Concrete for a 14×28 slab
4.84 cubic yards (240 × 80 lb bags)
for a 14×28 ft slab 4 inches thick: 130.7 cu ft. Bag counts include 10% extra; at 6 inches you need 7.26 yards.
A 14×28 foot slab covers 392 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 130.7 cubic feet of concrete, or 4.84 cubic yards. At this size ready-mix is cheaper and far less work than bags: about 5.5 yards, roughly $908 before delivery fees, against $1,560 for 240 bags of 80 lb mix.
Concrete for a 14×28 slab by thickness
| Thickness | Cubic yards | Cubic feet | 80 lb bags | 60 lb bags | 40 lb bags |
|---|---|---|---|---|---|
| 3 in | 3.63 | 98 | 180 | 240 | 360 |
| 4 in | 4.84 | 130.7 | 240 | 320 | 480 |
| 5 in | 6.05 | 163.3 | 300 | 400 | 599 |
| 6 in | 7.26 | 196 | 360 | 480 | 719 |
| 8 in | 9.68 | 261.3 | 480 | 639 | 959 |
Bag counts include 10% extra for spillage and uneven ground. Cubic yards and cubic feet are the exact volume.
How it’s worked out
- Convert the thickness to feet: 4 in ÷ 12 = 0.333 ft.
- Multiply length × width × thickness: 28 × 14 × 0.333 = 130.67 cu ft.
- Divide by 27 for cubic yards: 130.67 ÷ 27 = 4.84 cu yd.
- Add 10% and divide by the bag yield: 143.73 ÷ 0.6 = 240 bags of 80 lb mix (rounded up).
Under the slab, plan on 4 inches of compacted gravel: about 4.84 cubic yards. For driveways and anything that carries a vehicle, go to 5 or 6 inches and add rebar or wire mesh.
Change the numbers
Other slab sizes
- 14×26 slab
- 14×30 slab
- 15×28 slab
- 14×25 slab
- 12×28 slab
- 14×24 slab
- 14×32 slab
- 16×28 slab
- 14×22 slab
- 10×28 slab
- 14×20 slab
- 14×36 slab
Questions
- How many bags of concrete do I need for a 14×28 slab?
- At 4 inches thick, a 14×28 slab takes 240 bags of 80 lb concrete mix, 320 bags of 60 lb mix or 480 bags of 40 lb mix, including 10% extra.
- How many yards of concrete for a 14×28 slab?
- 4.84 cubic yards at 4 inches thick, 6.05 at 5 inches and 7.26 at 6 inches, before adding extra for waste.
- How much does a 14×28 concrete slab cost?
- The concrete alone for a 4 inch 14×28 slab costs about $1,560 in 240 bags of 80 lb mix (at about $7 a bag) or about $908 for 5.5 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $2,352 to $4,704 for 392 sq ft.
- How much does a 14×28 slab weigh?
- About 9.5 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).