21Requirements concerning prime cost item and provisional sum estimates

21 Requirements concerning prime cost item and provisional sum estimates (1) A builder must not enter into a domestic building contract that contains an amount, or an estimated amount, for— (a) a prime cost item that is less than the reasonable cost of supplying the item; (b) a provisional sum that is less than the reasonable cost of carrying out the work to which the sum relates. 1. 35 penalty units. (2) This section does not apply to items or sums that are to be supplied or specified by the building owner (or the building owner's agent). (3) In determining what is a reasonable cost, regard must be had to— (a) the information that the builder had, or reasonably should have had, at the date the contract was made; and (b) the nature and location of the building site[[8]](#endnote-9).