You finally decided to get around to building a new concrete block wall around your patio or pool, and need to know how many concrete blocks to buy. How do you calculate it? I'll show you how.
Buying too few blocks is a waste of time and energy as you'll have to stop the project, and go get more. What a drag!
Buying too many blocks is not only a waste of money, who wants to carry any more of the them than is absolutely necessary?!? Once to the job site is understood, but a second time to a dumpster??? Should have done a better take off...
The solution is an accurate block count before you ever even get in the car to go to the home improvement store. The formula is very simple and very accurate, assuming you know the length and height, in feet, of the wall you want to build. And if you DON'T know the length and height of your own wall, you might want to consider hiring someone else for the project. :-)
First you want to figure out how many courses you'll need. That's a fancy way of saying how many blocks tall. The thing to remember with masonry walls is the block is 8 inches tall. You CAN make your wall any height you want, but if you make it anything other than 4 or 8 inch intervals, you'll be making a LOT more work for yourself. For this How To, I'm going to stay with easy numbers.
To calculate courses, multiple the height in feet by 1.5. That's it. If your wall is going to be 4 feet tall, you'll need 6 courses of blocks. It doesn't matter if your wall is 6 or 600 long, what we're worried about in this step is height. As long as the wall is level, it's all the same.
Now that you have the number of courses, the next step is blocks for length. A standard block is 16 inches long, so the formula is: "length in feet times .75". So an 8 foot long row of blocks would need 6 blocks to form it.
From there, you simple multiply the number of blocks in a row by the number of courses, and you're off to buy the block at the concrete yard. For our example, you'll need 36 full blocks to make a 4 foot high x 8 foot long wall.
So again the formula for a block takeoff would be:
Length in feet * .75 * # of courses = number of blocks needed.
Pretty simple huh?