How Much Concrete for 80 Feet of Footing?
How much concrete for 80 feet of footing depends on the footing’s width and depth. A common residential footing 16 inches wide by 8 inches deep works out to about 2.63 cubic yards over 80 feet, before waste.
Concrete calculator →Footing math
- Cross-section: 16 in × 8 in = 1.333 ft × 0.667 ft = 0.889 sq ft.
- Volume: 0.889 × 80 ft = 71.1 cu ft.
- Yards: ÷ 27 = 2.63 yd³.
Related: How Much Concrete for 100 Feet of Footing?
Yards for common footing sizes over 80 feet
| Footing (width × depth) | Cubic feet | Cubic yards | Yards +10% |
|---|---|---|---|
| 12 × 6 in | 40.0 | 1.48 | 1.63 |
| 16 × 8 in | 71.1 | 2.63 | 2.90 |
| 20 × 8 in | 88.9 | 3.29 | 3.62 |
| 24 × 10 in | 133.3 | 4.94 | 5.43 |
| 24 × 12 in | 160.0 | 5.93 | 6.52 |
Sizing and depth
Code and soil bearing decide the footing size. Light walls often sit on 12 to 16 inch wide footings, while two-story loads or weak soils call for wider ones. Whatever the size, the bottom has to reach undisturbed soil below frost depth. See footing depth and the frost line.
Related: How Much Concrete for 20 Feet of Footing?
Trench pours run over
Earth-formed trenches eat extra concrete. Over-digging by an inch on each side of a 16-inch footing adds about 12 percent. Measure the trench after digging and size the order from those numbers.
Rebar and inspection
Most footings carry horizontal rebar set on chairs or dobies so it sits a few inches above the soil. Many jurisdictions require an inspection of the trench and steel before the pour, so schedule it before you book the truck.
Questions people ask
How many yards for 80 feet of 16x8 footing?
About 2.63 cubic yards before waste.
How many yards for 80 feet of 24x12 footing?
About 5.93 cubic yards.
How much extra should I order for a trench footing?
About 10 to 15 percent, since trench walls are rarely straight.
How deep should a footing be?
Below the local frost line and on undisturbed soil; your building department sets the minimum.
How thick should the base under the slab be?
About 4 inches of compacted gravel is common for residential slabs, more on soft or poorly drained soil.
Related guides
- How Much Concrete for a Retaining Wall Footing?
- Footing Depth and the Frost Line: How Deep to Dig
- How Much Concrete for a Deck Footing? Bags per Hole
- 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
- How Much Concrete for 50 Feet of Footing?
- How Much Concrete for 60 Feet of Footing?
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