How to take off construction works

[edit] Introduction

The term ‘taking off’ refers to the process of identifying elements of construction works that can be measured and priced. This is necessary to produce bills of quantities and requires that the design is complete and a specification has been prepared.

[edit] Dimension paper

Traditional taking off uses dimension paper which is made of a series of columns. The columns are:

1. The timesing column, which gives the factor of multiplication for the measurements in the dimension column.
2. The dimension column, where the measurements are set down as taken from the drawings.
3. The squaring column, where the calculated volumes, areas, and so on, are set out.
4. The description column, where the description of the work item in relation to the measurements is written.

[edit] Dimensions

The dimensions that are measured will be in one of the following forms:

Cubic measurements (e.g. 3 m x 3 m x 3 m).
Square measurements (e.g. 3 m x 3 m), also known as superficial measurements.
Linear measurements (e.g. 3 m).
Enumerated items (e.g. ‘Nr. 3’).
Item (e.g. ‘Testing’).

Dimensions are usually set down in order of horizontal length, horizontal width or breadth, and vertical depth or height. It is important for the sake of consistency throughout the taking off that this order is maintained.

[edit] Timesing

This is a method in which several items that have the same measurements can be set down without having to replicate calculations multiple times.

The number of times that the measurement in the dimension column is to be multiplied is set down in the timesing column and separated using a diagonal stroke. The same item can be timesed multiple times by setting down additional numbers in the timesing column.

In the first example below, the cubic measurement 3.00 x 2.00 x 1.00 is to be multiplied by 2.

In the second example below, the same measurement, once multiplied by 2, is then multiplied by 4.

[edit] Dotting on

Dotting on is used to add dimensions together in the timesing column rather than multiplying. The numbers are positioned diagonally in the column with the dot between them to avoid any confusion with decimals.

In the first example below, the cubic measurement 3.00 x 2.00 x 1.00 is multiplied by (1 + 4) 5.

In the second example below, the same measurement is multiplied by (1 + 4) 5, which is then multiplied by 2.

[edit] Waste calculations

It is important that any calculations done to work out the dimensions that are entered into the dimension column are written down as waste calculations on the right-hand side of the description column. This is so that if someone reviews the taking off to check for accuracy, the process by which the final figures have been calculated can be traced back.

[edit] Alterations

Where incorrect dimensions have been set down, they should be neatly crossed out with ‘nil’ written alongside in the squaring column. This indicates that the dimensions are cancelled. Care should be taken to avoid confusion with the ‘nil’ label in terms of how many figures are to be cancelled and which are still to be used in the calculations.

In the example below, the square measurement 4.00 x 2.00 has been cancelled.

[edit] Descriptions

The description of the item being measured is included in the description column alongside the calculations. The contents of the description should correspond to the New Rules of Measurement (NRM). Where there are more than one set of calculations associated with the same description, then they can be bracketed together on the outside of the squaring column.

[edit] Anding-on

This is where there are two or more descriptions that apply to the same measurement. The descriptions are separated in the description column by ‘&’ so as to clearly distinguish between them. They can also be bracketed together for clarity.

Where items are to be deducted or added, they are preceded by ‘Deduct’ or ‘Add’ in the description column.