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18–1 Plumbing Work
Plumbing, like electrical work, may be bid under either sin-
gle or separate contracts. Regardless of the type of contract,
the areas of responsibility and coordination still exist, and
the general contractor should have a basic understanding of
what his responsibilities to the plumbing contractor are.
The plumbing work must be installed in accordance
with all applicable building codes—federal, state, and local.
The code most commonly used in the United States is the
International Plumbing Code. The code contains informa-
tion relating to water supply, pipe sizes of all types, sewage
drainage systems, vents and venting, storm water drainage,
and various design data.
Field experience, familiarity with plumbing principles,
and an understanding of the drawings and specifications are
key points to the successful bidding of this item. Typical
symbols and abbreviations are shown in Figure 18.1.
18–2 Single Contracts
Plumbing is another area of work that will be subbed out to
a subcontractor. This subcontractor will prepare an estimate
and submit a bid prior to bid day. Even so, the estimator
should have a general knowledge of plumbing so that they
can determine whether the subcontractor’s bid is reasonable.
Again, by the use of common sense and complete files, an
approximate estimate can be obtained.
Using the working drawings and specifications, estima-
tors prepare a complete list of everything that will be
required. First, they determine exactly where the responsibil-
ity for the plumbing begins. It may begin at the property
line, 10 feet outside the structure, at the structure, or some-
where else; they should always check so as to have a clear pic-
ture of the project in mind.
The takeoff for plumbing includes the costs of water
pipes, gas pipes, sewer pipes, drains, soil and vent stacks, soil,
waste, vent pipes, and all rough work required for fixtures.
Information required includes size, length, pipe material,
weight, and fittings (unions, hangers, tees, wyes, elbows,
etc.). Also included are kinds and sizes of cleanouts, grease
traps, plugs, traps, valves, and the like. The trenches required
for plumbing pipe, especially from the road to the building,
may be the responsibility of the plumbing subcontractor or
the general contractor. If the general contractor is responsi-
ble for trenching, it should be noted as such on the estimate.
Pipe materials include cast iron, copper, lead, galvanized,
and plastic.
The finish plumbing list should include a list of all
items and fixtures furnished and installed by the contractor.
All different types and sizes of fixtures are kept separate. In
pricing the fixture, the estimator must also consider the
accessories and fittings required for each fixture. The listing
requires care in counting the fixtures on the working draw-
ings and making note of all specification requirements.
When listing the prices for the fixture, estimators note
whether the fixtures and accessories were priced separately.
The make, kind, type, and quality will greatly affect the
price of the fixtures and accessories. Again, there should be
no guesswork, but only accurate prices. Items that should be
included in this takeoff include lavatory, water closet,
shower with stall, shower without stall, bathtub, bathtub
with shower, slop sink, water heater, dishwasher, garbage
disposal, laundry tubs, and water cooler. Another situation
that must be noted is that which occurs when the owner or
others supply an item to the plumbing subcontractor for
installation. It is important that estimators know exactly the
limits of responsibility in this case, since this is often an area
of dispute.
To improve the accuracy from job to job, good estima-
tors keep a complete file of all costs. They request their
subcontractors to provide breakdowns of costs when the
subcontractors submit an application for payment. Esti-
mators constantly check one job against another; it is not
unusual that, by the use of their files, they can not only
detect high bids from their subcontractors, but also pickPLUMBING
CHAPTEREIGHTEEN