How to Calculate Construction Materials for a Cinder Block Wall

If you are adding on to your home or designing a separate structure and are using cinder blocks for its construction, you'll need to know how many cinder blocks will be needed to complete the project. Cinder block construction is sturdy and can be finished with stucco and paint. Or you can hang drywall over cinder block if it is an interior wall. All you need is a couple of items to estimate your needs.

Things You'll Need

• Tape measure
• Calculator

Instructions

1. Measure the area of the wall. Run a tape measure across the width of the wall's area and from top to bottom. Write down the measurements on a notepad. Then multiply the height by the width. For instance, if the wall is 12 feet height and 30 feet long, it will be 360 square feet.

2. Find the number of cinder blocks you'll need to fit the square footage. The average cinder block is 8-by-16 inches. The standard measurement used by contractors when determining the quantity of blocks needed to square feet is to multiply 1.125 by the square footage. Using the above example of 360 square feet, the number of cinder blocks needed is 405, which is 360 square feet times 1.125.

3. Add the waste percentage. In every construction project the builder will include a "waste margin." This is to account for any breakage of materials while completing the project. A rule of thumb is to add between 5 and 6 percent to the calculated materials. So if your cinder block wall calls for 405 blocks, add 5 or 6 percent, putting the total cinder blocks needed at 426 to 430.

References

• "Engineering Fundamentals: An Introduction to Engineering"; Saeed Moaveni; 2010
• "Basic Engineering for Builders"; Max Schwartz; 1993