Estimating in Building Construction

Finishes 197

third points will also help align the bottom chord of wood
trusses, and a built-in chamber is suggested to compensate
for further deflection. Because the trusses are made up of
relatively small members spanning large distances, they have
a tendency to be more difficult to align and level for the
application of wallboard.

Metal Studs. The metal studs (Figure 16.1) most com-
monly used are made of 25-gauge, cold-formed steel, electro-
galvanized to resist corrosion. Most metal studs have notches at
each end and knockouts located about 24 inches on center to
facilitate pipe and conduit installation. The size of the knock-
out, not the size of the stud, will determine the maximum size
of pipe, or other material, that can be passed through. Often,
when large pipes, ducts, or other items must pass vertically or
horizontally in the wall, double stud walls are used, spaced the

required distance apart. Studs are generally available in thick-

nesses of 1^5 ⁄ 8 ,2^1 ⁄ 2 ,3^5 ⁄ 8 , 4, and 6 inches. Metal runner track is used

at the top and bottom of the wall to connect the studs together,

just as the top and bottom plates connect a wood wall together.

In nonbearing walls, metal runner track is often used as head-

ers over openings. The metal runners used are also 25-gauge

steel and sized to complement the studs.

A variety of systems have been developed by the manu-

facturers to meet various requirements of attachment, sound

control, and fire resistance. Many of the systems have been

designed for ease in erection and yet are still demountable

for revising room arrangements. The estimator must care-

fully determine exactly what is required for a particular pro-

ject before beginning the takeoff.

The wallboard is typically attached with screws and, in

certain applications, with adhesives or nails. Different shapes

of studs are available to accommodate either the screws or

the nails. Metal studs and runners are sold by the pound or

by the linear foot. Once the linear footage of studs has been

determined, it is easy to calculate the weight required. The

linear footage of each different type of wall must be deter-

mined. The walls must be separated according to thickness

or the type of stud, backing board and wallboard, as well as

according to any variations in ceiling height, application

techniques, and stud spacing.

Once again, special care should be taken with double

walls so that the proper amount of material may be esti-

mated. If the studs and runners are sold by the pound, the

weight per linear foot should be determined from the manu-

facturers’ brochures and multiplied by the number of linear

feet to determine the total weight.

Open-Web Joists. The joists themselves are estimated

under metals (Chapter 12). A joist, however, may be used as

a base for wallboard. Because the bottom chords of the joists

are seldom well aligned and the spacing between joists is

often excessive, the most common methods of attachment

are with the use of furring and with a suspension system.

Each of these methods is discussed in this chapter.

Metal Furring. Metal furring (Figure 16.2) is used with

all types of supporting construction. It is particularly advan-

tageous where sound control or noncombustible assemblies

FIGURE 16.2.Metal Furring.

FIGURE 16.1.Metal Studs.