Nails used to fasten wallboard may be bright, coated, or
chemically treated; the shanks may be smooth or angularly
threaded with a nail head that is generally flat or slightly con-
cave. The angularly threaded nails are most commonly used
since they provide more withdrawal resistance, require less
penetration, and minimize nail popping. For a fire rating, it is
usually required to have 1 inch or more of penetration; and in
this case, the smooth shank nails are most often used. Nails
with small heads should never be used for attaching wall-
board to the supporting construction. The spacing of nails
generally varies from 6 to 8 inches on center, depending on
the size and type of nail and the type of wallboard being used.
Nails are bought by the pound. The approximate weight of
the nails that would be required per 1,000 sf (msf ) of gypsum
board varies between 5 and 7 pounds.
Screws may be used to fasten both wood and metal sup-
porting construction and furring strips. In commercial
work, the drywall screws have virtually eliminated the use of
nails. Typically, these screws have self-drilling, self-tapping
threads with flat recessed Phillips heads for use with a power
screwdriver. The drywall screws are usually spaced about 12
inches on center except when a fire rating is required, when
the spacing is usually 8 inches on center at vertical joists.
There are three types of drywall screws: one for fastening to
wood, one for sheet metal, and one for gypsum board. The
approximate number of screws required per 1,000 sf of gyp-
sum board based on vertical board application and spacing
of 12 inches on center is 1,000. If 8-inch on-center spacing is
used on the vertical joints, about 1,200 screws are required. If
the boards are applied horizontally with screws spaced 12
inches on center, only about 820 screws are required.
Adhesives may be used to attach single-ply wallboard
directly to the framing, concrete, or masonry, or to laminate
the wallboard to a base layer. The base layer may be gypsum
board, sound-deadening board, or rigid-foam insulation.
Often the adhesives are used in conjunction with screws and
nails that provide either temporary or permanent supple-
mental support. Basically, the three classes of adhesives used
are stud adhesives, laminating adhesives, and contact adhe-
sives. There are also various modifications within each class.
Information regarding the exact adhesives required should
be obtained from the specifications of the project and cross-
checked with the manufacturer. Also, determine the special
preparation, application, and equipment requirements from
the manufacturer. Information concerning coverage per gal-
lon and curing requirements should also be obtained.
Trim. A wide variety of trims are available in wood and
metal for use on drywall construction. The trim is generally
used to provide maximum protection and neat, finished
edges throughout the building. The wood trim is available
unfinished and prefinished in an endless selection of sizes,
shapes, and costs. The metal trim is available in an almost
equal amount of sizes and shapes. Finishes range from plain
steel, galvanized steel, and prefinished painted to trim with
permanently bonded finishes that match the wallboard; even
aluminum molding, plain and anodized, is available. Most
trim is sold by the linear foot, so the takeoff should also be
made in linear feet. Also to be determined is the manner in
which the moldings are to be attached to the construction.Joint Tape and Compounds. Joint tape and com-
pounds are employed when a gypsum wallboard is used, and
it is necessary to reinforce and conceal the joints between the
wallboard panels and to cover the fastener heads. These
items provide a smooth, continuous surface in interior walls
and ceilings.
The tape used for joint reinforcement is usually a fiber
tape designed with chamfered edges feathered thin, with a
cross-fiber design.
Joint compounds are classified as follows: (1) embed-
ding compound, used to embed and bond the joint tape; (2)
topping compound, used for finishing over the embedding
compound (it provides final smoothing and leveling over
fasteners and joints); and (3) all-purpose compound, which
combines the features of both of the other two, providing
embedding and bonding of the joint tape and giving a final
smooth finish. The compounds are available premixed by
the manufacturer or in a powdered form to be job-mixed.
The amount of tape and compound required for any
particular job will vary depending on the number of panels
used with the least number of joints and the method of fas-
tening specified. To finish 1,000 sf of surface area, about
380 lf of tape and 50 pounds of powder joint compound
(or 5 gallons of ready-mixed compound for the average
job) will be required.Blankets. Various types of blankets are used in conjunc-
tion with the drywall construction. The blankets are most
commonly placed in the center of the construction, between
studs, or on top of the suspended ceiling assembly. The two
basic types of blankets are heat insulating and sound con-
trol. The heat-insulating blankets are used to help control
heat loss (winter) and heat gain (summer), while the sound-
control blankets are used to improve sound transmission
classification (STC) ratings of the assembly. Both types are
available in a variety of thicknesses and widths. Once the
square footage of the wall or ceiling that requires the blanket
has been determined, the amount of blanket required is vir-
tually the same for metal stud walls, but the stud spacing
should be noted so that the proper width blanket will be
ordered. The estimator needs to check the specifications to
determine any special requirements for the blankets, such as
aluminum foil on one or both sides, paper on one or both
sides, and method of attachment. The most common
method of attachment is with staples.EXAMPLE 16-2 COMMERCIAL BUILDING DRYWALL
For the commercial building in Appendix A, determine the required
quantity of 5/8-inch-thick drywall. The information to perform this
takeoff comes from the stud quantification (Example 16-1). In that
takeoff, it was found that there were roughly (325.33 feet 20.67 feet)
346 lf of interior partitions. The floor to ceiling height is 10 feet. In this202 CHAPTER SIXTEEN