Concrete for a 5×14 slab

0.86 cubic yards (43 × 80 lb bags)

for a 5×14 ft slab 4 inches thick: 23.3 cu ft. Bag counts include 10% extra; at 6 inches you need 1.3 yards.

A 5×14 foot slab covers 70 square feet. At the standard 4 inch thickness for a patio, walkway or shed floor, that is 23.3 cubic feet of concrete, or 0.86 cubic yards. That is a small enough pour for bagged mix: 43 bags of 80 lb at about $280.

Concrete for a 5×14 slab by thickness

ThicknessCubic yardsCubic feet80 lb bags60 lb bags40 lb bags
3 in0.6517.5334365
4 in0.8623.3435886
5 in1.0829.25472107
6 in1.3356586129
8 in1.7346.786115172

Bag counts include 10% extra for spillage and uneven ground. Cubic yards and cubic feet are the exact volume.

How it’s worked out

  1. Convert the thickness to feet: 4 in ÷ 12 = 0.333 ft.
  2. Multiply length × width × thickness: 14 × 5 × 0.333 = 23.33 cu ft.
  3. Divide by 27 for cubic yards: 23.33 ÷ 27 = 0.864 cu yd.
  4. Add 10% and divide by the bag yield: 25.67 ÷ 0.6 = 43 bags of 80 lb mix (rounded up).

Under the slab, plan on 4 inches of compacted gravel: about 0.86 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

Concrete needed

0.86 cubic yards

23.3 cubic feet. With 10% extra, order 0.95 yards or 43 bags of 80 lb mix.

Area70 sq ft
Volume23.3 cu ft (0.86 cu yd)
80 lb bags43 (about $280)
60 lb bags58
40 lb bags86
Ready-mix to order1 yd (about $165 before delivery fees)
Weight of the slab1.7 tons

Other slab sizes

Questions

How many bags of concrete do I need for a 5×14 slab?
At 4 inches thick, a 5×14 slab takes 43 bags of 80 lb concrete mix, 58 bags of 60 lb mix or 86 bags of 40 lb mix, including 10% extra.
How many yards of concrete for a 5×14 slab?
0.86 cubic yards at 4 inches thick, 1.08 at 5 inches and 1.3 at 6 inches, before adding extra for waste.
How much does a 5×14 concrete slab cost?
The concrete alone for a 4 inch 5×14 slab costs about $280 in 43 bags of 80 lb mix (at about $7 a bag) or about $165 for 1 yards of ready-mix (at about $165 a yard, before delivery fees). Professionally poured slabs usually run $6 to $12 per square foot, about $420 to $840 for 70 sq ft.
How much does a 5×14 slab weigh?
About 1.7 tons at 4 inches thick (concrete weighs about 145 lb per cubic foot).

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