- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 03 Oct 2019
Performance specified work in construction contracts
Specifications vary considerably depending on the stage to which the design has been developed, ranging from performance (open) specifications that require further design by the contractor, to prescriptive (closed) specifications where the design is already complete when the project is tendered.
Most projects involve a combination of performance and prescriptive specifications. Items crucial to the design may be specified prescriptively (such as external cladding) whilst less critical items, or items requiring specialist design may be specified only by performance (such as service lifts).
Performance specifications describe the result that is required from particular items and leave it to the contractor or supplier to satisfy that requirement. In effect it requires them to complete the design. The nature of the performance required is typically defined by the desired outcome, or by reference to standards. See Performance specification for more information.
Performance specified work is increasingly common as buildings become more complex and the supply chain becomes more integrated, with contractors and suppliers having greater involvement in design at an earlier stage of the project.
Performance specified work used to be most commonly defined in a ‘contractors designed portion’ as a supplement to the main contract, but increasingly now it forms part of the requirements of the main contract itself.
 Related articles on Designing Buildings Wiki
Featured articles and news
A tool borrowed from statistics and applied to construction procurement.
Reports and factsheets for 2018, 2019 released.
Finding the right landscape maintenance contractor.
As organisations investigate options for return to work, WaaS may gain popularity.
CIOB prompts Government to include in its Industrial Strategy.
Aspects of daylighting design covered by EN 17037.
His life, art and legacy. 1 min book review.
An ambitious Victorian new town that was not delivered as planned.
Using weather and climate information to support infrastructure planning.
Chemicals can slow - and ideally stop - the spread of fire.
Consultation begins on once in a generation changes to the planning system.