metals: light gauge steel framing

light gauge steel framing members

• steel components are cold-rolled from steel sheet

light gauge steel framing uses

• for structural, loadbearing framing and
  exterior wall framing (subject to wind loads)

• for interior non-load bearing walls

c-studs and joists

• wall studs, floor joists, roof rafters, etc.

• depth: 1-5/8 to 12 in.

• width: 1-1/4 to 2-1/2 in.

• metal thickness” 0.018 to 0.097 in. (18 to 97 mils)

tracks

• top and bottom of wall framing; ends of floor framing

• analogous to wall plates and rim joists in light wood frame construction

channels

• bridging, blocking, and other reinforcing and bracing

• also called cold-formed channels

• standard sizes:

  • depth: ¾ to 2-1/2 in.

  • width: ½ in.

furring

• used for bridging, backing, furring

• also called hat channels

• standard sizes

  • depth: 7/8 or 1-1/2 in.

  • width: 1¼ in. at raised surface, 2½ in. at base

L-headers

• used for simplified header construction in bearing wall openings.

• break-formed angles (sheet metal bent in fabricator's shop to the specified size)

• header (top), jam (sides), sill (bottom)

framing accesories

• various sheet metal clips, stiffeners,
  bracing, and hangers are used to make
  connections and reinforce framing

slip track

• top track with extended legs and slotted holes

• allows fastening of nonloadbearing studs to track while permitting deflection in the track

• deflection in the slab above does
  not impart unintended loads into
  the wall framing.

sheet metal thickness

• thicker members are stronger and stiffer, but also heavier and more expensive

• traditionally expressed as gauge (or gage), with lower numbers corresponding to thicker metal

cutting light gauge sheet metal

• tin snips (aviator's snips): quiet,
  clean, slower than power methods

• power shears

• power saw with abrasive or
  carbide-toothed blade

• torch cutting

• brake lathe

fastening

• self-drilling, self-tapping screws are most common

• crimping tools mutually deform parts to be joined

• nail-like pins are power-driven

• welded joints can have higher strengths but are more labor intensive to make than mechanically fastened joints

• welding is best suited to thicker sheets that are less susceptible to melt-
  through (burn through) than thinner sheets

framing

• framing methods parallel wood light frame platform construction

• steel joists spaced from 12 to 24 in. O.C. (on centre) are framed into tracks or
  channels

anchorage detail: wall to foundation

in pic

configuration at corner

in pic

intersecting tracks at top corner

in pic

details: header and sill

in pic

floor joists

in pic

bracing

• The slender steel members require bracing at regularly spaced intervals to reduce the tendency to buckle

wall framing details

in pic

exterior wall

steel shelf pic

exterior wall pt. 2

brick veneer pic

exterior wall pt. 3

channel bracing pic

advantages compared to light wood framing

• versatile, flexible, simple to construct

• noncombustible (not prone to catching fire) and immune to insect attack and mold

• dimensionally stable, with consistent
  material properties

• lighter weight
  

  
  

disadvantages compared to light wood framing

• members require more frequent bracing

• non-renewable

• readily conducts heat, susceptible to corrosion