What are Specifications?

Specifications describe the nature and the class of the work, materials to be used in the work,
workmanship etc. and is very important for the execution of the work. The cost of a work depends much
on the specifications. Specifications should be clear.

Types of Specifications

Purpose of giving Specifications

The cost of an unit quantity of work is governed by its specifications.

Specification of a work is required to describe the quality and quantity of different materials required for
a construction work and is one of the essential contract documents.

This also specifies the workmanship and the method of doing the work. Thus specification of a work
serves as a guide to a supervising staff of a contractor as well as to the owner to execute the work to
their satisfaction.

A work is carried out according to its specification and the contractor is paid for the same. Any change in
specification changes the tendered rate.

As the rate of work is based on the specification, a contractor can calculate the rates of various items of
works in tender with his procurement rates of materials and labour. Thus tender rate without
specification of works is baseless, incomplete and invalid.

Specification is necessary to specify the equipment tools and plants to be engaged for a work and thus
enables to procure them beforehand.

The necessity of specification is to verify and check the strength of materials for a work involved in a
project.

Types of Specifications

General Specifications

Detailed Specifications

General Specifications

In general specifications, nature and class of works and names of materials that should be used are
described. Only a brief description of each and every item is given. It is useful for estimating the project.
The general specifications do not form a part of contract document.

Detailed Specifications

The detailed specifications form a part of a contract document. They specify the qualities, quantities and
proportions of materials and the method of preparation and execution for a particular item of works in a
project. The detailed specifications of the different items of the work are prepared separately and they
describe what the work should be and how they shall be executed. While writing the detailed
specifications, the same order sequence as the work is to be carried out is to be maintained.

RCC Specifications

Shuttering shall be done using seasoned wooden boards of thickness not less than 30mm.

Surface contact with concrete shall be free from adhering grout, nails, splits and other defects.

All the joints are perfectly closed and lined up.

The shuttering and framing is sufficiently braced.

Nowadays timber shuttering is replaced by steel plates.

All the props of approved sizes are supported on double wedges and when taken out, these wedges are
eased and not knocked out.

All the framework is removed after 21 days of curing without any shocks or vibrations.

All reinforcement bars conform IS specifications and are free from rust, grease oil etc.

The steel grills are perfectly as per detailed specifications.

Bars of diameter beyond 25mm diameter are bent when red hot.

The materials proportion should be as per the specifications of the concrete.

Number of Cement bags required for a specific cement concrete ratios

For cement concrete of ratio 1:1:2(1 cement:1sand/coarse sand:2graded stone aggregate) require 11no
bags of 50kg.

For cement concrete of ratio 1:1.5:3 require 7.8no bags of 50kg.

For cement concrete of ratio 1:2:4 require 6 no bags of 50kg.

For cement concrete of ratio 1:3:6 require 4.25no bags of 50kg.

For cement concrete of ratio 1:4:8 require 3.2 no bags of 50kg.

For cement concrete of ratio 1:5:10 require 2.50 no bags of 50kg.

For cement concrete of ratio 1:6:12 require 2.25 no bags of 50kg.

It describes the cost ,nature of work ,class of work and also the type of material to be used for that
work.The overall cost of the project depends on the specifications and there should not be any ambiguity
in the details of specifications. The drawing of the building gives only the alignment of the rooms but the
detail estimate can be prepared only by means of using drawing and its specifications. It depends on the
nature of work and purpose of work.
Types of Specifications

1. General or Brief Specification

· Gives an outline of materials used in that project right from foundation to superstructure. It does
not have detail on the quality of material needed for the project.

2. Detailed Specification

· Gives in detail description on the types of material and quality of material used in that project ,
which includes detail specification on material strength and quantity. The material used for the
construction should meet the standard given by IS or IRC depend on the type of Project. It is a part of a
contract document.

Standard Specification

It will be give by the Central Public Work Department (CPWD) or Public Work Department
(PWD) a book will have details of common specification used for most of the projects. The Detail
Specification will have a link to refer the Standard specification.

Special Specification

The specification which is not covered in the standard specification will be represented.

Open Specification or Manufacturer Specification

The physical or chemical properties of the material which is used in the projects. Eg.
Admixtures like Accelerators or Retarders or Some Stabilizing agents. It also includes the type materials
like steel,cement, Pipe quality etc.