Brick walls are measured in square metre if the thickness of the wall is
📏 Understanding Measurement of Brickwork
The method of measurement for brickwork in quantity surveying depends on its thickness. According to IS 1200, the standard practice is to measure substantial brickwork by volume (cubic metres), but to measure thin brickwork by area (square metres).
The key is to identify the threshold that separates "thick" from "thin" work. This threshold is typically defined by the thickness of a standard brick.
🔬 Detailed Analysis of the Options
A. 10cm
This is the correct answer. A wall thickness of 10 cm corresponds to a "half-brick wall" (a wall built with the 9 cm width of the brick plus a 1 cm mortar joint). IS 1200 specifies that half-brick walls (or any wall of one brick thickness or less) should be measured in square metres (m²), with the thickness stated in the description.
C. 20 cm
This is incorrect. A 20 cm thick wall is a "one-brick wall" (a wall built with the 19 cm length of the brick plus a 1 cm mortar joint). This is considered substantial brickwork and is the standard example of a wall measured in cubic metres (m³).
B. 15cm
This is incorrect. While this is an intermediate thickness, it is greater than a half-brick wall and would be measured by volume (m³) like a 20 cm wall. The 10 cm mark is the standard cut-off point.
D. None of these
This is incorrect because 10 cm is the precise and correct answer based on standard measurement practices.
📊 Summary: Units of Measurement vs. Wall Thickness
| Wall Thickness | Description | Unit of Measurement |
|---|---|---|
| 10 cm | Half-Brick Wall | Square Metre (m²) |
| 20 cm | One-Brick Wall | Cubic Metre (m³) |
| > 20 cm | Thick Walls | Cubic Metre (m³) |
💡 Study Tips
- The 10cm Rule: This is a fundamental rule in quantity surveying. If a brick wall is 10cm thick (or less), you measure its area.
- Link Thickness to Brick Size: Remember that a 10cm wall is a "half-brick" wall (using the 9cm width), and a 20cm wall is a "one-brick" wall (using the 19cm length). This helps you understand why the measurement unit changes.
- IS 1200 is the Authority: These rules aren't arbitrary; they come from the standard code for measurement, IS 1200.