A Background to Construction Specifications

This article discusses the construction specification, the types of specifications that may be required on a project and the importance of having them in place.

image showing engineers looking at a construction specification document.

Construction specifications is a critical aspect of the construction industry. It is a blueprint for the materials, methods, and standards to be followed during a project.  Think of it as the ultimate guide for every player in the construction industry – contractors, architects, engineers and all the key players. Now, let’s dig into the nitty-gritty of construction specification, why it’s a big deal, and how it makes sure construction projects hit the bullseye.

What is a Specification?

ISO 6707-2:2017 lays it out straight – a specification is a document that gives out detailed requirements for a product, material, process, or system. It’s like a rulebook, telling you what needs to be done and how to check if it’s done right.

Now, specifications, in the context of construction, usually throw in some clauses. These are like the extra details that team up with other design documents – drawings, building information models (BIM), reports, and designers’ risk assessments. Sometimes, drawings and BIM models have dimensions, but specifications step in when there’s too much info to jot down or when something can’t be visualized on paper.

In smaller projects, you might find these clauses right on the drawings. Some folks think this is a more foolproof way to talk to the folks working on-site. Specifications cover the nitty-gritty of both materials (think ‘all reinforcement to be…’) and workmanship (cue ‘fix reinforcement to the following tolerances…’).

When it comes to construction contracts, specifications often throw in preambles – stuff like ‘no radios on site’ or ‘provide welfare facilities.’ Usually, others, like quantity surveyors, draft these, and structural engineers don’t bother much unless they’re the spec gurus for the whole shebang. But here’s the deal – everyone in the contract game benefits from a well-written specification. It spells out the details that might get lost in other documents, making everything clearer and cutting down on the guesswork.

What are the Advantages of a Construction Specification?

Crafting a robust and detailed specification as a part of design documentation offers numerous benefits, including, but not restricted to:

  • Providing a crystal-clear definition of quality expectations for materials and workmanship, ensuring adherence to legislation and standards.
  • Enabling the development of effective inspection and test plans linked to the specification, enhancing quality control during project execution.
  • Defining terminology used across project documentation, with capitalized terms like ‘Hot Dip Galvanizing’ specifying standards, zinc coating thickness, metal cleaning protocols, etc. Referencing the drawing or BIM model to the specification imparts the full meaning of associated clauses.
  • Addressing materials aspects, such as specifying minimum masonry strengths, and citing specific workmanship requirements by referencing applicable standards.
  • Allowing the specification of preferred materials and products, while cautioning against potential issues, such as delays, by adopting a flexible approach like ‘or equal approved’ for specified brands or components.
  • Ensuring clarity in drawings, preventing them from being inundated with notes, as specifications fill in the gaps left by drawings alone.
  • Mitigating project risks, facilitating more precise pricing, and reducing the likelihood of delays and disputes.
  • Assisting in project handover and aiding future users in comprehending what was specified and, consequently, what should be incorporated into the structure.

Despite these advantages, a frequently cited drawback is the perception that ‘nobody ever reads’ specifications. To counter this, it is crucial to implement measures ensuring those who need to comprehend the specification are fully aware of its significance. Strategies like emphasizing specifications in precontract meetings or directly communicating with contractors before work commences can be effective in addressing this challenge.

Key Components of Construction Specification

There are five key components that must be included in any good construction specification. These are:

Project Scope and Objectives: A good specification document must begin with a clear definition of the project’s scope and objectives. This section sets the tone for the entire document, outlining the goals and expectations of the construction project.

Materials and Methods: One of the primary functions of construction specification is to detail the materials to be used and the methods by which construction tasks are to be executed. This ensures uniformity, quality control, and compliance with industry standards.

Quality Standards: Outlines the quality standards that must be adhered to throughout the project. This includes acceptable tolerances, testing procedures, and inspection requirements to guarantee the final product meets or exceeds predefined quality benchmarks.

Performance Criteria: Defines the performance criteria for various construction elements. This helps in evaluating the success of the project and ensures that the end result aligns with the client’s expectations.

Contractual and Legal Considerations: Construction specifications play a pivotal role in the contractual and legal aspects of a project. They establish a clear framework for responsibilities, liabilities, and dispute resolution, minimizing the risk of misunderstandings or disputes.

Types of specification

There are various forms of specification that can be found in construction, of which the main types are discussed below.

Performance specifications

Performance specifications focus on outcomes by establishing qualitative functional requirements and providing quantitative user and technical performance criteria. To mitigate the risk of a contractor claiming unattainability for specific performance criteria, it’s common practice to offer acceptable solutions.

These specifications are typically applied in projects where the building contract allows the contractor to take responsibility for designing parts of the structure, as seen in design-and-build contracts. They encompass details such as loadings, usage, materials, and vibration limitations.

While performance specifications permit contractor input into the final design, there’s a drawback – the potential for exploitation leading to a design falling short of the client’s ideal solution. However, a well-crafted performance specification can mitigate this risk.

Clients may opt for performance specifications when seeking to reduce fees from their professional team by shifting design responsibility to the contractor’s team, especially if they want to limit fee exposure until the project is more certain to proceed to construction. On the flip side, some clients prefer early investment, producing a robust specification with designer involvement and early collaboration with the contractor.

Prescriptive specifications

Prescriptive specifications adhere to tradition by laying down requirements, like specifying the use of a particular serial size of a steel member, without detailing its functional needs and performance criteria. These specifications find common use in situations where a construction contract lacks provisions for contractor design or when the client and its design team are confident about project specifics.

The downside of prescriptive specifications, however, lies in their limited value for money, as they typically exclude opportunities for contractor input. This limitation arises because these specifications don’t allow the flexibility for contractors to contribute their insights or suggestions, potentially impacting the overall efficiency and optimization of a project.

Technical regulations and standards

This type of specifications is set up by governments to establish technical regulations and standards, either as mandatory or advisory guidelines. The primary objective is to safeguard human health, safety, and the environment, along with ensuring national security. These regulations may encompass specifications related to product features, quality, as well as procedures for testing, certification, labeling, and other relevant aspects.

Standard specifications

Reusing prescriptive specifications across projects without thorough scrutiny poses risks, including errors like referencing outdated standards or inconsistencies such as specifying items not relevant to the project or providing conflicting parameters. It is crucial to meticulously review and update such specifications to prevent claims and delays.

To alleviate this challenge, practitioners can opt for ‘standard specifications.’ These are crafted by client bodies, trade associations, and other entities in the construction industry to ensure consistency and efficiency. These standards are regularly maintained and reviewed by the entities responsible for their creation.

Straying from these standard specifications can heighten risks for practitioners in case of disputes. For instance, if a bespoke specification demands tighter tolerances than those outlined in the equivalent standard specification, a contractor may argue that they are unreasonable.

The standard specifications, necessitate users to prepare project-specific documents that modify, supplement, or refer back to the standard specification. An illustrative example is the NSSS, detailing the information a specifier must include when utilizing the standard NSSS specification document.


This article has outlined the fundamental aspects of specifications, examining what a specification entails and exploring the different types prevalent in the construction industry. With careful consideration, a resilient and well-proportioned specification can be developed for any project. Despite the crucial role of specifications, it is disconcerting that their creation is occasionally treated as a last-minute task, lacking thoroughness and sometimes relying blindly on documents from previous projects. In the upcoming installment, we will delve into potential pitfalls associated with the reuse of specifications. Additionally, we will provide guidance on mitigating these risks and generating a sturdy specification.

Also See: Engineering Ethics: Professional Indemnity Claims

Sources & Citation

  • Designing Buildings Wiki (2019) Specifi cation for construction [Online] Available at: www.designingbuildings. co.uk/wiki/Specification_for_ construction (Accessed: March 2024)
  • The Institution of Structural Engineers (2019) An Introduction to Specifications Business Practice Notes (Accessed: March 2024)

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