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15–1 WINDOW AND CURTAIN
WALL FRAMES
Window and curtain wall frames may be made of wood,
steel, aluminum, bronze, stainless steel, or plastic. Each
material has its particular types of installation and finishes,
but from the estimator’s viewpoint, there are two basic types
of windows: stock and custom-made.
Stock windows are more readily available and, to the
estimator, more easily priced as to the cost per unit. The esti-
mator can count the number of units required and list the
accessories to work up the material cost.
Custom-made frames cannot be accurately esti-
mated. Approximate figures can be worked up based on
the square footage and type of window, but exact figures
can be obtained only from the manufacturer. In this case,
the estimator will call either the local supplier or the
manufacturer’s representatives to be certain that they are
bidding the job. Often, copies of the drawings and specifi-
cations are sent to them, which they may use to prepare a
proposal.
When checking proposals for the windows on a project,
the estimator needs to note whether the glass or other glaz-
ing is included, where delivery will be made, and whether
installation is done by the supplier, a subcontractor, or the
general contractor. The proposal must include all the acces-
sories that may be required, including mullions, screens,
and sills, and the material being bid must conform to the
specifications.
If the contractor is going to install the windows, the
estimator needs to check whether they will be delivered
preassembled or whether they must be assembled on the
job. The job may be bid by the square foot or linear foot
of frame, but the most common method is to bid in a
lump sum.
Shop drawings should always be required for win-
dows and curtain wall frames, because even stock sizes
vary slightly in terms of masonry and rough openings
required for their proper installation. Custom-made win-
dows always require shop drawings so that the manufac-
tured sizes will be coordinated with the actual job
conditions.
If the estimator decides to do a complete takeoff
of materials required, she should (1) determine the linear
footage of each different shape required of each type
of material, (2) determine the type and thickness
of glazing required, and (3) calculate the sheet sizes
required.Wood Windows. Wood windows are commonly made of
ponderosa pine, southern pine, and Douglas fir. Custom-
made frames may be of any of these species or of some of the
more exotic woods such as redwood and walnut. Finishes
may be plain, primed, preservative-treated, or even of wood
that is clad with vinyl.Vinyl Windows. The frames for vinyl windows are
made of extruded polyvinyl chloride (PVC). Vinyl windows
come in a variety of colors, with the color being added to
the PVC before extrusion. Vinyl windows are a common
choice for residences, because they are economical, energy
efficient, require little maintenance, and are available in
custom sizes.
The same general estimating procedure is followed for
wood and vinyl windows as for other frames since these
frames may be stock or custom-made. Shop drawings
should be made and carefully checked so that all items
required are covered by the proposal. If painting is required,
it must be covered in that portion of the specifications.DOORS AND WINDOWS
CHAPTER FIFTEEN