How Much Concrete Do I Need?

​For many people out there, one of the most crucial questions to ask is usually, “how much concrete do I need?” As honest and straightforward as the question is, many of us do not have practical, real-world applications for carrying out the mathematics to find the solution to this question. Thus, no one cares enough to retain it.

​So, before doing anything else, you need to relax because there is nothing hard at all. Basically, there are two steps to determining the amount of concrete you need for your project. Do not be scared of terms such as yield, density, or cubic feet.

Firstly, you want to determine the volume of space you want to fill with concrete. It does not matter if you want to fill the space with water or concrete -  volume is always constant and never changes. It is easy to determine volume since it’s a key ingredient in most construction projects.  Volume is measured in cubic feet.

The ready concrete mix comprises the blended mix, sand gravel, and other materials; typically, dry-ready concrete comes in different sizes and weights such as 45, 60, and 80 pounds.

Irrespective of the size of concrete you want, you must determine the volume in the cubic yard prior to purchasing the mixed concrete.

So how is volume calculated?
Volume is determined by multiplying a slab’s length, width, and depth. In the example below, we shall determine the volume in the cubic yard for a 100 square feet slab at either 4, 5, or 6” thickness.

Note:
•    1.3 cubic yards = 1 cubic meter (m3)
•    35.3 cubic feet = 1 cubic meter (m3)

Calculate Formula for Concrete
Calculate the thickness of the concrete you want. Determine the length and width that you aim to cover. And then the length of the width and length to find the square footage. Change the thickness to feet from inches. To calculate cubic feet, multiply the square footage and the thickness in feet, change cubic feet to cubic yards and multiply by .037.

Below is the mathematics for a 10sqft by 10sqft concrete patio:
10 by 10 square feet.
12 by 4 = .33
.33 by 100= 33 cubic feet.
.037* 33 = 1.22 cubic yards.

With the above, you are determining, and then you convert to cubic yards. In the case of concrete, the approach, L x W x H.  To determine the number of bags required for your project, divide the total cubic yards and divide it by the yield.

Use these yields:
•    40lb bag produces .011 cubic yards
•    60lb bag produces .017 cubic yards
•    80lb bag produces .022 cubic yards

Remember that each pour is different, and thus there will be cases where you will have to round up your calculations so that you do not lack concrete.

Tips When Estimating Concrete for Your Projects

Slabs and Footings
Length: 
•    The distance of the longest slide of your slab.
Width: 
•    The distance of the shorter section of the slab.
Height: 
•    Distance between the bottom and top section of the slab.

Staircase:
Run:
•    The length of the shortest section of each stair.
Rise:
•    The estimated height of each stair.
Platform Depth:
•    The estimated size of the shortest part of the top stair.
Width:
•    The measurement of the longest side of each stair.

Round Footings / Fence Post Holes
Radius:
Estimate the diameter of the footing or hole. The radius would be half of the estimation.
Height:
Size of the height of the footing or hole.

The above process should be as easy as it sound. But if not, do not worry, you can always get in touch with a concrete professional at Pueblo Concrete Contractors for professional assistance. Contact us to schedule an appointment. Better yet, you can call us on 719-299-0550 and we will be happy to help you with your concrete needs. Try our services today!