30 January 2020


What is a specification?

A specification is a detailed description of the dimensions, construction, workmanship, materials etc., of work done or to be done on a project, prepared by an architect, engineer or designer, often referred to as specifiers.

What's included and what's not included in a specification?

Populated by the specifier, a specification document describes in words what cannot be visualised or explained on a drawing or model. This document can be incredibly wide-ranging - covering the establishment of the site, the type of contract to be used, the performance criteria of the asset, the quality of the systems and products, which standards are applicable and how they should be executed, and even the products to be used.

Specifications do not include information on cost, product availability, quantity or drawn/visualised information so need to be read in conjunction with documents detailing quantities, schedules and drawings. For this reason, if and should a product be unavailable and a substitution is required, the specification document should be adhered to when choosing an alternative.

What are the types and advantages of writing a specification?

A very prescriptive specification at tender stage will ensure the client has a high degree of certainty about what will be delivered.

A performance specification gives suppliers more discretion, for example, to suggest innovative solutions and/or to act as a design brief for specialist sub-contractors.

A specification is a document that describes in words what cannot be visualised or explained on a drawing or model.

How should specifications be structured?

The structuring of specifications will vary from project to project but should reflect the work packages on a particular project and any sub-contracts. This structuring should make it easier for contractors to price a job and give a more accurate tender.

The use of a standard classification system, such as Uniclass 2015, is encouraged as it should remove any potential for confusion or ambiguity.

When are specifications produced?

The production of specification documents should happen in tandem with design work - with ever greater level of detail added as the design progresses. At tender stage, the specification serves as an essential reference guide for contractors looking to price up a job. Leaving specifications until the last minute - when production information is being prepared - is not to be advised.

So where does NBS come in?

For architects, engineers, designers and contractors, NBS provides specification writing software that enables them to write their own clear and concise specifications for their construction projects. The software is designed to make it easy to collate the data needed to produce robust specifications that power projects. 

Our latest construction specification software, NBS Chorus, can be described as a ‘master specification’ platform, which means that technical teams at NBS have pre-authored hundreds of master clauses – to provide repeatable, reusable templates and associated contextual guidance to help specifiers make decisions, whilst still giving them the freedom to write their own to complete project-specific requirements, to suit how they develop specifications.

For building product manufacturers, NBS help grow their business by exposing their products across the construction project timeline. Using tools such as RIBA Product SelectorNBS BIM Library and NBS Plus, building product manufacturers upload their product data for architects, engineers and designers to specify their products.