How many blocks to build a retaining wall 21ft long and 3ft high?

Answer 1

Depends on the size of the block.

However, an house brick is 9" x 3" x 4"

So assuming the brick is laid 9" long and 3" high a single course of wall would require!!!

21 x 12 = 252 "

Hence 252 / 9 = 28 bricks for the length

&

9 x 12 = 108 "

Hence

108 / 3 = 36 bricks in height

Hence 36 x 28 = 1008 bricks is required!!!!

If you wanted a double course wall (for support) that is 8 " wide. Then you need twice the number of bricks which is 2016 bricks.

Answer 2

To calculate the number of blocks needed to build a retaining wall, you first need to determine the area of the wall. In this case, the area is 21ft (length) x 3ft (height) = 63 square feet. Next, you need to know the size of the blocks you are using. Let's assume each block covers 1.5 square feet. Therefore, you would need 63 square feet / 1.5 square feet per block = 42 blocks to build the retaining wall.