How to read a bill of quantities (BOQ)

The main sections of a BOQ

Most bills follow the same broad order, whatever method of measurement they use.

• Preliminaries: project particulars, contract conditions, site constraints and the contractor’s general obligations.
• Preambles: how items are measured and what each rate must include.
• Measured work: every item of permanent work, grouped by work section, trade or element.
• Provisional sums: allowances for work that is not yet defined.
• Prime cost sums: allowances for nominated supplies or specialists.
• Dayworks: rates for work paid on time and materials.
• Summary or collection: totals from each page and section, carried to the tender sum.

Reading an item line

Each line has an item reference, a description, a quantity, a unit, and columns for the rate and the amount. The description is written to the method of measurement, so a short phrase carries a lot of meaning: “Concrete, grade C30, in foundations, poured against earth” tells you the material, the location and the formwork condition. The unit tells you how it is paid: cubic meters, square meters, linear meters, numbers or an item sum.

Why the preambles matter

Preambles explain what is deemed to be included in each rate. Under most methods of measurement, rates include for labor, materials, plant, waste, fixings and overheads unless stated otherwise. If formwork is measured separately, your concrete rate must not include it; if it is deemed included, it must. Reading the preambles first prevents both double counting and gaps.

Provisional sums, prime cost sums and contingencies

A provisional sum is a placeholder for work that cannot be described yet, and its final value is adjusted when the work is instructed. A prime cost sum covers goods or work by a nominated supplier or specialist, and the bill usually asks you to add your profit and attendance. Neither is a measured quantity. Read the instructions attached to each, and price the attendance and profit lines that go with them.

Checks before you price

Even a well-prepared bill can contain errors. Before pricing, measure the items with the most value or risk, such as concrete, reinforcement, structural steel and major finishes, and compare them with the bill. Check that every drawing and specification section appears somewhere in the bill, and note discrepancies as tender queries. On remeasured contracts, quantity errors affect cash flow; on lump-sum contracts they can become your risk.

Pricing the bill efficiently

Start with the items that carry the most value, which in most bills are a minority of the lines. Price them carefully from your own build-ups or subcontract quotes, then work through the remaining items. Use the preliminaries to price time-related costs once, rather than spreading them inconsistently across item rates, unless the tender requires distribution. Finally, check the arithmetic and the collection pages, and make sure every provisional sum, prime cost sum and attendance item has been carried into the summary.

BOQs in different markets

The idea of a bill is the same everywhere, but the rules differ. UK bills follow NRM2, Australian bills follow the ASMM, and many Gulf projects use POMI or a project-specific method. US projects rarely use full bills but often have unit-price bid schedules that work in a similar way. When you receive a bill, check which method it follows, because the method decides what each rate is deemed to include.