Chapter 12 Light Gauge Steel Frame Construction

Fundamentals of Building Construction, Materials & Methods, 6th Edition
Copyright © 2013 J. Iano. All rights reserved.
12 LIGHT GAUGE STEEL FRAME CONSTRUCTION
THE CONCEPT OF
LIGHT GAUGE
STEEL
CONSTRUCTION

Light Gauge Steel Construction Concepts
Light Gauge Steel Framing
Members
These are structural components that are cold-
rolled from steel sheet.

C-Section (studs and joists)
These are used as wall studs,
floor joists, and roof rafters in
light gauge steel construction,
and resemble a letter ‘C’ in
profile. Their depths range
from 1-5/8 inches to 12 inches.
Their widths range from 1-1/4
inches to 2-1/2 inches.
The thickness of the sheet steel
used varies from 0.018 inches
to 0.097 in. (or 18 to 97 mils)

Even though they are referred
to as C-sections, their official
designation uses the letter S.
An example designation of a
named C-section member
would be 600S162-54:
600: 6.00 inches deep
S: C-shaped Stud or joist
162: 1.625 (1-5/8) inches
wide
54: 54 mils metal thickness

Tracks
Tracks cap-off both the top
and bottom of stud wall
framing, as well as the
ends of floor joist framing.
They are analogous to the
sole and top plates and rim
joists, in light wood frame
construction.

The depth of tracks should
match the depth of studs
or joists being capped-off.
The width of tracks can
vary, from 1-1/4 inches to
2 inches.
For example 600T125-33:
6.00-inch-deep Track;
1.25 inches wide; 33 mils
metal thickness.

Channels
Channels are used for
bridging, blocking, and
for other reinforcing
and bracing purposes.
The four standard
depths they come in
are ¾ inch, 1-½ inches,
2 inches, or 2-1/2
inches, with a
consistent width of ½
inch.

For example, a
075U50-54 is 0.75
inches deep; U is for U-
shaped channel; 0.50
inches wide; 54 mils
metal thickness.
Channels are also
known as Cold-rolled
channels.

Furring
Furring is the application
of hat channels along
the face of a wall or
ceiling, in order to attach
finish material to those
channels and raise the
finish material away from
the ceiling or wall.
Hat Channel Gypsum
Board
Suspended
Ceiling
Structure

Furring
This might be done to
prevent dampness from
reaching the finish
material, to make space
for insulation behind the
material, or to level
ceilings or resurface
walls.
Hat Channel Gypsum
Board
Suspended
Ceiling
Structure

Hat Channels
Hat Channels come in
two standard sizes:
Depth is either 7/8” or
1-1/2”.
The width is 1¼” at the
raised surface, and 2½”
at the base.

For example,
087F125-30: 0.875
inches deep (7/8”); F is
for furring channel;
1.25 inches wide at
raised surface; 30 mils
metal thickness

L-Headers
L-Headers are used for
simplified header
construction in bearing
wall openings; they add
reinforcement to the
track at the top of the
stud wall, above
openings.
Section View

L-Headers
L-Headers are
comprised of a pair of
break-formed angles,
that is, sheet metal
bent in fabricator's
shop to the specified
size.
Section View

Typical dimensions: the
long leg can vary, from
6 to 10 inches; the
short leg is consistently
1½ inches long.
For example,
2-800L150-43:
2 (doubled) angles,
with the long leg
measuring 8.00 inches;
L represents L-Header;
1.5-inch short leg; 43
mils metal thickness.
Section View

Framing
Accessories
A variety of
sheet-metal clips,
stiffeners,
bracing, and
hangers are used
to make
connections and
reinforce framing.

Special Products
Proprietary shapes are products
that are stiffer or stronger as
compared to conventional
members of the same metal
thickness.
Right: Specially shaped
proprietary light-gauge member.

Heavily dimpling the
metal also results in a
more rigid light-gauge
framing member.

Slip Track
This is a top track
with extra deep
legs and slotted
holes, that allows
for the fastening of
non-loadbearing
studs to the track,
while also allowing
for a slight amount
of deflection in floor
slab above the
track.

Slip Track
The studs are cut
short to maintain a
slight gap beneath
the top of the
track.
Because of this
gab, deflection in
the slab above
does not bear down
onto the studs.

Jamb Stud
These are single,
deep framing
members designed
to replace the paired
studs at either side
of a framed opening,
such as a window or
door.

Sheet Metal Thickness
Thicker members are
stronger and stiffer,
but also heavier and
more expensive.
Traditionally, metal
thickness is
expressed as gauge,
with lower numbers
corresponding to
thicker metal.
Minimum thickness of steel sheet
Gauge
Loadbearing
framing
Nonloadbearing
framing
12 0.097 in. (2.46 mm)
14 0.068 in. (1.73 mm)
16 0.054 in. (1.37 mm) 0.054 in. (1.37 mm)
18 0.043 in. (1.09 mm) 0.043 in. (1.09 mm)
20 0.033 in. (0.84 mm) 0.030 in. (0.75 mm)
22 0.027 in. (0.69 mm)
25 0.018 in. (0.45 mm)

Gauge numbers are
still occasionally
used, but
contemporary
standards now
specify metal
thicknesses in
decimal inches
(specifically,
thousandths of an
inch, or mils).
Minimum thickness of steel sheet
Gauge
Loadbearing
framing
Nonloadbearing
framing
12 0.097 in. (2.46 mm)
14 0.068 in. (1.73 mm)
16 0.054 in. (1.37 mm) 0.054 in. (1.37 mm)
18 0.043 in. (1.09 mm) 0.043 in. (1.09 mm)
20 0.033 in. (0.84 mm) 0.030 in. (0.75 mm)
22 0.027 in. (0.69 mm)
25 0.018 in. (0.45 mm)

Cutting Light Gauge Sheet Metal
Methods of cutting light-
gauge steel framing:
• Tin snips – quiet and
clean, but slower than
power methods
• Power shears
• Power saw with
abrasive or carbide-
toothed blade
• Torch cutting

• Use of self-drilling, self-
tapping screws is the most
common method.
• Crimping tools mutually
deform parts to be joined.
• Power-driven nail-like pins
can be used.
Fastening Light Gauge Sheet Metal

Welded joints can achieve a
higher strength than
mechanical fastening but are
more labor-intensive and
costly to create than
mechanically fastened joints.
Welding is best-suited to
thicker sheets that are less
susceptible to melt-through
than thinner sheets.

• Top: Plug welds – round welds
made inside of an existing hole.
• Middle: Slot welds – welds between
two members, one containing an
elongated hole through which the
other member is exposed and
welded.
• Bottom: Flare ‘vee’ weld - bent
metal components that form a
groove for welding.

LIGHT GAUGE
STEEL FRAMING

Framing
Light gauge steel framing
parallels wood light frame
platform construction.
Steel joists, spaced from
12 to 24 inches on center,
are framed into capping
tracks or channels.

Web stiffeners are
inserted where
concentrated loads from
the walls might buckle
thin joist webs.
Construction panels
(sheathing) are fastened
to the structure with
mastic adhesive and
self-drilling screws.

Heavier beam
equivalents, such
as a ridge beam,
can be constructed
by nesting
standard c-section
joists.
End clips facilitate
joining of
perpendicular
members.

Joist hangers, gusset plates, and folded
channel ends are other connection methods.

Window header
with track,
supported on
jack studs
paired with
full-height
studs.

Bracing
The slender steel
members require
bracing at regular
intervals to
minimize the
tendency to buckle.
Cold-rolled channels
are used for this.

Specifying Light Gauge Steel
Framing
Light gauge steel framing
falls under two distinct
MasterFormat trades:
Division 5 Metals,
Section 05 40 00—Cold-
Formed Metal Framing
For structural, loadbearing
framing, and exterior wall
framing subject to wind
loads.

Division 9 Finishes
Section 09 22 16—
Non-Structural
Metal Framing
For interior, non-
loadbearing framing.

Compared to Light Wood Framing
Advantages:
• Versatile, flexible, and
simple to construct
• Noncombustible and
immune to insect
attack
• Dimensionally stable,
with consistent
material properties
• Lightweight

Compared to Light Wood Framing
Disadvantages
• Members require more
frequent bracing
• Steel readily conducts
heat and requires
extra attention to
eliminating thermal-
bridging effects
• It is susceptible to
corrosion

Chapter 12 Light Gauge Steel Frame Construction

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