the copy used for takeoff and appropriate revisions
made in the estimate.
Construction materials are subject to waste and
loss through handling, cutting to tit, theft, normal
breakage, and storage loss. Failure to make proper
allowance for waste and loss results in erroneous
Other error sources are inadvertent figure
transpositions, copying errors, and math errors.
The activity estimate provides a basis
preparing the estimates of material, equipment,
manpower requirements. An activity estimate,
example, might call for rough-in piping in a floor
slab. In an activity estimate, your immediate concern
is to identify the material necessary to do the
taskpipe, fittings, joining materials, and so forth.
The equipment estimate for this activity should
consider vehicles for movement of material and
special tools, such as portable power tools, a threader,
and a power vise. From the scope of the activity and
the time restraints, you can estimate the manpower
required. The information shown in the activity
estimate is also useful in scheduling progress and in
providing the basis for scheduling deliveries of
material, equipment, and manpower to the jobsite.
The techniques discussed in the next paragraphs
will help you produce satisfactory activity estimates.
But, before doing anything, you should become
knowledgeable about the project by studying the
drawings. Read the specifications and examine all
available information concerning the site and local
conditions. Only after becoming familiar with the
project are you ready to identify individual activities.
Now, here are two ideas that will help you make good
First, define activities. They may vary depending
on the scope of the project. An activity is a clearly
definable quantity of work. For estimating and
scheduling, an activity for a single building or job
should be a specific task or work element done by a
single trade. For scheduling of large-scale projects,
however, a complete building may be defined as an
activity. But, for estimating it should remain at the
single-task, single-trade level.
Second, after becoming familiar with the project
and defining its scope, proceed with identifying the
individual activities required to construct the project.
To identify activities, be sure each activity description
shows a specific quantity of work with clear, definite
limitations or cutoff points that can be readily
understood by everyone concerned with the project.
Prepare a list of these activities in a logical sequence
to check for completeness.
Material estimates are used to procure
construction material and to determine whether
sufficient material is available to construct or
complete a project.
The sample forms shown in
figures 9-2, 9-3, and 9-4 may be used in preparing
material estimates. The forms show one method of
recording the various steps taken in preparing a
Each step can readily be
understood when the work sheets are reviewed. A
work sheet must have the following headings: Project
Title, Project Location, Drawing Number, Sheet
Number, Project Section, Prepared By, Checked By,
and Date Prepared.
ESTIMATING WORK SHEET. The Esti-
mating Work Sheet (figure 9-2), when completed,
shows the various individual activities for a project
with a listing of the required material. Material
scheduled for several activities or uses is normally
shown in the Remarks section. The work sheet
should also contain an activity description, the item
number, a material description, the cost, the unit of
issue, the waste factors, the total quantities, and the
remarks. The Estimating Work Sheets should be kept
by the field supervisor during construction to ensure
the use of the material as planned.
MATERIAL TAKEOFF SHEET. T h e
Material Takeoff Sheet (MTO) is shown in figure 9-3.
In addition to containing some of the information on
the Estimating Work Sheet, the MTO also contains the
suggested vendors or sources, supply status, and the
required delivery date.
BILL OF MATERIAL. The Bill of Material
(BM) sheet (figure 9-4) is similar in content to the
Material Takeoff Sheet. Here, though, the infor-
mation is presented in a format suitable for data
processing. Use this form for requests of supply
status, issue, or location of material, and for preparing
purchase documents. When funding data is added,
use these sheets for drawing against existing supply
Between procurement and final installation,
construction material is subject to loss and waste.