Key takeaways
- LGSF uses cold-formed C-studs, U-tracks and bridging sections — the same material family for partition and structural applications, but different size ranges and steel grades.
- North American sections are in imperial dimensions (3-5/8 in, 6 in); metric markets use millimetre sizing — tooling is not interchangeable.
- Structural load-bearing applications require G550 / Grade 80 (550 MPa) steel; machines must be specified for the grade.
- Adjustable-width machines cover a range of depths from one tooling set; servo-adjustable machines change size in seconds under PLC control.
- CD and UD ceiling sections are standardised at 60x27 mm and 28x27 mm in metric markets.
What light gauge steel framing is
Light gauge steel framing (LGSF) uses cold-formed steel sections — typically C-studs, U-tracks, and Z or sigma bridging — as the primary structural members of walls, floors and roofs. The steel is thin (0.5–3.0 mm) but gains structural efficiency from its shape: the deep flanges and lips of a C-stud give high bending stiffness relative to the material weight.
LGSF is used in two distinct markets that share the same material but have different design standards, section sizes and installation practices: commercial non-residential framing (office fit-out, partitions, ceilings) and structural residential framing (load-bearing walls and floors in houses and low-rise apartments). The machines that produce these sections are similar in principle but differ in size range and strength requirements.
Section types and their roles
C-stud: the primary vertical or horizontal framing member. The C-profile (lipped channel) is used in walls as studs and headers, in floors as joists, and in roofs as rafters. Section sizes for partition work run from 48 mm to 92 mm web depth; structural sections run from 89 mm to 305 mm.
U-track (sometimes called U-channel): the horizontal runner into which studs insert at top and bottom of a wall. The U-track web is slightly wider than the stud web so the stud slides in without binding. Tracks do not carry significant vertical load — they locate the studs and transfer lateral load.
Z-bridging and X-bridging: horizontal members installed between studs to brace the compression flange against lateral-torsional buckling. Required on structural studs above a critical slenderness ratio.
CD and UD sections: the metric equivalent of C-stud and U-track used in ceiling suspension systems. CD is the ceiling stud (primary batten); UD is the perimeter channel. Dimensions are standardised at 60 mm x 27 mm for CD and 28 mm x 27 mm for UD in the most common metric sizing.
| Section | Role | Standard depths |
|---|---|---|
| C-stud | Structural framing member (wall, floor, roof) | 48–305 mm |
| U-track | Runner/header (locates and anchors studs) | Stud size + 2–4 mm clearance |
| CD ceiling stud | Ceiling grid primary member | 60 mm (metric standard) |
| UD ceiling channel | Ceiling perimeter and suspension | 28 mm (metric standard) |
| Z-bridging | Lateral bracing for studs | To match stud web depth |
Design standards and their effect on section choice
AISI S240 and S400 (North America) govern structural LGSF design in the US and Canada. Partition work in North America follows AISI S220 for non-structural applications.
EN 1993-1-3 (Eurocode 3 Part 1-3) governs in Europe and markets that follow European standards. Section properties and capacity tables differ between the two standards even for physically identical sections.
AS/NZS 4600 applies in Australia and New Zealand. Most Asian markets use either a local standard or reference Eurocode.
The practical effect for machine buyers: sections sold into the North American market are specified in imperial dimensions (3-5/8 in, 6 in, etc.); sections for metric markets are in millimetres. A machine tooled for metric CD/UD sections cannot produce US imperial studs without re-tooling, and vice versa.
Steel grade requirements
Partition and ceiling framing typically uses G300 or equivalent (300 MPa yield, metric) or ASTM A653 Grade 33 (230 MPa, imperial). Structural LGSF for load-bearing walls uses G550 (550 MPa) or ASTM A653 Grade 80 (550 MPa). The high-strength grades allow thinner material while meeting structural requirements, reducing weight and material cost.
High-strength steel is harder to form without springback and edge cracking. Machines intended for G550 or Grade 80 material use harder roll material, closer station spacing and often a slight overbend compensation built into the final stations. A machine designed for G300 material may produce out-of-tolerance sections when run with G550 — confirm the design grade before ordering.
Automated versus manual stud and track machines
Entry-level LGSF machines produce a single stud size at a fixed gauge. The operator changes the coil to change material thickness. These machines are low-cost and appropriate for contractors who produce one or two standard sections in volume.
Adjustable machines allow the web depth to be changed without replacing the roll tooling — the rolls are mounted on adjustable shafts and a central handwheel or motor moves them to the required width. These cover a range such as 50–200 mm in one setup, allowing a single machine to serve a wide market range.
Fully automatic servo-adjustable machines store section recipes and change from one size to the next in seconds under PLC control. These are used in high-volume prefabrication plants where changeover time is the binding constraint on production capacity.