Estimating in Building Construction

(Kalthiya AryanmXZGQq) #1
Project Manual 25

actually figuring the estimate, contractors will go through
the entire supplementary general conditions carefully, not-
ing all items that must be covered in the bid and deciding
how much to allow for each item.


3–9 Specifications

Specifications,as defined by the AIA, are the written
descriptions of materials, construction systems, and
workmanship. The AIA further states that defining
the quality of materials and the results to be provided by the
application of construction methods is the purpose of the
specifications.
Thespecifications(sometimes referred to as the techni-
cal specifications) generally follow the CSI MasterFormat.
These specifications include the type of materials required,
their required performance, and the method that must be
used to obtain the specified result. When a particular
method is specified, the contractor should base the bid on
that methodology. Although deviations may be allowed once
the contract has been signed, those items can be handled
through the use of change orders. If an alternative method is
assumed in the estimate and later denied by the architect, the
contractor would have to shoulder any losses.
The material portion of the specifications usually men-
tions the physical properties, performance requirements,
handling, and storage requirements. Often, specific brands
or types of material are listed as the standard of quality
required. Sometimes, two or three acceptable brands are
specified, and the contractor has a choice of which to sup-
ply. If the contractor wishes to substitute another manufac-
turer’s materials, it must be done in accordance with the
contract documents.
Results that may be specified include items such as the
texture of the material, appearance, noise reduction factors,
allowable tolerances, heat loss factors, and colors.


3–10 Alternates

In many projects, the owner requests prices for alternate
methods or materials of construction (Figure 3.5). These
alternates are generally spelled out on a separate listing in
the project manual, and they are listed on the proposal form.
The alternates may be either an add priceor a deduct price,
which means that contractors either add the price to the base


bid (the price without any alternatives) or deduct it from the
base bid. The price for any alternates must be complete and
include all taxes, overhead, and profit. When an owner has a
limited budget, the system of alternates allows a choice on
how to best spend the available money.
Since lump-sum contracts are awarded on the basis of the
total base bid, plus or minus any alternates accepted, there is
always concern that the owner will select alternates in a way
that will help a particular contractor become the low bidder.
This concern has become so great that some contractors will
not bid projects with a large number of alternates. To relieve
the contractor of this concern, many architects include in the
contract documents the order of acceptance of the alternates.
Alternates deserve the same estimating care and consideration
as the rest of the project, so contractors should not rush
through them or leave them until the last minute.

3–11 Addenda


The period after the basic contract documents have been
issued to the bidders and before the bids are due is known as
thebidding period.Any amendments, modifications, revisions,
corrections, and explanations issued by the architect/engineer
during the bidding period are effected by issuing the addenda
(Figure 3.6). The statements, and any drawings included, serve
to revise the basic contract documents. They notify the bidder
of any corrections in the documents, interpretations required,
and any additional requirements, as well as other similar mat-
ters. The addenda must be in writing.
Because the addenda become part of the contract docu-
ments, it is important that all prime contractors promptly
receive copies of them. Many architect/engineer offices send
copies to all parties who have the plans and the project man-
ual (include the plan rooms). The addenda are also of concern
to the subcontractors, material suppliers, and manufacturers’
representatives who are preparing proposals for the project, as
the revisions may affect their bids.
The receipt of the addenda for a particular project by
the reporting service will be noted in the information the
service sends to their subscribers. It is suggested that the
contractor call the architect/engineer’s office once several
days before bids are to be received, and again the day before
to check that all addenda have been received. Most proposals
have a space provided in which the contractor must list the
addenda received. Failure to complete this space may result

FIGURE 3.5.Alternates.
Free download pdf