Bill of Quantities

A bill of quantities, usually called a BoQ, is a structured schedule of construction work for pricing, describing items, units and quantities that contractors can rate in a tender. It is not merely a shopping list of materials, because measured work may include labour, plant, installation and other resources in the rate.

A quantity surveyor often prepares it from a sufficiently developed design, using measurement rules so that everyone describes work on a consistent basis. RICS New Rules of Measurement include NRM 2 for detailed measurement of building works, and the parties must identify the rules used, since a unit such as a square metre can have different inclusions depending on the measurement method and item description.

A typical line has an item number, description, unit, quantity, bidder's rate and extended amount, so 2,000 square metres of flooring priced at $85 per square metre extends to $170,000. That arithmetic is simple, but the description must explain substrate preparation, finish and other scope details where the measurement rules do not resolve them.

The BoQ gives bidders a shared pricing framework, so two bids are easier to compare when the same items and units are used. But the lowest total is not automatically the best value; review exclusions, qualifications, programme, contractor capability, payment terms and rates for items whose final quantity could change substantially.

The pricing schedule can also reveal unbalanced bids, since a contractor might put unusually high rates on early work to improve cash flow or on items expected to increase in quantity, and a low tender sum can mislead if a major quantity change will be valued at an inflated rate. The treatment of quantities depends on the contract.

In a remeasurement contract, final payment may use measured work actually completed and the applicable rates, so tender quantities may be estimates, whereas in a lump-sum contract the BoQ may play a different role in pricing, valuation or information. Do not tell an owner that every difference between the BoQ and completed quantity automatically changes the contract price.

An owner should read the BoQ together with its order of precedence and tender documents. If a drawing shows a door but the schedule omits it, the outcome depends on the contract and its risk allocation, so flag the mismatch before award rather than assume a later variation will be approved.

Provisional sums and contingencies need the same care: a provisional sum is an allowance for work not fully described or quantified at tender stage, not a firm fixed price for whatever work becomes necessary, so identify who controls its expenditure, what overhead and profit apply and how the final work will be valued. During construction, measured quantities and agreed rates may help value interim payments and variations, but a quantity surveyor or contract administrator needs evidence of work done and the relevant contract provision.

The original rate is not necessarily suitable for every changed item because method, timing, scale and conditions may differ, so use the contractual variation procedure and keep version control by recording the design issue, tender addenda and the final priced schedule accepted by the parties. The BoQ is most useful when it supports clear scope and disciplined contract administration; it cannot repair incomplete drawings by itself, so review high-risk quantities before award and track changes as work proceeds.