Bill of quantities v Schedule of rates

[edit] Introduction

This article explains the difference between a bill of quantities (BoQ) or a schedule of rates on construction projects. Both can be used to obtain prices from contractors and for valuing variations. The decision about whether to use a bill of quantities or a schedule of rates depends on the nature of the project as well as the chosen procurement route.

[edit] What is a bill of quantities?

A bill of quantities is a document prepared by the cost consultant (often a quantity surveyor) that provides project specific measured quantities of the items of work identified by the drawings and specifications in the tender documentation.

The bill of quantities is issued to tenderers for them to prepare a price for carrying out the works. The bill of quantities assists tenderers in the calculation of construction costs for their tender, and, as it means all tendering contractors will be pricing the same quantities (rather than taking off quantities from the drawings and specifications themselves), it also provides a fair and accurate system for tendering.

The contractor tenders against the bill of quantities, stating their price for each item. This priced bill of quantities constitutes the tenderer's offer.

Typically a bill of quantities will be appropriate on projects that have been designed in detail, and so the precise quantities required are known.

For more information see: Bill of quantities.

[edit] What is a schedule of rates?

A schedule of rates is a list in a contract setting out the staff, labour and plant hire rates that the contractor will use for pricing cost reimbursable instructed daywork. It does not contain any quantities for the specific work items and is typically used when the nature of work required is known but it cannot be quantified, or if continuity of programme cannot be determined.

On a much larger scale, a similar process might be used on a 'schedule of rates term contract', 'term contract' or 'measured term contract'. Tenderers quote unit rates against a document that is intended to cover all likely activities that might form part of the works. As the extent of the work is unknown, the unit rates include overheads and profit. General preliminaries such as scaffolding, temporary power, supervision and temporary accommodation will also have rates. On projects longer than around 18 months there might be escalation provisions based on annual percentage increases.

For more information see: Schedule of rates.

[edit] Summary

In summary, a bill of quantities will typically be used when a detailed design has been prepared and precise quantities can be calculated, whereas a schedule of rates will be used when quantities cannot be determined.

[edit] Related articles on Designing Buildings

• Admeasurement.
• Bill of quantities.
• Construction contract.
• Difference between lump sum and measurement contracts.
• Measurement contract.
• Preliminaries.
• Procurement route.
• Remeasurement.
• Schedule of rates.
• Tender documents.
• Term contract.
• Unit rates basis of payment.

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