Most Important Point In This Article

## Estimation for Building Works

The quantities of various items such as earthwork in excavation, foundation concrete, brickwork in foundation and plinth, brickwork in the superstructure, etc. can be estimated by any of the following three methods

**Centre Line Method****Long and Short Wall Method****Crossing Method**

**1. Centre Line Method**

In this method of estimation, the total center line length of walls in a building is first calculated, then the center line length is multiplied with the breadth and depth of respective item to get the total quantity at a time.

Fir different sections of walls in a building, the center-line length for each type shall be worked out separately.

In the case of verandah walls or partition joining with the main wall, the center-line length shall be reduced by half of the breadth of the layer of the main wall that joins with the partition or verandah wall at the same level. A number of such pints arc simnel first to calculate the center-line length.

By this method, estimates may be prepared more quickly, and this method is as accurate as of the other methods.

Only in the case of an unsymmetrical wall, which is generally rare, no advantage may be claimed by this method over others as the center-line length varies at every layer.

But to estimate circular, hexagonal, octagonal, etc. shaped buildings, this method shall specially be adopted.

Also, read: Bar Bending Schedule Formulas As Per IS:2502-1963 | Unit Weight of Steel Bars

**2. Long and Short Wall Method**

In this method the longer walls in a building (generally in one direction) are considered as long walls and measured from out to out: and the shorter or partition walls, in a perpendicular direction of the long walls, are considered as short walls and arc measured from in-to-in for a particular layer of work.

These lengths of long and short walls arc multiplied separately by the breadth and height of the corresponding layer and are added to get the quantity.

Such lengths of long and short walls vary in every layer of footing. To calculate the lengths of long and short walls determine first their centre to centre lengths individually from the plan.

Then the length of the longwall, out-to-out may be calculated after adding half breadth of a wall at each end with its centre to centre length.

Thus the length of the short wall measured in-to-in may find out after subtraction half breadth at each end from its centre to centre length.

Length of long-wall generally decreases from earthwork to brickwork in the superstructure and in the case of a short wall, its length increases.

In some of the working examples, it may be noticed that a wall is considered as a short wall at one end and as a long wall at the other end.

Such a case arises in a wall that joins as a long wall with another long wall previously considered.

The joining end of the wall later considered as long wall is actually treated as a short end, and such a wall is named as Long-Short wall.

**Length of Long Wall**= Center to Center Length of wall + Half Breadth on One Side + Half Breadth on the Other Side- Length of
**Short Wall**= Centre to Centre Length – One breadth. **Note:**The length of the long wall usually decreases from earthwork to brickwork, and the length of the short wall is increased.

Also, read: What Is Construction Contract | Types of Engineering Contracts | Percentage-Rate Contract

**3. Crossing Method **

In this method calculate the overall perimeter of the building and subtract from this four times the thickness of the wall to obtain the centre-line length.

This method is now rarely used.

**Examples,**

**Example, By Centre-Line Method **

To estimate the quantities, calculate first the total length of the center-line which remains constant for varying widths of works, and multiply this constant length of the centre-line with the respective breadth and height.

Thus quantities of all items may be calculated easily.

The total length of center-line = 2 **[** (3m + (2 x ( 30 cm/2) ) + (2.5m + (2 x ( 30 cm/2) )**]**

The total length of center-line = 12.2 m

### Elements of Building Estimate use **Centre-Line Method **

Sr. No. |
Description |
No. |
Length M. |
Breadth M. |
Height M. |
Qty. |
Total |
Unit |

1 | Earthwork in excavation | 1 | 12.2 | 0.7 | 0.75 | 6.405 | 6.405 |
Cu.m. |

2 | Lime Concrete in Foundation | 1 | 12.2 | 0.7 | 0.15 | 1.281 | 1.281 |
Cu.m. |

3 | Brickwork in foundation and Plinth | |||||||

(a) 50 cm layer | 1 | 12.2 | 0.5 | 0.2 | 1.22 | |||

(b) 40 cm layer | 1 | 12.2 | 0.4 | 1 | 4.88 | |||

6.1 |
Cu.m. |

**Example, By Long and Short wall Method **

Center to Center length of long walls = 3 + (2 x 0.115) = 3.3 m

Center to Center length of long walls = 2.5 + (2 x 0.115) = 2.80 m

The length of long walls out-to-out and short walls in-to-in vary in every laver of footing.

To calculate the length of long walls add a half breadth of that layer at each end with the centre to centre length and for short walls subtract half breadth of the layer from each end.

Lengths thus obtained may also be verified from the plan as shown in the above fig.

### Elements of Building Estimate use **Long and Short wall Method **

Sr. No. |
Description |
No. |
Length M. |
Breadth M. |
Height M. |
Qty. |
Total |
Unit |

1 |
Earthwork in excavation |
|||||||

Long Wall | 2 | 4.00 | 0.700 | 0.750 | 4.200 | |||

Short Wall | 2 | 2.10 | 0.700 | 0.750 | 2.205 | |||

6.405 |
Cu.m. |
|||||||

2 |
Lime Concrete in Foundation |
|||||||

Long Wall | 2 | 4.00 | 0.700 | 0.150 | 0.840 | |||

Short Wall | 2 | 2.10 | 0.700 | 0.150 | 0.441 | |||

1.281 |
Cu.m. |
|||||||

3 |
Brickwork in foundation and plinth |
|||||||

Long Wall |
||||||||

1st footing 50 cm | 2 | 3.80 | 0.500 | 0.200 | 0.760 | |||

2nd footing 40 cm | 2 | 3.70 | 0.400 | 1.000 | 2.960 | |||

Short Wall |
||||||||

1st footing 50 cm | 2 | 2.30 | 0.500 | 0.200 | 0.460 | |||

2nd footing 40 cm | 2 | 2.40 | 0.400 | 1.000 | 1.920 | |||

6.1 |
Cu.m. |

### Long Wall Short Wall Method

In this **method**, the **wall** along the length of room is considered to be **long wall** while the **wall** perpendicular to **long wall** is said to be **short wall**. To get the length of **longwall** or **shortwall**, calculate first the centre line lengths of individual **walls**.

**Like this post? Share it with your friends!**

**Suggested Read –**

- IS 456 Most Important Point Part- 1
- Difference Between CPM and PERT | What Is CPM & PERT
- Difference Between One Way Slab and Two Way Slab | What is Slab
- What Is FSI | What Is FAR | What Is Premium FSI | FSI Full-Form | FAR Full Form
- What Is Plaster | Plaster Ratio | History of Plastering | Requirements of Good Plaster
- What Is Floating Slab| Floating Slab Construction | How to Build a Floating Slab | Advantages & Disadvantages Floating Slabs
- What Is Structural Settlement | Causes For Structural Settlement | What Is Soil Settlement & Foundation Structural Settlement

Tshering Tobgyel says

i am happy about it. I am cleared now.

Krunal Rajput says

Thanks, Dear

Sandhya Rajput says

centre line method of estimation

Krunal Rajput says

In this method of estimation, the total center line length of walls in a building is first calculated, then the center line length is multiplied with the breadth and depth of respective item to get the total quantity at a time.

By using this method estimation can be finished more quickly.

MUHAMMAD SHOAIB KHAN AZIZI AL AMEERI says

i am from Pakistan….i like your work

there are so many things which make civil engineering so easy and perfect…now my request is that please use of all survey instruments like TS/THEODOLITE/AUTOLEVEL/GPS and etc.

THANKS FOR DO ALL THESE THING TO MAKE EASY CIVIL ENGINEERING