How Much Concrete for 30 Feet of Footing?
For 30 linear feet of a 16 by 8 inch footing, plan on about 0.99 cubic yards. How much concrete for 30 feet of footing at other sizes is in the table; trench footings poured against the soil often use more than the math because trench walls are never perfectly straight.
Concrete calculator →Footing math
- Cross-section: 16 in × 8 in = 1.333 ft × 0.667 ft = 0.889 sq ft.
- Volume: 0.889 × 30 ft = 26.7 cu ft.
- Yards: ÷ 27 = 0.99 yd³.
Related: How Much Concrete for 100 Feet of Footing?
Yards for common footing sizes over 30 feet
| Footing (width × depth) | Cubic feet | Cubic yards | Yards +10% |
|---|---|---|---|
| 12 × 6 in | 15.0 | 0.56 | 0.61 |
| 16 × 8 in | 26.7 | 0.99 | 1.09 |
| 20 × 8 in | 33.3 | 1.23 | 1.36 |
| 24 × 10 in | 50.0 | 1.85 | 2.04 |
| 24 × 12 in | 60.0 | 2.22 | 2.44 |
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 16 Feet of Footing?
Trench pours run over
When the footing is poured straight into a dug trench instead of forms, the sides wander and the bottom is rarely flat. Measure the actual trench at several points and add 10 to 15 percent, not the usual 5.
Rebar and inspection
Footing steel is usually two or more horizontal bars held up off the soil. Book the inspection first, then the concrete: a failed inspection with a truck on the way is an expensive afternoon.
Questions people ask
How many yards for 30 feet of 16x8 footing?
About 0.99 cubic yards before waste.
How many yards for 30 feet of 24x12 footing?
About 2.22 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 much does a cubic yard of concrete weigh?
Roughly 4,000 pounds, or about 2 tons, for normal-weight concrete.
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 20 Feet of Footing?
- How Much Concrete for 24 Feet of Footing?
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