Centre Line Method of Building estiamtion

Center Line Method Of Estimation | Centre Line Method | One Room & Two Room Estimate By Center Line Method

In the Center Line method, sum total length of center lines of walls, long and short has to be found out. Find the total length of center lines of walls of the same type.

Long and short have the same type of foundation and footing and they find the quantities by multi-plying the total center length by the respective breadth and height.

In this method, the length will remain the same for the excavation in a foundation for concrete in the foundation. For all footings and for the superstructure. (With slight difference when there are cross walls or the number of junctions).


Center Line Method Of Estimation

In center line method is quick but requires special attention and consideration at the junction, meeting points of cross walls, etc.

One Room Estimation

One Room & Two Room Estimate By Center Line Method
One Room Estimation

Center line length of one wall = Inner dimension of room + Wall thickness

= Inner dimension of room + ½ x Wall thickness of one side + ½ x wall thickness of other.

  • Centre line length of horizontal wall

= 4 + 0.45 + 0.45

= 4.90 m

  • Centre line length of vertical wall

= 3 + 0.45 + 0.45

= 3.90 m

Total Length of excavation for foundation

= 2(4.90 + 3.90)

= 17.6 m

Quantity of excavation for foundation

= Total length of centre line of walls x breath of trench x Depth of trench

= 17.6 x 0.9 x 1.2

= 19.01 m3

Read More: Building Estimate | Building Estimate Format In Excel | Estimation and Costing of Building


For rectangular, circular, or polygonal buildings having no inter or cross walls, this method is quite simple but for buildings having cross or partition walls, for every junction of partition or cross walls with main walls, a half breath of the respective item or footing is to be deducted from the total center length.

Net Centre line length – (½ x breath of wall x number of the junction)

The following points in relation to the center–line method should be noted.

The term junction is used to indicate the meeting points of cross walls or partition walls with main walls.

For instance, if there is one cross wall there will be two junctions. At the corner of a building, no junction is formed.

For rectangular buildings with No cross wall, there will not be any junction and hence no deduction from the center line length will be required. It is fact that a certain portion taken twice is counterbalanced by the same amount of portion left out at the corner.

The breath indicates the width of an item whose center line is being worked, for instance, it will be the width of a trench of excavation and foundation concrete. But for brick masonry up to plinth or for superstructure will be equal to the corresponding thickness of the wall.

Read More: Building Estimation Excel Sheet


Two Room Estimation By Center Line Method

For a two room building with inner cross wall, two junctions will be formed shown in fig.

One Room & Two Room Estimate By Center Line Method
Estimation by center line method

Total centre line length

= (2 x AB + 2 X BC + EF)

= (2 X 9.50 + 2 X 5.5 + 5.5)

If this center line length is multiplied by the width and depth, the quantity at junction P and Q will come twice, the quantity of each being equal to  ( ½ x width x Depth )

Hence the quantity of these two junctions must be deducted to get the net centerline length.

Net center line length                                                           

=( Total Centre line length – ( width/ 2) x No. of junction)

= 35. 50 – (½ x 0.90) x 2

= 34. 60 m

Read More: Cost Estimate | 10 Types of Cost Estimation | Types of Cost Estimates In Project Management | Types of Cost Estimates

Example of Building Estimation By Center Line Method

House Estimation by center line method,

Center Line Method Of Estimation | Centre Line Method | One Room & Two Room Estimate By Center Line Method
Plan
Center Line Method Of Estimation | Centre Line Method | One Room & Two Room Estimate By Center Line Method
Section of Building
Item
No.
Item Description (Work Details)NoLength
(L)
Breadth
(B)
Height
(H)
Quantity
1.Earthwork in excavation for the foundation144.40.91.1043.96
Total Centre Line Length = 48.9 m
No. of Junction = 10
L = 48.9 – (1/2) x 0.90 x 0.90 x 10
L = 44.4 m
OR
1.Brickbat cement concrete (1:4:8)for foundation144.40.90.27.99 m2
2.Brick masonry up to plinth in C.M.1:6
First Step:L= 48.0-1/2X0.5X10=46.40m146.40.50.36.96
Second Step:L= 48.9-1/2X0.4X10= 46.9m146.90.40.35.63
Third Step:L= 48.9-1/2X0.3X10= 47.4m1 47.40.30.8512.08
Steps:
First Step:11.10.90.150.15
Second Step:11.10.60.150.10
Third Step:11.10.30.150.05
For steps L =D1= 1.1m24.97 m2
3.Brick masonry above plinth up to slab level in C.M. 1:6
L= 48.9=1/2X0.2X10= 47.9m147.90.23.028.74 m2
Deduction For Doors & Windows
D131.100.22.11.39
D220.900.22.10.76
G111.20.22.10.50
W141.80.21.42.02
W211.20.21.40.34
W311.50.21.40.42
V20.60.20.60.14
Deduction for door/ windows(-)5.57 m2
Deduction For Linter Above Door & Windows with 15 cm Bearing at each End
D131.40.20.150.126
D221.20.20.150.072
G111.50.20.150.045
W142.10.20.150.25
W211.50.20.150.045
W311.80.200.150.054
V20.90.20.15.054
Deduction for lintel(-)0.646 m2
(Same as that obtained in the long wall-short wall method)Net quantity22.52 m2
OR
3.Smooth plaster inside the rooms and ceilings in C.M. 1:3 238.39 m2
Plaster For Wall
Drawing Room44.03.048.0
Bed Room24.03.024.0
23.03.018.0
Kitchen24.03.024.0
23.03.018.0
Bath23.03.018.0
21.73.010.2
W. C.21.33.07.8
21.13.06.6
In Front Of W. C.21.53.09.0
21.13.06.6
Ceiling Plaster:
Drawing Room14.04.016.0
Bedroom14.03.012.0
Kitchen13.04.012.0
Bath13.01.75.1
W. C.11.31.11.43
In front of W. C.11.51.11.65
238.39 m2
Deduction For Plaster:
D15/21.12.15.78
D24/20.92.13.78
G12/21.22.12.52
W14/21.81.45.04
W21/21.21.40.84
W31/21.51.41.05
(-)9.01 m2
Net quantity219.37 m2

Important Notes:

  1. The area of ventilation is less than 0.5 sq m, therefore no deduction is made.
  2. For Doors, Half the number of faces is deducted.
  3. For calculation of internal plaster, inner doors have two faces and the external door has one inner face
  4. For calculation of internal plaster, windows have one internal face.
  5. for windows, half the number of faces is deducted.

Reference & Credit: ESTIMATING COSTING AND VALUATION by Dr. R P Rethaliya


FAQs:

what do you mean by the center line method?

In this method, sum total length of center lines of walls, long and short has to be found out. Find the total length of center lines of walls of the same type.

You May Also Like:

Share This Post

Leave a Reply

Download Construction Excel Sheet

Popular Post on Website

Scroll to Top
DMCA.com Protection Status