International Construction Law Review
THE EFFECT OF BILLS OF QUANTITIES IN STANDARD FORMS
DR ANNE MAGDALINE NETTO
Department of Building, National University of Singapore
Introduction
Building contracts “with quantities” are widely used in the construction industry. The contractor’s price is based on the bills of quantities produced by the employer’s quantity surveyor. The contractor tenders upon this document by pricing each unit of measurement which are then grossed up to produce the total contract sum.
By definition a bill of quantities is “a detailed schedule of the quantities and items of work which it is anticipated will be carried out”.1
Where the drawings illustrate the work to be carried out, the bills of quantities describe and quantify the works in detail. In the absence of bills of quantities, the specification fulfils this function in addition to setting out the minimum required standards of workmanship and materials supplied.
Bills of quantities are used to fulfil three separate functions:
- as a basis for valuing variations;
- as a basis for assessment of interim payments; and
- as a basis for producing a final remeasurement or recalculation of the ultimate contract sum, whether or not the work has been varied.
In relation to the last function, differences between the original and the ultimate contract quantities can be brought about in three ways:
- there may be a simple mathematical error in “taking-off ” the quantities from the contract drawings;
- there may be a wrong assessment of the extent of the work for which the design has not been finalised;
- variations—extra work not included in the works for which the contract sum is payable.
Differences due to either errors in taking off or wrong estimates are called “automatic changes” because the difference in the quantities appears automatically once the original works are completed. “Ordered changes”, on the other hand, are caused by physical variation to the original works.
Pt 1]
Effect of Bills of Quantities in Standard Forms
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