What Are Preambles in Bills of Quantities?

By Staff WriterLast Updated Apr 15, 2020 2:31:27 PM ET

The preamble in bills of quantities serves to outline unit prices and methods of measurement used in the work that is completed. Bills of quantities are used in negotiating contracts in the construction industry.


The preamble of a bill of quantities is a summary of the work requested. The preamble is divided into sections that explain the project, materials needed, unit prices, provisional sums, methods of measurement and potential errors. In cases in which excavation is included in the project, the type of rock must be outlined in the preamble. In this section, it is also helpful to address issues related to unforeseeable costs associated with the project.

The purpose of a bill of quantities is to indicate the work requested for a project. When a contract is entered into, it is important to outline all work to be completed. This allows managers to perform periodic evaluations on the tasks completed and to ensure that these tasks match what was delineated in the bill of quantities. Materials, parts and labor must be itemized in the bill of quantities as reflected in the preamble. The itemized list creates the estimated cost of the project and allows construction companies to bid on taking the work.