Pre-Calculated Specs for a 12×12 Concrete Slab (4" Depth)
large dining patio, outdoor kitchen, or oversized storage pavilion80 lb Bags Needed88 bagsincl. 10% waste
Total Volume1.96 yd³52.8 cu ft
Sub-Base Gravel2.04 yd³~111 bags (50 lb)
#4 Rebar Needed~216 ft18" on-center grid
Expert Contractor Recommendation: With 88 bags (~7,040 lbs of concrete), hand-mixing risks exhaustion and dry "cold joints" between batches. Ordering a ready-mix truck delivery is strongly recommended.
Engineering Considerations for 12×12 Pours
A 12×12 slab covers exactly 144 square feet. This size is commonly used for a large dining patio, outdoor kitchen, or oversized storage pavilion. Because this project requires over 1.8 cubic yards (1.96 cu yds), hand mixing is strongly discouraged due to fatigue and cold joint vulnerability. Coordinate with a local ready-mix dispatch supplier.
| Bag Size | Total Bags Needed | Combined Dry Weight | Estimated Material Cost |
|---|---|---|---|
| 80 lb bag | 88 bags | 7,040 lbs (3,193 kg) | $510 - $660 |
| 60 lb bag | 118 bags | 7,080 lbs (3,211 kg) | $578 - $755 |
| 50 lb bag | 141 bags | 7,050 lbs (3,198 kg) | $599 - $776 |
| 40 lb bag | 176 bags | 7,040 lbs (3,193 kg) | $634 - $845 |