How to Calculate the Number of Concrete Blocks for a Wall

Concrete blocks are commonly used for wall construction. Calculating the number of blocks required is crucial for budgeting and material planning. Let’s calculate the number of concrete blocks for a wall with the following dimensions:

Wall Dimensions:

• Length: 18 ft
• Height: 14 ft
• Thickness: 9 inches (0.75 ft)

Concrete Block Dimensions:

• Length: 16 inches (1.33 ft)
• Height: 8 inches (0.67 ft)
• Thickness: 6 inches (0.5 ft)

Steps to Calculate:

Step 1: Calculate Wall Volume

The wall volume (including mortar) is calculated as:

Wall Volume = Length × Height × Thickness
Wall Volume = 18 × 14 × 0.75 = 189 cubic feet

Step 2: Calculate Block Volume (With Mortar)

Assuming a 0.5-inch mortar thickness, the dimensions of the block with mortar are:

• Length: 1.33 + 0.04 = 1.37 ft
• Height: 0.67 + 0.04 = 0.71 ft
• Thickness: 0.5 + 0.04 = 0.54 ft

The block volume with mortar is:

Block Volume = 1.37 × 0.71 × 0.54 = 0.522 cubic feet

Step 3: Calculate the Number of Blocks

The number of blocks required is:

Number of Blocks = Wall Volume ÷ Block Volume
Number of Blocks = 189 ÷ 0.522 ≈ 362 blocks

Step 4: Adjust for Wastage

To account for wastage, add 10% extra blocks:

Total Blocks = 362 + (10% of 362) = 362 + 36 ≈ 398 blocks

Final Results:

• Number of Concrete Blocks: 398 (including 10% wastage)

Tips for Accuracy:

• Always round up to the nearest whole number when purchasing blocks.
• Account for cutting and shaping blocks at corners or ends.
• Use good-quality mortar for better binding and durability.