The bill of quantities which is prepared by the quantity surveyor is designed primarily as a tendering document. Each contractor tendering for the project is able to price the work on exactly the same information with a minimum of effort. This therefore avoids duplication in quantifying the work, and allows for the fairest type of competition. The bill of quantities also provides a valuable aid to the pricing of variations and computation of valuations for interim certificates.
The bill of quantities provides a good basis for cost planning and, if prepared in annotated form, will help in the locational identification of the work.
The bill of quantities usually includes several sections such as preliminaries, preambles or descriptions of materials and workmanship, and the measured works. The preliminaries define the scope and nature of the work, contain details of the contract conditions, list of drawings and any special instructions to the contractor on pricing.
Prime cost sums will be inserted in the bill of quantities for work to be carried out by nominated subcontractors and statutory authorities or for goods to be supplied by nominated suppliers, and for which estimates or tenders have usually been obtained. Provisional sums cover work for which details have not been finalised or for which costs are unknown at the time of preparing the bill.
It is important that all drawings, schedules and specification particulars should be checked and steps taken to ensure that all cross references are correct. The quantity surveyor when measuring the work will be continually checking all particulars, including cross references, and will prepare a query list for the architect covering the omission of necessary information, discrepancies and ambiguities. This provides the architect with the opportunity to clarify these points and amend the documentation prior to tender stage. It is also advisable to check the adequacy of prime cost and provisional sums, ensure that no information is outstanding from consultants, that the quantity surveyor has all the latest information and incorporates it in the bill of quantities, and that all consents have been received and the conditions complied with.