Pre-Calculated Specs for a 8×8 Concrete Slab (4" Depth)
small lawn mower shed, generator pad, trash enclosure, or compact deck landing80 lb Bags Needed40 bagsincl. 10% waste
Total Volume0.87 yd³23.5 cu ft
Sub-Base Gravel0.91 yd³~50 bags (50 lb)
#4 Rebar Needed~108 ft18" on-center grid
Expert Contractor Recommendation: Mid-size project (40 bags / 0.87 yd³). Can be hand-mixed on site with a rented electric drum mixer or delivered via a short-load concrete truck.
Engineering Considerations for 8×8 Pours
A 8×8 slab covers exactly 64 square feet. This size is commonly used for a small lawn mower shed, generator pad, trash enclosure, or compact deck landing. At 0.87 cubic yards, this is an approachable DIY project that can be completed over a single weekend with a rented mechanical drum mixer.
| Bag Size | Total Bags Needed | Combined Dry Weight | Estimated Material Cost |
|---|---|---|---|
| 80 lb bag | 40 bags | 3,200 lbs (1,451 kg) | $232 - $300 |
| 60 lb bag | 53 bags | 3,180 lbs (1,442 kg) | $260 - $339 |
| 50 lb bag | 63 bags | 3,150 lbs (1,429 kg) | $268 - $347 |
| 40 lb bag | 79 bags | 3,160 lbs (1,433 kg) | $284 - $379 |