Provisional Sum
A Provisional Sum is an allowance included in a bill of quantities or contract for work that cannot be fully described or measured at tender stage. It provides financial provision for anticipated but undefined work.
Types of Provisional Sums
According to NRM 2, provisional sums are classified as:
- Defined provisional sums – Where the nature of the work is known but cannot be measured in detail (contractor must allow for programming and pricing preliminaries)
- Undefined provisional sums – Where neither the nature nor scope of work is known (contractor cannot be expected to allow for in programme or preliminaries)
Common Uses
Provisional sums are commonly included for:
- Statutory undertakers works (utilities connections)
- Archaeological investigations
- Unforeseen ground conditions
- Work dependent on third-party approvals
- Contingency items
Expenditure and Adjustment
Provisional sums are expended as instructed by the contract administrator. The difference between the provisional sum and actual cost is adjusted in the final account.
Related Terms
See also: Bill of Quantities, Contingency Costs, Prime Cost Sum
