Check statements given below with respect to diagram below:

$W=1000\times 1200$

$D=1200\times 2100$

Height of wall = 3 m

All dimensions are mentioned in mm.

A: The centre line of wall is 27.50 m.

B: The short wall and long wall length is 8.5 m and 19 m respectively.

C. The total brickwork after deduction is 20.718 m³.

Concept:

Long Wall and Short Wall

• The wall along the length of the room is considered to be long wall and the wall perpendicular to the length of the room is considered to be short wall.
• To get the measurement of materials and work, length of long wall or short wall, centre line lengths of individual walls is calculated first.
• Then the length of long wall, (out to out) may be calculated after adding half breadth at each end to its centre line length.
• Thus the length of short wall measured in to in and may be found by deducting half breadth from its centre line length at e each end. These lengths are multiplied by breadth and depth to get quantities.

Centre Line Method

• In this method of estimation, the total center line length of walls in a building is first ca|culated, then the center line length is multiplied by the breadth and depth of the respective items to get the total quantity of that item.
• This method is quick but requires special attention and consideration at the junctions meeting points of partition or cross walls, etc.
• For rectangular, circular, and polygon (hexagonal, octagonal, etc.) buildings having no inter or cross walls, this method is quite simple.
• Half the width is deducted at the junction points[as it is considered twice while estimating through the centre line method.

Calculations:

Given: Wall thickness = 300 mm, Long wall = 10 m, Short wall = 3 m. $W=1000\times 1200$, $D=1200\times 2100$

The below figure shows the centre line, long and short wall that has to be calculated.

The total centre line of the wall is $=2\times (10-2\times 0.15)+3\times (3-2\times 0.15)=27.5m$

The total long wall is $=2\times (10-2\times 0.15)=19.4m$

The total short wall is $=3\times (3-2\times 0.15)=8.1m$

Volume of brickwork to be deducted is for the windows and door.

Doors = 2, Windows = 7

So total volume of brick work to be deducted is $=2\times (1.2\times 2.1\times 0.3)+7\times (1\times 1.2\times 0.3)=4.032m^3$

Total volume of brickwork is $=27.5\times 3\times 0.3=24.75m^3$

So volume of brickwork after deduction is $=24.75-4.032=20.718m^3$