Northern Technical University

Technical Engineering College

Building & Construction Technology Engineering

Estimation, Specifications and Contracts

Fourth Year 2024 - 2025

Waseem T. Mohammed
 General rules in quantitative survey
Quantitative survey: Mathematical process used in estimating cost
of a new building construction, improvement, or reproduction. It
lists every item that will affect the cost of the proposed project.

The general rules are listed below

1. Measurement shall be made for finished item of work and
description of each item shall include materials, transport, labour,
fabrication tools and plant and all types of overheads for finishing
the work in required shape, size and specification.

2. In booking, the order shall be in sequence of length, breadth and

height or thickness.
3. All works shall be measured subject to the following tolerances:
a. Linear measurement shall be measured to the nearest 0.01m.
b. Areas shall be measured to the nearest 0.01 sqm
c. Cubic contents shall be worked out to the nearest 0.01 cum
 The general rules are listed below

4. Same type of work under different conditions and nature shall

be measured separately under separate items.

5. The bill of quantities shall fully describe the materials,

proportions, workmanships and accurately represent the work to
be executed.

6. In case of masonry (stone or brick) or structural concrete, the

categories shall be measured separately and the heights shall be
described:
a. From foundation to plinth level.
b. From plinth level to First floor level
c. From Fist floor to Second floor level and so on.
 Principles in selecting units of measurement for items:
The units of measurements are mainly categorized for their nature,
shape and size and for making payments to the contractor and also. The
principle of units of measurements normally consists the following:

1. Single units work like doors, windows, trusses etc., are

expressed in numbers.
2. Works consists linear measurements involve length like cornice,
fencing, hand rail, etc., are expressed in running meters (RM).
3. Works consists areal surface measurements involve area like
plastering, white washing, partitions of specified thickness etc., are
expressed in square meters (m2).
4. Works consists cubical contents which involve volume like earth
work, cement concrete, masonry etc. are expressed in Cubic meters
(m3).
Unified Standard Guide used in Quantity Surveying
 Detailed Estimate
Detailed estimates are prepared by carefully and separately
calculating in detail the costs of various items of the work that
constitute the whole project from the detailed working drawings after
the design has been finalized.
The mistakes, if any, in the rough cost estimate are eliminated in the
detailed estimate.
Detailed estimates are submitted to the competent authorities for
obtaining technical sanction.
The whole project is sub-divided into different items of work or
activities. The quantity for each item is then calculated separately
from the drawings as accurately as possible. The procedure is known
as taking out of quantities.
The quantities for each item may be estimated and shown in the
pattern which is called Bill of quantities
 Bill of quantities
No. of Description
Unit Number
Dimensions Quantity Notes
item of item Length Width height
1.
2.

Methods of taking out quantities

The quantities like earth work, foundation concrete, brickwork in

plinth and super structure etc…, can be workout by any of following
methods:

1. Long wall - short wall method.

2. Centre line method.

 1. 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 long wall or short wall, calculate first
the centre line lengths of individual walls.

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 into in and may be found by
deducting half breadth from its centre line length at each end.
 Long
lc/c

Short
Sc/c

𝟏 𝟏
𝑳𝒐𝒏𝒈 𝒘𝒂𝒍𝒍 = 𝒍𝒄/𝒄 + 𝒃𝒓𝒆𝒂𝒕𝒉 + 𝒃𝒓𝒆𝒂𝒕𝒉
𝟐 𝟐

𝟏 𝟏
𝑺𝒉𝒐𝒓𝒕 𝒘𝒂𝒍𝒍 = 𝑺𝒄/𝒄 − 𝒃𝒓𝒆𝒂𝒕𝒉 − 𝒃𝒓𝒆𝒂𝒕𝒉
𝟐 𝟐
 2. Centre line method:
This method is suitable for walls of similar cross sections. Here the
total centre line length is multiplied by breadth and depth of
respective item to get the total quantity at a time.

lc/c

Sc/c

𝑻𝒐𝒕𝒂𝒍 𝒍𝒆𝒏𝒈𝒕𝒉 = 𝒍𝒆𝒏𝒈𝒕𝒉𝒔 𝒄/𝒄

When cross walls or partitions or verandah walls join with main all,
the centre line length gets reduced by half of breadth for each
junction. such junction or joints are studied carefully while
calculating total centre line length. The estimates prepared by this
method are most accurate and quick

lc/c lc/c

Sc/c

𝟏
𝑻𝒐𝒕𝒂𝒍 𝒍𝒆𝒏𝒈𝒕𝒉 = 𝒍𝒆𝒏𝒈𝒕𝒉𝒔 𝒄/𝒄 − [ 𝒃𝒓𝒆𝒂𝒕𝒉 𝒙 𝑵𝒐. 𝒐𝒇 𝐣𝐮𝐧𝐜𝐭𝐢𝐨𝐧]
𝟐
 Example
Calculate the quantities of work to excavate the wall footing for a
room with internal clear dimensions of (4.2 m x 3.60 m), the wall
thickness is 36 cm and the width and depth of the footing (90 cm)
and (1 m) respectively using:
1. Long wall - short wall method.
2. Center line method.

4.2
3.6
1. Long wall - short wall method. 4.56

4.2

3.6
3.96

1 1
𝐿𝑜𝑛𝑔 𝑤𝑎𝑙𝑙 = 𝑙𝑐 𝑐+ 𝑏𝑟𝑒𝑎𝑡ℎ + 𝑏𝑟𝑒𝑎𝑡ℎ
2 2
1 1
𝐿𝑜𝑛𝑔 𝑤𝑎𝑙𝑙 = 4.56 + 0.9 + 0.9 = 𝟓. 𝟒𝟔 𝒎
2 2
1 1
𝑆ℎ𝑜𝑟𝑡 𝑤𝑎𝑙𝑙 = 𝑆𝑐/𝑐 − 𝑏𝑟𝑒𝑎𝑡ℎ − 𝑏𝑟𝑒𝑎𝑡ℎ
2 2
1 1
𝑆ℎ𝑜𝑟𝑡 𝑤𝑎𝑙𝑙 = 3.96 − 0.9 − 0.9 = 𝟑. 𝟎𝟔 𝒎
2 2
𝑇𝑜𝑡𝑎𝑙 𝑙𝑒𝑛𝑔𝑡ℎ = 2 5.46 + 2 3.06 = 𝟏𝟕. 𝟎𝟒 𝒎
2. Center line method 4.56

4.2

3.6
3.96

1
𝑇𝑜𝑡𝑎𝑙 𝑙𝑒𝑛𝑔𝑡ℎ = 𝑙𝑒𝑛𝑔𝑡ℎ𝑠 𝑐/𝑐 − [ 𝑏𝑟𝑒𝑎𝑡ℎ 𝑥 𝑁𝑜. 𝑜𝑓 junction]
2

𝑇𝑜𝑡𝑎𝑙 𝑙𝑒𝑛𝑔𝑡ℎ = 2 4.56 + 2 3.96 − 0 = 𝟏𝟕. 𝟎𝟒 𝒎

 Quantities of works to excavate (Volume) = Length x width x height

Quantities of works to excavate (Volume) = 17.04 x 0.9 x 1.0 =15.336 m3

Bill of quantities
Dimensions
No. of Description
Unit Number Quantity Notes
items of items Length Width height

Excavate
the wall
1. m3 1 17.04 0.9 1.0 15.336
footing for a
room
 Example:
Calculate the quantities of the following sub-items to perform the
wall footing shown in Figure:
1. Excavation works.
2. Placing a layer of broken bricks beneath the base.

3 3

3 3
A A

Plan

Sec. A - A
 1. Long wall - short wall method.
6.48
3.24 3.24

3 3

3.24 3 3

1 1 1 1
𝐿𝑜𝑛𝑔 𝑤𝑎𝑙𝑙 = 𝑙𝑐 𝑐+ 𝑏𝑟𝑒𝑎𝑡ℎ + 𝑏𝑟𝑒𝑎𝑡ℎ = 6.48 + 0.9 + 0.9 = 𝟕. 𝟑𝟖 𝒎
2 2 2 2
1 1 1 1
𝑆ℎ𝑜𝑟𝑡 𝑤𝑎𝑙𝑙 = 𝑆𝑐/𝑐 − 𝑏𝑟𝑒𝑎𝑡ℎ − 𝑏𝑟𝑒𝑎𝑡ℎ = 3.24 − 0.9 − 0.9 = 𝟐. 𝟑𝟒 𝒎
2 2 2 2

𝑇𝑜𝑡𝑎𝑙 𝑙𝑒𝑛𝑔𝑡ℎ = 2 7.38 + 3 2.34 = 𝟐𝟏. 𝟕𝟖 𝒎

2. Center line method
6.48
3.24 3.24

3 3

3.24 3 3

1
𝑇𝑜𝑡𝑎𝑙 𝑙𝑒𝑛𝑔𝑡ℎ = 𝑙𝑒𝑛𝑔𝑡ℎ𝑠 𝑐/𝑐 − [ 𝑏𝑟𝑒𝑎𝑡ℎ 𝑥 𝑁𝑜. 𝑜𝑓 junction]
2

1
𝑇𝑜𝑡𝑎𝑙 𝑙𝑒𝑛𝑔𝑡ℎ = 2 6.48 + 3 3.24 − 𝑥 0.9 2 = 𝟐𝟏. 𝟕𝟖 𝒎
2
 1. Excavation works:
Quantities of works to excavate (Volume) = Length x width x height
Quantities of works to excavate (Volume) = 21.78 x 0.9 x 1.1= 21.562 m3

2. Placing a layer of broken bricks beneath the base:

Area of broken bricks = Length x width = 21.78 x 0.9 = 19.60 m2

Bill of quantities
No. of Description Dimensions
Unit Number Quantity Notes
items of items Length Width height

Excavate
the wall
1. m3 1 21.78 0.9 1.1 21.562
footing for a
room

layer of
broken
2. bricks m2 1 21.78 0.9 ---- 19.60
beneath the
base