- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 08 Nov 2020
Undefined provisional sum
A provisional sum is an allowance (or best guess), usually estimated by a cost consultant, that is inserted into tender documents for a specific element of the works that is not yet defined in enough detail for tenderers to accurately price.
A provisional sum can be categorised as ‘defined’ or ‘undefined’.
Undefined provisional sums are less well described as they refer to work which is not completely designed. As such, the contractor cannot be expected to make allowance for them in their programming, planning and pricing preliminaries. This means the contractor may be entitled to an extension of time and/or additional payments when the actual works are undertaken.
An example of an undefined provisional sum might be work required below an existing structure, where the ground conditions, and so the extent of work required, cannot be determined until the structure is demolished and the ground opened up.
Defined provisional sums are those which have been described in sufficient detail that the contractor is expected to have made allowance for them in their programming, planning and pricing preliminaries.
 Find out more
 Related articles on Designing Buildings Wiki
Featured articles and news
Preparing for the return of employees.
Using rainscreen walls to address energy efficiency.
Integrity of fire product marketing - post-Grenfell - addressed.
Data measurement and carbon reduction efforts.
Actuate UK issues stark warning.
Department for Levelling Up, Housing and Communities replaces MHCLG.
Protecting heritage from disasters. Book review.
Three structures forever changed people's lives for the better.
ECA comments on findings of BEIS Green Jobs Task Force.
Why government can't support public transport forever.
Government introduces the Information Management Mandate.