Preparing a BQ

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A BQ (bill of quantities) is prepared for the Contractors or Principal Contractors estimator to provide an offer when tendering for a contract.

There are several methods used by Quantity Surveyors to prepare a BQ. One traditional method involves breaking down the process into two stages, as follows:

Taking off

As the name suggusts, this involves taking off dimensions from the construction drawing and entering them on a ruled paper called a 'dimension paper'. Clear and concise description detail in the form of explanatory notes is also included to allow the accurate understanding and pricing of the work items.

Working up

This process is undertaken in two stages:

Squaring

This involves squaring the measured dimensions and transferring the lengths, areas and volumes to the 'abstract' for abstracting.

Abstracting

The squared dimensions are arranged in convenient order for billing and reduced to recognised units of measurement.

Billing direct

The above method is long and tedious in practice. There is another method that can simplify the process called 'billing direct' that is suitable when the work is relatively straightforward and the number of work items limited.

This method involves taking off and transferring the measured work items directly from the dimension paper to the BQ, eliminating the need to abstract. Each work item is taken off as a separate article in the order in which it will be presented on the BQ, thereby, reducing time and cost of preparing a BQ.

Writing the bill of quantities

This involves listing the various individual or aggregated construction work items with their measured quantities and units of measurement in a suitable order under elemental headings in the BQ document.

For example, in the sample bill of quantities the aggregated construction work item (description, quantity and unit of measurement) is listed under the elemental heading of 'New Class'.

New Class

Item

Description

Quantity

Unit

£ rate

£ cost

1

Construct 1.5metre wide granite dust path on Autoway 150 geotextile sheet using 150mm depth recycled Type 1 granular sub base and 25mm depth 6mm granite dust surfacing in accordance with drawing 1

500

lin.m

 

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