Job Book 9th Edition - Book - Page 225
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Stage 4 > Technical Design: Supplementary Material: 4/SM4
4/SM4: Bill of quantities
Pricing a bill of quantities is the traditional method of obtaining comparable
tenders for projects where the design has been fully detailed beforehand. Where
an accurate or full bill of quantities becomes part of the contract documentation,
it usually means that quality and quantity included in the price will be as stated
in the contract bills. It is therefore important to ensure that the bill accurately
reflects the intentions of the architect and does not conflict with information
shown on the drawings.
Notional bill or approximate quantities
Where it is not possible to present the cost consultant with a completely detailed
design and specification, it may be possible to invite tenders on the basis of a
notional bill or approximate quantities. These should be reasonably accurate as
to description and items, with only the amounts left subject to measurement
after completion.
Work which cannot be quantified with certainty, even in an accurate bill of
quantities, may be covered by the introduction of provisional sums (for either
defined or undefined work), prime cost sums (where an accurate figure can be
placed on a subcontract or supply item) or an approximate quantity (where the
item is certain but the quantity is not).
The inclusion of a contingency sum is nothing more than a provisional figure
for undefined work of an unforeseeable nature. All such items require later
instructions from the architect before the contractor can act on them.
Standard Method of Measurement
A uniform basis of measuring work for inclusion in a bill of quantities may be
found in the Standard Method of Measurement of Building Works (SMM), currently
in a seventh edition. For building work this is most likely to be using the Common
Arrangement and in accordance with SMM. The contents of a bill prepared in
this way are likely to include the following:
Preliminaries/general conditions
• Items which are not specific to work sections but which have an identifiable
cost (e.g. site facilities, insurances).
• Items for fixed and time-related costs (e.g. plant, temporary works).
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