NEC3 - Preliminaries why are the still used/referenced?

Why do people still include/refer to “premins” in NEC contracts ? there is no reference in NEC to this and the definition is never clear as to what exactly “prelims” include. A search of any standard ECC returns no results for “prelims”. Is more guidance needed on the use of the “Schedule of Cost Components” from the NEC ? Many NEC4 help books start refering to time related prelims and one off lump sum prelims still.


Preliminaries, or prelims, is a term which is generally understood within the construction industry.

The Code of Estimating Practice published by the Chartered Institute of Building (CIOB) describes preliminaries as:

‘…the cost of administering a project and providing general plant, site staff, facilities, and site based services and other items not included in the rates.’

Preliminaries cannot be reasonably defined at a ‘general level’ as the requirement will depend on numerous factors, including; type of work, location, industry specific requirements, particular constraints or requirements (contractual, statutory and project specific), etc, which would determine the type and quantity of preliminaries required.

Standard methods of measurement refer to ‘preliminaries’ which would explain their inclusion under a main option B or D Bill of Quantities. For main options A and C a corresponding description would most likely be included within the Activity Schedule.

It is important to understand the inclusion and use of preliminaries to facilitate the assessment of a compensation event quotation, both in terms of cost and time, even though the presentation is in the form of the (Short or Shorter) Schedule of Cost Components.