How do you pay Provisional sum in contracts?

A provisional sum in a contract is an estimated amount set aside for specific work or items that cannot be precisely defined at the time of contract formation. Payment for a provisional sum is typically made when the actual cost of the work is determined, either through a separate agreement or by obtaining quotes from subcontractors. The contractor will then invoice the client for the actual costs incurred, adjusted for the provisional sum amount. It's essential to document any changes and ensure that both parties agree on the final costs before payment is made.