Provisional Sum

The phrase 'provisional sum' is fairly common in the building industry.

In extension building, a 'provisional sum' would be a term that your builder or architect would refer to as an unknown cost, so a provisional sum of money is included. A provisional sum occurs in a situation where there may be an intricate design that the architect has drawn, that could need a structural engineer to detail and specify how and the materials used. Such details are not always available at the time of pricing, so a provisional sum is used.

 

When this is the case, when the relevant information is available, and you can get the item priced, quite simply, the provisional sum is removed from the contract price and is then replaced with the actual costs.