Types of Specifications in Quantity Surveying

Types of Specifications in Quantity Surveying: Quantity surveying is a crucial profession in the construction industry, dealing with the financial and contractual management of construction projects. One of the fundamental aspects of this field is the preparation and interpretation of specifications. Specifications in quantity surveying provide detailed descriptions of the work to be done, the materials to be used, and the standards to be followed. They serve as a vital tool for ensuring that all parties involved in a project are on the same page regarding the quality and scope of work. Here, we delve into the different types of specifications commonly used in quantity surveying.

How Many Types of Specifications in Quantity Surveying?

In quantity surveying, there are six main types of specifications: Descriptive Specifications, Performance Specifications, Proprietary Specifications, Reference Standard Specifications, Method Specifications, and Design Specifications. Each type serves a unique purpose, ranging from detailed descriptions of materials and methods (Descriptive) to focusing on the end results (Performance), specifying particular brands (Proprietary), adhering to established standards (Reference Standard), outlining exact procedures (Method), and detailing design and dimensions (Design). Understanding these specifications is crucial for ensuring project quality, clarity, and successful execution.

1. Descriptive Specifications

Descriptive specifications, also known as prescriptive specifications, provide detailed descriptions of the materials, products, and workmanship required for a project. These specifications do not specify the end result but focus on the process and materials to be used. This type is ideal for projects where the quality of materials and methods used is crucial.

Key Features:

  • Detailed descriptions of materials and workmanship.
  • Focus on process rather than the end product.
  • Used when the quality of materials and methods is critical.


For a concrete mix, a descriptive specification might detail the proportions of cement, sand, and aggregate, the mixing process, and the curing time required.

2. Performance Specifications

Performance specifications focus on the desired outcome or performance of the final product rather than the specific methods or materials used to achieve that outcome. This type of specification allows contractors some flexibility in how they achieve the required performance, encouraging innovation and efficiency.

Key Features:

  • Focus on the end result or performance criteria.
  • Allows flexibility in methods and materials.
  • Encourages innovative solutions.


A performance specification for a heating system might state that the system must maintain an indoor temperature of 22°C with a specified energy efficiency level, without detailing how this should be achieved.

3. Proprietary Specifications

Proprietary specifications specify a particular product, brand, or supplier to be used for a project. This type is often used when a specific product is required due to its unique properties, performance, or aesthetic qualities. While this ensures a certain standard, it can limit the contractor’s flexibility and may increase costs.

Key Features:

  • Specifies a particular product, brand, or supplier.
  • Ensures specific performance or aesthetic qualities.
  • Can limit flexibility and increase costs.


A proprietary specification might require the use of a specific brand of paint that has a particular color and durability that no other product matches.

4. Reference Standard Specifications

Reference standard specifications refer to standards established by recognized organizations or authorities. These specifications ensure that materials and workmanship meet predefined quality and performance criteria. They often reference standards from organizations such as ASTM, ISO, or ANSI.

Key Features:

  • Reference established standards and guidelines.
  • Ensure materials and workmanship meet predefined criteria.
  • Provide clarity and consistency.


A reference standard specification might require that all steel used in a project must comply with ASTM A36 standards for structural steel.

5. Method Specifications

Method specifications detail the exact procedures and techniques to be used during construction. They leave little room for deviation, ensuring that the work is carried out in a specific manner. This type of specification is used when the method of construction is critical to the project’s success.

Key Features:

  • Detailed procedures and techniques.
  • Little room for deviation.
  • Critical when specific methods are essential.


A method specification for installing a waterproof membrane might outline the exact steps to be followed, including surface preparation, membrane application, and inspection procedures.

6. Design Specifications

Design specifications, also known as design criteria specifications, detail the design and dimensions of the components to be used in a project. These specifications often include drawings, calculations, and other technical information. They are used when specific design details are crucial to the project’s success.

Key Features:

  • Detailed design and dimensions.
  • Include drawings and technical information.
  • Critical when design details are crucial.


A design specification for a steel beam might include the exact dimensions, load-bearing capacity, and connection details required.

Importance of Specifications in Quantity Surveying

Specifications are essential in quantity surveying for several reasons:

  • Clarity and Communication: They provide clear and precise instructions, ensuring that all parties understand the project’s requirements.
  • Quality Control: Specifications set the standards for materials and workmanship, ensuring that the project meets the desired quality.
  • Legal Protection: They serve as a contractual document, protecting both the client and the contractor in case of disputes.
  • Cost Management: Accurate specifications help in the precise estimation of quantities and costs, aiding in budget management.


In quantity surveying, understanding and preparing different types of specifications is fundamental. Each type serves a unique purpose, from ensuring high-quality materials and workmanship to providing flexibility and encouraging innovation. By mastering the art of specification writing, quantity surveyors can significantly contribute to the successful execution of construction projects, ensuring they meet the desired standards, stay within budget, and are completed on time.

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