Structural Metal Studs

Structural stud build US Frame Factory

Structural cold-form / light-gauge studs are used in axial load-bearing walls, curtain walls, interior partitions, floor joists, and roof trusses. Structural metal studs is required for most commercial and industrial buildings, and depending on code regulations, residential buildings can also require steel.

Sizes and Metal Thicknesses

Structural Metal Studs graphic chart with color coating and mill thickness
  • Web sizes: 3-1/2” (350S), 3-5/8” (362S), 4” (400S), 5-1/2” (550S), 6” (600S), 8” (800S), 10” (1000S), 12” (1200S), 14” (1400S)
  • Flange stud sizes are: 1-1/4″, 1-5/8”, 2”, 2-1/2”, 3″, 3.5″
  • Metal thickness for structural application: 118 mils (10 gauge) the thickest, 97 mils (12 gauge), 68 mils (14 gauge), 54 mils (16 gauge), 43 mils (18 gauge), and 33 mils (20 ga).
  • Coating: All US Frame Factory Steel is coated with zinc and either has a coating weight of G90 and G60. This means the zinc coating is 0.90 oz/sqft or 0.60 oz/sqft respectively. For interior, non-load bearing, drywall studs, we use G40 coating or an equivalent Galvanneal coating.

Sizing Interior Structural Metal Studs

To determine the load-bearing capacity, you’ll need to know the weight of the wall itself, any additional finishes (e.g. drywall, plaster), and any other loads (e.g. shelves, cabinetry). This will help you determine the minimum required size and thickness of the structural studs. According to the International Building Code, interior (non-load bearing) walls must be built to handle an interior pressure lateral load of at least 5 psf perpendicular to the wall. For walls spanning many floors with several exterior openings, loads of 7.5psf to 10psf are used. Clark Dietrich has helpful information pertaining to metal stud sizing. Their most useful tool is the structural stud look up which will tell you what stud to use for your desired wall height and thickness. Note, the most common stud flange is 1-5/8″.

Sizing Exterior Curtain Walls

Exterior curtain walls are made of structural studs in commercial or industrial projects. Their purpose is to support exterior cladding such as brick, glass, and stucco. When trying to decide on sizing, the key factors think about are:

  • Local building code requirements for size and strength
  • Wind Loads (this will involve performing wind load calculations to determine the size and strength of the wall required to resist the wind loads)
  • Thermal performance and desired insulation levels
  • Structural support required to hold the wall in place.
  • The weight of exterior cladding

SteelNetwork has a nice page of framing tables (starting on page 17). I recommend using their tables when sizing Curtain Walls (see photo below).

Curtain wall sizing table, metal studs used outside colorado, CO
A curtain wall used on a hospital in Boulder, CO
Structural metal studs, an exterior curtain wall in Jacksonville FL.
An exterior curtain wall in Jacksonville FL.

Floor Joist: Sizing

The International Building Code (IBC) and American Iron and Steel Institute (AISI) provide guidelines for which metal stud floor joists to use and how to space them out. They recommend a maximum spacing of 24 inches on center for metal studs. BMP-Group has a useful table for floor joist sizing. We made an estimating tool that takes your joist spacing and room dimensions and calculates the proper floor joists lengths.

Metal stud floor joist sizing table
Floor Joists Installed in Dallas, TX

Metal Stud Screws: Sizing

AISI S100-12 North American Specification for the Design of Cold-Formed Steel governs the screw capacity utilized in structural elements. Important factors are the number of screws and pullover values. We’ve only used single #12 screws for each joint or double #10 screws in builds.

Fasteners (Screws and Welds) – Metal Framing Manufacturer – EB Metal

Table Notes AllowableStructural Members.screw connection capacities are based upon section E4 of the AISI S100-12, North American Specification for the Design of Cold-Formed Steel henare connected.connecting materials of different steel thicknesses or tensile strengths, use the lowest values. Tabulated values assume two sheets of equal thickness Screw shear and tension capacities were developed using published…

Structural Metal Header Sizing

US Frame Factory Box beam header example strength
Typical Box Beam Header detail

Headers are crucial in load-bearing walls because they act like bridges. Here’s why:

  • Load Bearing Walls: These walls support weight from above, like floors and roofs.
  • Openings Interrupt Support: Doors, windows, or other openings cut through this load-bearing path.
  • Header Spans the Gap: The header is a strong beam installed above the opening. It redirects the weight from above the opening to the wall sections on either side.

In steel framing the primary header type used is a box header. The American Iron and Steel Institute did a great deep dive into box beam design and web stiffeners. There are two types of headers: L headers and Box Headers. They discuss the advantages of each starting on page 32.

The Canadian Sheet Steel Building Institute provides a full sizing table starting on page 79.

Stud Bracing

US Frame Factory Structural Metal Studs X bracing for lateral strength
Strap X bracing

Engineers frequently require stud bracing for exterior curtain walls and interior walls. Steel studs are thin and tall. Without bracing, they are prone to buckle sideways or twist under loads (e.g., wind or seismic forces).This can add a lot of strength without increasing the gauge of studs.

Metal Studs can be braced 3 ways.

Additional Racecourses

Center channel bracing thought hole punches

Flat strap bracing

Structural Metal Studs inner stud bracing
Inner stud channel bracing
Structural Metal Studs flat strap bracing
Flat Strap Bracing

Application Example

This small job that has elements discusses, different gauge studs, some 6″ walls. The trusses are structural 20 gauge (362S162-33), the exterior curtain load baring walls are 18 gauge(350S162-43), the headers are made of 6″ 16 gauge (600S162-52) and 350T162-54 track. There is also stud bracing made of 2″ 18 gauge stud bracing. We also have X bracing made of 7.5″ 18 gauge flat strapping. See the 3D Matterport below. These are the structural drawings for this particular house.

CAD and programs for design

CFS-Designer (Cold-Form Steel Desginer) is a program created by Sampson Strong-tie that is basically computerized data base of span charts. You can download a free trail and experiment with a variety of different loads and spans.

AGACAD’s Metal Framing suite for Revit is a BIM (Building Information Modeling) software designed to streamline the design, detailing, and fabrication of light-gauge steel framing for buildings.

StrucSoft MWF Pro Metal is a software tool that works within Revit to help you design buildings using light gauge steel framing. It automates the process of figuring out where to place steel supports in walls, floors, and ceilings. This saves time, prevents mistakes, and creates detailed plans for builders, including instructions for machines that can prefabricate parts.

US Frame Factory

Thank for checking out our article. We are a roll-form operation in South Louisiana that manufactures both structural metal studs and non-structural drywall studs. The whole purpose of this page is simply to share resources we found with builders. We ship nation wide and to different countries. If you’re looking to buy metal studs/steel framing accessories please checkout our main page or contact sales.