Cut joints with a groover while the concrete is soft or with a saw within the first day.
Questions people ask
How many yards of concrete for a 15x22 slab at 4 inches?
About 4.07 cubic yards, or 4.48 with 10 percent extra.
How many yards for a 15x22 slab at 6 inches?
About 6.11 cubic yards.
How many 80 lb bags for a 15x22 slab?
About 184 bags at 4 inches thick, before any waste allowance.
How many square feet is a 15x22 slab?
330 square feet.
How much does a cubic yard of concrete weigh?
Roughly 4,000 pounds, or about 2 tons, for normal-weight concrete.
When is bagged concrete practical?
Usually for jobs under about a cubic yard. Beyond that, mixing dozens of bags by hand gets slow and batches may not blend well.
Related guides
- How Much Area Does a Yard of Concrete Cover?
- How Many Bags of Concrete in a Yard? 40, 60, 80 lb
- Gravel Base Under a Concrete Slab: Depth and Tons
- How Many Yards in a Concrete Truck? Mixer Sizes
- Concrete Short Load Fee: What It Is and How to Cut It
- 60 lb vs 80 lb Concrete Bags: Yield, Count, and Cost
- Rebar vs Wire Mesh in a Slab: Which One to Use
- Cost to Pour a Concrete Slab: Per Square Foot
- How Much Concrete for a 15x18 Slab?
- How Much Concrete for a 15x20 Slab?
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