# How to measure for concrete slabs

Written by g.k. bayne
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All concrete is sold by the cubic yard. A cubic yard is equal to a cube that is three feet wide by three feet high by three feet deep. The total volume is equal to 27 cubic feet. Measuring a slab for the amount of concrete required is useful for double-checking the amount delivered by the concrete company. Many times they will figure the amount for you. It is always a good idea to know beforehand just how much material is needed so you will not be shorted for pouring the slab.

Skill level:
Moderate

• Tape measure
• Pencil
• Paper

## Instructions

1. 1

Measure the overall area into which the concrete for the slab will be poured. In this case the slab is 12 feet wide by 14 feet long. Multiplying the two measurements, the area is equal to 168 square feet.

2. 2

Place the tape measure down the side of the slab to measure the depth of the concrete. Typical depth for most slabs is four inches. Convert the four inches into feet. Divide four inches by 12 inches and the foot measurement is equal to 0.33 feet.

3. 3

Multiply the area of the slab at 168 square feet by the slab's depth of 0.33 feet to find the overall cubic volume of the slab. The cubic footage of the slab is equal to 55.44 cubic feet.

4. 4

Find the yardage of concrete required to pour this slab. Divide 55.44 cubic feet by 27 cubic feet per cubic yard. The yardage required to pour this slab is 2.05 cubic yards of concrete.

#### Tips and warnings

• Circular slabs are measured in much the same manner. Use the formula for finding the area of a circle, which is equal to pi times the radius of the slab squared (a = 3.1416 x r^2).
• Radius is equal to half the overall diameter of the circle. A 10-foot circular slab would have an area equal to 78.54 square feet.
• Slabs with odd shapes should be broken down to small squares or rectangles. Calculate the amount of concrete needed for each small shape and then add the values together for the total yardage.

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