Provisional sums & prime costs
Allowances in a building contract for work or materials that aren't fully decided when the contract is signed. They can be confusing, so here's how they work.
We only use them where there's a benefit to your project. Our aim is to resolve as much of the design and selections as possible before contract, so the allowances that remain are few and realistic.
Provisional sums (PS)
A provisional sum is an allowance for the supply and installation of a part of the work.
We use one when we know the work is needed, but the design isn't detailed enough yet to price it accurately. Common examples are:
- cabinetry and joinery
- earthworks
- floor coverings.
Prime costs (PC)
A prime cost item is an allowance for the supply only of specific materials or items. Installation is already included in the contract price.
PC allowances are usually expressed as a rate per item or per square metre, for example:
- a rate per square metre for wall tiles
- an allowance for each tapware item or appliance.
When the final cost is different
If the final cost of an item is more or less than its allowance, the contract price is adjusted. Your building contract sets out exactly how each allowance is adjusted. We'll walk you through them before you sign.