How Much Concrete for a 24×24 Garage Slab?
Quick Answer
A 24×24 foot garage slab poured 6 inches thick needs 10.67 cubic yards of concrete. Order about 11.7 cubic yards to allow for a 10% waste factor. A slab this large is always a ready-mix delivery job.
- 6-inch garage slab: 10.67 cubic yards (288 cubic feet)
- Order ~11.7 cubic yards with 10% waste
- 4-inch version: 7.11 cubic yards
- Ready-mix cost: $1,600–$2,050 delivered
Formula
Multiply the slab dimensions in feet, then divide by 27 for cubic yards. Garage slabs are typically 6 inches thick to carry vehicle weight, so thickness is 6 ÷ 12 = 0.5 ft.
Step-by-Step Calculation
- 1
Slab area
24 × 24 = 576 square feet
- 2
Volume at 6 inches
576 × 0.5 = 288 cubic feet
- 3
Convert to cubic yards
288 ÷ 27 = 10.67 cubic yards
- 4
Add 10% waste
10.67 × 1.10 = 11.7 cubic yards
24×24 Garage Slab Concrete by Thickness
| Thickness | Cubic Feet | Cubic Yards | With 10% Waste | Ready-Mix Cost* |
|---|---|---|---|---|
| 4 inches | 192 | 7.11 | 7.8 | $1,065–$1,245 |
| 5 inches | 240 | 8.89 | 9.8 | $1,335–$1,555 |
| 6 inches | 288 | 10.67 | 11.7 | $1,600–$1,870 |
*Ready-mix at $150–$175 per cubic yard. A garage slab should be at least 6 inches with rebar or wire mesh reinforcement.
Frequently Asked Questions
How thick should a garage slab be?
A minimum of 4 inches for light use, but 6 inches is strongly recommended for garages that hold vehicles or heavy equipment. Add rebar or welded wire mesh and pour over a compacted gravel base.
How much does a 24×24 garage slab cost?
Materials alone run $1,600–$2,050 at 6 inches. A fully poured and finished 24×24 garage slab costs $3,500–$8,600 (about $6–$15 per sq ft) with labor, reinforcement, and grading.
Do I need rebar in a garage slab?
Yes. Use #4 rebar in a 16 to 24 inch grid, or welded wire mesh, to control cracking and carry vehicle loads. Thickened edges around the perimeter add extra strength.