Figure 1-52.—Chase wall construction.
buildings are framed in a combination of metal and
wood.
The metal framing members generally used are
cold-formed steel, electrogalvanized to resist corrosion.
Thicknesses range from 18 gauge to 25 gauge, the latter
being most common. Most metal studs have notches at
each end and knockouts located about 24 inches OC (fig.
1-51) to facilitate pipe and conduit installation. the size
of the knockout, not the size of the stud, determines the
maximum size of pipe or other material that can be
passed through horizontally.
Chase (or double stud) walls (fig. 1-52) are often
used when large pipes, ducts, or other items must pass
vertically or horizontally in the walls. Studs are
generally available in thicknesses of 1 5/8, 2 1/2, 3 5/8,
4, and 6 inches. The metal runners used are also
25-gauge (or specified gauge) steel or aluminum, sized
to complement the studs. Both products have features
advantageous to light-frame construction. The metal
studs and runners do not shrink swell, twist, or warp.
Termites cannot affect them, nor are they susceptible to
dry rot. Also, when combined with proper covering
material, they have a high fire-resistance rating.
A variety of systems have been developed by
manufacturers to meet various requirements of
attachment, sound control, and fire resistance. Many of
the systems are designed for ease in erection, yet they
are still remountable for revising room arrangements.
The framing members are assembled with power
screwdrivers and using self-drilling, self-tapping
screws. The floor assembly is fastened to the foundation
or concrete slab with studs (special nails) driven through
the stud track (runner) by a powder-actuated stud driver.
The plywood subfloor is installed over the metal floor
framing system with self-drilling, self-tapping screws
and structural adhesive. Wall sections are assembled at
the jobsite or delivered as preassembled panels from an
off-site prefabrication shop. Conventional sheathing is
attached to the framework with self-tapping screws.
Door frames for both the interior partitions and
exterior walls are integral with the system. They are
preprinted and may come complete with necessary
1-31
