For home repairs or renovations, one of the first major calculations that you need to know is how to compute the volume of the concrete footers. The concrete footer is used to support the wall, and is usually eight inches or more in depth, and should be at least twice the width of the wall that it supports. Knowing the calculations for the concrete footer volume is necessary in ensuring that you will end up with the appropriate amount of cement for your home. Here’s how to calculate concrete footer volume.
Measure. To begin, you will need to measure the depth, length, and the width of the concrete footings in your home. You can use a tape measure to do this easily, since the tape measure comes with bent edges to make it easier for you to attach the measuring tape to the edges of the footing. You can also use markers that will be pinned onto the earth, in case the concrete footers that you are measuring are longer than the typical length of the tape measure. Jot down the measurements on a sheet of paper.
Multiply. Once the measurements are ready, the next step is to compute for the volume. This can be done by using the formula: L x W x D, which means that the depth, width, and length should be multiplied together. For example, a concrete footing, which is .66 feet deep, 50 feet long, and 2.5 feet in width, should end up with a volume of 82.5 cubic feet. Keep in mind when calculating concrete, however, that the measurement is in cubic feet, and most cement are packaged and delivered in cubic yards. This means that you will need to convert the measurement for you to be able to figure out exactly how much concrete footer you will need when doing concrete work.
Divide. For the conversion from cubic feet to cubic yard, you need to divide the measurement by 27, which is the standard number for cubic feet to yard conversions. This means that 82.5 cubic feet of concrete volume will be equal to 3.05 cubic yards of cement. You can also proceed with a direct formula of (L x W x D)/27. This formula simply means that the product of the length, width, and the height of the footing is divided immediately into 27.
Increase. As a rule, however, you will need to add another five percent into the total cubic yards of cement that you will purchase. Keep in mind that footings are not always measured with perfect accurateness, and the last thing that you want is to end up with insufficient cement for the footing. By adding five percent to the total sum of cement footing you need, you can order safer cement measures. The computation for the added five percent is by multiplying the cubic yard by 1.05. For 3.05 cubic yards of cement, you should order a total of 3.20 cubic yards.
These tips will help you when calculating how much concrete is needed for your project. Once you have the exact measurements, you can proceed to order the cement. Mix according to instructions, and pour into the footing. Add steel rods along the concrete for easier leveling, and you should end up with just enough concrete for the footings.