Number of bricks required for one cubic metre of brick masonry is
🧱 Understanding the Calculation
To determine the number of bricks needed for a certain volume of masonry, we need to divide the total volume of the masonry by the volume occupied by a single brick, including its share of the mortar joint.
Standard Brick Size: The actual size of a standard modular brick in India is 190 mm × 90 mm × 90 mm.
Nominal Brick Size: This is the most important concept for this calculation. The nominal size is the actual size of the brick plus the thickness of the mortar joint surrounding it. With a standard 10 mm mortar joint, the nominal size becomes 200 mm × 100 mm × 100 mm.
🔢 Step-by-Step Calculation
Let's break down the calculation to arrive at the answer.
Step 1: Determine the Nominal Size of one brick.
Actual Size = 190mm x 90mm x 90mm
Mortar Thickness = 10mm
Nominal Size = (190+10) x (90+10) x (90+10)
Nominal Size = 200mm x 100mm x 100mm
Step 2: Calculate the Volume of one brick with mortar.
Volume = 200mm * 100mm * 100mm
Volume = 2,000,000 mm³
Step 3: Convert this volume to cubic meters (m³).
(Since 1m = 1000mm, 1m³ = 1000³ mm³ = 1,000,000,000 mm³)
Volume in m³ = 2,000,000 / 1,000,000,000
Volume = 0.002 m³
Step 4: Calculate the number of bricks per cubic meter.
Number of Bricks = (Total Volume of Masonry) / (Volume of one brick with mortar)
Number of Bricks = 1 m³ / 0.002 m³
Number of Bricks = 500
📝 Important Considerations
What about the volume of mortar?
A common point of confusion is how to account for the mortar. Our calculation already includes it by using the nominal brick size. We can verify this:
- Volume of 500 actual bricks = 500 × (0.19m × 0.09m × 0.09m) = 0.7695 m³
- Volume of mortar = Total Volume - Volume of Bricks = 1m³ - 0.7695m³ = 0.2305 m³
- This means in 1 cubic metre of brickwork, approximately 23% of the volume is mortar.
Wastage
The 500 bricks calculation is a theoretical value. In practice, some bricks will be broken during transport or cut for fitting at corners and edges. It is standard practice to add 5% to 10% for wastage when ordering materials.
💡 Study Tips
- Memorize the Nominal Size: The key to this calculation is the nominal brick size: 200 x 100 x 100 mm. This is easy to remember and makes the math simple.
- Volume is Key: The calculation is based on volume. The volume of one nominal brick (0.002 m³) is a very useful number to know.
- The Magic Number 500: For a standard modular brick, 500 bricks per cubic meter is the standard theoretical answer you should remember for exams.
- Theoretical vs. Practical: Understand that 500 is the number needed for a perfect calculation, but in the real world, you would always order more to account for wastage.