A specification document is a key element in any construction project
A construction specification is a well-structured, detailed description of the quality, standards, workmanship, materials, and completion of work to be done which evolves across a project. A good specification helps maintain the quality of detailing and workmanship and saves time, money and potential issues later on. It can also decrease the time it takes to process consent applications, improve the accuracy of quotes, reduce the number of changes or rework on the building site and prevent disputes between the builder, designer and owner.
The specification information describes in words things that cannot be visualized or explained in drawings and the model. The content can include site requirements, contract information, client requests, performance criteria to be achieved, the quality of products needed, references to various standards applicable to the materials and systems selected, how work is to be completed and tested, and maintenance of the building in-use.
A specification defines how a building is to be constructed, altered, demolished or removed. For a new project, it must define the intended use of the building, detail all the systems and materials used and provide procedures for installation, inspection and maintenance during and after construction.
To estimate the cost of a project without a specification is impossible and to enter into a contract without one is very short sighted. Too many building contracts are entered into with vague information, resulting in a myriad of problems; the most common being significant cost overruns. The specification should form an integral part of the building contract. It is also important to note that there is no such thing as a standard specification as no two structures are alike or use the same materials.
Specifications are often prepared by architects, engineers, and designers, referred to as specifiers, and the various parties each use the specification in a slightly different way. The designer uses it to accurately describe the components and expected standard of the build, the builder uses it to carry out the construction and the owner uses it as part of their agreement with the builder. As the specification is used as the guide for all parties to the construction, it is essential that the specifier has the required knowledge of regulatory requirements and construction techniques to create a good specification.
Different types of specification can be used at different stages of a project’s development. At an early stage, requests from the brief and high-level design ideas can be captured as an Outline description, then requirements of the building, systems and products can be specified in performance terms in a Descriptive or Performance specification, such as the acoustic, thermal, or structural requirements, and the specification further developed into more Prescriptive clauses selecting the standards, grades, and materials of component products. Proprietary specification includes product information like range names, reference codes, and key properties selected from manufacturer choices. The specification is often developed in tandem with Preliminaries, managing the contractual and project-wide requirements, and will continue to evolve as changes are requested, eventually forming handover data, for example as a record specification.
There are seven key principles to writing a robust specification, and are called the 7 Cs of specification:
- CLEAR: Use clear, plain language and short phrases to list requirements. Avoid ambiguity to improve understanding for all users
- CONCISE: Don’t include information that isn’t required or relevant – make the specification project-specific.
- CORRECT: Clarify requirements, refer to outcomes, and reference relevant standards wherever possible.
- COMPLETE: Check the depth of information is appropriate.
- COMPREHENSIVE: Ensure all aspects of the project are covered and use cross-references to avoid repetition or conflicts.
- CONSISTENT: Use standard structure, terminology, and style. Keep outputs neat when published, so they are easy to navigate and understand for all receivers.
- CO-ORDINATED: Ensure that drawing references in the specification are kept to up-to-date to match model annotations and other contract documentation.
Like any good technical document, a specification should present information in an easy to follow and logical sequence. Its aim is to ensure that each stage of the project proceeds smoothly without time delays, inaccurate costings or legal issues and enables parties involved in the construction to communicate effectively.