Bill of quantities

A bill of quantities (BOQ) is a document used in tendering in the construction industry in which materials, parts, and labor (and their costs) are itemized. It also (ideally) details the terms and conditions of the construction or repair contract and itemises all work to enable a contractor to price the work for which he or she is bidding.

Creation

Bills of quantities are prepared by quantity surveyors and or Building Estimators, and “Indeed the bill of quantities was the raison d’etre for the development of quantity surveying as a separate profession.”.^[1] They are prepared by a “taking off” process in which the cost of a building or other structure is estimated from measurements in the Structural Engineer's drawings. These are used to create a cost estimate such as in regard to the square area in meters of walls and roofs, the numbers of doors and windows, and systems as heating, plumbing and electrics. Similar types of work are then brought together under one item, a process known as "abstracting".

Estimating books provide the relevant costs of the materials and labour costs of the operations or trades used in construction. As the rates for materials and labour change due to inflation, these books are frequently republished.

The practice historically of estimating building costs in this way arose from non-contractual measurements, taken off drawings to assist tenderers in quoting lump sum prices.

There are different styles of bills of quantities, mainly the Elemental BOQ and Trade Bills.

Contingency sum

A Contingency sum is an item found within a Bill of quantities (BoQ).

The item refers to unforeseeable cost likely to be incurred during the contract.

There are two types of contingency sum. The first refers to a specific item i.e. 'additional alterations to services when installing said shower unit'; where an item for alterations to existing services is not contained within the BoQ but some work is envisaged.

The second type of sum is where money can be allocated to any item, within the BoQ, in the same way as the above example or used as 'additional work to be undertaken by the contractor, at the request of the contract administrator'.

The first is usually approximated by the client’s PQS and the second by the contractors QS (or commercial manager).

Additional requirements is referred as Bill of materials (BOM).

Criticisms

Bills of quantities compounds labour and material costs by combining them into a single rate that is then adjusted in regards to material quantities. They also do not consider all the main costs incurred by contractors such as construction plant, temporary works, and payments made on an interim bases in regard to work completed. Thus they do not actually model real costs. An alternative form of cost document that took account these costs was developed at Building Research Establishment called operational bills.^[2][3][4]

Bills of quantities may prevent contractors from developing effective cost control systems.^[5]

They impair transparency in regard to changes and costs “It has suggested that the reason why bills of quantity still find favour with contractors “is the opportunity it provides for creating a smoke screen around the contractor's original intentions. Thus, front end loading may go undetected, and new rates may be negotiated almost from scratch”. ^[6]

See also

• Bill of materials (BOM)
• Operational bills

References

1. ^ Potts, K. (2004). Quantity surveying tools and techniques: A review of client and contractor requirements COBRA The international construction research conference of the Royal Institution of Chartered Surveyors 7-8 September ISBN 1-842-19193-3
2. ^ Skoyles, E. R. (1966) Examples from operational bills OCLC 61861509
3. ^ Skoyles, E. R. (1967) Preparation of an operational bill. Building Research Station ISBN 978-0-85125-019-9 OCLC 271085985
4. ^ Potts, K. (2008). Construction Cost Management: Learning from Case Studies, Routledge. ISBN 978-0-415-44286-2
5. ^ Potts KF (1995). Major construction works contractual and financial management. Longman. ISBN 978-0582102989
6. ^ Fenn, P. Gameson, R. (1992). Construction Conflict Management and Resolution: Proceedings of the First International Construction Management Conference, the University of Manchester, Taylor & Francis, ISBN 978-0419181408 p. 262

Books

• Seeley IH. (1998). Building Quantities Explained 5th Revised edition, Macmillan ISBN 978-0-333-71972-5

• Seeley IH. (1997). Quantity Surveying Practice, 2nd Revised Macmillan; ISBN 978-0-333-68907-3

• Lee S. Trench W. Willis A. (2005) Elements of Quantity Surveying. 10th Edition edition WileyBlackwell; ISBN 978-1-4051-2563-5

• Ashworth A. Hogg K. (2007). Willis’s Elements of Quantity Surveying 12 Rev Ed edition Blackwell Publishing. ISBN 978-1405145787